2215 Raggio Parkway, Reno, Nevada 89512-1095 (775) 673-7300 

Section 211(B) Tier 2 High End Exposure Study of Conventional 

and Oxygenated Gasoline 

COMPILED FINAL REPORT 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

Barbara Zielinska, Eric M. Fujita, John C. Sagebiel, and David E. Campbell 

Division of Atmospheric Sciences 

Desert Research Institute 

Nevada System of Higher Education 

2215 Raggio Parkway 

Reno, NV 89512 

March 25, 2009 
ii

ACKNOWLEDGMENTS

 We wish to acknowledge the financial support for this study by the American Petroleum 

Institute and Drs. Will Ollison and Lorraine Twerdok of the API for their administrative support 

and technical guidance. We also thank the API review committee and the staff of the U.S. 

Environmental Protection Agency for reviewing the draft exposure protocols and interim project 

results. We also acknowledge the vehicle testing performed during the control experiments in 

San Antonio by Lawrence Smith and Patrick Merritt at Southwest Research Institute and 

evaluation of potential biomarkers during the initial pilot study by Dr. Jacob McDonald of the 

Lovelace Respiratory Research Institute. We also acknowledge the assistance of Ted Johnson of 

TRJ Environmental, Inc. for his input on the candidate microenvironments and review of our 

draft exposure protocols. We also acknowledge the following DRI personnel for their assistance: 

Larry Sheetz for modifications to the sampling platforms; Aaron Centric, Diana Ceballos and 

Mark McDaniel for field sampling; Diana Ceballos for evaluation of the SPME method; and 

Katarzyna Rempala and Michael Keith for the organic speciation analysis.
iii

TABLE OF CONTENTS

 Page

Acknowledgments........................................................................................................................... ii

EXECUTIVE SUMMARY .............................................................................................................1

1. Quantification of Personal Exposures to Motor Vehicle Emissions in High Exposure 

Microenvironments in Atlanta, Houston, and Chicago during Summer and Winter. ........... 1-1

1.1 Introduction ................................................................................................................... 1-1

1.2 Experimental .................................................................................................................. 1-2

1.2.1 Selection of Microenvironments .......................................................................... 1-2

1.2.2 Monitoring Methods ............................................................................................ 1-4

1.2.3 Exposure Biomarkers ........................................................................................... 1-5

1.3 Results and Discussion .................................................................................................. 1-6

1.3.1 Variation of day-to-day exposures by ME in each city ....................................... 1-6

1.3.2 Distribution of exposures within MEs in each city (1-minute time series) ....... 1-22

1.3.3 Oxygenated and conventional gasoline (difference between cities) .................. 1-34

1.3.4 Effect of meteorology on exposure .................................................................... 1-38

1.3.5 Comparison of summer and winter exposures ................................................... 1-40

1.3.6 Correlations to breath concentrations ................................................................ 1-44

1.4 Conclusions ................................................................................................................. 1-48

1.5 References ................................................................................................................... 1-49

2. Relative Contributions of Vehicle Evaporative and Exhaust Emission to 

Concentrations of Volatile Air Toxics in High Exposure Microenvironments in 

Houston .................................................................................................................................. 2-1

2.1 Introduction ................................................................................................................... 2-1

2.2 Experimental Approach ................................................................................................. 2-2

2.3 Results ..................................................................................................................... 2-3

2.4 Conclusions ................................................................................................................... 2-4

2.5 References ................................................................................................................... 2-10

3. Determination of the Quantitative Relationships between Levels of Volatile Air 

Toxics and Carbon Monoxide Measured In High End Microenvironments and At 

Nearby Air Quality Monitoring Stations ............................................................................... 3-1

3.1 Introduction ................................................................................................................... 3-1

3.2 Experimental .................................................................................................................. 3-2

3.3 Results and Discussion .................................................................................................. 3-3

3.4 Conclusions ................................................................................................................... 3-4

3.5 References ..................................................................................................................... 3-4

4. Relationships of Attached Garage and Home Exposures to Fuel Type and Emission 

Levels of Garage Sources ...................................................................................................... 4-1

4.1 Introduction ................................................................................................................... 4-1

4.2 Experimental .................................................................................................................. 4-1
iv

4.2.1 Vehicles and Vehicle Test Methods .................................................................... 4-1 

4.2.2 Fuel Testing ......................................................................................................... 4-2 

4.2.3 Test House ........................................................................................................... 4-2 

4.3 Results ..................................................................................................................... 4-4 

4.3.1 Fuel Analyses ....................................................................................................... 4-4

4.3.2 Vehicle Regulated and Hot Soak Emissions ........................................................ 4-5 

4.3.3 Garage and Kitchen Exhaust/Evaporative Fuel Component Levels .................... 4-7 

4.3.3.1 Background and Overall Concentrations .............................................. 4-7 

4.3.3.2 Seasonal Impacts ................................................................................... 4-8 

4.3.3.3 Fuel and Vehicle Effects ....................................................................... 4-9 

4.3.3.4 Comparison with Emissions Data ....................................................... 4-16 

4.3.3.5 Relationships of Garage and Kitchen Concentrations ........................ 4-19 

4.4 Discussion ................................................................................................................... 4-21 

5. Effect of Ventilation, Proximity, and Emission Levels on In-Cabin Exposures of 

Trailing Vehicle. .................................................................................................................... 5-1 

5.1 Introduction ................................................................................................................... 5-1 

5.2 Experimental .................................................................................................................. 5-1 

5.2.1 Fuel Testing ......................................................................................................... 5-2 

5.2.2 Relationship between Exhaust Emission Rates and In-Cabin Exposure - 

Trailing Vehicle Test ................................................................................... 5-2 

5.2.2.1 Test Protocol ......................................................................................... 5-2 

5.3 Results ..................................................................................................................... 5-6 

5.3.1 Background and Overall Concentrations ............................................................. 5-6 

5.3.2 Vehicle and Fuel Effects .................................................................................... 5-12 

5.3.3 Trailing Vehicle Effects ..................................................................................... 5-14 

5.3.4 Comparison with FTP Data ............................................................................... 5-16 

5.4 Discussion ................................................................................................................... 5-18 

Appendix A ................................................................................................................................. 144* 

Appendix B ..................................................................................................................................223 

Appendix C ..................................................................................................................................236 

Appendix D ..................................................................................................................................237 

Appendix E ..................................................................................................................................300 

Appendix F...................................................................................................................................398 

Appendix G ..................................................................................................................................450 

Appendix H ..................................................................................................................................453 

Appendix I ...................................................................................................................................464 

* Appendix pagination corresponds to Adobe Reader page count index.
v

LIST OF FIGURES

 Page

Figure E-1. Distribution of reconstructed 1-min BTEX exposures in high-end Atlanta 

MEs. Edges of the box = first and third quartiles; black line = median; red line = 

average. Minimum and maximum values (ppbv) are shown at the bottom and top 

of the plots. Whisker covers 99.3% of the data distribution. Filled circles > 3 

times the box interval, empty circle are within that interval. The y-axis represents 

the percentage of data distribution. ................................................................................ES-9

Figure E-2A. Comparison of average concentrations of benzene, 1,3-BD, HCHO and CO 

in three cities in Summer .............................................................................................ES-10

Figure E-2B. Comparison of average concentrations of benzene, 1,3-BD, HCHO and CO 

in three cities in Winter ................................................................................................ES-11

Figure E-3. MTBE/benzene ratio and contribution of evaporative emissions in Houston 

MEs ..............................................................................................................................ES-13

Figure E-4. Mean ratios of ME concentrations to corresponding hourly measurements at 

the regional air monitoring station in Houston. ...........................................................ES-14

Figure E-5. The effect of fuel and vehicle operation mode (i.e. normal or malfunction) on 

observed concentrations in the kitchen ........................................................................ES-17

Figure 1.3.1-1. Time-integrated exposure levels in different MEs in Atlanta, Summer 

2002 and 2003 ................................................................................................................ 1-14

Figure 1.3.1-2. Time-integrated exposure levels in different MEs in Atlanta, Winter 2004 ..... 1-16

Figure 1.3.1-3. Time-integrated exposure levels in different MEs in Chicago, Summer 

2003................................................................................................................................ 1-17

Figure 1.3.1-4. Time-integrated exposure levels in different MEs in Chicago, Winter 

2004................................................................................................................................ 1-18

Figure 1.3.1-5. Time-integrated exposure levels in different MEs in Houston, Summer 

2004................................................................................................................................ 1-20

Figure 1.3.1-6. Time-integrated exposure levels in different MEs in Houston, Winter 

2005................................................................................................................................ 1-21

Figure 1.3.2-1. 1-Minute time series for in-cabin exposures: ME1 (congested freeway), 

ME2 (urban canyon); ME4 (underground garage) and ME5 (toll plaza) ...................... 1-30

Figure 1.3.2-2. 1-Minute time series for in-cabin exposures: ME6 (tunnel); ME13 

(following high-emitting vehicle); ME3 (in-cabin refueling) and out-of-cabin 

refueling, ME7 ............................................................................................................... 1-31

Figure 1.3.2-3. 1-Minute time series for out-of cabin outdoor exposures:ME8 (sidewalk); 

ME10 (surface parking); ME11 (underground garage) and ME12 (toll plaza) ............. 1-32

Figure 1.3.2-4. Correlations between 5-minute canister samples and surrogate 1-minute 

values, averaged over corresponding 5 minutes. ........................................................... 1-33
vi

Figure 1.3.3-1. MTBE and EtOH concentrations in Houston and Chicago, 

respectively..Note different y-axis scales for Chicago Sumer and Winter .................... 1-35

Figure 1.3.3-2. Comparison of benzene, 1,3-BD, HCHO, and CO average concentrations 

in three cities in Summer ............................................................................................... 1-36

Figure 1.3.3-3. Comparison of benzene, 1,3-BD, HCHO, and CO average concentrations 

in three cities in Winter .................................................................................................. 1-37

Figure 1.3.5-1. Time integrated average exposure levels in different MEs in Atlanta in 

Summer and Winter season. .......................................................................................... 1-41

Figure 1.3.5-2. Time integrated average exposure levels in different MEs in Chicago in 

Summer and Winter season ........................................................................................... 1-42

Figure 1.3.5-3. Time integrated average exposure levels in different MEs in Houston in 

Summer and Winter season ........................................................................................... 1-43

Figure 1.3.6-1. Average breath BTEX, 1,3-BD, MTBE, EtOH, and CO2 concentrations in 

three cities in Summer ................................................................................................... 1-45

Figure 1.3.6-2. Average breath BTEX, 1,3-BD, MTBE, EtOH, and CO2 concentrations in 

three cities in Winter ...................................................................................................... 1-46

Figure 1.3.6-3. Correlations between 1-minute surrogate benzene and 1,3-BD max values 

and post-exposure breath concentrations (upper panel) and comparison of these 

concentrations in different ME and cities (lower panel) ................................................ 1-47

Figure 2-1.Fractional contributions of evaporative emissions to total motor vehicles 

emissions in Houston by ME. .......................................................................................... 2-9

Figure 3.1a. Location of ME sampling and fixed monitoring stations in Chicago Metro 

Area. ................................................................................................................................. 3-9

Figure 3.1b. Location of ME sampling and fixed monitoring stations in Houston Metro 

Area. ............................................................................................................................... 3-10

Figure 3-2a. Comparison of average versus the maximum 1-minute benzene levels by 

city, season and microenvironment................................................................................ 3-12

Figure 3-2b. Comparison of average versus the maximum 1-minute 1,3-butadiene levels 

by city, season and microenvironment. .......................................................................... 3-13

Figure 3-2c. Comparison of average versus the maximum 1-minute formaldehyde levels 

by city, season and microenvironment. .......................................................................... 3-14

Figure 4.3-1. Effect of fuel and mode on observed concentrations in the garage. The 

legend “N” is normal and “F” is malfunction. The 1,3-BD value for Houston-F is 

suspect. ........................................................................................................................... 4-10

Figure 4.3-2. Effect of fuel and mode on observed concentrations in the kitchen. The 

legend “N” is normal and “F” is malfunction. The 1,3-BD value for Houston-F is 

suspect. ........................................................................................................................... 4-11
vii

Figure 4.3-3. Effect of fuel and mode on observed sedan garage levels. The legend “N” is 

normal and “F” is malfunction. The 1,3-BD level for Houston-F is suspect, see 

text.................................................................................................................................. 4-12

Figure 4.3-4. Effect of fuel and mode on observed truck garage levels. The legend “N” is 

normal and “F” is malfunction. The 1,3-BD level for Houston-F is suspect, see 

text.................................................................................................................................. 4-12

Figure 4.3-5. Concentrations of 1,3-butadiene, MTBE and BTEX and CO as measured 

from canisters in the garage and the adjacent kitchen in Summer 2002 ........................ 4-14

Figure 4.3-6. Concentrations of 1,3-butadiene, MTBE and BTEX (A) and CO (B) as 

measured from canisters in the garage and the adjacent kitchen in Winter 2005. 

M=sample missing or invalid. ....................................................................................... 4-15

Figure 4.3-7. Comparison of SHED results with the observed canister concentration in 

the garage for benzene. .................................................................................................. 4-16

Figure 4.3-8. Comparison of the SHED results with the observed SPME hot soak 

concentration in the garage for benzene A: all data, B: two outliers removed. ............. 4-16

Figure 4.3-9. Comparison of FTP Bag 1 emissions and observed garage levels of 1,3-BD. .... 4-17

Figure 4.3-10. Comparison of FTP Bag 1 benzene emissions and observed garage levels. ..... 4-18

Figure 4.3-11. Comparison of hot soak FTP Bag 1 benzene emissions and observed 

SPME garage values. ..................................................................................................... 4-18

Figure 4.3-12. Comparison of garage and kitchen concentrations for 1,3-BD. A – all data, 

B- with two outliers removed (see text). ........................................................................ 4-19

Figure 4.3-13. Comparison of garage and kitchen concentrations of carbon monoxide. .......... 4-20

Figure 4.3-14. Comparison of garage and kitchen concentrations of benzene. ......................... 4-20

Figure 5.2-1. Map of Driving Test Location near San Antonio. The blue markers indicate 

the location of the driving tests. ....................................................................................... 5-4

Figure 5.2-2. Map of Driving Test Location near Moore, TX. ................................................... 5-5

Figure 5.2-3. Elevation Profile of the Driving Route near Moore, TX. ..................................... 5-5

Figure 5.3-1. Comparison of Summer and Winter Background Concentrations with 

Standard Deviations. HCHO is divided by 10 for scale. ................................................. 5-7

Figure 5.3-2. Concentrations of 1,3-BD, MTBE and BTEX (A) and CO (B) as measured 

in the cabin of the trailing vehicle, Summer 2002 ........................................................... 5-8

Figure 5.3-3. Concentrations of 1,3-BD, MTBE and BTEX and CO as measured in the 

cabin of the trailing vehicle, Winter 2005 ....................................................................... 5-9

Figure 5.3-4. Comparison of Summer and Winter Concentrations for the Trailing tests. ......... 5-10

Figure 5.3-5. Comparison of Summer Background and Test Values. ....................................... 5-11

Figure 5.3-6. Comparison of Winter Background and Test Values. ......................................... 5-11
viii

Figure 5.3-7. Scatter plot of Normal Emitter and High Emitter Mean In-cabin Values for 

all species except HCHO and EtOH. ............................................................................. 5-13

Figure 5.3-8. Time Series of In-Cabin (PID1) and Outside (PID2) PID Values. ...................... 5-15

Figure 5.3-9. Comparison of FTP Bag 2 Benzene Emissions to In-cabin Concentration in 

the Trailing Vehicle. ...................................................................................................... 5-16

Figure 5.3-10. Comparison of FTP Bag 2 MTBE emissions to in-cabin concentrations in 

the trailing vehicle.......................................................................................................... 5-17

Figure 5.3-11. Comparison of FTP Bag 2 1,3-BD Emissions to In-cabin Concentrations 

in the Trailing Vehicle. .................................................................................................. 5-17
ix

LIST OF TABLES

 Page

Table E-1. Measurement methods used in the Section 211(B) Tier 2 High-End Exposure 

Screening Study. Data applications for specific methods are classified as 

reference, confirmatory, and surrogate. ...............................................................................3

Table E-2. The effects of changing vehicle, fuel and operational mode (i.e. normal or 

malfunction) on observed concentrations in the trailing vehicle cabin. ............................17

Table 1.2.1-1. Microenvironmental Sampling. ............................................................................ 1-3

Table 1.3.1-1. Summer average, maximum, and minimum ME concentrations (ppbv) of 

BTEX, 1,3-BD, HCHO, CH3CHO, EtOH, MTBE, and CO (ppmv) .............................. 1-7

Table 1.3.2-1A. Correlation coefficients (R2) and associated statistic for relationships of 

time-integrated measurements with continuous methods (NMVOC and CO) for 3 

cities, without ME3 and ME7 ........................................................................................ 1-24

Table 1.3.2-1B. Correlation coefficients (R2

) and associated statistic for relationships of 

time-integrated measurements with continuous methods (NMVOC and CO) for 

ME3 and ME7 in 3 cities ............................................................................................... 1-25

Table 1.3.2-2. Summary of the reconstructed 1-minute data (ppbv), Summer ......................... 1-26

Table 1.3.2-3. Summary of the reconstructed 1-min data (ppbv), Winter ................................. 1-27

Table 1.3.2-4. Summary of the 5-minute canister data (ppbv) .................................................. 1-28

Table 1.3.4-1. Average, minimum, and maximum ambient temperatures and RH ................... 1-38

Table 2-1. Conventional gasoline versus reformulated gasoline RFG (from EPA OMS 

web page http://www.epa.gov/OMSWWW/rfgnew.htm, updated by S. Romanow, 

OMS)................................................................................................................................ 2-5

Table 2-2. Summary of sample collections in urban MEs ........................................................... 2-6

Table 2-3. Mass ratios of MTBE to benzene in Houston by ME. ............................................... 2-7

Table 2-4. Mass ratios of MTBE to benzene in vehicle exhaust, gasoline vapor and liquid 

gasoline. ........................................................................................................................... 2-8

Table 2-5. Fractional contributions of evaporative emissions to total motor vehicles 

emissions in Houston by ME. .......................................................................................... 2-9

Table 3-1. Summary of sample collections in urban microenvironments ................................... 3-5

Table 3-2. Average and standard deviation in ratios of the time-integrated CO from 

canister samples to the corresponding hourly CO from regional ambient air 

monitoring sites for Houston, Atlanta and Chicago by season and 

microenvironment. ........................................................................................................... 3-6

Table 3-3. Average and standard deviations in ratios of BTEX and 1,3-BD from timeintegrated canister samples to the corresponding hourly automated GC data from 

the ambient air monitoring sites in Houston. ................................................................... 3-7
x

Table 3-4. Houston benzene ME/ambient ratio comparison with HAPEM benzene ME 

factors ............................................................................................................................... 3-8

Table 4.2-1. Summary of vehicles used. ...................................................................................... 4-2

Table 4.2-2. Protocol for attached garage experiments. .............................................................. 4-3

Table 4.3-1. Summary of properties for the six test fuels. ........................................................... 4-5

Table 4.3-2. Regulated and Hot Soak Emissions from the Ford F-150, Summer 2002. ............. 4-6

Table 4.3-3. Regulated and Hot Soak Emissions from the Ford F-150, Winter 2005. ................ 4-6

Table 4.3-4. Regulated and Hot Soak Emissions from the Toyota Camry, Summer 2002 ......... 4-6

Table 4.3-5. Regulated and Hot Soak Emissions from the Toyota Camry, Winter 2005 ............ 4-6

Table 4.3-6. Summary of Background Concentrations in Kitchen and Garage. Units are 

ppbv, except as noted. ...................................................................................................... 4-7

Table 4.3-7. Summary of Test Concentration Ranges in Kitchen and Garage. Units are 

ppbv, except as noted. ...................................................................................................... 4-8

Table 4.3-8. Seasonal Impact on Observed Maximum Concentrations (Units are ppbv, 

except as noted)................................................................................................................ 4-8

Table 4.3-9. Seasonal Impact on Observed Maximum Concentrations (Units are ppbv, 

except as noted), Normal Mode Vehicles Only. .............................................................. 4-8

Table 4.3-10. Seasonal Impact on Observed Average Concentrations (Units are ppbv, 

except as noted), Normal Mode Vehicles Only. .............................................................. 4-8

Table 4.3-11. Effect of Fuel and Operational Mode of the Sedan on Observed Levels in 

the Kitchen and Garage (Units are ppbv, except as noted). ............................................. 4-9

Table 4.3-12. Effect of Fuel and Operational Mode of the Truck on Observed Levels in 

the Kitchen and Garage (Units are ppbv, except as noted). ............................................. 4-9

Table 5.2-1. Protocol for Trailing Vehicle Tests ......................................................................... 5-3

Table 5.3-1. Summary of Summer and Winter Background Concentrations. ............................. 5-6

Table 5.3-2. Summary of Test Concentrations for Summer, Winter and Overall. Units are 

ppbv, except CO as noted. ............................................................................................... 5-7

Table 5.3-3. Summary of Concentrations Observed During Idle Tests. Units are ppbv 

except CO as noted. ....................................................................................................... 5-12

Table 5.3-4. Effect of Vehicle, Fuel, and Operational Mode. Units are ppbv, except CO as 

noted. Number of measurements = n ............................................................................. 5-13

Table 5.3-5. Influence of high emitting vehicles and each fuel on trailing vehicle in-cabin 

concentrations. Units are ppbv except CO as noted. ..................................................... 5-14

Table 5.3-6. Summary of Seasonal Differences in the High Emitter Samples. ......................... 5-14

Table 5.3-7. Comparison of High and Low In-cabin Ventilation Conditions, Winter 2005 

only. Units are ppbv except CO as noted. ...................................................................... 5-15
ES-1 

EXECUTIVE SUMMARY

This study evaluated the upper-end distribution of inhalation exposures to evaporative 

and combustion emissions from conventional and oxygenated-gasoline. This final report 

describes the measurement methods and protocol used in the study and summarizes the 

validation and initial analysis of the assembled database. The main findings and conclusions are 

emphasized in this final report and additional details and descriptions of the data are provided in 

several supporting appendices. 

Introduction and Background

The 211b Research Group is an unincorporated group of USA fuel and fuel additive 

manufacturers affiliated by contractual obligation to meet the testing requirements of Section 

211(b) (2) and 211(e) of Clean Air Act. The American Petroleum Institute (API) manages the 

required work on behalf of the 211b Research Group. 

Mobile source air toxics (MSAT) may pose an adverse health risk, especially in 

microenvironments with high exposures to vehicle exhaust or evaporative emissions. Although 

programs such as reformulated gasoline (RFG) are intended to reduce the emissions of MSAT 

and ozone precursors, uncertainties remain regarding population exposures associated with both 

oxygenate-gasoline blends and conventional gasoline. Accordingly, the EPA issued requirements 

for a test program in accordance with the Alternative Tier 2 provisions of the fuels and fuel 

additives (F/FA) regulations, which are required pursuant to Section 211 of the Clean Air Act. 

To satisfy those testing requirements, API contracted with a research team consisting of the 

Desert Research Institute (DRI), Southwest Research Institute (SwRI), Lovelace Respiratory 

Research Institute (LRRI), and TRJ Environmental, Inc (TRJ) to conduct a study of the high-end 

distribution of inhalation exposures to evaporative and combustion emissions of conventional 

and oxygenated-gasoline (MTBE-gasoline, and ethanol-gasoline). 

The results of this study provide data that will allow estimation of the upper-end of the 

frequency of annual average inhalation exposures to evaporative and combustion emissions of 

gasoline and oxygenated-gasoline. EPA may accomplish this by using the scripted exposures in 

high-end microenvironments with EPA regulatory exposure models, such as the Hazardous Air 

Pollutant Exposure Model (HAPEM). HAPEM is a screening-level exposure model for assessing 

average long-term inhalation exposure of the general population, or specific sub-populations, 

over spatial scales ranging from urban to national. The information from this study will permit 

sensitivity analyses to determine the range of these exposures, especially during heavy traffic, in 

residential and public parking garages and during refueling. The study also provides data for 

determining the relative proportion of evaporative versus combustion emissions in higher 

exposure microenvironments. 

The specific objectives of the study are to provide information allowing EPA to: 

• Quantify personal exposures to motor vehicle gasoline evaporative and combustion 

emissions in microenvironments (MEs) representing the upper end of the population 

exposure frequency distribution (99th + percentile) of such exposures; 
ES-2 

• Determine quantitative relationships between personal exposures in selected MEs and 

fixed site measurements in these MEs and at nearby air monitoring stations;

• Determine how personal exposures differ among cities and seasons in which methyl tbutyl ether (MTBE)- and ethanol (EtOH)-gasolines are used compared with a city where 

oxygenated fuels are not used.;

• Extrapolate study data to other cities and other oxygenated fuels; 

• Apportion the relative contributions of vehicle fuel combustion versus evaporative 

emissions to personal exposures in high-end MEs; 

• Determine the relationship between vehicle tailpipe and evaporative emissions and 

exposure levels in a trailing vehicle cabin and in a residence with an attached garage. 

Experimental Methods and Approach

The study was conducted in several phases. First, DRI evaluated the suitability of 

available measurement methods for meeting the technical objectives of the study. These methods 

included continuous and time-integrated measurements of carbon monoxide (CO), total volatile 

organic compounds (VOC), and the following MSAT species: benzene, toluene, ethylbenzene 

and xylenes (BTEX), 1,3-butadiene (1,3-BD), methyl tertiary butyl ether (MTBE), formaldehyde 

and acetaldehyde. Exposure measurements included well-established time-integrated methods 

for measurements of hydrocarbons and carbonyl compounds. These samples provide data of 

known precision and accuracy for each chemical species of interest during each exposure 

measurement, which typically covered a 20 to 40 min period. Several continuous and semicontinuous methods were used to provide time-resolved data ranging from 1 to 10 minutes. 

Continuous exposure measurements included benzene, toluene, ethylbenzene, and xylenes 

(BTEX) by a portable mass spectrometer (MS), carbon monoxide (CO) by a portable 

electrochemical analyzer and by a nondispersive infrared (NDIR) analyzer, and estimates of total 

volatile organic compounds by a portable photoionization detector (PID). Semi-continuous 

measurements of BTEX were also obtained from analysis of solid phase microextraction (SPME) 

fibers. 

Because exposure levels in most microenvironments were expected to vary with time, the 

measurement protocol included continuous measurements of target species with time resolution 

of 1 minute or less. This requirement necessitated the use of instruments such as the Kore 

MS200 and the Alpha Omega formaldehyde analyzer, which have not previously been proven 

for such application and did not perform sufficiently well in field conditions during the pilot 

studies. Furthermore, there are no acceptable continuous methods for 1,3-butadiene, MTBE, 

ethanol, acetaldehyde or nonmethane hydrocarbons (NMHC) that could be used in portable 

modes of operation with adequate sensitivity. Therefore, our sampling strategy consists of a 

three-tier approach shown in Table E-1, which lists the overlapping measurement methods used 

in the Section 211(B) Tier 2 High-End Exposure Screening Study and their intended application. 
ES-3 

Table E-1. Measurement methods used in the Section 211(B) Tier 2 High-End Exposure Screening Study. Data applications for 

specific methods are classified as reference, confirmatory, and surrogate. 

Continuous Semi-Cont Integrated

Method T15 CO NDIR CO ppbRAE MS200 HCHO SPME Canister DNPH Adsorbent

Applicable Environments outdoor and 

in-cabin 

all outdoor and 

in-cabin

higher end

MEs

outdoor All all all all

Time Resolution 1 min seconds seconds 1 min 1 min 10 min 20-40&5 min 20-40 min 20-40 min

Detection Limits 0.1 ppm 0.04 ppm 1 ppb 1-3 ppbv 1 ppbv 0.2 ppbv 0.05 ppbC 0.1 ppbv 0.2 ppbv

Data Application S 1 S S C C C R R R

CO SC SC R

PID 2 SC

BTEX S (a) S (a) SC (c) C C R

1,3-Butadiene S (a) S (a) S (c) R

MTBE S (a) S (a) S (c) C R

Formaldehyde S (b) S (b) S (d) C R

Acetaldehye S (b) S (b) S (d) R

Ethanol S (e) S (e) S (f) R

NMHC S (a) S (a) S (c) R

1. Category of data application include surrogate (S), confirmatory (C) reference (R), and surrogate compounds or signal (SC)

2. Sum of molecules ionizable at 10.6 eV and detected by photoionization detector.

S (a). Time series will be reconstructed from the canister/CO ratio for exhaust-dominated samples.

S (b). Time series will be reconstructed from the DNPH/CO ratio for exhaust-dominated samples except outdoor daytime samples.

S (c). Time series will be reconstructed from the canister/PID ratio for exhaust- or evap-dominated samples in outdoor MEs.

S (d). Time series will be reconstructed from the DNPH/PID ratio for exhaust-dominated samples except outdoor daytime samples.

S (e). Time series will be reconstructed from the solid adsorbent/CO ratio for exhaust-dominated samples.

S (f). Time series will be reconstructed from the solid adsorbent/PID ratio for exhaust and evap-dominated samples.
ES-4 

The measurements are classified in one of three tiers: reference, surrogate, and 

confirmatory. The base set or “reference” (R) measurements consist of three well-established 

time-integrated measurements. These include: canister sampling and analysis by gas 

chromatography with flame ionization detection for CO, BTEX, 1,3-butadiene, MTBE, and 

nonmethane hydrocarbons (NMHC); 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling and 

analysis by high performance liquid chromatography with UV detection for formaldehyde and 

acetaldehyde; and solid adsorbent sampling and analysis of ethanol by gas chromatography with 

mass spectrometry. These three methods combined measure all species of interest over the entire 

sampling period within each microenvironment. Although these integrated methods do not 

characterize peak exposures in microenvironments with highly varying exposure levels, they 

serve several other purposes. They provide a basis for validating continuous and semi-continuous 

data. They also provide a basis for deriving correlations between the time-integrated values with 

time averages of continuous data from the CO and PID instruments. Thus the continuous data 

were used as “surrogates” (S) for reconstructing the time series of specific MSAT based on these 

correlations. For example, data for BTEX, 1,3-butadiene, and MTBE from the canister 

measurements were correlated to continuous CO and PID data to reconstruct their time series in 

exhaust-dominated environments. In a similar manner, the time series of formaldehyde was 

reconstructed from the correlation of the integrated DNPH samples with CO. Outdoor afternoon 

samples were excluded due to potential contributions of carbonyl compounds formed from 

atmospheric reactions of hydrocarbons. Table E-1 shows other correlations that can be used in 

this manner. Two pilot studies were conducted in Reno, NV to test the proposed measurement 

methods under field conditions and to refine the exposure protocols. Two experimental 

approaches were used in the main study. 

Controlled Exposure Measurements in San Antonio

First, DRI and SwRI conducted exposure measurements in San Antonio under controlled 

conditions to establish quantitative relationships between vehicle tailpipe and evaporative 

emissions and exposure levels in two specific microenvironments, a trailing vehicle cabin and in 

a residence with an attached garage. The two vehicles (2.2L 4-cylinder 1993 Toyota Camry and 

a 5.0L V8 1995 Ford F150 Pickup truck) used in these controlled exposure experiments were 

tested at the SwRI laboratory for FTP (Federal Test Procedure) exhaust and hot soak evaporative 

emissions (Merritt, 2005). The tests were performed with the vehicles in normal and in 

malfunction condition while operating on summer and winter grade fuels from Houston, Atlanta 

and Chicago in summer 2002 and winter 2005. Measured FTP exhaust NMHC emission rates for 

the sedan and truck averaged 0.21 and 0.31 g/mi, respectively, in normal mode. Both emission 

rates are below the certified emission standards. The induced malfunctions raised NMHC 

emission rates by a factor of 16.7 for the sedan to 3.58 g/mi and factor of 7.0 for the truck to 2.20 

g/mi. Differences in NMHC emission rates among the three regional fuels were not significant. 

The p values of the regression between Atlanta and Houston and Atlanta and Chicago fuels were 

0.07 and 0.08, respectively for normal mode and 0.01 and 0.04, respectively for malfunction 

mode. The percent relative standard deviations of the NMHC emission rates for the sedan and 

truck were 15% and 14%, respectively, in normal mode and 3% and 6%, respectively with the 

induced malfunctions. 

The two test vehicles in normal operation and with induced malfunction were used to 

determine exposure in a cabin of a third vehicle which trailed the test vehicle. During each test, 

the trailing vehicle was driven behind the test vehicle over a travel loop of several miles in a 
ES-5 

rural area south of San Antonio. Measurements were made during the first 10 minutes without 

the test vehicle in order to established background exposure levels. Each trailing vehicle run 

included three scenarios (based on the proximity to the leading vehicle: far, near, and passing) 

for each low and high speed (30 mph and 60 mph) according to a prescribed schedule. Separate 

integrated samples were collected for background and separate periods corresponding to the 

driving and idle portions of each test for each fuel (i.e., Atlanta, Houston and Chicago) and 

emission condition (i.e., normal and malfunction mode). Data from the integrated reference 

methods showed observable relationships between exhaust emission rates and in-cabin exposures 

in a trailing vehicle.

The same two test vehicles (with and without malfunctions) were used to determine 

indoor exposure in a home with an attached residential garage. The vehicles were parked in a 

closed garage also containing a gasoline powered lawnmower and gasoline storage container 

filled with the test fuels, with in-garage and adjacent room monitoring conducted before, during 

and after the vehicle cool-down period. Time-integrated canister and cartridge samples were 

collected for each test (one in the garage and one in the adjacent room). A set of continuous and 

semi-continuous measurements by serial 10 minute average solid phase micro-extraction

(SPME) sampling were made during test period of two hours. 

Personal Exposures in Houston, Chicago and Atlanta

In the second approach, DRI measured personal exposures in selected MEs representing 

the upper end of the frequency distribution of potential population exposures. The study was 

conducted in Houston, TX, Chicago, IL and Atlanta, GA where MTBE-gasoline, ethanolgasoline and conventional gasoline are used, respectively. These cities also satisfy additional 

requirements of the study for ongoing ambient air monitoring programs and geographic and 

climatologic diversity among the three cities. Sampling was performed during winter and 

summer and under conditions that were conducive to higher exposures within each ME (e.g., 

downwind, low wind speeds, rush hour traffic). Continuous measurements included both NDIR 

and electrochemical CO, two PIDs and in-cabin and fuel tank skin temperature. From 3 to 5 

time-integrated canister and DNPH cartridge samples were collected for the following twelve 

microenvironments; 

 

• ME1-cabin exposure in congested freeway during commute, 

• ME2-cabin exposure in urban canyon, 

• ME3-cabin exposure during refueling, 

• ME4-cabin exposure in underground garage, 

• ME5-cabin exposure at toll plaza, 

• ME6- cabin exposure in on-road tunnel (Houston and Chicago only), 

• ME7-outside exposure during refueling, 

• ME8-outdoor exposure at busy street, 

• ME9-outdoor exposure at bus stop, 

• ME10-outdoor exposure at surface parking lot during and after event, 

• ME11-outside exposure in underground garage, 12-outdoor exposure at toll plaza, 

• ME13-cabin exposure following a high emitter (Atlanta only) 
ES-6 

In addition, 5-minute integrated canister samples were collected for ME6, ME7, ME10, and 

ME13 during peak exposures that corresponded to collection of breath samples. 

Exposure Protocol and Study Plan, and Study Schedule 

The Exposure Protocol and Study Plan was developed and refined based upon results of 

the pilot studies and initial field measurements during summer 2002. The following chronology 

describes the main stages in the study and development of the Study Plan. 

• First Pilot Study.

•

 Prior to the main field studies, DRI and LRRI conducted a 5-day pilot 

study in Reno, NV, during February 2002 to test alternative measurement approaches 

under field conditions similar to those that were encountered in the main study (Zielinska 

et al., 2002c). DRI and LRRI also evaluated the stability of the designated VOC species 

in breath and urine samples. Based upon the result of this pilot study, the exposure 

protocols and measurement methods, sampling and analytical procedures were refined 

and proposed in the June 13, 2002 Exposure Protocol and Study Plan (Zielinska et al., 

2002a). 

Summer 2002 Field Studies.

•

 The field measurements in San Antonio, Houston, and 

Atlanta were completed in adherence to the June 2002 protocol during summer 2002. 

These data were presented in three separate reports: Interim Data Report (Zielinska et al., 

2002b), Summer 2002 Atlanta Field Study Report (Zielinska et al., 2003a) and Summer 

2002 San Antonio and Houston Field Study Report (Zielinska et al., 2004a). The work in 

Chicago in the summer of 2002 was postponed, pending further evaluation of the 

measurement protocol and assessment of the data collected in 2002. 

Second Pilot Study.

• The final version of the protocol was applied to the summer 2003 and winter 2004/5 field 

study in Atlanta, Chicago and Houston and in the winter 2005 in San Antonio. A data 

report was previously prepared for the summer 2003 field study in Atlanta and Chicago 

(Zielinska et al. 2004b). 

 The second pilot study in Reno was conducted to refine the exposure 

protocol and further evaluate the surrogate approach and SPME measurements (Zielinska 

et al., 2003c). Several improvements were implemented in the mobile sampling platform 

during this time. Additional changes were incorporated into the final version of Exposure 

Protocol and Study Plan (Zielinska et al., 2003d) based upon discussions between EPA 

and DRI on the results of these reports. The final study protocol approved by the U.S. 

EPA is included in the Appendix A of this Final Report. 

API Section 211(B) Tier-2 Exposure Database 

The data have been organized into four data files (API Data_Continuous.xls, API 

Data_SPME.xls, API Data_Time-integrated.xls and API Data_Reconstructed.xls) containing the 

continuous, SPME, time-integrated and reconstructed exposure data. All files include data fields 

describing the sample collection conditions (e.g.; microenvironment, fuel type, test mode) as 

well as data flags indicating problems with the analytical or sample collection methods. Tables 
ES-7 

explaining the meaning of each data field are also included with each file. The files are supplied 

in Excel workbook format for convenience, but have been formatted to be compatible with 

common database software (the value -99 is used for missing data points, and time is in hhmm 

text format)

The time-integrated data contains speciation results from canister, DNPH cartridge, and 

TENAX adsorbent tubes, plus time-averaged values of pollutants and environmental parameters 

that were measured continuously during the batch sample collection periods. Within the timeintegrated data file there are 4 sub-categories that are presented separately due to the differing 

number of experimental variables for each type: 1) microenvironment exposure measurements 

from the three cities, 2) breath samples collected from subjects participating in 4 of the 

microenvironments, 3) residence with attached garage, and 4) trailing vehicle exposure tests. 

The SPME data is assembled in essentially the same manner as the time-integrated data, 

but contains only the BTEX hydrocarbon compounds and uses some different sample descriptors 

where necessary to identify which portion of each test the sample was collected. The same 

sample IDs are used to facilitate comparison of the two sampling methods.

The third data file contains 1-minute averages of the pollutants and environmental 

parameters that were measured continuously during the microenvironment exposure tests in the 3 

cities. Data were typically logged every 10 seconds during testing, but to reduce measurement 

noise, make the data set more manageable, and reduce the effect of minor timing discrepancies 

between instruments due to imperfect clock synchronization or differences in sample line 

residence time, the data was time averaged by minute. Each data record in this file has both a 

time/date stamp and an identification code that relates it to the corresponding time-integrated 

sample. Data flags are given to identify any missing or invalid data for each minute. Due to the 

large size of this file, the various sample descriptors have not been included but these can be 

derived from the identification code as described in the included key. 

The fourth data file contains 1-min reconstructed data for benzene, 1,3-butadiane and 

formaldehyde based on PID and NDIR CO continuous data, as described in Chapter 1 of this 

report. Both full time integrated canister and DNPH-carbonyl samples and 5-min canister 

samples collected over a peak exposure in selected MEs, are included.

Study Findings

Quantification of Personal Exposures to Motor Vehicle Emissions in High Exposure 

Microenvironments in Atlanta, Houston and Chicago during Summer and Winter (Chapter 1) 

• Since different fuels were used in each of the tree cities, only combined effect of city/fuel 

was examined in this study.

• Day-to-day variations in high-end (99th + percentile) benzene, 1,3-butadiene, 

formaldehyde, and CO concentrations in different MEs were substantial and independent 

of city and season, probably related to the activity and emission rates of sources in the 

given MEs which differ from day to day. 
ES-8 

• With the exception of refueling, exposure levels were generally lower in outdoor MEs 

and higher in enclosed MEs. 

• The 20-min average exposures to benzene during refueling ranged up to few hundred 

ppbv and showed substantial day-to-day variability. 

• In-cabin exposures during on-road vehicle operation were less variable than in-cabin 

exposures in garages and toll plazas.

• Exposure levels of BTEX species were highest in refueling MEs, which are dominated by 

evaporative emissions whereas exposures to CO, formaldehyde, and 1,3-butadiene were 

highest in cold-start dominated MEs.

• BTEX and 1,3-butadiene measured by the time-integrated canister method correlated 

well with continuous PID and CO measurements, respectively, in all MEs except 

refueling. Correlation of formaldehyde with continuous CO was weak, probably due to 

photochemical production of this compound. 

• Continuous PID and CO (NDIR) data can be used to reconstruct 1-minute time series for 

benzene and 1,3-BD, respectively, provided that the averaged continuous measurements 

are above the detection limits of the instruments (25 ppbv and 0.5 ppmv, respectively). 

CO data can also be used to reconstruct 1-minute formaldehyde data; however, less 

reliably so due to poorer correlation between these species.

• Reconstructed 1-minute time-series data for benzene and 1,3-butadiene, averaged over 

five minutes, correlated well with the corresponding 5-minute canister samples after 

excluding the Houston refueling ME data, which were distorted by high concentrations of 

MTBE.

• The concentrations of benzene and 1,3-butadiene measured in post peak exposure breath 

samples closely tracked the corresponding microenvironmental 1-minute maximum 

reconstructed surrogate values.

• Increases in concentrations of measured species occur in all breath samples that were 

collected within a minute of a peak exposure. In Atlanta and Chicago, the highest breath 

concentrations of BTEX and 1,3-BD were observed in ME7 (refueling) and ME11 

(underground garage), respectively. In Houston, high concentrations of MTBE were 

measured in ME7. 

Figure E-1 shows the distribution of reconstructed 1-min BTEX concentrations in high-end MEs 

in Atlanta in Summer. One-min time resolution reflects the high short-time peak concentrations 

necessary to characterize 99th + percentile exposure. The Atlanta winter distribution as well as 

Houston and Chicago MEs look very similar.

Figure E-2 A and B shows the comparison of 1,3-butadiane, benzene, formaldehyde and CO 

averaged concentrations in three cities in Summer and Winter, respectively. 
ES-9 

Figure E-1. Distribution of reconstructed 1-min BTEX exposures in high-end Atlanta MEs. Edges of the box = first and third quartiles; 

black line = median; red line = average. Minimum and maximum values (ppbv) are shown at the bottom and top of the plots. Whisker 

covers 99.3% of the data distribution. Filled circles > 3 times the box interval, empty circle are within that interval. The y-axis represents 

the percentage of data distribution. 

2.4

132

9.2

14.2

1.4

65

10.1

9.8

1.3

583

18.0

40.0

3.1

304

17.5

25.8

0.6

25

3.7

7.3

2.2

2454

13.3

97.6

0.8

58

5.1

5.8

2.6

80

7.0

9.4

2.1

98

14.1

24.3

60.1

465

152.4

172.1

5.8

40

11.7

13.3

2.9

533

11.9

29.7

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME8_9 ME10 ME11 ME12 ME13

0

20

40

60

80

100

120

2.4

132

9.2

14.2

1.4

65

10.1

9.8

1.3

583

18.0

40.0

3.1

304

17.5

25.8

0.6

25

3.7

7.3

2.2

2454

13.3

97.6

0.8

58

5.1

5.8

2.6

80

7.0

9.4

2.1

98

14.1

24.3

60.1

465

152.4

172.1

5.8

40

11.7

13.3

2.9

533

11.9

29.7

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME8_9 ME10 ME11 ME12 ME13

0

20

40

60

80

100

120

2.4

132

9.2

14.2

1.4

65

10.1

9.8

1.3

583

18.0

40.0

3.1

304

17.5

25.8

0.6

25

3.7

7.3

2.2

2454

13.3

97.6

0.8

58

5.1

5.8

2.6

80

7.0

9.4

2.1

98

14.1

24.3

60.1

465

152.4

172.1

5.8

40

11.7

13.3

2.9

533

11.9

29.7

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME8_9 ME10 ME11 ME12 ME13

0

20

40

60

80

100

120

1. In-Cabin Congested Freeway 5. In-Cabin Toll Plaza 10. Outdoor Surface Parking

2. In-Cabin Urban Canyon 7. Outdoor Refueling 11. Outdoor Underground Garage

3. In-Cabin Refueling 8. Sidewalk 12. Outdoor Toll Plaza

4. In-Cabin Underground Garage 9. Sidewalk/Bus Stop 13. Following High Emitters
ES-10 

Benzene

0

20

40

60

80

100

120

140

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

1,3-Butadiene

0

2

4

6

8

10

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

Formaldehyde

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

CO

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppm

Houston Atlanta Chicago

Figure E-2A. Comparison of average concentrations of benzene, 1,3-BD, HCHO and CO in three cities in Summer
ES-11 

Benzene

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

 

1,3-Butadiene

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

Formaldehyde

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Houston Atlanta Chicago

 

CO

0

5

10

15

20

1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppm

Houston Atlanta Chicago

Figure E-2B. Comparison of average concentrations of benzene, 1,3-BD, HCHO and CO in three cities in Winter
ES-12 

Relative Contributions of Vehicle Evaporative and Exhaust Emissions to Concentrations of 

Volatile Air Toxics in High Exposure Microenvironments (Chapter 2)

• MTBE/benzene ratios were used to estimate the relative contributions of evaporative and 

exhaust emissions to MSAT. This basis for this approach is that the proportion of MTBE 

in exhaust is reduced during combustion relative to its proportion in the fuel while 

benzene is enriched in exhaust relative to its proportion in the fuel due to toluene and 

xylene dealkylation. Consequently, MTBE to benzene ratios are substantially lower in 

exhaust than in liquid fuel or headspace vapors. Exposures at the two refueling MEs (3 & 

7) were dominated by evaporative emissions as expected, with MTBE/benzene ratios in 

Houston of 20 to 30. Ratios for all other MEs were between 1 and 4. 

• The fractional contribution of evaporative and exhaust emission were estimated for each 

ME based on exhaust MTBE/benzene ratios from several dynamometer exhaust tests and 

on-road tunnel measurements and evaporative MTBE/benzene ratios for the SwRI SHED 

tests and composition of gasoline headspace vapor. Exposures during refueling (ME3, 

ME7) are 100% due to evaporative emissions within the uncertainties associated with the 

measurements and method. All other MEs are dominated by tailpipe emissions with 

fractional evaporative contributions < 10%. 

Figure E-3 shows the MTBE/benzene ratio and contribution of evaporative emissions in Houston 

MEs

Quantitative Relationships Between Levels of Volatile Air Toxics and Carbon Monoxide 

Measured in High-End Exposure Microenvironments and at Nearby Air Quality Monitoring 

Stations (Chapter 3)

• MEs in close proximity to running vehicle engines have enhanced CO relative to ambient 

levels at nearby air quality monitoring sites with enrichment ratios approaching 40 where 

ventilation is limited, as in underground garages. Average in-cabin CO/ambient ratios in 

congested freeway traffic range from 2-9. ME locations less proximate to operating 

vehicles, such as gas stations and urban sidewalks, have CO/ambient ratios of 0.5-2. 

• The mean ratio of in-vehicle exposures on congested freeways (ME #1) to ambient levels 

at a monitoring station of 9.8 ± 3.8 ratio for Houston exceed the HAPEM5 median 

proximity factor of 4.9 (triangular distribution mode:range 1.9:0-14.3) and HAPEM4 

proximity factor of 6.9 for this ME (Rosenbaum, 2005; Long & Johnson, 2004), although 

by less than expected. 

Figure E-4 shows the mean ratios of ME concentrations to corresponding hourly measurements 

at the regional air monitoring station in Houston.
ES-13 

Figure E-3. MTBE/benzene ratio and contribution of evaporative emissions in Houston MEs 

Evaporative Emissions Contribution

0.0

0.2

0.4

0.6

0.8

1.0

1 2 3 4 5 6 7 8 9 10 11 12

ME

Fraction

summer

winter

MTBE/benzene

0

20

40

60

80

1 2 3 4 5 6 7 8 9 10 11 12

ME

Ratio

summer

winter

 1. In-vehicle congested freeway 5. In-vehicle toll plaza 9. Outdoor bus stop

 2. In-vehicle urban canyon 6. In-vehicle road tunnel 10. Outdoor surface parking 

 3. In-vehicle refueling 7. Outdoor refueling 11. Outdoor underground garage

 4. In-vehicle underground garage 8. Outdoor sidewalk 12. Outdoor toll plaza
ES-14 

Figure E-4. Mean ratios of ME concentrations to corresponding hourly measurements at the regional air monitoring station in Houston. 

Houston- Summer

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12

Microenvironment

ME/Station Ratio

Benzene

Toluene

m&p-Xylenes

Houston - Winter

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12

Microenvironment

ME/Station Ratio
ES-15 

Relationship of Attached Garage and Home Exposures to Fuel Type and Emission Levels of 

Garaged Sources (Chapter 4)

• Two target components, formaldehyde and ethanol, had high kitchen background values 

indicating indoor sources of these compounds. Average kitchen formaldehyde levels 

were higher in summer than winter, probably due to enhanced off-gassing of building 

materials and/or penetration of ambient photochemical formaldehyde. 

• Kitchen BTEX, MTBE and CO species are higher in winter than summer. The exception 

is toluene which shows a minimal difference that actually averages higher in summer for 

normal mode vehicles. This is consistent with indoor toluene emissions from paints, 

adhesives, cleaning, and personal care products. 

• MTBE and ethanol are highest for fuels containing those species, as anticipated. 

• FTP exhaust and SHED evaporative emissions were tested for each vehicle, fuel, and 

emissions mode, and compared to observed levels in the garage. Neither canister nor 

SPME samples show strong (r2=0.003 and 0.005, respectively) correlations with hot soak 

emissions, although cold-stabilized FTP Bag 2 benzene appears reasonably correlated 

(r2= 0.4) to the cold-start SPME.

• Correlations of kitchen levels with garage concentrations were weak (r2 generally below 

0.1) and could not be used to predict kitchen exposures from garage levels.

Figure E-5 shows the effect of fuel and vehicle operational mode (i.e. normal or malfunction) on 

observed concentrations of 1,3-butadiene, BTEX, MTBE, formaldehyde, ethanol, acetaldehyde,

and CO in the kitchen. 

Effect of Ventilation, Proximity, and Emission Levels on In-Cabin Exposures of Trailing Vehicle 

(Chapter 5)

• Summer and winter in-cabin values were similar in magnitude with the exception of 

formaldehyde which was higher in the summer, possibly due to higher photochemical 

activity and higher temperatures that led to more off-gassing of formaldehyde in the 

vehicle cabin interior. 

• Trailing vehicle cabin values were larger than background values (as measured during the 

first 10 min run without the test vehicle) except for formaldehyde which was actually 

lower than background in winter tests. 

• Idle test sample values were on average twice those encountered in driving tests, 

suggesting that proximity and proximity duration may substantially impact in-cabin 

trailing vehicle concentrations. 
ES-16 

• Average in-cabin levels were affected by both state of maintenance of the vehicle and 

fuel composition. Use of Atlanta fuel resulted in higher BTEX concentrations in the 

trailing vehicle cabin, which is consistent with higher aromatic contents of Atlanta fuel, 

especially in summer. Similarly BTEX concentrations were consistently higher during 

the summer, which is also in concert with higher aromatic contents of summer fuels, 

especially for Atlanta. Averaging over the fuels and vehicles, the high emitter mode 

resulted in 2.2 times higher in-cabin exposure levels for the trailing vehicle than the 

normal emitter mode except for HCHO which was relatively unchanged from 

background. 

• Trailing vehicle ventilation status affected in-cabin values; the concentrations observed 

by continuous PID and CO monitors were more variable under high ventilation. This may 

be rationalized as the vehicle moving into and out of the exhaust plume of the leading 

vehicle with in-cabin values changing rapidly under high ventilation; whereas under low 

ventilation, in-cabin concentrations trapped as the vents were closed stayed relatively 

constant during the remainder of low ventilation conditions. 

• Trailing vehicle tests indicated that the largest impact on in-cabin values came from the 

emissions mode (normal or malfunction) of the leading vehicle. 

Table E-2 shows the effects of changing vehicle, fuel and operational mode (i.e. normal or 

malfunction) on observed concentrations of 1,3-butadiene, BTEX, MTBE, formaldehyde, 

acetaldehyde, and CO in the trailing vehicle cabin. 
ES-17 

0

5

10

15

20

25

30

35

40

45

50

Budi13

Benze

Tolue

Etbz

Mp_xyl

O_xylMTBE

CO,ppm

Formal

EtOH

Acetal

compound

ppbv

Atlanta-N

Atlanta-F

Houston-N

Houston-F

Chicago-N

Chicago-F

339,542

Figure E-5. The effect of fuel and vehicle operation mode (i.e. normal or malfunction) on 

observed concentrations in the kitchen 

Table E-2. The effects of changing vehicle, fuel and operational mode (i.e. normal or 

malfunction) on observed concentrations in the trailing vehicle cabin. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

Truck only (n=12) 0.64 1.40 2.32 0.45 1.46 0.61 0.87 1.56 4.55 3.67

Car only (n=12) 0.59 1.13 1.87 0.33 1.11 0.45 0.53 1.42 5.90 3.59

Atl fuel only (n=8) 0.53 1.44 2.79 0.51 1.66 0.68 0.14 1.41 5.99 3.39

Hou fuel only (n=8) 0.89 1.52 2.20 0.48 1.58 0.66 2.17 1.91 5.61 4.37

Chi fuel only (n=8) 0.48 0.87 1.32 0.20 0.66 0.28 0.03 1.22 4.20 3.19

Normal only (n=12) 0.06 0.46 1.05 0.21 0.73 0.31 0.16 0.41 5.21 3.26

High emitter only (n=12) 1.06 1.95 2.99 0.55 1.77 0.71 1.21 2.50 5.37 3.37

St Dev high emitter only 28% 36% 38% 41% 44% 44% 177% 52% 52% 64%
ES-18 

Evaluation of Measurement Method’s Performance

 The integrated canister and DNPH sampling methods produced nearly 100 percent data 

capture of high quality data as confirmed by internal consistency checks. However, some 

challenges were encountered in applying two continuous confirmatory measurements, the Kore 

MS200 and formaldehyde analyzers. In most of the MEs, the MS200 had vacuum problems, 

most probably due to the high humidity in Houston, Chicago and Atlanta, and did not produce 

useful data. The instrument performed much better during first and second Pilot Study in Reno, 

probably because of much lower humidity. Although the formaldehyde analyzer was upgraded, 

it still required extensive user intervention and did not run reliably under the conditions 

encountered. The sensitivity of the instrument to environmental noise associated with driving 

limited its utility under mobile sampling. With proper operation and better characterization of 

instrument performance, the supplemental continuous formaldehyde analyzer may prove useful 

for ambient monitoring at fixed location. 

 The SPME also had excellent data capture, as did the continuous instruments for CO and 

PID. The two PIDs were compared both in controlled tests and collocated during the MEs. In 

both cases, they tracked each other quite well. Differences appear to be due to an offset in one 

unit, and a slightly different response speed between the two units. The NDIR CO and

electrochemical CO (Langan T15) instruments compared favorably, usually within 1 ppm. The 

detailed description of data quality and QA/QC procedures are presented in Appendix H. 

Conclusions

Exposure levels are directly related to the activity and emission rates of sources in the 

microenvironment and inversely related to the distance between sources of emissions and the 

measurement location and extent of dilution of emissions, which are a function of meteorological 

conditions and the presence of physical obstruction that inhibit dispersion. All of these factors 

contribute to the large temporal and spatial variations in pollutant exposures that exist within 

each of the microenvironments. Testing at SwRI showed that the differences in exhaust and 

evaporative emission rates among the three regional fuels were not statistically significant except 

for MTBE. With the exception of MTBE, the small differences due to fuel formulation are 

masked by the large variations of exposure levels within each of the microenvironments. 

The information from control exposure experiments in San Antonio provided useful 

context for interpreting the varying exposures in the high-end microenvironments in Atlanta, 

Houston and Chicago. We found that the results of the trailing vehicle experiments were 

qualitatively consistent with our observations in the three cities. In-cabin exposure levels even in 

congested traffic were on the order of a factor of two higher than background. Congested stopand-go conditions resulted in some increase in exposure levels due to shorter gaps between 

vehicles and highest on-road exposures were measured when following high emitters. In-cabin 

exposures during low ventilation conditions were relatively constant and retained the levels at 

the time ventilation was cut off.

Evaporative emissions were the only substantial components of high-end ME exposures 

during vehicle refueling operations, where they are dominant. Since refueling MEs had the 

highest relative levels of these components, they constituted the peak exposures, although overall 

the average population time spent in these high end MEs is likely the shortest. The contributions 
ES-19 

of evaporative emissions for all other MEs were typically about 5% of the total measured 

exposures. Results were similar for both seasons, although evaporative contributions during 

refueling were marginally less during summer, possibly due to more rapid dispersion of vapors 

and evaporation of fuel spilled during each refueling test at higher summer temperatures. These 

results suggest that the contemporary Houston vehicle fleet contained relatively few carbureted 

or leaking vehicles given that evaporative emissions were not a substantial source in the nonrefueling MEs tested. Refueling emissions released from pressurized fuel systems and spilled 

fuels appeared to be the primary source of peak evaporative exposures. The lack of a seasonal 

variability in the evaporative contribution was also consistent with this supposition. Although it 

was not feasible to try to distinguish further between liquid and headspace vapor contributions by 

the method used, the extremely low MTBE/benzene ratios observed for the roadway, sidewalk, 

and parking MEs strongly suggest that the impact from leaking liquid gasoline emissions were 

minor. 

HAPEM5 proximity factors may need to be adjusted since they were based on a 1998 

scoping study where measurements ‘highlighted trailing behind heavy duty diesel vehicles and 

diesel city buses when possible’. Houston ME/ambient ratio comparisons also generally exceed 

the other HAPEM factors. Refueling ratios (ME3, ME7) for benzene were higher than the 

corresponding HAPEM factors as expected, given the refueling protocol provisions maximizing 

exposure discussed above and below. Concentrations of exhaust compounds such as CO and 1,3-

butadiene were enhanced under reduced ventilation situations. 

It must be recognized that the various microenvironments were selected with a goal to 

capture the 99th percentile exposure levels within each type of microenvironment, as prescribed 

by EPA and API. We also selected specific sampling times and locations with the greatest 

potential for higher exposures. These selections were based on considerations of various 

emission surrogates such as traffic counts, diurnal variations in average highway speeds, length 

of queues at toll plazas, number of cars refueling or entering and exiting parking garages. 

Surrogates of dispersion included wind roses and diurnal variations in temperature. 

Measurements in microenvironments with unrestricted dispersion were made in the early 

morning or evening during calm conditions and minimal vertical mixing. In moderate wind 

conditions, we drove parallel to the prevailing wind to reduce the impact of cross winds. Thus, 

the ranges of exposures determined in this study are skewed toward the higher end of the 

distribution of exposures for each microenvironment. 

References

Long, T. and T. Johnson (2004). Development of Penetration and Proximity Microenvironment 

Factor Distributions for the HAPEM5 in Support of the 1999 National-Scale Air Toxics 

Assessment (NATA). Memorandum prepared by TRJ Environmental, Inc. for the U.S. 

Environmental Protection Agency, Research Triangle Park, NC, April 5, 2004 

Merritt, P. (2005). Evaporative and Tailpipe Emissions Support for S211b Tier 2 Exposure 

Study. Final report submitted by Southwest Research Institute to Desert Research 

Institute on July 29, 2005. 
ES-20 

Rosenbaum, A. (2005). The HAPEM5 User’s Guide. Report prepared by ICF Consulting for the 

U.S. Environmental Protection Agency, Research Triangle Park, NC, March 2005. 

Zielinska, B., E. M. Fujita, J.C. Sagebiel, D. E. Campbell, L.R. Smith, T. Johnson (2002a). 

Exposure Protocol and Study Plan for the Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. Prepared for American Petroleum 

Institute, 1220 L Street, Washington, DC 20005-4007. June 13, 2002 

Zielinska, B., E. M. Fujita, J. C. Sagebiel, D. E. Campbell, J. McDonald (2002b). Interim Data 

Report for Section 211 (B) Tier 2 High-End Exposure Screening Study of Baseline and 

Oxygenated Gasoline. Prepared for American Petroleum Institute, 1220 L Street, 

Washington, DC 20005-4007. November 15, 2002. 

Zielinska, B, J. Sagebiel, E. Fujita, D. Campbell, J. McDonald, T.J. Kelly, and D. W. Joseph 

(2002c). Section 211(B) Tier 2 High-End Exposure Screening Study of Baseline and 

Oxygenated Gasoline-Pilot Study. Prepared for American Petroleum Institute, 1220 L 

Street, Washington, DC 20005-4007. June 13, 2002 

Zielinska, B, E.M. Fujita, and J.C. Sagebiel (2003a). Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline-Summer 2002 Atlanta Field Study 

on Baseline Gasoline. Prepared for American Petroleum Institute, 1220 L. Street, 

Washington, DC 2005-4070. March 13, 2003. 

Zielinska, B., J.C. Sagebiel, D. Campbell, D. Ceballos, M. McDaniel, and E.M. Fujita (2003b). 

Section 211 (B) Tier 2 High End Exposure Screening Study of Baseline and Oxygenated 

Gasoline-2nd Reno Pilot Study. Prepared for American Petroleum Institute, 1220 L 

Street, Washington, DC 20005-4007. June 13, 2003 

Zielinska, B., E. M. Fujita, J.C. Sagebiel, D. E. Campbell, L.R. Smith, T. Johnson (2003d). 

Exposure Protocol and Study Plan for the Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. Prepared for American Petroleum 

Institute, 1220 L Street, Washington, DC 20005-4007. Final Version. October 1, 2003 

Zielinska, B., J.C. Sagebiel, D. Campbell, E.M. Fujita (2004a). Section 211 (B) Tier 2 High End 

Exposure Screening Study if Baseline and Oxygenated Gasoline-Summer 2002 San 

Antonio and Houston Field Studies. Prepared for American Petroleum Institute, 1220 L. 

Street, Washington, DC 2005-4070. March 5, 2004. 

Zielinska, B., J.C. Sagebiel, D. Campbell, E.M. Fujita (2004b). Section 211 (B) Tier 2 High End 

Exposure Screening Study if Baseline and Oxygenated Gasoline-Summer 2003 Chicago 

and Atlanta Field Studies. Prepared for American Petroleum Institute, 1220 L. Street, 

Washington, DC 2005-4070. July 5, 2004. 
1-1

1. Quantification of Personal Exposures to Motor Vehicle Emissions in High 

Exposure Microenvironments in Atlanta, Houston, and Chicago during 

Summer and Winter.

1.1 Introduction

 Gasoline-powered vehicles emit a portion of ozone-forming volatile organic compounds 

(VOC) and mobile source air toxics (MSAT) in the urban areas of the country. Elevated 

exposures to gasoline-related MSAT have been reported in certain microenvironments (MEs), 

such as in vehicle cabins during commuting on congested roadways (Batterman et al., 2002; 

Chan et al. 1991; Rodes et al., 1998; Fedoruk and Kerger 2003; Weisel et al., 1992; Jo and Park, 

1999), refueling (Vayghani and Weisel 1999; Vainitalo et al., 1999; Lindstrom and Pliel, 1996) 

or in urban canyons (Rodes et al., 1998; Chan et al. 1991). 

 Although oxygenated fuel and reformulated gasoline (RFG) programs are intended to 

reduce the emissions of ozone precursors and MSAT , uncertainties remain regarding the 

population exposures associated with oxygenated and conventional gasoline. Accordingly, in 

2001 EPA issued testing requirements under Alternative Tier 2 provisions of the fuel and fuel 

additive (F/FA) health effects testing regulations, required pursuant to Section 211(b) of the 

Clean Air Act. 

 The population exposure study reported here targets conventional gasoline and two 

oxygenated blends containing methyl tertiary butyl ether (MTBE) and ethanol (EtOH) and 

conducts studies in prospective high-end microenvironments (MEs) likely associated with the 

most-exposed populations. Personal exposures are quantified in selected MEs representing the 

upper end of the frequency distribution of potential population exposures. The studies take place 

in cities that have ongoing ambient air monitoring programs, located in hot and cold parts of the 

country, using one of the three target fuels. Sampling was performed during winter and summer 

seasons and under conditions (e.g., downwind, low wind speeds, rush hour traffic, fuel spillage, 

trailing high emission vehicles) thought to maximize exposure within each ME. The same 

sampling protocols (e.g., location, duration, cabin ventilation) were used in both seasons 

whenever possible. A number of fuel emission and exhaust components [carbon monoxide (CO), 

carbon dioxide (CO2), benzene, toluene, ethylbenzene, xylenes (BTEX), MTBE, 1,3-butadiene 

(1,3-BD), EtOH, formaldehyde (HCHO), and acetaldehyde (CH3CHO)] were measured within 

thirteen MEs in personal breathing zones, and in breath immediately after measured peak 

exposures. The results of these microenvironmental studies were intended to include the upperend (99+th percentile) of the frequency of annual average inhalation exposures to evaporative and 

combustion emissions from the three targeted gasolines. The study also estimates the relative 

proportion of evaporative and combustion emissions by ME in breathing zone air. 
1-2

The specific objectives of the study are to provide information allowing EPA to: 

• Quantify personal exposures to motor vehicle gasoline evaporative and combustion 

emissions in MEs representing the upper end of the population exposure frequency 

distribution (99+th centile) of such exposures; 

• Determine quantitative relationships between personal exposures in selected MEs and

fixed site measurements in these MEs and at nearby air monitoring stations; 

• Determine how personal exposures differ across seasons and cities using the three target 

fuels (conventional-, MTBE-, and EtOH-gasoline); 

• Extrapolate study data to other cities and other oxygenated fuels; and

• Apportion the relative contributions of vehicle fuel combustion vs. evaporative emissions 

to personal exposures in high-end MEs. 

1.2 Experimental

1.2.1 Selection of Microenvironments

 Houston (TX), Chicago (IL) and Atlanta (GA) were selected as the study sites. These 

cities have ongoing ambient monitoring programs and dispense MTBE-RFG, EtOH-RFG, and 

conventional gasoline formulations, respectively. One of the goals of the project was to sample 

high-end MEs, plausibly characterized in the upper 99+th percentile of exposures to

exhaust/evaporative emissions from gasoline-fueled vehicles. Selection of high-end MEs1

was 

made in consultation with EPA and independent peer reviewers according to the selection 

criteria described in the Exposure Protocol and Study Plan (Zielinska et al, 2003a) included in 

Appendix A. Table 1.2.1-1 lists the MEs chosen along with the number of replicate 

measurements taken in each ME, whether biomarker (breath) measurements were taken for that 

ME, and the sampling time spent in each ME.

 

1 ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin 

toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; 

ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: In-cabin trailing high-emitter 

vehicle
1-3

Table 1.2.1-1. Microenvironmental Sampling.

ME # ME Description Replica

tes

Biomar

ker

SamplingTime 

(min)** 

1 In-Cabin Congested Freeway 5 40 (20 H and 20 L)

2 In-Cabin Urban Canyon 3 40(20 H and 20 L)

3 In-Cabin Refueling 5 20 (10 H and 10 L) 

4 In-Cabin Underground Garage 5 40 (20 H and 20 L)

5 In-Cabin Toll Plaza 3 40 (20 H and 20 L)

6* In-Cabin Roadway Tunnel 5 yes 40 (20 H and 20 L)

7 Out-of-Cabin Refueling 5 yes 20

8 Out-of-Cabin Sidewalk 3 40

8/9 Out-of-Cabin Sidewalk/Bus Stop 3 40

10 Out-of-Cabin Surface Parking 3 40

11 Out-of-Cabin Underground Garage 5 yes 40

12 Outdoor Toll Plaza 3 40

13* In-Cabin Trailing High-Emitting 

Vehicles

5 yes 40 (20 H and 20 L)

 *ME6 was sampled in Houston & Chicago and ME13 in Atlanta 

** H refers to high ventilation and L to low ventilation conditions (see Monitoring 

 Methods below) 

The ME number refers to the same type of ME in each city studied. Since ME6 refers to a 

roadway tunnel and a suitable tunnel was not found in Atlanta, ME13 (following a high emitting 

vehicle) was substituted. 

Prior to selecting specific ME locations, Desert Research Institute (DRI) personnel 

surveyed potential high-end MEs in each city. The objectives of these surveys with portable gas 

analyzers were to determine the suitability of candidate sampling locations with respect to 

access, maximal exposure levels, and the variability of these exposures. The sampling period in 

each ME was selected to coincide with maximum activity level (i.e., emissions and exposure) as 

described in the Protocol (Appendix A). In the absence of data on the range of actual emission 

component exposures in various MEs in each city, we considered available surrogate parameters 

for emission and dispersion to select locations and sampling periods with the greatest potential 

for maximal exposures. These emission surrogates included diurnal traffic counts, variations in 

highway speeds, length of queues at toll plazas, concurrent numbers of cars refueling, and count 

rates entering and exiting parking garages. Surrogates for dispersion included diurnal wind roses 

and variations in temperature. Where possible we drove parallel to the prevailing wind direction

to reduce the impact of cross winds and sampled downwind of the nearest emission sources. Our 

sampling strategy also recognized that vehicle exhaust emissions are significantly higher for 

identified high emitting vehicles and all vehicles during cold starts (e.g., at parking lots, 

underground garages, and service stations) and accelerations (e.g., at toll plazas, roadway 

intersections). All of these factors are important in understanding the high-end perspective of 

sampling and the temporal and spatial variations that exist within these high-end MEs. 
1-4

1.2.2 Monitoring Methods

Instrumented Van. All in-cabin and out-of-cabin exposure measurements were performed 

with the mobile sampling van, a 1996 Chrysler Minivan, DRI-modified for on-road and 

stationary sampling. The power system included two banks of rechargeable AGM gel batteries 

with minimal H2 out-gassing during either charge or discharge. Each bank had a 1750 watt 

inverter for 110v AC power and direct connections for 12v DC, giving maximum flexibility. The 

suspension of the vehicle was upgraded to support the additional battery and instrument weight. 

Seats were removed and replaced with an adjustable equipment racks. For refueling experiments, 

a second fuel pump was installed to facilitate prompt removal of fuel. In-cabin and exterior 

temperature and relative humidity sensors were installed along with an additional sensor 

measuring fuel tank temperature. The data acquisition system has eight analog-to-digital inputs 

to record instrument outputs, which include a global positioning satellite (GPS) sensor, and 

compiles spatially-located data into a single database. All in-cabin equipment was manifolded to 

sample from a point in the driver's breathing zone. This manifold inlet could also be extended 

outside for stationary sampling purposes (e.g., into the subject breathing zone during refueling 

tests). Infiltration of outside air was adjusted by opening or closing windows in the front and rear 

of the cabin and switching the heating/AC system from vent to recirculate. In this manner two 

ventilation modes, high (all open) and low (all closed), were included in all in-cabin tests. 

Equipment Cart. For sidewalk, bus stop and outdoor toll plaza tests, sampling equipment 

was placed on a cart that was pushed along the sidewalk of a busy street in an urban canyon 

(ME8), patrolled a bus stop sidewalk at a high traffic density intersection (ME9) or was stationed 

next to a toll booth during rush hour traffic (ME12). Sampling inlets were positioned in the 

subject breathing zone. Detailed protocols for sampling in each ME are described in the 

Exposure Protocol and Study Plan (Zielinska et al, 2003a), included in Appendix A. 

Measurements in each ME were repeated three to five times for each city-season as noted in 

Table 1.2.1-1. 

Sampling and Analysis Methods. Three approaches were used to measure targeted 

compounds in the high-end MEs: (1) reference method time-integrated samplers to quantify 

concentrations over 20-40 minute sampling periods; (2) continuous surrogate method monitors to 

determine short-term concentration variations over 10-60 second sampling periods; and (3) 

supplemental methods to provide additional short-term surrogate concentration estimates over 

intermediate time frames of several minutes. Supplemental methods included newer methods that 

have not been fully adapted or ruggedized for field use. The supplemental methods provide 

independent checks and periodic corroboration of the surrogate approach used to estimate timeseries values for species not directly measured by the surrogate methods. 

1. The reference methods include passive and pressurized whole-air canister samplers used 

to collect ambient and breath CO, CO2, BTEX, MTBE, and 1,3-BD; acidified 2,4-

dinitrophenylhydrazine (DNPH) cartridges to collect HCHO and CH3CHO; and a multibed (TenaxTA-Carbotrap-Carbosieve) solid adsorbent tube for ambient EtOH (Chicago 

only). After collection, these samples are sent to the DRI Organic Analytical Laboratory 

for analysis. Canister CO and CO2 are chromatographed and converted to methane for 

analysis by flame ionization detection (GC/FID); BTEX, MTBE, and 1,3-BD are 

quantified by capillary GC/FID [GC/mass spectrometry (MS) for breath samples] using a 

separate system (Zielinska et al, 1998). The DNPH cartridges are eluted with acetonitrile 
1-5

and aldehydes analyzed by high performance liquid chromatography (LC) with 

photodiode array ultraviolet (UV) detection of their hydrazone derivatives. The multi-bed

sorption tubes are thermally desorbed into a GC and quantified by MS. These methods 

are basically standard TO-15, -11A, and -17 EPA procedures with some improvements 

incorporated by DRI as described in Appendix B.

2. The surrogate methods include both active non-dispersive infrared (NDIR) and passive 

T-15 Langan electrochemical cell devices for CO, and an active photo-ionization detector 

(PID) for volatile organic compounds (VOCs) with ionization potentials below 10.6 eV 

(principally olefins and aromatic species). These continuous instruments respond to 

concentration changes within a few seconds and provide sensitive proportionate measures 

of the short-term variability of exhaust and evaporative species quantified by the timeintegrated reference methods. Surrogate methods are used to generate normalized 

continuous time-series of concentrations for BTEX, MTBE, EtOH, 1,3-BD, and the 

aldehydes quantified by the reference methods.

3. The supplemental methods include both active continuous BTEX and HCHO instruments 

with several minute response times and a passive microextraction fiber sampling a 

flowing analyte stream for BTEX over a 10-minute period. The continuous BTEX 

monitor, a Kore MS200, quantifies species diffusing through its semi-permeable 

membrane inlet by 70eV electron impact ionization and time-of-flight MS. The HCHO 

instrument bubbles ambient air into a flowing aqueous 2,4-pentanedione and ammonia 

reagent to produce a HCHO-specific product, 3,5-diacetyl-1,4-dihydrolutidene, that is

quantified by UV fluorescence. The 75 um film solid phase microextraction 

carboxen/polydimethylsiloxane (SPME-CAR/PDMS) fiber is passively exposed in a 

flowing air stream for 10 minutes, retracted into its syringe holder, and promptly injected 

into a GC with PID/FID detection optimized for BTEX quantification.

All sampling and analysis methods are described in detail in Appendix B. In addition, 

the validation of the SPME method is described in detail in Appendix C. Quality Assurance 

procedures are described in Appendix H. 

1.2.3 Exposure Biomarkers 

Breath measurements were used as exposure biomarkers in four high-end MEs: out-ofvehicle cabin refueling (ME7); parking in an underground garage (ME11); driving through a 

roadway tunnel (ME6); and trailing a high emitting vehicle (ME13). The test subject took three 

breath samples. One sample was taken before initiating ME sampling; the second, ten seconds 

immediately after completing the active refueling task or within a minute of experiencing a 

measured peak exposure in the other three MEs, and a third, immediately following the second.

The 3rd sample was analyzed if there was a problem with the second sample. The subject used a 

1-liter evacuated canister, placing its inlet tube into his mouth and breathing smoothly and 

regularly through the mouth around the tube until a resting tidal breathing pattern was 

established. At the end of a normal tidal exhalation, the subject closed his mouth around the 

tube, opened the canister valve expelling his expiratory reserve and filled the canister, collecting

one liter of the expiratory reserve. When the canister was filled, the technician closed the canister 

valve to capture the sample (Pleil and Lindstrom, 2002; Lindstrom and Pleil, 1996). All breath 

samples were analyzed by GC/MS for BTEX, MTBE, 1,3-BD, and EtOH as described by Pleil 
1-6

and Lindstrom (2002); CO2 was methanized and quantified by GC/FID. Four subjects, labeled as 

1, 2, 3, and 4 in the time- integrated database, were utilized for breath sample measurements.

1.3 Results and Discussion

This section summarizes the distributions of high-end exposure levels observed for each 

ME by city and season. These exposure levels are examined as 20 to 40 minute averages from 

the integrated reference measurements, 5-10 minute averages from the surrogate data as 

corroborated by the supplemental measures, and as peak exposures using the one minute 

reconstructed surrogate time series.

1.3.1 Variation of day-to-day exposures by ME in each city

Table 1.3.1-1 and 1.3.1-2 summarize the three city, summer-winter, 20-40 minute 

average, maximum, and minimum ME canister levels of CO, benzene, and sum of BTEX and the 

HCHO and CH3CHO values from DNPH cartridges. Average, maximum, and minimum in/outcabin temperature and relative humidity (T/ RH) values are also listed. In-cabin T/RH values are 

in parentheses. Figures 1.3.1-1 through 1.3.1-6 show the day-to-day variations in benzene, 1,3-

BD, HCHO, and CO concentrations.

In general, exposure levels should be proportionate to the number of sources and their 

emission rates in the ME and inverse to increasing distance to the emission source and the extent 

of emissions dilution. Dilution is a function of meteorology and the presence of physical 

obstructions that may inhibit emissions dispersion. With the exception of refueling activities, we 

generally find that exposure levels are lower in outdoor environments and higher in enclosed 

environments. However, substantial variations exist among outdoor environments with respect to 

proximity to emission sources and the magnitude of their emissions. For example, the 40-minute 

average exposures for most urban canyon sidewalk/bus stop samples are on the order of a 1-2 

ppbv for benzene, whereas benzene exposures on outdoor surface parking lots or toll plaza 

aprons are usually higher. Refueling samples range up to few hundred ppbv benzene over 20 

minute sampling times and show substantial day-to-day variability. In-cabin exposures during 

vehicle roadway operation show more consistency sample to sample and more temporal 

uniformity than the other MEs. 

As it could be expected, MTBE and the BTEX species show the highest concentrations in

refueling MEs dominated by evaporative emissions whereas CO, HCHO and 1,3-BD are highest 

in cold-start dominated MEs (underground garage, roadway tunnel, toll plaza, surface parking). 

Several Houston refueling 1,3-BD values had to be invalidated due to the interferences stemming 

from elevated MTBE concentrations in these MEs. MTBE decomposes slightly (on the order of 

1 – 5%) at GC injector temperatures forming isobutene (2-methylpropene), a decomposition 

product that elutes just prior to 1,3-BD on the DB-1 (or equivalent) chromatographic column. 

When concentrations of isobutene are much higher than 1,3-BD, they tail into the butadiene peak 

biasing its apparent concentration upward. This interference was confirmed by GC/MS. As noted 

in Tables 1.3.1-1 and 1.3.1-2, one value for ME3 and two for ME7 were invalidated in summer 

samples and one value for ME3 and four for ME7 in winter samples.
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-7

Table 1.3.1-1. Summer average, maximum, and minimum ME concentrations (ppbv) of BTEX, 1,3-BD, HCHO, CH3CHO, EtOH, 

MTBE, and CO (ppmv) 

Atlanta (Conventional Fuel)

ME ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

Replicates 5 3 5 5 3 5 3 3 3 5 3 5

1,3-butadiene Ave. 1.7 0.3 0.6 3.6 0.3 0.3 0.2 0.1 1.3 3.6 0.7 1.0

Min. 1.2 0.1 0.1 1.2 0.0 0.1 0.1 0.0 0.4 1.2 0.5 0.7

Max. 2.2 0.4 2.1 7.3 0.7 0.6 0.2 0.4 2.2 6.2 0.8 1.1

Benzene Ave. 6.8 2.0 12.3 20.4 2.4 25.9 1.0 1.6 4.6 28.1 3.6 6.0

Min. 4.2 1.4 5.8 6.0 1.7 6.2 0.9 1.4 1.6 17.7 3.0 3.7

Max. 9.3 2.4 22.9 40.3 3.7 74.2 1.1 1.8 9.0 35.3 3.9 9.3

Toluene Ave. 13.6 4.2 30.6 63.2 4.2 43.7 2.5 4.1 9.8 76.5 5.3 18.0

Min. 8.4 2.4 15.7 19.7 3.1 10.5 2.4 3.6 3.3 49.2 4.9 9.1

Max. 21.2 5.4 43.0 122.6 6.2 104.1 2.8 4.7 19.4 93.6 5.6 37.6

Ethylbenzene Ave. 2.2 0.7 4.1 9.9 0.7 4.6 0.4 0.7 2.0 12.8 0.8 2.6

Min. 1.5 0.4 1.8 3.4 0.5 1.1 0.4 0.6 0.6 8.2 0.8 1.6

Max. 3.5 0.9 5.1 18.7 1.0 8.7 0.5 0.9 4.0 17.2 0.9 4.8

Xylene Ave. 8.7 2.9 15.2 37.0 2.6 17.1 1.8 3.0 8.0 48.8 3.6 10.3

Min. 5.5 1.6 6.6 12.5 1.5 4.4 1.8 2.6 2.9 30.9 3.4 6.1

Max. 13.7 3.7 18.5 69.2 3.9 29.2 1.9 3.8 15.5 63.4 3.9 19.1

Formaldehyde Ave. 6.6 6.7 9.3 25.7 5.1 10.0 10.7 11.2 12.8 33.2 7.6 8.6

Min. 3.9 5.0 5.5 15.4 4.4 7.2 9.6 10.5 8.8 22.2 7.0 7.3

Max. 8.4 8.5 11.1 32.3 6.2 11.5 11.3 12.5 19.7 50.6 8.3 11.1

Acetaldehyde Ave. 6.6 4.6 4.3 10.8 2.8 3.4 2.7 3.0 4.0 12.2 2.4 5.2

Min. 2.0 3.5 1.2 7.3 2.1 1.1 2.5 2.1 2.5 7.4 1.5 4.4

Max. 18.6 6.5 5.9 15.1 3.4 5.1 3.1 4.0 6.8 20.9 3.5 6.7

CO canister Ave. 6.1 1.4 0.7 8.5 2.1 0.6 0.8 1.1 2.7 14.5 3.1 4.0

Min. 3.7 0.7 0.4 1.7 2.0 0.2 0.7 1.0 0.8 9.8 2.8 2.3

Max. 11.7 2.1 1.4 16.2 2.4 1.2 1.0 1.1 5.6 20.0 3.5 6.2

Temp  ̊C Ave. (22.3) (27.2) (31.7) 27.8 32.3 (24.6)

(in-cabin) Min. (21.2) (19.6) (30.5) 22.1 31.0 (23.6)

Max. (23.9) (33.6) (33.8) 30.4 33.8 (25.6)

RH, % Ave. (57.8) (60.0) (51.8) 65.3 47.4 (48.8)

(in-cabin) Min. (56.0) (43.0) (46.0) 56.0 41.0 (46.0)

Max. (59.0) (73.0) (60.0) 86.0 51.0 (54.0)

Note: Urban canyon loop for Atlanta: Peachtree Street NW, Forsyth-Carnegie, Spring Street NW, and Harris Street 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-8

Chicago (Oxygenated Fuel - Ethanol)

ME ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

1,3-butadiene Ave. 0.4 0.5 0.1 2.4 0.3 1.3 0.1 0.3 0.3 0.6 1.4 0.5

Min. 0.2 0.3 0.0 1.5 0.2 1.2 0.0 0.3 0.1 0.4 0.2 0.3

Max. 0.5 1.0 0.1 4.0 0.3 1.6 0.3 0.4 0.4 0.9 2.6 0.8

Benzene Ave. 2.7 2.9 2.1 8.9 1.5 5.8 4.9 2.5 1.7 3.3 5.1 3.1

Min. 1.7 1.6 0.5 5.6 1.4 4.2 0.6 1.8 1.3 1.8 1.2 2.6

Max. 4.9 5.2 4.6 12.2 1.5 8.7 11.4 3.6 2.2 5.7 8.2 3.4

Toluene Ave. 4.8 4.7 6.6 23.3 2.8 15.0 11.2 3.4 2.4 7.5 11.8 3.6

Min. 2.4 2.6 1.4 13.6 2.3 6.7 0.7 2.0 1.5 3.5 3.4 2.6

Max. 9.3 7.5 18.6 37.8 3.3 25.5 27.3 6.1 3.5 13.6 18.4 4.3

Ethylbenzene Ave. 0.8 0.7 1.7 3.3 0.4 1.9 1.4 0.6 0.5 0.8 2.0 0.6

Min. 0.4 0.3 0.2 1.8 0.3 1.4 0.1 0.4 0.3 0.7 0.6 0.4

Max. 1.3 1.2 7.2 4.5 0.5 2.8 2.6 0.9 0.8 1.1 3.0 0.7

Xylene Ave. 3.1 2.7 7.2 13.4 1.7 6.6 5.9 2.1 1.8 3.2 7.8 2.3

Min. 1.6 1.2 0.9 6.9 1.4 5.1 0.5 1.4 1.1 2.7 2.2 1.9

Max. 5.1 4.5 29.8 17.1 2.0 9.4 10.2 3.4 3.0 4.0 12.1 2.8

Formaldehyde Ave. 7.7 5.5 10.5 16.1 5.9 8.9 11.7 6.2 6.1 6.7 10.5 8.8

Min. 5.4 4.6 8.4 10.7 5.3 8.0 3.4 3.8 3.7 5.9 5.8 6.2

Max. 9.4 7.3 13.7 26.7 6.5 10.1 24.6 7.6 7.8 8.1 14.1 11.6

Acetaldehyde Ave. 6.3 7.7 6.3 10.9 5.1 8.4 4.5 3.8 3.7 3.4 6.5 5.4

Min. 3.6 4.1 2.8 8.1 4.5 7.4 2.5 3.7 2.2 2.5 3.4 3.8

Max. 8.6 14.7 9.4 15.0 5.8 8.8 6.1 4.0 4.5 4.4 8.3 7.8

CO canister Ave. 2.2 1.7 0.4 5.3 1.4 5.1 0.6 1.0 1.4 1.2 3.1 3.0

Min. 1.5 1.3 0.3 4.0 1.1 4.0 0.3 0.8 0.9 1.0 0.6 2.5

Max. 3.0 2.4 0.6 8.2 1.6 7.1 0.7 1.2 1.7 1.8 5.1 3.7

EtOH Ave. 6.7 10.5 13.0 15.4 5.7 20.6 28.3 0.0 0.8 1.3 12.2 3.1

Min. 0.0 4.9 0.0 0.0 0.7 12.5 0.0 0.0 0.0 0.0 0.0 0.0

Max. 12.1 20.0 36.7 30.4 10.4 29.4 115.4 0.0 2.4 3.8 42.1 4.9

Temp  ̊C Ave. (23.3) (22.3) (28.3) (26.8) (21.0) (21.7) 26.7 25.0 26.0 22.6 27.3 31.5

(in-cabin) Min. (21.2) (21.9) (25.6) (25.9) (20.3) (20.2) 23.5 23.4 24.5 20.7 22.7 30.2

Max. (25.8) (23.2) (30.2) (28.4) (21.4) (25.0) 28.8 26.5 27.8 24.6 29.7 33.5

RH, % Ave. (51.6) (44.7) (51.5) (60.2) (56.0) (53.0) 58.2 54.3 52.7 69.7 56.0 42.3

(in-cabin) Min. (46.0) (41.0) (45.0) (55.0) (53.0) (50.0) 49.0 53.0 50.0 66.0 45.0 30.0

Max. (55.0) (48.0) (63.0) (65.0) (60.0) (57.0) 67.0 56.0 55.0 73.0 66.0 56.0

Note: Urban canyon loop for Chicago: Lake Street, Wabash Avenue, Van Buren Street, and State Street
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-9

Houston (Oxygenated Fuel – MTBE)

ME ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

1,3-butadiene Ave. 0.7 0.4 0.6* 1.7 0.9 1.4 1.2* 0.3 0.1 0.4 1.6 0.9

Min. 0.3 0.3 0.3 0.2 0.6 0.8 0.5 0.2 0.1 0.3 0.5 0.4

Max. 1.0 0.5 0.7* 4.5 1.2 2.8 2.1* 0.5 0.2 0.5 2.9 1.4

Benzene Ave. 1.9 1.4 52.6 5.1 2.5 3.7 130.7 1.4 0.6 1.6 5.4 3.2

Min. 1.3 1.2 5.6 1.0 1.9 2.5 13.3 0.7 0.3 1.0 2.3 1.3

Max. 2.7 1.9 175.1 11.1 3.1 7.1 281.9 2.6 0.7 1.9 9.8 5.0

Toluene Ave. 3.4 2.7 80.3 11.5 4.6 6.6 183.0 3.3 1.0 2.7 12.0 5.8

Min. 2.1 2.2 15.9 2.5 3.0 4.1 27.4 1.7 0.7 1.9 5.6 1.7

Max. 4.2 3.3 277.5 22.7 5.5 13.7 425.6 4.4 1.3 3.1 19.4 12.2

Ethylbenzene Ave. 0.6 0.5 10.6 2.4 0.9 1.3 21.0 0.7 0.2 0.7 2.6 1.3

Min. 0.4 0.5 2.6 0.6 0.6 0.9 3.5 0.3 0.1 0.5 1.1 0.3

Max. 0.7 0.7 35.0 5.2 1.1 2.5 50.8 1.3 0.2 0.8 4.5 2.9

Xylene Ave. 2.6 2.3 35.7 9.3 3.8 5.4 71.5 2.7 0.9 2.6 10.1 5.6

Min. 1.7 2.0 10.2 2.5 2.6 3.8 10.2 1.1 0.6 1.8 4.5 1.3

Max. 3.4 2.8 110.2 18.5 4.4 10.3 143.0 5.1 1.0 3.2 16.8 12.2

Formaldehyde Ave. 5.9 4.3 5.2 6.8 6.5 5.8 7.3 5.5 4.1 5.3 8.4 7.3

Min. 3.4 2.9 4.1 4.9 4.4 5.2 4.5 4.9 2.7 4.5 6.0 5.1

Max. 10.9 5.1 7.7 8.1 8.9 6.2 10.2 6.4 6.4 5.8 10.1 10.0

Acetaldehyde Ave. 0.7 0.6 0.8 0.8 0.8 0.7 1.0 0.7 0.5 0.7 1.0 0.8

Min. 0.5 0.4 0.7 0.6 0.6 0.6 0.7 0.6 0.4 0.6 0.7 0.6

Max. 1.2 0.6 1.1 0.9 1.0 0.7 1.3 0.8 0.8 0.7 1.1 1.1

CO canister Ave. 1.7 1.5 1.0 2.9 1.7 2.7 0.6 0.6 0.5 0.8 3.1 2.5

Min. 1.2 0.9 0.7 0.5 1.7 1.8 0.3 0.5 0.4 0.5 1.1 1.8

Max. 2.1 2.6 1.6 7.0 1.8 4.5 0.8 0.6 0.7 1.1 6.2 3.2

MTBE Ave. 2.8 1.3 1325.5 11.2 5.6 8.8 3129 2.9 1.3 2.6 12.2 8.7

Min. 2.1 0.8 79.8 4.8 3.7 5.1 414.3 1.3 1.2 2.1 6.3 1.5

Max. 3.8 1.7 4284.1 18.8 7.9 16.5 5767 5.4 1.4 2.9 23.7 20.1

Temp  ̊C Ave. (23.7) (24.5) (28.2) (28.3) (22.5) (24.5) 33.1 31.1 31.4 31.7 28.1 30.0

(in-cabin) Min. (22.9) (23.5) (26.0) (24.0) (21.3) (23.3) 28.4 28.5 27.9 28.5 21.8 29.5

Max. (25.2) (25.7) 30.9 (33.6) (24.7) (25.6) 35.0 33.4 33.6 36.5 37.1 30.4

RH, % Ave. (54.8) (47.0) (47.6) (47.0) (55.3) (50.2) 53.6 58.3 58.7 58.0 48.8 67.5

(in-cabin) Min. (50.0) (42.0) (41.0) (36.0) (53.0) (47.0) 47.0 41.0 48.0 40.0 41.0 65.0

Max. (62.0) (51.0) (58.0) (57.0) (57.0) (57.0) 70.0 75.0 77.0 69.0 58.0 70.0

Note: Urban canyon for Houston: Louisiana , Clay, Walker, and Smith Streets *For 1,3-BD in Houston, one extreme value for ME3 and two for ME7 were invalidated. 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-10

Table 1.3.1-2. Winter average, maximum, and minimum ME concentrations (ppbv) of BTEX, 1,3-BD, HCHO, CH3CHO, EtOH, 

MTBE, and CO (ppmv) 

Atlanta (Conventional Fuel)

ME ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

Replicates 5 3 5 5 3 6 3 3 3 5 3 5

1,3-BD Ave. 0.6 0.3 0.4 4.1 0.3 1.5 0.2 0.2 0.7 4.0 0.4 1.6

Min. 0.3 0.0 0.1 1.7 0.2 0.2 0.1 0.1 0.3 1.0 0.3 0.9

Max. 0.8 0.4 0.7 7.9 0.5 3.6 0.3 0.3 1.5 6.3 0.5 2.8

Benzene Ave. 2.6 1.4 8.4 26.4 1.4 38.5 0.9 1.0 3.5 21.0 2.4 6.7

Min. 1.9 0.3 1.6 6.1 1.1 10.0 0.7 0.6 1.3 3.2 1.6 3.5

Max. 3.5 2.3 17.6 49.9 1.7 99.4 1.2 1.3 6.4 28.6 3.2 11.1

Toluene Ave. 5.3 4.0 14.5 60.5 3.5 58.8 1.5 1.8 8.7 53.0 3.7 17.7

Min. 3.7 0.8 4.0 14.5 2.2 23.3 1.0 1.2 2.8 7.1 2.2 9.1

Max. 7.3 6.5 26.4 112.7 4.5 125.1 2.5 2.7 15.4 87.4 6.0 33.5

Ethylbenzene Ave. 1.0 0.8 1.7 11.5 0.6 4.8 0.3 0.3 1.5 9.7 0.6 2.8

Min. 0.7 0.1 0.5 2.5 0.5 2.7 0.2 0.2 0.5 1.4 0.4 1.5

Max. 1.5 1.4 2.6 22.1 0.9 7.4 0.4 0.5 2.7 15.0 1.0 5.4

Xylene Ave. 4.4 3.2 6.4 42.6 2.6 17.2 1.1 1.3 5.7 37.2 2.4 11.4

Min. 3.0 0.4 2.2 9.7 2.0 10.2 0.8 0.9 2.0 5.4 1.5 6.0

Max. 6.2 5.7 9.3 79.7 3.7 26.4 1.6 1.8 10.5 58.5 3.8 22.1

Formaldehyde Ave. 6.2 8.6 21.9 19.6 4.6 3.4 2.6 2.0 5.0 11.4 3.4 8.4

Min. 2.6 5.1 4.1 5.6 3.3 2.3 1.4 1.1 3.4 4.0 3.0 5.7

Max. 8.0 12.4 89.1 28.1 6.0 5.0 4.1 3.1 6.2 15.7 3.7 10.4

Acetaldehyde Ave. 2.8 2.9 5.4 8.2 2.0 2.0 1.7 1.5 2.3 6.8 2.5 4.3

Min. 0.9 2.5 1.5 4.2 1.1 1.1 1.5 0.9 1.3 2.8 1.7 3.6

Max. 5.6 3.5 17.4 12.0 3.1 2.6 2.1 1.9 2.9 9.8 3.0 5.2

CO canister Ave. 2.6 1.5 0.8 17.7 1.2 1.2 0.8 0.9 1.9 13.2 2.4 5.7

Min. 2.0 1.3 0.5 4.3 0.9 0.4 0.7 0.6 0.9 2.9 1.5 2.7

Max. 3.2 1.8 1.4 36.1 1.5 2.2 1.0 1.1 3.9 21.9 2.8 9.0

Temp  ̊C Ave. (21.3) (24.6) (17.9) (21.1) (22.8) 10.1 4.8 3.8 10.6 14.5 9.4 (22.2)

(in-cabin) Min. (15.2) (23.1) (15.0) (14.0) (20.6) 5.9 4.1 1.2 5.1 5.5 6.0 (17.9)

Max. (28.4) (25.8) (20.2) (24.6) (24.0) 16.7 5.5 5.7 14.2 19.4 15.3 (26.4)

RH, % Ave. (35.0) (32.3) (40.4) (41.8) (31.0) 54.8 58.0 63.0 52.0 47.4 55.7 (37.2)

(in-cabin) Min. (21.0) (28.0) (28.0) (30.0) (27.0) 41.0 45.0 45.0 38.0 26.0 22.0 (23.0)

Max. (48.0) (36.0) (56.0) (47.0) (34.0) 81.0 71.0 73.0 63.0 65.0 77.0 (50.0)
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-11

Chicago (Oxygenated Fuel - Ethanol)

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

1,3-BD Ave. 0.6 0.4 2.8 4.4 0.2 0.5 0.7 0.3 0.3 0.5 2.4 0.3

Min. 0.2 0.2 0.0 1.6 0.1 0.4 0.2 0.2 0.2 0.1 1.3 0.2

Max. 1.2 0.6 13.2 7.7 0.2 0.9 1.2 0.5 0.3 0.8 3.2 0.4

Benzene Ave. 1.2 1.3 5.2 16.4 0.7 2.3 20.4 1.0 1.0 1.8 12.9 1.2

Min. 0.5 1.0 0.2 5.7 0.7 1.4 1.4 0.9 0.9 0.6 5.6 0.9

Max. 2.2 1.6 12.9 24.2 0.8 4.8 39.1 1.2 1.1 2.9 20.7 1.9

Toluene Ave. 1.8 2.5 4.6 29.0 1.1 3.1 13.8 1.4 1.2 2.9 22.7 1.3

Min. 0.5 2.0 1.2 10.8 1.0 1.8 2.1 1.2 1.1 0.9 12.3 0.9

Max. 3.1 2.9 8.9 39.1 1.3 6.5 26.6 1.8 1.4 4.9 36.4 2.0

Ethylbenzene Ave. 0.5 0.4 0.6 5.5 0.2 0.6 1.4 0.3 0.3 0.6 4.4 0.3

Min. 0.2 0.3 0.0 1.9 0.1 0.4 0.5 0.2 0.2 0.2 2.3 0.2

Max. 0.8 0.5 1.4 7.6 0.2 1.4 3.0 0.4 0.3 1.0 7.4 0.4

Xylene Ave. 1.9 1.5 2.8 22.7 0.8 2.5 6.9 1.1 0.9 2.3 18.3 1.1

Min. 0.9 1.2 0.2 7.5 0.7 1.4 1.9 0.8 0.9 0.7 10.3 0.8

Max. 3.6 1.8 6.0 31.2 0.9 5.2 15.7 1.4 1.0 3.8 29.5 1.8

Formaldehyde Ave. 7.2 4.6 4.3 13.9 2.8 5.3 3.2 2.9 3.5 4.4 9.1 3.0

Min. 2.1 3.2 2.3 7.2 1.8 2.9 1.8 2.5 2.8 3.3 2.9 2.5

Max. 21.5 6.0 7.7 18.2 3.5 7.8 4.3 3.2 4.2 5.9 15.3 3.6

Acetaldehyde Ave. 5.0 3.1 3.6 12.7 2.3 3.8 2.8 2.1 2.5 2.5 7.6 2.2

Min. 1.1 2.4 2.4 5.9 1.4 1.5 2.0 1.6 2.1 1.4 1.6 2.0

Max. 16.8 4.5 7.4 17.7 2.9 6.9 3.8 2.7 3.1 3.8 12.8 2.6

CO canister Ave. 1.5 1.0 0.4 12.0 0.9 2.2 0.7 0.9 0.9 1.7 11.0 1.7

Min. 1.1 0.4 0.4 4.5 0.8 1.7 0.2 0.7 0.8 0.6 3.8 1.3

Max. 2.1 1.4 0.5 18.4 1.0 3.4 1.8 1.1 1.0 2.7 16.8 2.0

EtOH Ave. 6.8 2.1 5.1 1.4 4.3 1.6 2.2 1.8 4.0 3.3 3.7 0.9

Min. 1.6 0.0 2.8 0.1 1.4 0.0 0.0 0.0 0.0 1.3 1.9 0.0

Max. 12.3 3.1 9.8 2.6 7.9 2.7 4.8 3.9 8.0 5.9 6.0 2.3

Temp  ̊C Ave. (21.5) (22.8) (17.3) (21.6) (22.6) (20.9) 1.6 4.9 6.5 6.4 (17.0) 1.9

(in-cabin) Min. (18.1) (21.3) (11.2) (15.9) (21.6) (16.3) -3.3 1.3 2.1 4.1 (13.6) 0.0

Max. (30.6) (24.8) (19.8) (24.7) (23.5) (24.7) 6.6 9.5 12.3 8.7 (22.1) 4.6

RH, % Ave. (19.2) (23.7) (22.0) (37.5) (17.7) (24.8) 44.7 46.3 42.7 37.0 (41.4) 53.0

(in-cabin) Min. (9.0) (21.0) (13.0) (25.0) (13.0) (14.0) 32.0 32.0 27.0 32.0 (29.0) 25.0

Max. (25.0) (25.0) (32.0) (60.0) (21.0) (41.0) 62.0 62.0 60.0 42.0 (61.0) 77.0
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon loop; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: 

Out-of-cabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; 

ME13: In-cabin trailing high-emitter vehicle

1-12

Houston (Oxygenated Fuel - MTBE)

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

1,3-BD Ave. 0.4 1.2 1.8* 3.8 0.5 1.1 1.9* 0.1 0.2 1.7 2.7 0.8

Min. 0.3 0.4 0.4 0.4 0.4 0.1 1.9* 0.1 0.1 0.2 0.4 0.5

Max. 0.6 2.7 3.6 5.7 0.6 2.3 1.9* 0.2 0.2 4.3 4.3 1.3

Benzene Ave. 1.4 3.7 17.7 10.6 1.7 2.7 55.0 0.5 0.6 5.0 7.8 2.5

Min. 1.1 1.4 2.3 1.6 1.4 0.7 7.7 0.5 0.4 1.5 1.4 1.8

Max. 2.0 8.2 56.6 14.5 2.1 4.2 97.7 0.7 0.8 11.9 13.7 3.8

Toluene Ave. 3.0 6.5 25.6 21.8 3.6 4.6 64.3 0.8 1.1 10.5 17.3 4.2

Min. 2.3 2.9 4.2 4.2 3.2 1.6 10.9 0.7 0.8 3.5 3.1 2.7

Max. 5.2 13.4 69.7 30.9 3.8 6.7 106.0 1.0 1.4 21.7 31.4 6.3

Ethylbenzene Ave. 0.7 1.4 2.4 4.3 0.8 0.9 4.5 0.2 0.3 1.9 3.3 0.8

Min. 0.5 0.7 0.7 1.1 0.7 0.4 1.8 0.2 0.2 0.7 0.7 0.5

Max. 1.1 2.6 4.4 5.9 0.8 1.4 8.0 0.2 0.3 4.3 5.8 1.2

Xylene Ave. 3.4 6.3 10.9 17.6 3.5 4.4 18.7 0.8 1.1 8.1 13.9 3.6

Min. 2.5 3.3 3.6 5.5 3.5 1.5 4.4 0.7 0.7 3.4 3.7 2.1

Max. 5.9 11.5 18.4 24.7 3.6 6.9 35.2 1.0 1.4 17.5 25.0 6.3

Formaldehyde Ave. 4.5 8.2 7.1 10.5 3.8 7.6 5.7 2.1 2.5 4.0 5.7 5.0

Min. 3.0 4.7 4.6 7.9 2.7 5.4 3.5 1.9 2.0 1.2 2.9 4.0

Max. 5.1 12.6 8.4 12.1 4.5 8.8 10.6 2.3 3.1 7.6 8.6 6.1

Acetaldehyde Ave. 1.9 4.3 6.5 5.3 1.9 4.4 5.3 1.7 1.7 4.5 3.4 2.0

Min. 1.2 2.5 3.5 4.7 1.5 2.6 3.2 1.4 1.2 3.4 1.0 1.8

Max. 2.4 7.0 9.2 5.9 2.2 6.1 10.0 1.9 1.9 5.7 4.9 2.4

CO canister Ave. 1.4 3.7 1.2 7.8 1.8 2.9 1.0 0.4 0.5 3.4 6.0 2.7

Min. 0.9 1.4 0.5 1.1 1.6 0.8 0.3 0.3 0.4 0.7 1.1 1.7

Max. 1.6 6.9 2.7 12.5 2.1 5.5 2.6 0.5 0.7 8.4 9.8 4.5

MTBE Ave. 3.9 10.2 890.6 25.4 4.2 7.3 2568.9 0.5 0.7 15.1 26.0 6.7

Min. 1.4 2.6 23.3 1.8 3.2 3.3 347.8 0.5 0.6 6.5 2.7 2.6

Max. 8.1 25.3 3135.3 68.1 4.8 10.4 5629.9 0.6 0.8 20.9 63.6 13.2

Temp  ̊C Ave. (22.3) (22.9) (21.6) (22.6) (21.0) (22.4) 15.7 9.8 11.4 17.1 15.5 14.9

(in-cabin) Min. (18.0) (20.4) (19.3) (19.9) (19.1) (19.9) 10.9 7.2 7.9 13.4 10.3 7.9

Max. (26.5) (24.3) (23.4) (25.2) (22.2) (24.8) 20.9 12.2 14.7 21.0 18.6 20.2

RH, % Ave. (41.2) (36.7) (52.0) (54.2) (49.3) (46.0) 67.0 61.0 55.3 63.0 69.6 77.7

(in-cabin) Min. (29.0) (33.0) (37.0) (36.0) (43.0) (34.0) 55.0 53.0 46.0 48.0 43.0 70.0

Max. (58.0) (42.0) (61.0) (69.0) (56.0) (54.0) 77.0 71.0 67.0 76.0 87.0 83.0

*Note: For 1,3-BD in Houston, one extreme value for ME3 and four for ME7 were invalidated
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-13

 

 Microenvironment ppbv

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

5

10

15

20

25

30

35

40

45

50

55

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppbv

Atlanta, Summer 2002-2003

Benzene

ME1 ME2 ME3 ME

4

ME

5

ME

7

ME

8

ME9 ME10 ME11 ME12 ME13

0

8

16

24

32

40

48

56

64

72

80

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironments

ppbv

Atlanta, Summer 2002-2003

1,3 - Butadiene

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

0.8

1.6

2.4

3.2

4

4.8

5.6

6.4

7.2

8

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

2

4

6

8

10

12

14

16

18

20

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-14

Atlanta Summer 2002-2003

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

2

4

6

8

10

12

14

16

18

20

22

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Figure 1.3.1-1. Time-integrated exposure levels in different MEs in Atlanta, Summer 2002 and 2003 

Microenvironment

ppbv

Atlanta, Winter 2004

Benzene

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

10

20

30

40

50

60

70

80

90

100

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 Microenvironment ppbv

Atlanta, Winter 2004

1,3-Butadiane

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

0.8

1.6

2.4

3.2

4

4.8

5.6

6.4

7.2

8

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-15

Microenvironment

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

4

8

12

16

20

24

28

32

36

40

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 Microenvironment ppb

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

3

6

9

12

15

18

21

24

27

30

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Atlanta Winter 2004

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME7 ME8 ME9 ME10 ME11 ME12 ME13

0

2

4

6

8

10

12

14

16

18

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-16

Figure 1.3.1-2. Time-integrated exposure levels in different MEs in Atlanta, Winter 2004 

 

 Microenvironments ppbv

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

3

6

9

12

15

18

21

24

27

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironments

ppbv

Chicago, Summer 2003

Benzene

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1.5

3

4.5

6

7.5

9

10.5

12

13.5

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironments

ppbv

Chicago, Summer 2003

1, 3-

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5 Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironments

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

0.8

1.6

2.4

3.2

4

4.8

5.6

6.4

7.2

8

8.8

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-17

Figure 1.3.1-3. Time-integrated exposure levels in different MEs in Chicago, Summer 2003 

 

Chicago Summer 2003

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

2

4

6

8

10

12

14

16

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppbv

Chicago, Winter 2004

Benzene

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

4

8

12

16

20

24

28

32

36

40

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironments

ppbv

Chicago, Winter 2004

1,3-Butadiene

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

0.8

1.6

2.4

3.2

4

4.8

5.6

6.4

7.2

8

Maximum

Minimum

75

%25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-18

 Microenvironment ppbv

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

2

4

6

8

10

12

14

16

18

20

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Chicago Winter 2004

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

2

4

6

8

10

12

14

16

18

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Figure 1.3.1-4. Time-integrated exposure levels in different MEs in Chicago, Winter 2004 

Microenvironment

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

2

4

6

8

10

12

14

16

18

20

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-19

 Microenvironments ppbv

Houston, Summer 2004

1,3-Butadiane

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1

2

3

4

5

6

7

8

9

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 Microenvironment ppbv

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1.5

3

4.5

6

7.5

9

10.5

12 Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppbv

Houston, Summer 2004

Benzene

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

30

60

90

120

150

180

210

240

270

300

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-20

Houston Summer, 2004

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1

2

3

4

5

6

7

8

9

10

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Figure 1.3.1-5. Time-integrated exposure levels in different MEs in Houston, Summer 2004 

 Microenvironments ppbv

Houston, Winter 2005

1,3-Butadiane

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

0.6

1.2

1.8

2.4

3

3.6

4.2

4.8

5.4

6

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Microenvironment

ppbv

Houston, Winter 2005

Benzene

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

10

20

30

40

50

60

70

80

90

100

Maximum

Minimum

75%

25%

Median

Outliers

Extremes
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-21

Microenvironment

ppm

CO

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1.5

3

4.5

6

7.5

9

10.5

12

13.5

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 Microenvironment ppbv

Formaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1.5

3

4.5

6

7.5

9

10.5

12

13.5

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Houston Winter 2005

Acetaldehyde

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1

2

3

4

5

6

7

8

9

10

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

Figure 1.3.1-6. Time-integrated exposure levels in different MEs in Houston, Winter 2005 
1-22

1.3.2 Distribution of exposures within MEs in each city (1-minute time series)

The study protocol (Appendix A) specifies a sampling period of 20 (ME3/ME7) to 40 

minutes beginning at the top of the hour to correlate with the local air quality monitoring 

network sampling periods. Because large variations are expected within these time frames in 

exposures for most MEs, the protocol includes continuous measurements of target species with 

time resolutions of about a minute. The supplemental Kore MS200 MS (deployed for BTEX) 

and Alpha Omega HCHO analyzer used to measure these species at 1-minute resolutions directly 

had not been earlier proven under such field conditions and only worked well intermittently. 

Furthermore, there were no acceptable continuous methods for 1,3-BD, MTBE, EtOH, 

CH3CHO, or non-methane VOCs (NMVOC) that could be used in portable modes of operation 

with the necessary sensitivity. Accordingly, our sampling strategy consisted of a three-tiered

approach classified as reference, surrogate, and confirmatory measurements. The base set or 

reference (R) measurements consist of three well-established time-integrated methods (canisters, 

DNPH, and solid adsorbent cartridges) as described in Section 1.2.2. These three methods 

together measure all species of interest over the 20-40 minute sampling periods within each ME 

and had excellent data capture rates. Although the integrated methods do not characterize shortterm peak exposures in MEs with highly varying exposure levels, they provide a basis for 

quantifying and deriving correlations between the integrated values and continuous surrogate (S)

measures, such as the CO and PID NMVOC monitors, in order to reconstruct short-term time 

series. For example, data for BTEX, and 1, 3-BD from the canister measurements can be used to 

normalize continuous CO and NMVOC traces taken over the same periods to construct 

component time series in exhaust-dominated environments. In a similar manner, the time series 

of HCHO values can be reconstructed from the correlation of the integrated DNPH samples with

continuous CO measures. 

Tables 1.3.2-1A and 1.3.2-1B list correlation coefficients (R2

), slopes, P-values and 

performance statistic for correlations of benzene, 1,3-BD, HCHO, and CO measured from 

canisters with NMVOC PID and continuous CO, measured by NDIR, for all ME with exception 

of ME3 and ME7, and for ME3 and ME7 only, respectively. It can be seen from Table 1.3.2-1A 

that 1,3-BD correlates with CO somewhat better than with NMVOC so continuous CO values 

were used for reconstructing 1-minute time series for 1,3-BD for all MEs with exception of 

refueling experiments (ME3 and ME7). However, for refueling MEs (Table1.3.2-1B), the 

correlations are worse, although the correlations of benzene with NMVOC are still statistically 

significant for all three cities. The correlations of 1,3-BD with NMVOC PID and CO_NDIR are 

not statistically significant, since neither 1,3-BD, nor CO is abundant in evaporative emissions. 

Thus, the calculation of 1-min time series for 1,3-BD in ME3 and ME7 is not valid for 

evaporative gasoline exposure. However, these species are often measured at some gas stations, 

since they originate from exhaust emissions of higher-emitting vehicles. In addition, HCHO does 

not correlate very well with CO probably due to the photochemical production of this compound 

in outdoor MEs. 

The reconstructed 1-minute peak exposures were calculated based on the method used in 

the Atlanta Summer 2002 and Atlanta and Chicago Summer 2003 (Zielinska et al, 2003b, 2004b) 

reports. The NMVOC PID time series was used to reconstruct benzene values (the remaining 

TEX species follow the benzene time series) and the CO time series was used to reconstruct 

HCHO and 1,3-BD values. No CO and NMVOC data were used where the average CO or 
1-23

NMVOC was below the approximate detection limit of the instruments (0.5 ppmv and 25 ppbv, 

respectively). In each case the approach was the same. The mean value of the compound to be 

reconstructed was multiplied by the ratio of the surrogate mean to the instantaneous reading. For 

example, to produce the 1st minute value for benzene, the mean benzene canister value was 

multiplied by the 1st minute NMVOC reading divided by the mean NMVOC reading. For HCHO

and 1,3-BD, the NDIR CO value was used for all cases where it was available and valid. 

A summary of the reconstructed data is presented in Tables 1.3.2-2 and 1.3.2-3 for 

benzene, 1,3-BD and HCHO (the complete data set is submitted in electronic form) for summer 

and winter, respectively. The average maximum and minimum values for each ME in each city 

and season are shown. The reconstructed time series are graphically presented in Figure 1.3.2-1 

through 1.3.2-3 for selected MEs to illustrate the variability of exposure. 

For in-cabin exposures in Figure 1.3.2-1 and upper part of Figure 1.3.2-2, the first 20 

minutes of measurement was carried out under high ventilation conditions (i.e. window open, air 

recirculation off), whereas for the remaining 20 minutes at low ventilation (i.e. window closed, 

air conditioning or heating on, air recirculation on). As can be seen, the second 20 minutes of 

measurement are less variable. In addition, the concentration of benzene is rising steadily for this 

latter sampling period, reflecting the rising NMVOC signal, probably due to accumulation of 

outgasing emissions from vehicle cabin material and the breath of people present in the vehicle 

cabin. 

For refueling experiments (in-cabin ME3 and active out-of-cabin refueling ME7) the 

highest exposures occurred during the active refueling performed during the second 10 minutes

of the sampling period. The highest concentrations are observed for BTEX species as expected 

from evaporative and spillage emissions during active refueling. HCHO and 1,3-BD present in 

exhaust emissions are lower and usually not correlated with benzene, as can be seen for ME3 in 

Fig. 1.3.2-2. 

As shown in Figure 1.3.2-3, outdoor exposures (ME8, ME9 and ME12) are usually low 

and less variable. HCHO seems higher than benzene and 1,3-BD as is also evident from Figures 

1.3.1-1 to 1.3.1-6 and Tables 1.3.1-1 and -2. On the other hand, outdoor surface parking (ME10) 

and out-of-cabin underground garage (ME11) MEs show much higher variability corresponding 

to vehicles exiting the parking lots after the game (ME10) or at the end of a work day (ME11). 

We collected 5-minute canister samples at peak of exposures for ME7, ME11, and ME6 

in Houston and Chicago and ME13 in Atlanta. Table 1.3.2-4 shows the average concentrations of 

BTEX, 1,3-BD and MTBE for these selected samples (full data set provided in electronic form). 

Figures 1.3.2-4 show the correlations for benzene and 1,3-BD, respectively, quantified from 

these 5-minute canisters and averaged over corresponding 5-minute surrogate 1-minute 

measurements. ME7 values for Houston were removed from these correlations since high MTBE 

levels distort NMVOC PID signal correlation to benzene. An obvious outlier from Atlanta (ME7, 

summer) was also removed. As seen from these figures, correlations are reasonable, especially 

for benzene (R2 = 0.87). 
1-24

Table 1.3.2-1A. Correlation coefficients (R2) and associated statistic for relationships of time-integrated measurements with 

continuous methods (NMVOC and CO) for 3 cities, without ME3 and ME7 

PID CO_NDIR

r2 Slope Intercept df FstatFcrit P-value r2 Slope Intercept df FstatFcrit P-value

Atlanta

Benzene 0.88 7.36 2.38 88 675 3.9 0.00% 

1,3-BD 0.55 31.05 20.29 88 107 3.9 0.00% 0.68 2.43 1.25 41 88 4.1 0.00%

Formaldehyde 0.39 0.35 1.79 41 27 4.1 0.00%

CO_can 0.93 0.90 -0.01 41 514 4.1 0.00%

Chicago

Benzene 0.82 7.86 -0.85 87 406 4.0 0.00%

1,3-BD 0.61 25.55 6.33 87 136 4.0 0.00% 0.70 2.35 0.82 46 106 4.052 0.00%

Formaldehyde 0.20 0.38 0.65 46 11 4.052 0.15%

CO_can 0.94 0.95 -0.07 46 687 4.052 0.00%

Houston

Benzene 0.70 9.02 26.16 71 162 4.0 0.00%

1,3-BD 0.70 24.86 28.75 71 169 4.0 0.00% 0.81 2.00 0.11 43 181 4.1 0.00%

Formaldehyde 0.29 0.70 -1.37 43 18 4.1 0.01%

CO_can 0.88 1.08 -0.38 43 309 4.1 0.00%

Notes: F-stat = performance statistic for regression slope of 2-tailed paired data: Critical F-value for 95% confidence is shown.

P-value = probability that correlation is not significant

df = degrees of freedom (number of data pairs - 2) 
1-25

Table 1.3.2-1B. Correlation coefficients (R2) and associated statistic for relationships of time-integrated measurements with 

continuous methods (NMVOC and CO) for ME3 and ME7 in 3 cities 

PID CO_NDIR

r2 Slope Intercept df FstatFcrit P-value r2 Slope Intercept df FstatFcrit P-value

Atlanta

Benzene 0.57 12.15 1274.84 53 70 4.0 0.00% 

1,3-BD 0.34 159.97 729.81 47 5 4.0 2.47% 0.06 -0.03 0.55 12 1 4.7 41.71%

Formaldehyde 0.01 0.02 1.09 2 1 18.5 38.31%

CO_can 0.41 0.58 0.59 2 2 18.5 28.05% 

Chicago

Benzene 0.96 15.76 -4.47 25 590 4.2 0.00%

1,3-BD 0.04 43.11 238.60 25 1 4.2 30.37% insufficient data available

Formaldehyde insufficient data available

CO_can insufficient data available

Houston

Benzene 0.52 10.94 2896.65 27 30 4.2 0.00%

1,3-BD 0.22 116.19 1878.18 19 5 4.4 3.36% 0.01 0.01 0.92 5 1 6.6 34.28%

Formaldehyde 0.42 -0.22 2.72 3 2 10.1 22.15%

CO_can 0.75 0.78 -0.08 3 11 10.1 4.49%

Notes: F-stat = performance statistic for regression slope of 2-tailed paired data: Critical F-value for 95% confidence is shown.

P-value = probability that correlation is not significant

df = degrees of freedom (number of data pairs - 2) 
1-26

Table 1.3.2-2. Summary of the reconstructed 1-minute data (ppbv), Summer 

City ME Benzene 1,3-BD HCHO

min max min max min max

A 01 0.00 47.38 0.00 16.59 0.00 34.25

A 02

A 03 0.00 103.60 0.00 0.67 0.00 29.42

A 04 0.00 49.48 0.00 8.20 0.00 92.53

A 05

A 07 0.00 976.35

A 08

A 09

A 10 0.95 18.57 0.00 8.55 0.00 75.30

A 11 7.68 51.30 0.90 9.19 12.82 70.80

A 12 1.62 11.57 0.31 3.40 3.79 29.95

A 13 0.00 253.74 0.00 19.14 0.00 141.72

C 01 0.00 31.98 0.01 0.85 0.00 13.56

C 02 0.00 11.42 0.01 1.75 0.11 13.09

C 03 0.00 30.18

C 04 0.50 15.39 0.74 4.61 3.64 35.66

C 05 0.80 0.00 17.55

C 06 0.10 65.31 0.20 11.65 1.13 64.03

C 07 0.00 111.01

C 08 0.29 0.40 3.81 7.65

C 09 0.15 0.45 3.66 7.85

C 10 0.01 2.14 0.04 14.25

C 11 0.20 20.73 0.09 4.11 0.00 25.99

C 12 0.31 0.77 6.15 11.60

H 01 0.95 6.89 0.06 9.25 0.50 47.92

H 02 0.82 2.02 0.03 7.95 0.27 78.24

H 03 0.00 1346.97 0.23 3.66 1.67 26.55

H 04 2.09 13.44 0.48 6.00 1.86 23.44

H 05 1.19 4.04 0.14 2.80 0.63 26.49

H 06 1.31 16.95 0.12 6.23 0.89 25.61

H 07 0.00 1948.10 2.85 45.79

H 08 0.27 2.80 0.00 0.68 0.00 17.17

H 09 0.18 0.87 0.04 0.43 1.20 17.69

H 10 0.90 5.71 0.11 3.93 1.47 50.49

H 11 1.88 15.71 0.14 6.08 1.13 53.69

H 12 0.85 17.54 0.08 2.74 0.95 13.09
1-27

Table 1.3.2-3. Summary of the reconstructed 1-min data (ppbv), Winter 

City ME Benzene 13-BD Formaldehyde

min max min max min max

A 01 0.02 1.28 0.25 15.70

A 02 1.60 3.87 0.07 1.34 0.82 15.71

A 03 0.59 107.31

A 04 2.71 67.30 0.07 13.32 0.22 43.93

A 05 0.02 1.98 0.24 17.49

A 07 0.00 1080.63 3.44 19.02

A 08 0.74 2.17 0.23 0.41 3.15 5.69

A 09 1.06 1.81 0.27 0.53 2.48 4.79

A 10 3.11 13.55 0.08 3.07 1.35 41.48

A 11 1.66 49.76 0.05 17.32 0.21 50.86

A 12 0.81 6.53 0.17 1.33 1.11 11.75

A 13 0.53 33.96 0.05 6.36 0.20 42.78

C 01 0.17 1.20 0.07 7.40 0.26 64.35

C 02

C 03 0.00 98.94

C 04 3.72 31.25 0.97 8.97 4.45 25.70

C 05 0.04 0.72 0.65 11.37

C 06 0.13 8.53 0.06 1.63 0.45 14.92

C 07 0.00 511.90 0.58 4.57 0.86 6.75

C 08 0.10 1.71 0.94 10.07

C 09 0.00 0.53 0.00 8.02

C 10 0.07 2.54 0.47 18.27

C 11 3.01 33.48 0.11 5.63 0.45 26.76

C 12 0.00 0.65 0.00 8.87

H 01 0.60 6.34 0.06 3.13 0.58 23.47

H 02 0.82 13.93

H 03 0.47 335.71 0.11 1.86 0.74 12.11

H 04 1.22 17.85 0.11 6.57 2.40 33.89

H 05 0.67 3.25 0.07 1.68 0.69 16.77

H 06 0.46 7.77 0.01 4.72 0.15 23.07

H 07 0.15 1203.84 0.25 20.29

H 08 0.35 0.62

H 09 0.28 1.06

H 10 1.16 32.64 0.08 12.89 0.13 22.73

H 11 3.71 18.66 1.23 12.10 2.41 16.98

H 12 1.43 3.76
1-28

Table 1.3.2-4. Summary of the 5-minute canister data (ppbv) 

City Atlanta, Summer Atlanta, Winter

ME 7 11 13 7 11 13

Replicates 5 5 4 6 5 5

1,3-BD Ave. 1.53 5.39 1.20 6.48 7.23 1.79

Min. 0.04 3.97 0.79 0.78 0.51 0.48

Max. 4.09 7.50 1.90 15.47 10.13 2.72

Benzene Ave. 163.98 33.26 6.30 89.52 27.95 8.11

Min. 3.06 24.80 4.36 13.52 1.51 1.90

Max. 475.82 45.07 10.34 256.31 42.40 16.02

Toluene Ave. 253.17 94.52 15.30 139.88 70.84 29.44

Min. 8.90 68.88 10.97 48.39 3.94 4.62

Max. 649.81 126.79 20.41 360.24 113.45 67.34

Ethylbenzene Ave. 23.15 16.06 2.42 8.82 11.89 3.91

Min. 1.45 11.89 1.89 3.86 0.64 0.69

Max. 57.14 22.88 2.93 20.24 19.79 8.50

Xylene Ave. 79.33 62.04 9.60 29.86 48.27 17.52

Min. 6.21 44.84 7.39 15.90 2.69 3.01

Max. 202.27 87.73 12.72 64.24 77.88 38.85

City Chicago, Summer Chicago, Winter

ME 6 7 11 6 7 11

Replicates 5 5 5 5 4 4

1,3-BD Ave. 1.51 0.21 2.33 0.73 2.19 4.00

Min. 0.94 0.03 0.80 0.51 1.44 1.79

Max. 2.66 0.39 3.01 1.45 2.74 5.75

Benzene Ave. 8.87 13.56 7.75 2.22 84.25 12.00

Min. 4.11 0.56 2.50 1.59 24.98 6.15

Max. 24.00 37.23 10.00 3.94 160.53 17.32

Toluene Ave. 25.53 22.74 19.40 3.56 56.51 23.92

Min. 5.87 0.57 5.57 2.14 32.96 12.82

Max. 78.10 61.34 25.73 6.48 100.48 36.75

Ethylbenzene Ave. 2.69 2.77 3.31 0.59 6.11 4.03

Min. 1.23 0.11 1.17 0.36 2.12 2.01

Max. 6.80 6.78 4.63 1.04 11.90 6.00

Xylene Ave. 9.43 11.19 12.74 2.89 25.92 18.75

Min. 4.83 0.38 4.35 1.67 9.31 9.43

Max. 23.42 26.91 18.57 5.33 51.91 27.41
1-29

City Houston, Summer Houston, Winter

ME 6 7 11 6 7 11

Replicates 4 5 5 5 5 5

1,3-BD Ave. 4.55 4.04 4.22 1.79 76.11 3.18

Min. 1.24 1.36 0.55 0.81 13.03 0.39

Max. 10.07 6.72 12.85 3.18 174.21 5.15

Benzene Ave. 12.51 918.86 11.05 4.32 379.48 9.47

Min. 4.17 181.85 1.99 2.53 49.61 1.91

Max. 27.86 2429.61 26.71 7.91 607.22 16.60

Toluene Ave. 21.28 815.73 27.31 7.30 420.64 19.84

Min. 6.59 360.54 4.79 4.98 64.85 2.98

Max. 50.32 1142.43 62.52 13.52 835.98 38.04

Ethylbenzene Ave. 4.25 94.58 5.34 1.32 23.92 3.85

Min. 1.47 44.53 1.12 0.85 4.22 0.50

Max. 10.08 135.65 13.00 2.70 51.83 7.59

Xylene Ave. 5.31 368.47 6.40 5.78 100.90 16.07

Min. 6.74 132.36 4.38 4.13 16.87 2.14

Max. 11.78 553.69 15.03 10.98 205.55 32.78

MTBE Ave. 36.50 26977.95 30.06 15.28 9705.27 32.96

Min. 13.65 3319.53 5.71 5.47 2019.60 14.29

Max. 67.35 61643.39 48.23 39.34 15484.50 65.53
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-30

ME1, Houston Summer 2004

0

2

4

6

8

10

12

14

070807100712071407160718072007220724072607280730073207340736073807400742074407460748

ppbv

benz_pid bud13_co form_co

 

ME2, Atlanta Winter 2004

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

07450746074707480749075007510752075307540755075607570758075908000801080208030804080508060807080808090810081108120813081408150816081708180819082008210822082308240825

Benzene, 1,3-BD, ppbv

0

2

4

6

8

10

12

14

16

18

Formaldehyde, ppbv

benz_pid 13-BD_co Form_co

ME4, Atlanta Summer 2003

0

5

10

15

20

25

30

1720 1723 1726 1729 1732 1735 1738 1741 1744 1747 1750 1753 1756 1759

ppbv

benz_pid 13-BD_co Form_co

 

ME5, Houston Summer 2004

0

2

4

6

8

10

070507070709071107130715071707190721072307250727072907310733073507370739074107430745

ppbv

benz_pid bud13_co form_co

Figure 1.3.2-1. 1-Minute time series for in-cabin exposures: ME1 (congested freeway), ME2 (urban canyon); ME4 (underground 

garage) and ME5 (toll plaza)
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-31

ME6, Houston Summer 2004

0

2

4

6

8

10

12

14

16

18

074707490751075307550757075908010803080508070809081108130815081708190821082308250827

ppbv

benz_pid bud13_co form_co

ME13, Atlanta Winter 2004

0

5

10

15

20

25

30

35

113111331135113711391141114311451147114911511153115511571159120112031205120712091211

ppbv

benz_pid 13-BD_co Form_co

ME3, Chicago, Winter 2004

0

20

40

60

80

100

120

1330 1332 1334 1336 1338 1340 1342 1344 1346 1348 1350

ppb

benz_pid 13BD_co Form_co

 

Figure 1.3.2-2. 1-Minute time series for in-cabin exposures: ME6 (tunnel); ME13 (following high-emitting vehicle); ME3 (in-cabin 

refueling) and out-of-cabin refueling, ME7

ME7, Houston Summer 2004

0

500

1000

1500

2000

2500

124812491250125112521253125412551256125712581259130013011302130313041305130613071308

 ppbv

bud13_co form_co benz_pid
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-32

ME8, Atlanta Winter 2004

0

1

2

3

4

5

6

11551157115912011203120512071209121112131215121712191221122312251227122912311233

ppbv

benz_pid 13-BD_co Form_co

ME10, Chicago, Summer 2003

0

5

10

15

20

25

2100210121022103210421052106210721082109211021112112211321142115211621172118211921202121212221232124212521262127212821292130213121322133213421352136213721382139214021412142214321442145214621472148214921502151215221532154215521562157215821592200

Benzene, 1,3-BD,ppb

0

5

10

15

20

25

30

35

40

45

 Formaldehyde, ppb

benz_pid bud13_co form_co

Me11, Houston Summer 2004

0

5

10

15

20

25

162016221624162616281630163216341636163816401642164416461648165016521654165616581700

ppbv

benz_pid bud13_co form_co

ME12, Chicago Winter 2004

0

1

2

3

4

5

6

7

161616181620162216241626162816301632163416361638164016421644164616481650165216541656

ppbv

benz_pid 13BD_co Form_co

Figure 1.3.2-3. 1-Minute time series for out-of cabin outdoor exposures:ME8 (sidewalk); ME10 (surface parking); ME11 

(underground garage) and ME12 (toll plaza) 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-33

Figure 1.3.2-4. Correlations between 5-minute canister samples and surrogate 1-minute values, averaged over corresponding 5 

minutes. 

Benzene - No ME7 in Houston

y = 1.0955x - 2.7164

R2

 = 0.8747

0

50

100

150

200

250

300

350

400

450

500

0 50 100 150 200 250 300 350

5-Min Ave Surrogates

5-Min Can

1,3-Butadiane - No ME7 in Houston

y = 1.1847x + 0.5092

R2

 = 0.5695

0

2

4

6

8

10

12

14

0 2 4 6 8 10

5-min Ave Surrogates

5-min Can
1-34

1.3.3 Oxygenated and conventional gasoline (difference between cities)

The MTBE and EtOH concentration variability by ME in Houston and Chicago is shown 

in Figure 1.3.3-1. The complete data are provided in electronic form. Although MTBE is 

measured in all Houston MEs, the concentrations recorded during refueling are relatively high, in 

the range of a few ppmv. In contrast, Chicago ethanol concentrations are lower, especially during 

winter time. We generally use the same gas station in each city (absent problems with the gas 

station manager) and we select a station with high traffic close to a major freeway. For example, 

the gas station in Houston was situated next to Tollway 8 and was always very busy. 

 The high concentrations of MTBE during refueling in Houston caused occasional 

problems with 1,3-BD quantification in canister samples as discussed at Section 1.3.1. In 

addition, MTBE PID response changed the slope of canister benzene and NMVOC PID 

regressions in Houston MEs from those observed in Chicago and Atlanta, as shown in Table 

1.3.2-1. However, when ME3 and ME7 data are removed from correlations, the slopes are more 

consistent among the three cities.

 Figures 1.3.3-2 and -3 show comparisons of average benzene, 1,3-BD, HCHO, and CO 

concentrations by ME in the three cities by season. Tables 1.3.1-1 and 1.3.1-2 provide the data 

for all species measured with the time-integrated methods. For refueling MEs, the highest 

benzene concentrations are observed in Houston, in both seasons. However, for underground 

garage MEs, Atlanta shows the highest concentrations of benzene, HCHO, and CO. It is however 

not clear whether these findings result from the different fuels, choice of specific ME locations, 

or the greater variability of high-end ME exposures in general. 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-35

ppbv

Houston, Summer 2004

MTBE

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

600

1200

1800

2400

3000

3600

4200

4800

5400

6000

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 

ppbv

Houston, Winter 2005

MTBE

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

600

1200

1800

2400

3000

3600

4200

4800

5400

6000

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

ppbv

Chicago, Summer 2003

Ethanol

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

15

30

45

60

75

90

105

120

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 

ppbv

Chicago, Winter 2004

Ethanol

ME1 ME2 ME3 ME4 ME5 ME6 ME7 ME8 ME9 ME10 ME11 ME12

0

1.5

3

4.5

6

7.5

9

10.5

12

13.5

Maximum

Minimum

75%

25%

Median

Outliers

Extremes

 Figure 1.3.3-1. MTBE and EtOH concentrations in Houston and Chicago, respectively..Note different y-axis scales for Chicago Sumer 

and Winter 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-36

Benzene

0

20

40

60

80

100

120

140

1 2 3 4 5 6 7 8 9 10 11 12 13

ppbv

Houston Atlanta Chicago

 

1,3-Butadiene

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10 11 12 13

ppbv

Houston Atlanta Chicago

Formaldehyde

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13

ppbv

Houston Atlanta Chicago

CO

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13

ppm

Houston Atlanta Chicago

Figure 1.3.3-2. Comparison of benzene, 1,3-BD, HCHO, and CO average concentrations in three cities in Summer
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-37

Benzene

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Atlanta Chicago Houston

1,3-Butadiene

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Atlanta Chicago Houston

Formaldehyde

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Atlanta Chicago Houston

CO

0

5

10

15

20

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppm

Atlanta Chicago Houston

Figure 1.3.3-3. Comparison of benzene, 1,3-BD, HCHO, and CO average concentrations in three cities in Winter 
1-38

1.3.4 Effect of meteorology on exposure 

As shown in Figures 1.3.3-1 through 1.3.3-6 the highest day-to-day variations in in-cabin 

or out-of-cabin exposures occur during refueling, in ME3 and ME7. ME4 and ME11 relate to 

exposures in an underground garage so these MEs are not subject to different meteorological 

conditions. However, wind speed and direction play an important role in refueling MEs. As a 

general rule, we performed refueling experiments under calm conditions (wind speeds ≤ 4 mph). 

Also, it was usually possible to find a pump location that was relatively sheltered from the direct 

influences of the wind. Subjects generally stood downwind during refueling tests. As a result, 

correlations of wind speed and concentrations in the refueling MEs were weak. For example, 

summer ME7 BTEX levels were highest in Chicago with a steady wind speed of 2-3 mph and

lowest at variable wind speeds of 1-3 mph. 

Table 1.3.4-1 lists average outdoor ambient temperatures and relative humidity by ME, 

city, and season. The detailed data recorded during each test are provided in electronic form.

Table 1.3.4-1. Average, minimum, and maximum ambient temperatures and RH

City Season ME Replicate Temperature ( oC) RH (%)

ave min max ave min max

A S 1 5 27.6 27 29 58.4 56 60

A S 2 3 24.3 22 27 42.6 33 63

A S 3 5 32.0 26 37 61.8 44 74

A S 4 5 32.2 31 33 52.2 46 61

A S 5 3 24.2 22 26 49.9 36 72

A S 7 5 29.5 22 34 63.0 57 86

A S 8 3 33.7 29 39 41.0 29 65

A S 9 3 33.7 29 39 41.0 29 65

A S 10 3 31.9 22 41 42.6 20 69

A S 11 5 33.2 32 35 47.8 42 51

A S 12 3 27.1 24 32 58.8 42 77

A S 13 5 41.2 37 46 49.4 47 54

C S 1 5 27.0 26 28 52.2 46 55

C S 2 3 25.0 24 26 45.7 42 49

C S 3 6 30.5 24 35 51.8 45 63

C S 4 5 26.4 23 28 60.8 56 66

C S 5 3 29.7 26 33 56.7 54 61

C S 6 5 30.0 29 31 53.4 50 57

C S 7 5 28.6 24 31 59.0 50 68

C S 8 3 25.0 23 27 55.0 54 56

C S 9 3 26.3 25 28 53.3 51 55

C S 10 3 21.0 20 23 70.3 67 73

C S 11 5 28.4 22 33 56.6 46 67

C S 12 3 31.7 30 34 43.0 31 57

H S 1 5 33.8 30 37 55.6 51 63
1-39

City Season ME Replicate Temperature ( oC) RH (%)

ave min max ave min max

H S 3 5 36.8 30 41 48.6 42 59

H S 4 5 31.0 30 33 43.0 37 53

H S 5 3 29.3 29 30 56.0 54 58

H S 6 5 37.8 32 42 51.0 48 57

H S 7 5 36.6 29 40 54.0 48 70

H S 8 3 31.0 28 33 59.3 42 76

H S 9 3 31.7 28 34 59.3 49 78

H S 10 3 36.0 27 53 58.0 40 69

H S 11 5 31.8 27 35 49.6 41 59

H S 12 3 30.0 30 30 68.0 66 70

A W 1 5 12.2 4 27 35.4 21 49

A W 2 3 10.0 7 13 33.0 29 37

A W 3 5 11.8 7 18 40.8 29 56

A W 4 5 15.2 9 19 42.0 30 47

A W 5 3 13.3 7 17 31.0 27 34

A W 7 6 10.7 7 17 55.8 42 82

A W 8 3 3.7 1 6 64.3 45 76

A W 9 3 3.7 1 6 63.3 45 73

A W 10 3 10.3 7 15 52.7 38 64

A W 11 5 15.4 8 21 47.8 27 64

A W 12 3 9.3 6 15 55.7 22 77

A W 13 5 14.2 4 26 37.2 23 50

C W 1 5 7.0 0 12 19.8 10 26

C W 2 3 6.7 4 9 24.0 21 26

C W 3 5 6.3 4 11 22.0 14 32

C W 4 5 11.4 13 16 30.2 26 60

C W 5 3 7.0 3 10 18.0 13 22

C W 6 5 6.8 3 10 25.0 14 42

C W 7 5 6.9 2 9 27.0 32 63

C W 8 3 4.7 1 9 46.7 32 63

C W 9 3 6.3 2 12 43.3 28 61

C W 10 3 6.0 1 9 37.3 32 42

C W 11 5 13.6 11 15 42.0 30 62

C W 12 3 2.0 0 5 53.7 25 78

H W 1 5 14.8 9 24 41.6 30 59

H W 2 3 14.7 9 21 37.3 34 43

H W 3 5 16.2 10 23 52.8 38 62

H W 4 5 15.6 10 19 54.4 36 69

H W 5 3 15.0 8 20 49.7 44 56

H W 6 5 22.4 14 25 46.6 34 55

H W 7 5 15.8 10 22 67.6 56 77

H W 8 3 9.7 7 12 61.0 53 71

H W 9 3 11.7 8 15 56.0 47 67

H W 10 3 16.3 14 21 63.3 48 76

H W 11 5 15.4 9 19 69.8 43 87

H W 12 3 15.0 8 20 78.0 70 83
1-40

1.3.5 Comparison of summer and winter exposures

Figures 1.3.5-1 through 1.3.5-3 shows the differences between exposures in each city 

during the summer and winter seasons. For Chicago, the concentrations of benzene, 1,3-BD, and 

CO are higher in the underground garage (ME4 and ME11) during winter season. The same is 

true for ME3 and ME7, although CO concentrations are low and comparable for these refueling 

MEs, as expected. However, HCHO is clearly higher during the summer season in all MEs, 

perhaps a result of photochemical formation of this compound. In Houston, benzene is clearly 

much higher in refueling MEs in summer. However, for ME4 and ME11, winter concentrations 

are also marginally higher for benzene, 1,3-BD and CO. HCHO is less consistent, but clearly 

higher in summer in outdoor MEs (8, 9, 10, and 12). For Atlanta, the differences are not very 

large between winter and summer seasons, and not very consistent between different species and 

MEs. However, HCHO is clearly higher in summer in outdoor MEs (7, 8, 9, 10, and 12). 
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-41

Figure 1.3.5-1. Time integrated average exposure levels in different MEs in Atlanta in Summer and Winter season. 

Atlanta, Benzene

0

10

20

30

40

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Benzene_S Benzene_W

Atlanta, 1,3-Butadiane

0

1

2

3

4

5

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

1,3-BD_S 1,3-BD_W

Atlanta, Formaldehyde

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Formal_S Formal_W

Atlanta, CO

0

5

10

15

20

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppmv

CO_S CO_W
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-42

Figure 1.3.5-2. Time integrated average exposure levels in different MEs in Chicago in Summer and Winter season

Chicago, Benzene

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Benzene_S Benzene_W

Chicago, 1,3-Butadiane

0

1

2

3

4

5

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

1,3-BD_S 1,3-BD_W

Chicago, CO

0

2

4

6

8

10

12

14

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppmv

CO_S CO_W

Chicago, Formaldehyde

0

2

4

6

8

10

12

14

16

18

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Formal_S Formal_W
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-43

Figure 1.3.5-3. Time integrated average exposure levels in different MEs in Houston in Summer and Winter season 

Houston, Benzene

0

20

40

60

80

100

120

140

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Benzene_S Benzene_W

Houston, 1,3-Butadiane

0

1

2

3

4

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

1,3-BD_S 1,3-BD_W

Houston, Formaldehyde

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppbv

Formal_S Formal_W

Houston, CO

0

2

4

6

8

10

0 1 2 3 4 5 6 7 8 9 10 11 12 13

ME

ppmv

CO_S CO_W
1-44

1.3.6 Correlations to breath concentrations

Figures 1.3.6-1 and 1.3.6-2 shows the average concentrations of BTEX, 1,3-BD, MTBE, 

EtOH and CO2

Figure 1.3.6-3 (upper panel) shows the correlations between 1-minute maximum

surrogate values for benzene and 1,3-BD and post-exposure breath concentrations of these 

species. The correlation is somewhat better for 1,3-BD (R

measured in pre- and a post-peak exposure breath for three MEs in each city and 

season. Detailed data are submitted in the electronic form. As it can be seen from these figures, a 

considerable increase in concentrations of measured species occurs in all cases immediately after 

a peak exposure. In Atlanta and Chicago, the highest breath concentrations of BTEX and 1,3-BD 

were observed in ME7 (refueling) and ME11 (underground garage). In Houston, high 

concentrations of MTBE were measured in ME7 in summer and winter. Although high 

concentrations of EtOH were measured in breath in all Chicago MEs, it is not clear if this is due 

wholly to the presence of EtOH in Chicago fuel, since pre-exposure breath concentrations were 

occasionally higher than the post-exposure concentrations. Subjects were cautioned against 

consuming alcoholic beverages or using alcoholic personal care products prior to breath testing 

but EtOH may also be a metabolic product for certain other food types. For example, it has been 

reported (Turner et al., 2006) that increased ethanol levels were observed in the breath of healthy 

individuals if sweet drinks/food had been consumed within 2 hr prior to providing breath 

samples.

2

 = 0.46) than for benzene (R2 = 0.26); 

however, benzene concentrations in these MEs are much higher than breath concentrations. As 

shown in the lower panel of Figure 1.3.6-3, both benzene and 1,3-BD concentrations in breath 

track well these compound concentrations in all MEs. Note that the logarithmic scale was used 

for benzene and that no ME3 and ME7 data were included in 1,3-BD correlations for Houston. 

Also, some 1-minute surrogate 1,3-BD and benzene values are missing for certain MEs. As 

explained in Section 1.3.2, if the CO or NMVOC values were below the approximate detection 

limits of the continuous CO and PID instruments (0.5 ppmv and 25 ppbv, respectively), no 1-min 

surrogate data were calculated. Data used for these plots are submitted in electronic form.
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-45

Figure 1.3.6-1. Average breath BTEX, 1,3-BD, MTBE, EtOH, and CO2 concentrations in three cities in Summer

Chicago, Summer 2003

0

2

4

6

8

10

12

14

ME6pre ME6post ME7pre ME7post ME11pre ME11post

BTEX, ppb

0

20

40

60

80

100

120

140

EtOH, ppb

BTEX EtOH
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-46

Figure 1.3.6-2. Average breath BTEX, 1,3-BD, MTBE, EtOH, and CO2 concentrations in three cities in Winter 

Chicago, Winter 2004

0

5

10

15

20

25

30

ME6-pre ME6-post ME7-pre ME7-postME11-pre ME11-

post

BTEX, ppbv

0

50

100

150

200

250

300

350

400

450

EtOH, ppbv

BTEX EtOH
ME1: In-cabin congested freeway; ME2: In-cabin urban canyon; ME3: In-cabin refueling; ME4: In-cabin underground garage; ME5: In-cabin toll plaza; ME6: In-cabin roadway tunnel; ME7: Out-ofcabin refueling; ME8:Out-of-cabin sidewalk; ME9: Out-of-cabin sidewalk/bus stop; ME10: Out-of-cabin surface parking; ME11: Out-of-cabin underground garage; ME12: Outside toll plaza; ME13: 

In-cabin trailing high-emitter vehicle

1-47

Figure 1.3.6-3. Correlations between 1-minute surrogate benzene and 1,3-BD max values and post-exposure breath concentrations 

(upper panel) and comparison of these concentrations in different ME and cities (lower panel)

Benzene

y = 0.0105x + 4.7492

R2

 = 0.2314

0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500

1-min max

Peak Breath

1,3-Butadiane

y = 0.6102x + 0.1788

R2

 = 0.4612

0

2

4

6

8

10

12

0 2 4 6 8 10 12 14

1-min max

Peak Breath

Benzene

0

1

10

100

1000

10000

AS07M_1AS07M_3AS07M_5AS11M_2AS11M_4AS13M_1AS13M_5

AW07M_2AW07M_4AW07M_6AW11M_2AW11M_4AW13M_1AW13M_3AW13M_5

CS06M_2CS06M_4CS07M_2CS11M_2CS11M_4

CW06M_5CW07M_4CW11M_1CW11M_4

HS06M_2HS06M_4HS07M_1HS07M_3HS07M_5HS11M_3HS11M_5

HW06M_2HW06M_4HW07M_1HW07M_3HW07M_5HW11M_3HW11M_5

benz_1min benz_breath

1,3-Butadiane

0

2

4

6

8

10

12

14

AS11B_1BAS11B_3BAS13B_1BAS13B_5B

AW11B_2BAW11B_4BAW13B_1B

CS06B_1BCS06B_3BCS11B_2BCS11B_4B

CW06B_1BCW06B_3BCW06B_5BCW11B_1BCW11B_4B

HS06B_1BHS06B_3BHS06B_5BHS11B_2BHS11B_4B

HW06B_1BHW06B_3BHW06B_5BHW11B_3BHW11B_5B

1-Min Max

0

2

4

6

8

10

12

Breath

1,3-BD_1min 1,3-BD_breath
1-48

1.4 Conclusions

Summary findings related to the three city study are as follows:

• Day-to-day variations in high-end (99+th

• With the exception of refueling, exposure levels are generally lower in outdoor MEs

and higher in enclosed MEs. 

percentile) benzene, 1,3-BD, HCHO, and 

CO concentrations in different MEs are substantial and independent of city and 

season, but related to the activity and emission rates of sources in the given MEs

which differ from day to day. 

• The 20-min average refueling benzene exposures range up to few hundred ppbv and 

show substantial day-to-day variability.

• In-cabin exposures during on-road vehicle operation are more consistent and uniform 

than for other in-cabin MEs. 

• BTEX species show the highest concentrations in refueling MEs dominated by 

evaporative emissions whereas CO, HCHO, and 1,3-BD are the highest in the coldstart dominated MEs. 

• BTEX and 1,3-BD measured by time-integrated canister method show good 

correlations with continuous NMVOC and CO measurements, respectively. HCHO

correlation with continuous CO is modest, probably due to photochemical production 

of this compound. 

• Continuous NMVOC (PID) and CO (NDIR) data can be used to reconstruct 1-minute 

time series for benzene and 1,3-BD, respectively, provided that the averaged 

continuous measurements are above the detection limits of the instruments (25 ppbv 

and 0.5 ppmv, respectively). CO data can also be used to reconstruct 1-minute HCHO

data; however, less reliably so due to poorer correlation between these species.

• Reconstructed 1-minute time-series data for benzene and 1,3-BD, averaged over the 

five minute time frame corresponding to the collection of 5-minute canister samples, 

correlate well after excluding the Houston refueling ME with relatively high TVOC 

levels that distort typical correlation coefficients and elevated MTBE levels which 

bias 1,3-BD measurements.

• The concentrations of benzene and 1,3-BD measured in post peak exposure breath 

samples track corresponding ME 1-minute maximum reconstructed surrogate values 

well.

• Increases in concentrations of measured species occur in all breath samples collected 

within a minute of a peak exposure. In Atlanta and Chicago, the highest breath 

concentrations of BTEX and 1,3-BD were observed in ME7 (refueling) and ME11 

(underground garage), respectively. In Houston, high concentrations of MTBE were 

measured in ME7. 

• The largest differences in benzene, 1,3-BD, and CO concentrations between summer 

and winter seasons are observed in Chicago, consistent with the largest ambient 

temperature differences for this city. These concentrations are higher in winter. For 

Atlanta and Houston such differences are less pronounced. HCHO is consistently 

higher in summer season in outdoor environments, probably due to the photochemical 

production of this compound. 
1-49

1.5 References

Batterman, S. S, Peng C-y, Braun, J. (2002). Levels and composition of volatile organic 

compounds on commuting routes in Detroit, Michigan. Atmos. Environ., 36:6013-6030. 

Chan, C-C., H. Ozkaynak, J. D. Spengler and L. Sheldon (1991). Driver exposure to volatile 

organic compounds, CO ozone, NO2 under different driving conditions. Environ. Sci. 

Technol., 25: 964-972. 

Fedoruk, M.J. and Kerger, B.D. (2003). Measurements of volatile organic compounds inside 

automobiles. Journal of Exposure Analysis and Environmental Epidemiology, 13:31-41 

Lindstrom A.B. and J.D. Pleil (1996). Alveolar Breath Sampling and Analysis to Assess 

Exposures to Methyl Tertiary Butyl Ether (MTBE) During Motor Vehicle Refueling. J. 

Air & Waste Manage. Assoc., 46:676-682. 

Pleil, J. D.and A. Lindstrom (2002). A review of the USEPA’s single breath canister (SBC) 

method for exhaled volatile organic biomarkers. Biomarkers, 7:189-208. 

Rodes, C., L. Sheldon,, D. Whitaker, et al., (1998). Measuring Concentrations of Selected Air 

Pollutants Inside California Vehicles. Final report, ARB Contract # 95-339. California 

Air Resources Board. 

Turner, C., P. Spanel and D. Smith (2006). A longitudinal study of ethanol and acetaldehyde in 

the exhaled breath of healthy volunteers using selected-ion flow-tube mass spectrometry. 

Rapid Commun. Mass Spectrom., 20:61-68. 

Vayghani, S. A. and C. Weisel (1999). The MTBE air concentrations in the cabin of automobiles 

while fueling. Journal of Exposure Analysis and Environmental Epidemiology, 9:261-

267. 

Weisel, C., N. J. Lawryk, P. J. Lioy (1992). Exposure to emissions from gasoline within 

automobile cabins. J. Expo Anal Environ Epidem, 2(1):79-96. 

Zielinska, B., E. Fujita, J. Sagebiel, G. Harshfield, E. Uberna, T. Hayes, and F. Keene (1998). 

Arizona Hazardous Air Pollutants Monitoring Program. J. Air Waste Manage. Assoc.,

48:1038-1050. 

Zielinska, B., E. M. Fujita, J.C. Sagebiel, D. E. Campbell, L.R. Smith, T. Johnson (2003a). 

Exposure Protocol and Study Plan for the Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. Prepared for American Petroleum 

Institute, 1220 L Street, Washington, DC 20005-4007. Final Version. October 1, 2003. 

Zielinska, B, E.M. Fujita, and J.C. Sagebiel (2003b). Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline-Summer 2002 Atlanta Field Study 

on Baseline Gasoline. Prepared for American Petroleum Institute, 1220 L. Street, 

Washington, DC 2005-4070. March 13, 2003. 

Zielinska, B, J.C. Sagebiel, D.Campbell and E.M. Fujita, (2004a). Section 211 (B) Tier 2 High 

End Exposure Screening Study of Baseline and Oxygenated Gasoline-Summer 2003 

Chicago and Atlanta Field Study on Baseline Gasoline. Prepared for American Petroleum 

Institute, 1220 L. Street, Washington, DC 2005-4070. March 13, 2003. 
2-1

2. Relative Contributions of Vehicle Evaporative and Exhaust Emission to 

Concentrations of Volatile Air Toxics in High Exposure 

Microenvironments in Houston

2.1 Introduction

The Desert Research Institute (DRI) conducted measurements to quantify exposures to 

automotive emissions in microenvironments representing the upper-end (> 99th percentile) of the 

distribution of inhalation exposures to evaporative and exhaust emissions of conventional- and 

oxygenated-gasoline. The study was conducted as part of the Section 211(b) Tier 2 High-End 

Exposure Study of Conventional and Oxygenated Gasoline. DRI and SwRI conducted 

measurements under controlled conditions to establish quantitative relationships between tailpipe 

and evaporative emission rates to exposure levels in a vehicle cabin and attached residential 

garage. Field exposures also were measured in several high-end exposure microenvironments in 

Atlanta, Chicago, and Houston during winter and summer. Target species (TVOC, CO, BTEX, 

HCHO,1,3-BD, MTBE, EtOH) were measured within microenvironments, breathing zones, and 

breath. This section apportions the relative contributions of fuel combustion and evaporative 

emissions to exposures measured various high-end microenvironments, based on differing 

abundances of MTBE and benzene in exhaust and evaporative emissions. This particular analysis 

approach was applied to the exposure data from Houston because it is the only city included in 

the Section 211(b) exposure screening study to use MTBE as the oxygenated additive. 

Federal reformulated gasoline (RFG) was introduced in 1995 in nine metropolitan areas 

of the United States that were not in attainment of the ambient air quality standard for ozone. The 

RFG program is implemented year-round in these areas as an emission reduction program to 

control ambient ozone and mobile source air toxics (MSAT). Non-oxygenated conventional 

gasoline was used in Atlanta during the period of study. Ethanol was used to oxygenate 

reformulated gasoline in Chicago and MTBE in the Houston area. Table 2-1 summarizes the 

major differences in fuel composition between conventional and RFG. Exhaust emissions 

include a mixture of un-combusted fuel components (e.g., BTEX, MTBE, EtOH, TVOC) and 

species produced during combustion (e.g., benzene, 1,3-BD, HCHO, CO). The relative 

abundances of combustion by-products in the exhaust profile vary with emission control 

technology, level of vehicle maintenance, and operating mode. 

Liquid gasoline contains many target compounds (BTEX, MTBE, EtOH, TVOC) in 

common with gasoline-vehicle exhaust. Gasoline headspace vapor, vapor in equilibrium with 

liquid gasoline, also contains these combustion compounds but is enriched in the more volatile 

species such as benzene, MTBE, and EtOH. Composite liquid and headspace vapor profiles 

across different brands and grades of gasoline were developed in conjunction with the Tuscarora, 

Fort McHenry, and SOS on-road exhaust experiments, for the Auto-Oil program, COAST, the 

Paso del Norte Study, and the 1995/96 RFG Study (Zielinska et al., 1997). Gasoline 

compositions were also determine for western Washington (Fujita et al., 1997c), Austin (Fujita, 

et al. 1999a), San Francisco Bay Area (Kirchstetter et al., 1999), Houston (Fujita et. al., 2001), 

and Los Angeles (Fujita et al, 1997; Fujita et al., 2003). 
2-2

There are several sources of evaporative emissions including hot soak emissions driven 

by residual engine heat following cessation of vehicle operation, diurnal emissions associated 

with fuel tank ‘breathing’ during diurnal temperature and barometric pressure cycling, running 

losses resulting from fuel tank radiant heating by roadways or from injector fuel recirculation 

during vehicles operation, resting losses from gasoline permeation through rubber and plastic 

components of the fuel lines, and simple fuel system leakage. From an analysis of ambient air 

samples and reconciliation with VOC source profiles, Pierson et al. (1999) conclude that 71 ± 

9% of motor vehicle VOC emissions are emitted from tailpipes, 17 ± 6% result from non-tailpipe 

liquid fuel emissions (fuel system leakage) , and 12 ± 4% are due to headspace vapor emissions. 

2.2 Experimental Approach

The profiles for vehicle exhaust, liquid gasoline, and gasoline headspace vapor include 

many of the same species but notable differences in the ratio of species, a difference that can be 

used to apportion tailpipe and evaporative emission source strengths. The proportion of MTBE in 

exhaust is reduced during combustion relative to its proportion in the fuel. Conversely, benzene 

is enriched in exhaust relative to its proportion in the fuel due to toluene and xylene dealkylation. 

Consequently, MTBE to benzene ratios are substantially lower in exhaust than in liquid fuel or 

headspace vapors. MTBE and benzene were measured in all microenvironments in Houston as 

well as in fuel and vehicle exhaust samples. The fractional evaporative contribution, X, was 

estimated using following formula.

X = (RME - REXH)/ (RVAP - REXH) 

RME is the measured microenvironmental MTBE/benzene ratio, REXH is the exhaust 

MTBE/benzene ratio, and RVAP is the evaporative MTBE/benzene vapor ratio; either of whole 

gasoline or headspace vapor depending upon type of evaporative emissions expected in a 

particular ME (e.g., whole liquid gasoline for hot soak, leaks, or spills and headspace vapors if 

refueling). Some MEs are influenced by a combination of whole gasoline and headspace vapor 

emissions.

For the present study, the Southwest Research Institute (SwRI) procured two test vehicles 

and determined their evaporative/tailpipe emissions in the normal/malfunction modes using the 

three test fuels. The test vehicles, a sedan and full-sized V8 truck, were chosen within the 1993-

1996 model years from vehicles with 90,000-110,000 odometer miles. The chosen 1993 Toyota 

Camry (2.2L 4-cylinder engine) and 1995 Ford F150 Pickup truck (5.0L V8 engine) were 

operated in normal, as purchased, modes and in “high emitter” modes with the catalytic 

converter removed and emission levels above 2 grams per mile NMHC as measured on the FTP 

driving cycle. While converter removal sufficed for the F150 truck, a calibrated manifold leak 

was also needed to achieve the ≥ 2g/mile Camry emissions. SwRI determined dynamometer FTP 

emissions for each vehicle with all three fuels in the two emission modes (24 tests). Emission 

control components could be reproducibly adjusted to represent normal and reasonable high-end 

approximations (≥ 2g/mile) of real world exhaust emissions.

The FTP exhaust emission test uses the 1372 second Urban Dynamometer Driving 

Schedule (UDDS) that is divided into cold/start transient 505 (Bag 1) and cold stabilized 867 
2-3

(Bag 2) second segments. This portion of the FTP is followed by a 10-minute soak and a hot/start 

transient 505 (Bag 3) test. The FTP evaporative emission test includes one hour Diurnal Heat 

Build (DHB) and Hot Soak Loss (HSL) tests. THC/VOC emissions are recorded during the HSL 

segment of the test. Prior to the FTP cold-start exhaust test, the DHB is conducted by fueling the 

test vehicle to 40 percent of tank capacity with fuel < 55°F, attaching a heating blanket outside 

the fuel tank, placing a thermocouple in the tank fuel, hooking it up to computer control, and 

beginning the test as fuel reaches 60°F (increasing at 0.4°F per minute for the 60-minute test to a 

84°F final temperature). In the HSL segment, conducted immediately following exhaust 

emission testing, the vehicle is driven into an evaporative emission enclosure and allowed to 

“soak” in the enclosure for one hour. THC/VOC emissions are measured at the beginning and 

end of the one-hour segment and hot soak evaporative emissions are calculated. 

Test fuel samples were subject to standard tests for Reid Vapor Pressure (RVP), 

distillation range, Specific Gravity, Sulfur, Benzene, HC Category (saturates, olefins, aromatics), 

Oxygenated species (MTBE/EtOH), carbon weight percent, hydrogen weight percent, oxygen 

weight percent, and octane number. Gasoline headspace vapor compositions were predicted from 

the measured composition of liquid gasoline using the Raoult’s Law method described by 

Kirchstetter et al. (1999). This method is based on the proportionality between the compound 

headspace partial pressure and its liquid mole fraction times the vapor pressure of the pure 

species. The individual vapor pressures are determined using the Wagner equation (Reid et al. 

1987). 

DRI measured seasonal in-cabin breathing zone exposures for urban roadways and other 

high-end MEs in Houston (6/3-7/9/04; 2/1-2/8/05), Chicago (8/5-8/20/03; 3/3-3/17/04), and 

Atlanta (7/28-8/8/02; 8/23-9/3/03; 2/10-2/29/04) using a combination of time-integrated samples 

and continuous instruments listed in Table 2-2. Three replicate exposure measurements were 

made for low variability MEs and five for MEs with higher variability (i.e., ME13-trailing high 

emitting vehicles, ME11-underground garages, and ME7-outdoor refueling). Measurements in 

each ME were taken over a period of 20-40 minutes beginning at the top of the hour. Shorter 

sampling times were used for refueling events and parking garage exits after sporting events. 

Sampling and analytical methods are described in Section 1 of the report and in the study plan 

(Zielinska et al., 2003). 

2.3 Results

The measured MTBE/benzene ratios are summarized in Table 2-3 for the Houston MEs. 

Exposures at the two refueling MEs (3 & 7) were dominated by evaporative emissions as 

expected, with MTBE/benzene ratios of 20 to 30. Ratios for all other MEs were between 1 and 4. 

The exhaust, headspace, and liquid fuel MTBE/benzene ratios measured in this and other recent 

studies are shown in Table 2-4. MTBE/benzene exhaust ratios among the dynamometer tests 

average slightly less than 1 with the tunnel ratios nearer 2, possibly due to the added running loss 

emissions in tunnels. The MTBE/benzene ratios in liquid gasoline and vapor are similar, 

averaging 15-20. Ratios for the SwRI SHED tests vary somewhat with calculated headspace 

compositions and values from earlier listed studies. 
2-4

The estimated fractional contributions of evaporative emissions to total motor vehicles 

emissions for the various Houston MEs, using the above method, are summarized in Table 2-5 

and Figure 2-1. Uncertainties are the standard deviation of the ratios calculated from replicate 

test measurements for each ME (represents the variability of ratio within observed sample set). 

Exposures during refueling (ME3, ME7) are 100% due to evaporative emissions within the 

uncertainties associated with the measurements and method. All other MEs are dominated by 

tailpipe emissions with fractional evaporative contributions < 10%. 

2.4 Conclusions

The results presented in Table 2-5 indicate that evaporative emissions are only substantial 

components of high end ME exposures during vehicle refueling operations, where they are 

dominant. Since refueling MEs have the highest relative levels of these components (see sections 

1 and 3), they constitute the peak exposures, although overall the average population time spent 

in these high end MEs is likely the shortest. The contribution of evaporative emissions for all 

other MEs was typically about 5% of the total measured exposure. Results were similar for both 

seasons, although evaporative contributions during refueling were marginally less during 

summer, possibly due to more rapid dispersion of vapors and evaporation of fuel spilled during 

each refueling test at higher summer temperatures. The clear distinction in evaporative 

contribution between refueling and non-refueling MEs, along with the relative consistency in 

MTBE/benzene ratios shown in Table 2.4, gives some confidence in the approach. 

These results suggest that the contemporary Houston vehicle fleet contains relatively few 

carbureted or leaking vehicles given that evaporative emissions are not a substantial source in the 

non-refueling MEs tested. Refueling emissions released from pressurized fuel systems and 

spilled fuels appear to be the primary source of peak evaporative exposures. The lack of a 

seasonal variability in the evaporative contribution is also consistent with this supposition. 

Although it was not feasible to try to distinguish further between liquid and headspace vapor 

contributions by the method used, the extremely low MTBE/benzene ratios observed for the 

roadway, sidewalk, and parking MEs suggest that the contributions of emissions from leaking 

liquid gasoline is relatively small. 

The contributions of exhaust and evaporative emissions to ambient volatile air toxics were 

estimated for Houston only since it is the only city among the three in the study with oxygenated 

gasoline containing MTBE. While the contributions of evaporative emissions relative to exhaust 

emissions may vary with differences in average prevailing meteorological conditions, such 

differences are unlikely to result in significantly different conclusions in other cities with regard 

to the relative contributions of exhaust and evaporative emissions to ambient concentrations of 

volatile air toxics. It must also be noted that the vehicle used in this study for the refueling tests 

was a 1996 vehicle. All vehicles prior to the 1998 model year do not have onboard refueling 

vapor recovery (ORVR) systems, and therefore higher refueling emissions. Although refueling 

stations in Houston had Stage II vapor recovery systems, the ORVR system also reduces vapor 

losses when the fuel cap is opened by lowering the internal pressure of the fuel tank. The 

implementation of ORVR systems may further reduce the relative contributions of evaporative 

emissions.
2-5

Table 2-1. Conventional gasoline versus reformulated gasoline RFG (from EPA OTAQ web 

page http://www.epa.gov/OMSWWW/rfgnew.htm, updated by S. Romanow, OTAQ).

 Fuel Parameter Values (national basis) 

 Conventional Gasoline Gasohol

Oxyfuel 

(2.7% wt)

 "Summer" 

Phase I RFG 

 Averagea Rangeb Average Average Averagee 

 8.7-S 6.9-15.1 9.7-S 8.7-S 7.0-7.9f 

 11.5-W 11.5-W 11.5-W 

 T50 (°F) 207 141-251 202 205 199 

 T90 (°F) 332 286-369 316 318 325 

 Aromatics (volume %) 28.6 6.1-52.2 23.9 25.8 22.3 

 Olefins (volume %) 10.8 0.4-29.9 8.7 8.5 12.5 

 Benzene (volume %) 1.60 0.1-5.18 1.60 1.60 0.64 

 Sulfur (ppm) 338 10-1170 305 313 269 

 MTBEd (volume %) -- 0.1-13.8 -- 15 11g 

 EtOHd (volume %) -- 0.1-10.4 10 7.7 10h 

 RVPc (PSI) 

a As defined in the Clean Air Act.

b 1990 Motor Vehicle Manufacturer’s Association (MVMA) survey.

c Winter (W) Reid Vapor Pressure (RVP) higher than Summer (S) to maintain vehicle performance.

d Oxygenate concentrations shown are for separate batches of fuel; combinations of both methyl tertiary butyl ether 

(MTBE) and ethanol (EtOH) in the same blend can never be above 15 volume percent total.

e Except as noted, values in this column are volume-weighted average based on preliminary analysis of a portion of 

1996 RFG batch reporting data submitted to EPA by refineries and importers. Numbers are subject to change.

f The lower RVP number is average for RFG designated for sale in VOC Control Region 1; the higher RVP number 

for VOC Control Region 2. In general, Region 1 areas are to the south and/or west.

g This is a “typical” value for an RFG batch containing MTBE as the sole oxygenate; this provides about 2% 

oxygen by weight.

h This is a “typical” value for an RFG batch containing ethanol. Ethanol is not combined with other oxygenates in 

VOCcontrolled RFG. There are economic incentives for blending ethanol at this level, which provides about 3.5% 

oxygen by weight

i. T(50) and T(90) refers to temperatures at which 50% and 90%, respectively, of gasoline volume is distilled. 
2-6

Table 2-2. Summary of sample collections in urban MEs 

ME # ME Description Replicates Biomarker

5 min 

Canister

Sampling Time 

(min)

1 In-Cabin Congested Freeway 5 40

2 In-Cabin Urban Canyon 3 40

3 In-Cabin Refueling 5 20

4 In-Cabin Underground Garage 5 40

5 In-Cabin Toll Plaza 3 40

6* Roadway Tunnel 5 40

7 Outdoor Refueling 5 yes yes 20

8 Sidewalk 3 40

8/9 Sidewalk/Bus Stop 3 40

10 Outdoor Surface Parking 3 40

11 Outdoor Underground Garage 5 yes yes 40

12 Outdoor Toll Plaza 3 40

13* In-cabin Trailing High-Emitting Vehicles 5 yes yes 40

*ME13 was substituted for ME6 in Atlanta and Chicago.
2-7

Table 2-3. Mass ratios of MTBE to benzene in Houston by ME. 

Microenvironment ME Summer Winter

Freeway 1 1.72 ± 0.49 2.88 ± 1.33

Urban Canyon 2 1.10 ± 0.41 2.56 ± 0.80

In-Cabin Refueling 3 24.91 ± 12.19 41.96 ± 21.35

In-Cabin Underground Garage 4 3.22 ± 1.49 2.35 ± 1.78

In-Cabin Toll Plaza 5 2.49 ± 0.77 2.99 ± 1.14

Tunnel 6 2.74 ± 0.42 5.33 ± 6.63

Outdoor Refueling 7 28.82 ± 12.01 55.77 ± 26.83

Sidewalk 8 2.34 ± 0.19 1.15 ± 0.06

Bus Stop 9 2.87 ± 1.13 1.31 ± 0.18

Surface Parking 10 1.94 ± 0.36 6.93 ± 6.57

Outdoor Underground Garage 11 2.60 ± 0.37 3.30 ± 1.50

Outdoor Toll Plaza 12 2.48 ± 1.81 2.78 ± 1.18
2-8

Table 2-4. Mass ratios of MTBE to benzene in vehicle exhaust, gasoline vapor and liquid gasoline. 

Test Set Fuel Year Average Stdev Reference

Ratios in LDGV Exhaust

CRPAQS/GDS dyno exhaust Los Angeles 2001 0.62 1.35 Fitz et al. 2003

CRPAQS/GDS dyno warm-starts Los Angeles 2001 0.43 1.43 Fitz et al. 2003

CRPAQS/GDS dyno hi-em Los Angeles 2001 1.11 3.17 Fitz et al. 2003

SWRI FTP - summer Houston 2004 0.44 0.24 Merritt, 2005

SWRI FTP - winter Houston 2005 1.40 0.55 Merritt, 2005

SWRI FTP- normal Houston 2004 and 2005 0.60 0.45 Merritt, 2005

SWRI FTP- malfunction Houston 2004 and 2005 1.24 0.71 Merritt, 2005

Ratios in Tunnel and Roadway Samples

WEO3 on-road Los Angeles 2000 2.96 1.03 Fujita et al.2003a; Fujita et al., 2003b 

LA tunnels-corrected for running loss Los Angeles 1995 and 1996 0.32 0.99 Fujita et al., 2003b 

LA tunnels, uncorrected Los Angeles 1995 and 1996 1.69 0.54 Fujita et al., 2003b 

API houston tunnel (ME6) Houston 2004 and 2005 3.36 1.35 This study

Ratio in Gasoline Vapor

LA vapor Los Angeles 1995 16.63 Fujita et al., 2003b 

WEO3 vapor Los Angeles 2000 44.98 Fujita et al.2003a; Fujita et al., 2003b 

SWRI shed - malfunction Houston 2004 and 2005 20.52 29.20 Merritt, 2005

SWRI shed - malfunction, outlier removed Houston 2004 and 2005 5.93 1.60 Merritt, 2005

estimated from fuel content - summer Houston 2004 32.8 Merritt, 2005

estimated from fuel content - winter Houston 2005 43.9 Merritt, 2005

Ratios in Liquid Gasoline

LA gasoline - 1995 RFG Los Angeles 1995 11.79 Fujita et al., 2003b 

WEO3 gasoline Los Angeles 2000 19.56 5.23 Fujita et al.2003a; Fujita et al., 2003b 

gds gasoline Los Angeles 2001 17.15 5.49 Gabele, 2003

API gasoline - summer Houston 2004 13.28 Merritt, 2005

API gasoline - winter Houston 2004 17.87 Merritt, 2005
2-9

Table 2-5. Fractional contributions of evaporative emissions to total motor vehicles emissions in 

Houston by ME. 

Microenvironment ME Summer Winter

Freeway 1 0.04 ± 0.02 0.03 ± 0.03

Urban Canyon 2 0.02 ± 0.01 0.03 ± 0.02

In-Cabin Refueling 3 0.76 ± 0.38 0.95 ± 0.50

In-Cabin Underground Garage 4 0.09 ± 0.05 0.02 ± 0.04

In-Cabin Toll Plaza 5 0.06 ± 0.02 0.04 ± 0.03

Tunnel 6 0.07 ± 0.01 0.09 ± 0.16

Outdoor Refueling 7 0.88 ± 0.37 1.28 ± 0.63

Sidewalk 8 0.06 ± 0.01 -0.01 ± 0.00

Bus Stop 9 0.08 ± 0.04 0.00 ± 0.00

Surface Parking 10 0.05 ± 0.01 0.13 ± 0.15

Outdoor Underground Garage 11 0.07 ± 0.01 0.04 ± 0.04

Outdoor Toll Plaza 12 0.06 ± 0.06 0.03 ± 0.03

Evaporative Emissions Contribution

0.0

0.5

1.0

1.5

2.0

1 2 3 4 5 6 7 8 9 10 11 12

ME

Fraction

summer

winter

Figure 2-1.Fractional contributions of evaporative emissions to total motor vehicles emissions in 

Houston by ME. 
2-10

2.5 References

Fujita, E.M., Z. Lu, L. Sheetz, G. Harshfield, T. Hayes, and B. Zielinska (1997c). Hydrocarbon 

Source Apportionment in Western Washington. Report prepared for the State of 

Washington Department of Ecology, Lacy, WA, September, 1997. 

Fujita, E.M., R.E. Keislar, J.L. Bowen, W. Goliff, F. Zhang, L.H. Sheetz, M.D. Keith, J.C. 

Sagebiel, and B. Zielinska (1999a). 1998 Central Texas On-Road Hydrocarbon Study. 

Final report prepared for the Texas Department of Transportation, Austin, TX under 

subcontract to PBS&J, Austin, TX, March, 1999. 

Fujita E.M. (2001). Hydrocarbon Source Apportionment for the 1996 Paso del Norte Ozone 

Study. Science of the Total Environment, 276:171-184. 

Fujita, E.M., D.E. Campbell, B. Zielinska, J.C. Sagebiel, J.L. Bowen, W. Goliff, W.R. 

Stockwell, and D.R. Lawson (2003a). Diurnal and Weekday Variations in Source 

Contributions of Ozone Precursors in California’s South Coast Air Basin. J. Air & Waste 

Manage. Assoc. 53:844-863. 

Fujita, E.M. and D. Campbell (2003b). Validation and Application Protocol for Source 

Apportionment of Photochemical Assessment Monitoring Stations (PAMS) Ambient 

Volatile Organic Compound (VOC) Data. Final report prepared for the U.S. 

Environmental Protection Agency under EPA Star Grant #GR826237-01-0, August 31, 

2003. 

Gabele, P. Support of the Gasoline/Diesel Particulate Matter Split Study. Final report submitted 

by U.S. Environmental Protection Agency to Department of Energy through Interagency 

Agreement (IAG) No. DE-AI04-2001AL67138, March 17, 2003. 

Kirchstetter, T.W., B.C. Singer, R.A. Harley, G.R. Kendall, and J.M. Hesson (1999). Impact of 

California Reformulated Gasoline on Motor Vehicle Emissions: 2. Volatile Organic 

Compound Speciation and Reactivity. Environ. Sci. Technol., 33:329-336. 

Pierson, W., E. Schorran, E. Fujita, J. Sagebiel, D. Lawson, and R. Tanner (1999). Assessment 

of Non-Tailpipe Hydrocarbon Emissions from Motor Vehicles. J. Air Waste Manage. 

Assoc., 49: 498-519. 

Reid, R.C., J.M. Prausnitz and B.E. Poling (1987). Composition of Vapor Emitted from a 

Vehicle Gasoline Tank During Refueling. SAE Technical Paper Series, paper no. 

860086. 

Zielinska, B. E.M. Fujita, and J.C. Sagebiel, D. Campbell, L.R. Smith and T. Johnson (2003). 

Exposure Protocol and Study Plan for the Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. Prepared for American Petroleum 

Institute, 1220 L. Street, Washington, DC 20005-4007. Final Version. October 1, 2003.
3-1

3. Determination of the Quantitative Relationships between Levels of 

Volatile Air Toxics and Carbon Monoxide Measured In High End 

Microenvironments and At Nearby Air Quality Monitoring Stations

3.1 Introduction

The U.S. Environmental Protection Agency conducts national-scale assessments of air 

toxics in order to set program priorities, characterize risks, and track progress towards achieving 

the goals of the national air toxics program as established by the 1990 Clean Air Act 

Amendments (CAAA). As part of the National Air Toxics Assessment (NATA), EPA conducted 

a national screening-level assessment for 1996 and 1999 to characterize the potential risks 

associated with inhalation exposures to 33 air toxics and diesel particulates. The screening-level 

assessment estimated outdoor air toxics concentrations across the US and related these 

concentrations to population exposures. 

The Assessment System for Population Exposure Nationwide (ASPEN) model was used 

by EPA to estimate outdoor air toxics concentrations across for every census tract in the 

continental United States, Puerto Rico and the Virgin Islands. To enable the simulation of a large 

number of air toxics nationwide, a number of simplified approaches are incorporated into the 

model. The model uses a simplified approach to simulate atmospheric chemistry such as reactive 

decay and secondary formation (production of an air toxics compound due to chemical reactions 

in the atmosphere). A uniform background concentration is added for some pollutants for which 

information is available to compensate because the model simulates only pollutant transport 

within 50 kilometers of any individual source. For those air toxics with high levels of 

background concentrations, the model’s ability to predict ambient concentrations are greatly 

impacted by the accuracy of background estimates. Past comparisons with limited monitoring 

data show that the modeled air toxics concentrations are generally within two orders of 

magnitude of measured concentrations. 

For the exposure-modeling portion of the analysis, EPA used the Hazardous Air Pollutant 

Exposure Model (HAPEM). The HAPEM modeling approach simulates the movements of 

various population groups through zones of varying air quality. Each zone is defined by a 

geographic location (typically a census tract) and a microenvironment (ME). The patterns of 

movements among the zones are determined by diary-derived activity data and commuting data 

acquired from the U.S. census. Ambient concentrations are estimated by the ASPEN dispersion 

model based on local emissions and meteorological data. The pollutant concentration in a 

specific ME is estimated as a function of the ambient concentration by a linear expression 

containing three terms that vary with ME: the penetration factor (the indoor/outdoor ratio in the 

absence of indoor sources), the additive factor (accounts for contribution of indoor sources), and 

the proximity factor (accounts for distance to specific outdoor sources such as roadways). 

Estimates for these factors for 33 HAPS have been obtained from various field studies and from 

previous modeling exercises. In general, there is a high degree of uncertainty associated with 

HAPEM exposure estimates because of the limited data available for estimating the ME factors 

(Rosenbaum, 2005). 
3-2

The DRI conducted measurements quantifying exposures to automotive emissions in 

microenvironments (MEs) representing the upper-end (> 99th percentile) of the distribution of 

inhalation exposures to evaporative and exhaust emissions of conventional and oxygenatedgasoline. The study was conducted as part of the Section 211(b) Tier 2 High-End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. DRI and SwRI conducted measurements 

under controlled conditions to establish quantitative relationships between tailpipe and 

evaporative emission rates to exposure levels in a vehicle cabin and attached residential garage. 

Field exposures also were measured in several high-end exposure MEs in Atlanta, Chicago, and 

Houston during winter and summer. Target species (TVOC, CO, BTEX, HCHO,1,3-BD, MTBE, 

EtOH) were measured within MEs, breathing zones, and breath. This section examines the 

quantitative relationships between CO exposure levels in these MEs to the corresponding fixed 

site measurements at nearby air monitoring stations. These comparisons are extended for 

Houston to volatile organic mobile source air toxics, which was the only city among the three 

with available data. These relationships are compared to the HAPEM proximity factors (Long 

and Johnson, 2004) that were used in the National Air Toxics Assessments. 

3.2 Experimental

DRI measured seasonal in-cabin breathing zone exposures for urban roadways and other 

high-end MEs in Houston (6/3-7/9/04; 2/1-2/8/05), Chicago (8/5-8/20/03; 3/3-3/17/04), and 

Atlanta (7/28-8/8/02; 8/23-9/3/03; 2/10-2/29/04) using a combination of time-integrated samples 

and continuous instruments for thirteen different MEs listed in Table 3-1. Three replicate 

exposure measurements were made for low variability MEs and five for MEs with higher 

variability (i.e., ME13-trailing high emitting vehicles, ME11-underground garages, and ME7-

outdoor refueling). Measurements in each ME were taken over a period of 20-40 minutes 

beginning at the top of the hour. Shorter sampling times were used for refueling events and 

parking garage exits after sporting events. 

The integrated samples included whole-air canister samples for CO, BTEX, MTBE, and 

1,3-BD, acidified 2,4-diphenylhydrazine (DNPH) cartridges for HCHO and CH3CHO, and a 

multi-bed (TenaxTA-Carbotrap-Carbosieve) solid adsorbent tube for EtOH. Continuous 

measurements included both non-dispersive infrared (NDIR) and passive electrochemical 

(Langan T-15) devices for CO and an active photo-ionization detector (PID) for TVOC with an 

ionization potential below 10.6 eV (principally olefins and aromatic species). Sampling and 

analytical methods are described in Section 1 and in the study plan (Zielinska et al., 2003). 

Ambient CO and VOC data were retrieved from EPA’s Air Quality System (AQS) for the 

specific periods of the field study in each city and compared to the ME measurements. The 

ambient monitoring and ME locations are mapped for each city in Figures 3-1a to 3-1c although 

some ME locations are overlapped by adjacent MEs. AQS VOC data were not available for 

Atlanta; incomplete data were available for a single site (Northbrook, IL) in Chicago located 20 

miles N/NW of city center that is unlikely representative of urban Chicago. Speciated hourly 

GC/FID VOC data were available from two sites in Houston for both summer and winter. All 

sites reporting CO and VOC data within each metropolitan area were averaged together for the 

purposes of comparison. The average CO and benzene concentrations did not show substantial 

spatial variation within each city. 
3-3

3.3 Results and Discussion

Exposure levels are directly related to source emission rates in the ME and inversely 

related to source distance and the extent of dilution, itself a function of meteorology and any 

physical obstructions that inhibit dilution. Hourly values from air quality monitoring stations in 

urban areas typically represent neighborhood scale exposure levels while 20-40 minute measures 

from MEs listed in Table 3-1 are intended to represent the high end exposures exceeding the 99th 

percentile. Consequently, the tabulated ME ratios reflect exposures scripted to reflect ‘worstcase’ conditions rather than population-average ME factors for these locations. Such information 

should be used solely to evaluate extreme exposures and not misinterpreted as ‘typical’ ME 

exposures encountered by the general population. 

Quantitative relationships for CO between ME measures and fixed site measurements at 

nearby air monitoring stations are examined first. CO is non-reactive and commonly measured 

year-round as a primary mobile source emission that is generally correlated with BTEX and 1,3-

BD. Table 3-2 shows the averages and standard deviations of the ratios of time-integrated CO 

from canister samples to the corresponding hourly CO from the ambient air monitoring stations 

in Houston, Atlanta, and Chicago by season and ME. As expected, the ratios are higher in MEs 

that are nearer to operating vehicle engines, especially in underground garages where dispersion 

of pollutants is limited. The average ratios for in-cabin exposures in congested freeway traffic 

ranged from 2 to 9 with lower ratios in the winter. Ratios were highest in Atlanta and lowest in 

Chicago. The seasonal and city-specific differences hold for most of the other MEs. Notable 

exceptions to the seasonal differences are the underground garages where the ratios are higher in 

the winter in all three cities, most likely due to the higher cold-start emissions. Garage size, 

ventilation, and spatial-temporal vehicle activity patterns account for the variance differences 

between underground garages. The garage in Atlanta is smaller, less ventilated, and more used 

than the garages in Houston or Chicago. While CO is a good exhaust species tracer, correlation 

with evaporative emissions is less. ME/ambient ratios are generally lower for CO than most of 

the other pollutants. This is most likely due to higher urban background levels of CO. 

Table 3-3 shows average Houston BTEX and 1,3-BD ME/ambient ratios (± SD), i.e., the 

time-integrated canister value to the corresponding hourly monitoring station GC/FID value. In 

contrast to CO, BTEX ME/ambient ratios are substantially higher for refueling (ME 3, ME 7). 

The BTEX ratios are closer to corresponding ratios derived for CO during winter but higher 

during summer. Since 1,3-BD is an exhaust species, the relative variation of ME/ambient ratios 

is similar to CO. 1,3-BD measures in MEs with high MTBE were invalid due to interferences 

(see Section 1). 

The integrated exposure measurements are 20-40 minute averages. Continuous CO and 

VOC PID measurements show higher peak (1-5 minutes) exposures. Continuous instruments 

provide sensitive proportionate measures of short-term target species variability since continuous 

time-averaged traces are well correlated to the corresponding time-integrated measurements. 

Consequently, the normalized continuous CO or VOC PID measures were used to reconstruct 1-

minute time-series concentrations for specific components. Either CO or VOC PID traces are 

suitable surrogates in exhaust-dominated MEs; VOC PID values are suitable surrogates in 

evaporative emissions-dominated MEs such as refueling. Reconstructed time-series and ranges 
3-4

of estimated 1-minute values are summarized in Section 1. Figures 3-2a through 3-2c show 20-

40 minute average and maximal estimated 1-minute values for benzene, 1,3-BD, and HCHO, 

respectively. Short-term exposures from evaporative-dominated ME3 and ME7 range more 

widely than those from other exhaust-dominated MEs. 

3.4 Conclusions

MEs in close proximity to running vehicle engines have enhanced CO relative to ambient 

levels with enrichment ratios approaching 40 where ventilation is limited, as in underground 

garages. Average in-cabin CO/ambient ratios in congested freeway traffic range from 2-9 with 

lower winter ratios. ME locations less proximate to operating vehicles, such as gas stations and 

urban sidewalks, have CO/ambient ratios of 0.5-2. 

The Houston benzene ME1/ambient ratio of 9.8 ± 3.8 for exceed the HAPEM5 median 

proximity factor of 4.9 (triangular distribution mode:range 1.9:0-14.3) and HAPEM4 proximity 

factor of 6.9 for this ME (Rosenbaum, 2005; Long and Johnson, 2004), although by less than 

expected. The HAPEM4 factors may be elevated compared to present conditions since 

measurements occurred before 1991 when benzene fuel levels and roadway fleet emissions were 

higher than today. HAPEM5 proximity factors may also need to be adjusted since they were 

based on a 1998 scoping study where measurements ‘highlighted trailing behind heavy duty 

diesel vehicles and diesel city buses when possible’. Houston ME/ambient ratio comparisons 

also generally exceed the other HAPEM factors listed in Table 3-4. Refueling ratios (ME3, ME7) 

for benzene were substantially higher than the corresponding HAPEM factors also as expected. 

Concentrations of exhaust compounds such as CO and 1,3-BD were enhanced under reduced 

ventilation situations. 

3.5 References

Rosenbaum, A. (2005). The HAPEM5 User’s Guide. Report prepared by ICF Consulting for the 

U.S. Environmental Protection Agency, Research Triangle Park, NC, March 2005. 

Long, T. and T. Johnson (2004). Development of Penetration and Proximity Microenvironment 

Factor Distributions for the HAPEM5 in Support of the 1999 National-Scale Air Toxics 

Assessment (NATA). Memorandum prepared by TRJ Environmental, Inc. for the U.S. 

Environmental Protection Agency, Research Triangle Park, NC, April 5, 2004. 

Zielinska, B. E.M. Fujita, and J.C. Sagebiel, D. Campbell, L.R. Smith and T. Johnson (2003). 

Exposure Protocol and Study Plan for the Section 211 (B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline. Prepared for American Petroleum 

Institute, 1220 L. Street, Washington, DC 20005-4007. Final Version. October 1, 2003. 
3-5

Table 3-1. Summary of sample collections in urban microenvironments 

ME # ME Description Replicates Biomarker

5 min 

Canister

Sampling Time 

(min)

1 In-Cabin Congested Freeway 5 40

2 In-Cabin Urban Canyon 3 40

3 In-Cabin Refueling 5 20

4 In-Cabin Underground Garage 5 40

5 In-Cabin Toll Plaza 3 40

6* Roadway Tunnel 5 40

7 Outdoor Refueling 5 yes yes 20

8 Sidewalk 3 40

8/9 Sidewalk/Bus Stop 3 40

10 Outdoor Surface Parking 3 40

11 Outdoor Underground Garage 5 yes yes 40

12 Outdoor Toll Plaza 3 40

13* In-cabin Trailing High-Emitting Vehicles 5 yes yes 40

*ME13 was substituted for ME6 in Atlanta and Chicago.
3-6

Table 3-2. Average and standard deviation in ratios of the time-integrated CO from canister samples to the corresponding hourly CO 

from regional ambient air monitoring sites for Houston, Atlanta and Chicago by season and microenvironment. 

Summer Winter

 Microenvironment Houston Atlanta Chicago Houston Atlanta Chicago

1 Congested Freeway, In-Cabin 4.6 ± 1.0 9.1 ± 6.5 2.6 ± 0.4 4.0 ± 1.0 5.4 ± 1.9 1.7 ± 0.4

2 Urban Canyon, In-Cabin 5.2 ± 2.5 3.9 ± 3.9 2.9 ± 1.4 12.1 ± 10.9 2.7 ± 5.6 1.0 ± 0.5

3 Refueling, In-Cabin 3.6 ± 0.9 1.4 ± 2.7 0.7 ± 0.3 4.1 ± 3.2 1.3 ± 0.6 0.5 ± 0.1

4 Underground Garage, In-Cabin 8.4 ± 8.0 16.9 ± 0.8 7.9 ± 3.4 21.4 ± 12.5 38.8 ± 0.2 12.6 ± 5.8

5 Toll Plaza, In-Cabin 4.1 ± 1.0 6.4 ± 0.0 1.6 ± 0.5 3.6 ± 0.6 2.7 ± 0.0 1.0 ± 0.1

6 Tunnel, In-Cabin 8.4 ± 1.7 6.3 ± 1.5 9.7 ± 5.2 2.5 ± 0.4

7 Refueling, Outdoor 1.9 ± 0.8 1.2 ± 1.8 0.9 ± 0.3 3.3 ± 2.5 2.1 ± 1.4 0.8 ± 0.9

8 Sidewalk 1.9 ± 0.5 1.9 ± 0.5 1.1 ± 0.2 1.3 ± 0.6 1.9 ± 0.9 0.9 ± 0.0

9 Sidewalk/BusStop 1.5 ± 0.3 2.4 ± 0.3 1.6 ± 0.6 1.8 ± 0.1 1.9 ± 0.2 1.1 ± 0.2

10 Surf Parking, Outdoor 3.3 ± 1.2 5.3 ± 0.7 2.1 ± 1.3 4.7 ± 2.9 3.3 ± 0.6 1.4 ± 0.5

11 Underground Garage, Outdoor 8.6 ± 7.4 26.8 ± 3.6 3.9 ± 2.3 17.1 ± 11.2 32.9 ± 2.0 12.4 ± 7.2

12 Toll Plaza, Outdoor 7.6 ± 2.7 6.5 ± 8.8 3.2 ± 0.2 6.2 ± 4.3 7.4 ± 16.5 1.8 ± 0.3

13 Following High Emitter, In-Cabin 8.4 ± 2.6 12.0 ± 4.2
3-7

Table 3-3. Average and standard deviations in ratios of BTEX and 1,3-BD from time-integrated canister samples to the corresponding 

hourly automated GC data from the ambient air monitoring sites in Houston. 

 Microenvironment Benzene Toluene Etbenzene m&p-Xylene o-Xylene 1,3-Butadiene

Summer

1 Congested Freeway, In-Cabin 9.8 ± 3.8 7.8 ± 1.9 5.4 ± 1.8 5.2 ± 0.6 6.6 ± 1.5 8.1 ± 3.6

2 Urban Canyon, In-Cabin 7.4 ± 3.0 6.8 ± 1.1 5.6 ± 3.3 5.6 ± 1.4 5.8 ± 2.4 7.3 ± 1.2

3 Refueling, In-Cabin 565 ± 791 446 ± 666 140 ± 188 115 ± 136 117 ± 147

4 Underground Garage, In-Cabin 19.4 ± 13.9 17.2 ± 15.0 16.0 ± 13.7 14.2 ± 12.8 17.1 ± 17.0 50.0 ± 66.4

5 Toll Plaza, In-Cabin 9.1 ± 4.4 7.8 ± 3.6 6.8 ± 4.9 6.2 ± 3.4 7.1 ± 3.8 7.8 ± 5.2

6 Tunnel, In-Cabin 25.9 ± 14.1 12.4 ± 6.8 7.8 ± 2.9 7.5 ± 2.7 8.9 ± 2.7 37.9 ± 20.0

7 Refueling, Outdoor 1312 ± 1811 974 ± 1356 335 ± 479 219 ± 227 197 ± 198

8 Sidewalk 15.4 ± 10.6 10.6 ± 4.4 12.5 ± 15.3 11.9 ± 14.0 14.2 ± 17.1 5.8 ± 2.4

9 Sidewalk/BusStop 4.7 ± 2.0 2.9 ± 1.3 1.8 ± 0.4 1.9 ± 0.5 2.3 ± 0.6 2.0 ± 1.3

10 Surf Parking, Outdoor 11.5 ± 5.5 8.3 ± 2.8 7.4 ± 2.1 6.7 ± 3.1 7.0 ± 3.2 5.5 ± 1.9

11 Underground Garage, Outdoor 16.7 ± 5.3 15.7 ± 7.2 13.8 ± 7.2 11.1 ± 7.2 14.4 ± 9.6 39.6 ± 29.5

12 Toll Plaza, Outdoor 14.7 ± 8.5 11.3 ± 10.2 9.2 ± 8.3 8.5 ± 7.6 11.0 ± 10.6 13.4 ± 13.1

Winter

1 Congested Freeway, In-Cabin 4.6 ± 1.6 6.4 ± 3.7 6.4 ± 3.0 8.8 ± 5.2 9.7 ± 5.1 0.36 ± 0.06

2 Urban Canyon, In-Cabin 17.0 ± 21.7 22.7 ± 27.7 22.1 ± 26.4 31.1 ± 36.9 26.7 ± 28.9

3 Refueling, In-Cabin 35.0 ± 25.4 36.5 ± 27.2 22.7 ± 18.2 25.3 ± 19.2 24.2 ± 16.3

4 Underground Garage, In-Cabin 37.2 ± 15.8 32.3 ± 12.9 24.0 ± 9.4 23.2 ± 8.5 25.0 ± 9.7

5 Toll Plaza, In-Cabin 3.5 ± 1.7 3.7 ± 1.5 4.3 ± 1.7 4.6 ± 2.0 5.3 ± 2.1

6 Tunnel, In-Cabin 8.5 ± 6.7 9.0 ± 6.9 7.0 ± 4.5 8.9 ± 6.4 9.9 ± 7.2 1.91 ± 0.54

7 Refueling, Outdoor 160 ± 148 119 ± 92 49.1 ± 39.2 56.1 ± 54.3 44.6 ± 33.7

8 Sidewalk 2.8 ± 0.8 2.6 ± 1.0 2.7 ± 0.7 3.6 ± 1.7 3.7 ± 1.3 0.09 ± 0.10

9 Sidewalk/BusStop 3.3 ± 0.3 3.6 ± 0.3 3.5 ± 1.1 4.2 ± 0.7 4.3 ± 0.8

10 Surf Parking, Outdoor 4.3 ± 3.0 7.5 ± 6.4 5.7 ± 2.9 6.1 ± 2.1 6.0 ± 2.5

11 Underground Garage, Outdoor 28.3 ± 16.5 25.0 ± 13.0 20.8 ± 11.3 21.9 ± 11.1 22.9 ± 10.7 0.60 ± 0.03

12 Toll Plaza, Outdoor 4.8 ± 0.7 4.5 ± 1.4 4.5 ± 1.8 4.9 ± 1.6 5.4 ± 1.9
3-8

Table 3-4. Houston benzene ME/ambient ratio comparison with HAPEM benzene ME factors 

ME Summer Winter HAPEM4 

PROX

HAPEM5 PROX

Distribution (mode;median) 

HAPEM5 PROX 

Range 

1 Congested Freeway, In-Cabin 9.8 4.6 5.2, 6.9* Triangular 1.9; 4.9 0-14.4

2 Urban Canyon, In-Cabin 7.4 17 4.4 Triangular 1.9; 4.9 0-14.4

3 Refueling, In-Cabin 565 35 4.4 Triangular 1.6; 2.7 0-7.1

4 Underground Garage, In-Cabin 19 37 1.0 Triangular 1.6; 2.7 0-7.1

5 Toll Plaza, In-Cabin 9.1 3.5 4.4 Triangular 1.9; 4.9 0-14.4

6 Tunnel, In-Cabin 26 8.5 4.4 Triangular 1.9; 4.9 0-14.4

7 Refueling, Outdoors 1300 160 4.4 Triangular 1.6; 2.7 0-7.1

8 Sidewalk 15 2.8 4.4 Triangular 1.6; 2.7 0-7.1

9 Sidewalk, BusStop 4.7 3.3 4.4 Triangular 1.6; 2.7 0-7.1

10 Surface Parking, Outdoors 12 4.3 4.4 Triangular 1.6; 2.7 0-7.1

11 Underground Garage, Outdoors 17 28 1.0 Triangular 1.6; 2.7 0-7.1

12 Toll Plaza, Outdoors 15 4.8 4.4 Triangular 1.6; 2.7 0-7.1

* truck, car 
3-9

Figure 3.1a. Location of ME sampling and fixed monitoring stations in Chicago Metro Area. 
3-10

Figure 3.1b. Location of ME sampling and fixed monitoring stations in Houston Metro Area. 
3-11

Figure 3.1c. Location of ME sampling and fixed monitoring stations in Atlanta Metro Area.
3-12 

Benzene - Estimated Average 1-minute Concentrations

0

20

40

60

80

100

120

140

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

Benzene - Estimated Maximum 1-minute Concentrations

0

500

1000

1500

2000

2500

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

Figure 3-2a. Comparison of average versus the maximum 1-minute benzene levels by 

city, season and microenvironment. 
3-13 

1,3-Butadiene - Estimated Average 1-minute Concentrations

0

1

2

3

4

5

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

1,3-Butadiene - Estimated Maximum 1-minute Concentrations

0

5

10

15

20

25

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

Figure 3-2b. Comparison of average versus the maximum 1-minute 1,3-butadiene levels 

by city, season and microenvironment. 
3-14 

Formaldehyde - Estimated Average 1-minute Concentrations

0

10

20

30

40

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

Formaldehyde - Estimated Maximum 1-minute Concentrations

0

20

40

60

80

100

120

140

160

01020304050708091011121301020304050708091011121301020304050607080910111213010203040506070809101112010203040506070809101112010203040506070809101112

Summer Winter Summer Winter Summer Winter

Atlanta Chicago Houston

Conc (ppbv)

Figure 3-2c. Comparison of average versus the maximum 1-minute formaldehyde levels 

by city, season and microenvironment. 
4-1

4. Relationships of Attached Garage and Home Exposures to Fuel 

Type and Emission Levels of Garage Sources 

4.1 Introduction

This chapter describes experiments to determine relationships between measured 

fuel and exhaust components in the attached garage, adjacent room (kitchen), and 

garaged vehicle emission levels. The same vehicles, fuels and vehicle malfunctions used 

here are used in Chapter 5 to explore the effects of ventilation, proximity, and leading 

vehicle emission levels on trailing vehicle in-cabin exposures. These measurements are 

also described in the executive summary and Chapter 1. 

Measurements were performed during June-July 2002 and February-March 2005 

in San Antonio, TX on a sedan and a pickup truck using either non-oxygenated 

conventional gasoline, gasohol (E10), or an MTBE-oxygenated gasoline. The vehicles 

were tested in both a normal emissions mode and a malfunctioning high emitter mode 

where emissions were adjusted to exceed 2 grams of non-methane hydrocarbons 

(NMHC) per mile as measured by the Federal Test Procedure (FTP).

4.2 Experimental 

Methods and procedures specific to the attached garage experiments are 

summarized below. Sampling and analyses methods are described in Chapter 1 and 

Appendix B. 

4.2.1 Vehicles and Vehicle Test Methods

The Southwest Research Institute (SwRI) procured two test vehicles and 

determined their evaporative/tailpipe emissions in the normal/malfunction modes using 

the three test fuels. The test vehicles, a sedan and full-sized V8 truck, were chosen within 

the 1993-1996 model years from vehicles with 90,000-110,000 odometer miles. The 

chosen 1993 Toyota Camry (2.2L 4-cylinder engine) and 1995 Ford F150 Pickup truck 

(5.0L V8 engine) were operated in normal, as purchased, modes and in “high emitter” 

modes with the catalytic converter removed and emission levels above 2 grams per mile 

NMHC as measured on the FTP driving cycle. While converter removal sufficed for the 

F150 truck, a calibrated manifold leak was also needed to achieve the ≥ 2g/mile Camry 

emissions. SwRI determined dynamometer FTP emissions for each vehicle with all three 

fuels in the two emission modes (24 tests). Emission control components could be 

reproducibly adjusted to represent normal and reasonable high-end approximations (≥ 

2g/mile) of real world exhaust emissions. The vehicle properties are summarized in Table 

4.2-1 and included in the SwRI report (Appendix F). 
4-2

Table 4.2-1. Summary of vehicles used. 

Vehicle Make Model Year Engine Malfunction

Truck Ford F150 1995 5.0 L V8 Removed Catalyst.

Sedan Toyota Camry 1993 2.2 L 4 

cylinder 

Removed Catalyst and added 

leak to manifold. 

Regulated exhaust emissions (THC, NMHC, CO, NOx), fuel economy, and 

specific VOCs (MTBE, EtOH, BTEX, 1,3-BD, HCHO) were determined in 

dynamometer FTP tests. During hot-soak SHED tests, THC and specific VOCs (minus 

HCHO) were also determined. 

The FTP exhaust emission test uses the 1372 second Urban Dynamometer 

Driving Schedule (UDDS) that is divided into cold/start transient 505 (Bag 1) and cold 

stabilized 867 (Bag 2) second segments. This portion of the FTP is followed by a 10-

minute soak and a hot/start transient 505 (Bag 3) test. The FTP evaporative emission test 

includes one hour Diurnal Heat Build (DHB) and Hot Soak Loss (HSL) tests. THC/VOC 

emissions are recorded during the HSL segment of the test. Prior to the FTP cold-start 

exhaust test, the DHB is conducted by fueling the test vehicle to 40 percent of tank 

capacity with fuel < 55°F, attaching a heating blanket outside the fuel tank, placing a 

thermocouple in the tank fuel, hooking it up to computer control, and beginning the test 

as fuel reaches 60°F (increasing at 0.4°F per minute for the 60-minute test to a 84°F final 

temperature).

In the HSL segment, conducted immediately following exhaust emission testing, 

the vehicle is driven into an evaporative emission enclosure and allowed to “soak” in the 

enclosure for one hour. THC/VOC emissions are measured at the beginning and end of 

the one-hour segment and hot soak evaporative emissions are calculated. 

4.2.2 Fuel Testing

Test fuel samples were subject to standard tests for Reid Vapor Pressure (RVP), 

distillation range, Specific Gravity, Sulfur, Benzene, HC Category (saturates, olefins, 

aromatics), Oxygenated species (MTBE/EtOH), carbon weight percent, hydrogen weight 

percent, oxygen weight percent, and octane number. These results are presented in Table 

4.3-1. 

4.2.3 Test House 

Fuel component levels were measured in the garage and in a room (kitchen) 

adjacent to an attached garage using the fuels and test vehicles in normal and high emitter 

modes. Appendix I shows the layout of the house. The double garage contained an active 

ceiling fan that minimized emissions stratification and hot spots within the garage. The 

garage also contained a plastic gasoline container and gasoline-powered lawnmower 

filled with the test fuels. The exhaust fan over the kitchen’s stove was not used during the 
4-3

experiments. However, the central air conditioning was active during the summer tests.

Garage and kitchen monitoring was conducted according to the scenarios described in 

Table 4.2-2. Window and door openings, of the garage vehicle door, the kitchen door 

between the garage and kitchen, and kitchen window were scripted. Time-integrated 

canister, DNPH and solid adsorbent (for EtOH) cartridges, and SPME samples were 

collected for each test. EtOH was measured for Chicago fuel only. Continuous or semicontinuous measurements were also operated during the exposure periods. Measurements 

were taken over scripted 30-minute scenario intervals through collocated sampling inlets 

at breathing height (1.5 m) a meter distant from nearby walls in the kitchen and 

unventilated garage. Continuous PID TVOC and Langan CO instruments sampled from 

the kitchen before (background) and during 2002 tests. For the winter 2005 samples, a 

second PID TVOC and the NDIR CO instrument were used to monitor the garage 

continuously. In the summer 2002 samples, the continuous MS200 BTEX and A-Ω 

HCHO monitors sampled cyclically through collocated inlets in the garage and kitchen 

every 10 minutes. 

A half-filled two-gallon plastic gasoline storage container with vent opened was 

placed adjacent to a fueled lawnmower, with gas tank half filled, against the center of the 

rear garage wall common with the kitchen. The container and lawnmower filled with the 

appropriate fuel were placed in the garage one day before the series of vehicle tests for 

that fuel began and remained there over the duration of the tests. Scenario conditions 

were changed every 30 minutes over the 3-hour protocol as described in the Table 4.2-2. 

Ambient garage temperatures were recorded each 30 minutes. Tests were conducted 

daily (excluding weekends) over a two week period. 

Table 4.2-2. Protocol for attached garage experiments. 

Condition Time 

(min)

Garage 

Door 

Kitchen 

Door 

Kitchen 

Window

Inlet 

Location

Continuous 

Instruments

SPME Integrated 

Canisters/ 

Cartridges

Background

No vehicle, 

but lawn 

mower & gas

10

closed closed closed

garage yes

2 2 10 kitchen yes

10 garage yes

Hot soak 

vehicle,

lawnmower, 

& gas

10

closed

opened 1 

min

& closed

closed

kitchen yes

2 

2 

10 garage yes

10 kitchen yes

Cooling 

vehicle,

lawnmower, 

& gas

10 closed closed closed garage yes

2 10 kitchen yes

10 garage yes

Cold vehicle, 

lawnmower, 

& gas

10 closed closed open kitchen yes

2 10 garage yes

10 kitchen yes
4-4

Cold start,

idling, 

lawnmower, 

& gas

10 open opened 1 

min

& closed

closed garage yes

2 10 kitchen yes

10 garage yes

No vehicle, 

but 

lawnmower, 

& gas

10 closed closed closed kitchen yes

2 10 garage yes

10 kitchen yes

The first scenario condition, background, assesses levels in the kitchen and garage 

prior to the beginning of vehicle testing. In the garage, background will include emissions 

from the gasoline container and lawn mower. The hot soak condition should most closely 

reflect the hot soak SHED tests performed by SwRI. In this condition, the exposure 

scenario is that of a person coming home from shopping and conveying purchases 

through the kitchen-garage door into the home, allowing some enhanced air exchange 

between the garage and the kitchen. The next condition, cooling vehicle, reflects a period 

where the trapped garage air remains in the kitchen. The cold vehicle condition is 

performed with the kitchen window open to allow outside fresh air exchange within the 

kitchen (keeping the garage door closed). The cold start condition simulates a person 

warming up his car in an open garage prior to leaving; the kitchen door is open for one 

minute to account for the extra trips to and from the vehicle. The vehicle is started and 

then idled for the entire 30 minutes. The final condition, no vehicle, represents kitchen 

exposures after the vehicle has left. One integrated canister and cartridge samples were 

collected over background test and another one over all five phases of the garage 

experiments, as shown in Table 4.2-2. 

4.3 Results

4.3.1 Fuel Analyses

The results of the fuel analyses are presented in Table 4.3-1. Fewer tests were run 

on the Summer 2002 fuels. 

The results confirm that there was no oxygenate in the Atlanta conventional fuel, 

that MTBE was present in the Houston fuel, and that ethanol was present in the Chicago 

fuel. Across seasons total aromatics were similar in the oxygenated fuels but higher in the 

conventional fuel. Benzene levels range from 0.5-1.2 % with the conventional summer 

fuel highest. The Reid Vapor Pressure (RVP) is higher in the winter fuels to ensure cold 

start reliability. 
4-5

Table 4.3-1. Summary of properties for the six test fuels. 

O2 Total wt% = total oxygen weight % 

MeOH = methanol; EtOH = ethanol

4.3.2 Vehicle Regulated and Hot Soak Emissions 

 The vehicle emission tests were conducted as described in Section 4.2. The details 

of these tests are described in the SwRI Report, attached in Appendix F. Tables 4.3-2 

through 4.3-5 show the measured regulated exhaust and hot soak emissions from the test 

vehicles for summer and winter test fuels. The FTP results show that all emissions 

increased and the high emitter target of ≥ 2 grams NMHC per mile was achieved. 
4-6

 Table 4.3-2. Regulated and Hot Soak Emissions from the Ford F-150, Summer 2002. 

Table 4.3-3. Regulated and Hot Soak Emissions from the Ford F-150, Winter 2005. 

Table 4.3-4. Regulated and Hot Soak Emissions from the Toyota Camry, Summer 2002 

Table 4.3-5. Regulated and Hot Soak Emissions from the Toyota Camry, Winter 2005 
4-7

4.3.3 Garage and Kitchen Exhaust/Evaporative Fuel Component Levels 

This section summarizes emission component concentrations observed in the 

kitchen and attached garage. As discussed in Chapter 1, measured 1,3-BD levels are 

biased upwards in the presence of high MTBE concentrations. In addition, a single 

garage sample (sedan with gasohol in normal mode) was invalidated. The sample 

contained high anomalous levels of BTEX, BTEX/1,3-BD and BTEX/CO ratios were 25- 

and 88-fold higher, respectively, in the normal mode than the high emitter tests, 

suggesting an anomalous source of BTEX such as an unrecorded garage fuel spill.

BTEX and 1,3-butadiane data presented in Tables 4.3-6 to 4.3-12 are from the 

canister samples and ethanol is from the sorbent cartridges, as described in Chapter 1 and 

Appendix B.. 

4.3.3.1 Background and Overall Concentrations 

The background samples, taken before the vehicle was brought into the garage, 

are presented in Table 4.3-6 for both the average (top section, separated for summer and 

winter) and ranges of the data. Note that the max-min ranges denote the single highest 

values for each species individually across tests. Gaps indicate missing samples. Both 

HCHO and EtOH show relatively higher levels in the kitchen. HCHO off-gases from 

residential furnishings and construction materials. EtOH is emitted from people, foods, 

cleaning & personal care products, domestic garbage, and alcoholic beverages. 

Table 4.3-6. Summary of Background Concentrations in Kitchen and Garage. Units are 

ppbv, except as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Kitchen Backgrounds

Summer 0.08 1.70 6.50 0.67 2.30 1.05 0.42 0.35 49.83 1215.58 13.57

Winter 0.21 3.93 7.47 4.82 7.47 4.32 1.31 0.87 13.51 5.47

Garage Backgrounds

Summer 0.02 2.68 8.87 0.92 3.25 1.14 0.20 0.15 20.29 6.28

Winter 0.12 2.29 5.40 0.85 3.13 1.21 1.11 0.78 7.70 2.65

Kitchen, all

Min 0.02 0.73 3.33 0.37 1.25 0.50 0.00 0.15 5.50 53.60 3.00

Max 1.33 11.76 15.49 38.21 32.27 24.64 6.16 5.29 106.63 2194.10 24.56

Garage, all

Min 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.85 0.90 1.20

Max 0.90 11.47 25.72 3.19 11.33 4.27 3.78 7.01 35.63 1475.60 13.89

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

The ranges of all samples taken during the vehicle-related scenario portions are presented 

in Table 4.3-7. As expected, the lower concentrations stem from normal mode vehicles 

and higher levels from the high emitter mode. 
4-8

Table 4.3-7. Summary of Test Concentration Ranges in Kitchen and Garage. Units are 

ppbv, except as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Kitchen, all

Min 0.02 0.18 2.49 0.25 0.78 0.43 0.00 0.00 0.00 158.80 0.00

Max 1.64 11.17 15.58 3.02 9.06 5.12 13.27 10.85 95.59 670.20 23.86

Garage, all

Min 0.03 1.33 2.48 0.39 1.25 0.51 0.00 0.20 0.00 5.80 0.00

Max 36.35 65.44 93.67 18.23 50.72 19.36 185.63 39.16 174.20 27.70 30.79

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

4.3.3.2 Seasonal Impacts 

 

Seasonal max trends are inconsistent. Table 4.3-8 shows that differences seen in 

the kitchen are smaller than in the garage. The garage has higher exhaust 1.3-BD and 

HCHO in the summer, but lower CO values than in the winter. 

Table 4.3-8. Seasonal Impact on Observed Maximum Concentrations (Units are ppbv, 

except as noted). 

. Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Kitchen Max-S 1.42 7.77 14.64 1.84 6.44 2.98 10.49 1.62 95.59 670.20 23.86

Max-W 1.64 11.17 15.58 3.02 9.06 5.12 13.27 10.85 54.78 15.51

Garage Max-S 36.35 65.44 93.67 18.23 50.72 19.36 93.63 28.60 174.20 27.70 30.79

Max-W 8.47 24.68 34.61 6.05 22.78 8.04 185.63 39.16 54.78 15.51

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

 Tables 4.3-9 and 4.3-10 provide max and average values for normal mode 

vehicles only. The maximum values for the normal vehicles are generally lower with 

winter mean values higher than summer.

Table 4.3-9. Seasonal Impact on Observed Maximum Concentrations (Units are ppbv, 

except as noted), Normal Mode Vehicles Only. 

Normal Only Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Kitchen Max-S 0.29 4.87 14.35 1.80 6.44 2.48 1.59 0.81 95.59 519.70 23.86

Max-W 1.55 11.17 14.80 2.76 8.50 3.44 13.27 3.07 31.31 11.00

Garage Max-S 4.76 21.02 48.73 6.99 19.92 7.73 8.95 3.86 58.53 27.70 13.79

Max-W 8.47 24.68 34.61 6.05 22.78 8.04 185.63 39.16 54.78 15.51

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde 

Table 4.3-10. Seasonal Impact on Observed Average Concentrations (Units are ppbv, 

except as noted), Normal Mode Vehicles Only. 
4-9

Normal Only Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Kitchen Ave-S 0.16 3.25 11.54 1.39 4.58 1.97 0.56 0.39 53.33 339.25 13.48

Ave-W 0.43 4.38 7.24 1.31 4.12 1.72 3.76 0.92 14.54 4.99

Garage Ave-S 1.87 8.72 20.36 3.06 8.67 3.51 2.47 1.82 26.44 17.35 6.26

Ave-W 2.35 8.15 14.44 2.54 9.00 3.39 36.64 6.45 18.72 4.79

4.3.3.3 Fuel and Vehicle Effects

This section addresses fuel, vehicle, and operational mode separately for all 

seasons. For the sedan, Table 4.3-11 indicates highest mean MTBE values for Houston 

fuel and EtOH for Chicago, as expected, with high-emitter/malfunction effects strongest 

in the garage. 

Table 4.3-11. Effect of Fuel and Operational Mode of the Sedan on Observed Levels in 

the Kitchen and Garage (Units are ppbv, except as noted). 

. Location Fuel Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Normal Garage Atlanta 0.55 2.40 6.09 0.98 3.24 1.38 0.82 0.31 7.16 1.78

Houston 0.95 3.56 9.78 1.51 5.20 2.08 10.81 0.56 22.25 5.11

Chicago 1.19 3.40 8.29 1.39 4.91 2.06 0.48 0.45 11.75 27.70 3.81

Kitchen Atlanta 0.06 2.01 8.42 1.03 3.61 1.45 0.10 0.10 63.45 16.78

Houston 0.24 2.82 7.49 1.10 3.69 1.59 3.35 0.52 24.01 6.65

Chicago 0.06 3.82 8.45 1.26 4.40 1.91 0.27 0.29 13.38 158.80 2.48

Malfunction Garage Atlanta 1.42 26.80 44.40 4.03 13.08 4.86 16.67 6.27 23.35 9.03

Houston 2.54 12.45 25.68 4.20 14.11 5.53 49.97 13.29 30.72 7.35

Chicago 1.92 9.54 11.26 1.65 5.64 2.18 1.13 12.16 13.08 19.00 7.35

Kitchen Atlanta 0.86 9.13 15.11 2.06 6.47 2.92 0.35 5.59 21.99 6.97

Houston 0.23 4.14 9.68 1.74 5.42 2.65 10.19 1.30 26.19 8.37

Chicago 0.23 2.81 6.04 1.03 3.51 1.53 0.30 0.76 25.93 670.20 9.88

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

For the truck, Table 4.3-12 indicates lesser fuel impacts on normal mode garage 

levels than for the sedan. For the malfunction mode, Houston fuel garage values exceed 

those of the other two fuels. 

Table 4.3-12. Effect of Fuel and Operational Mode of the Truck on Observed Levels in 

the Kitchen and Garage (Units are ppbv, except as noted). 

. Location Fuel Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

Normal Garage Atlanta 2.40 11.28 26.45 3.79 11.05 4.32 0.44 2.13 38.17 8.25

Houston 1.39 9.69 24.99 3.83 11.12 4.46 10.46 2.15 38.12 8.85

Chicago 2.55 9.64 15.61 2.99 8.56 3.41 1.74 2.87 0.00 7.00 0.00

Kitchen Atlanta 0.12 1.65 8.23 0.83 2.58 1.04 0.10 0.28 35.68 8.88

Houston 0.37 4.57 9.68 1.62 4.85 2.28 7.20 0.82 45.47 13.40

Chicago 0.92 8.02 14.08 2.27 6.97 2.78 1.95 1.94 21.61 519.70 7.25

MalfunctionGarage Atlanta 3.74 16.19 26.42 3.87 12.22 4.58 0.38 8.03 45.11 9.79

Houston 22.41 45.06 64.14 12.14 36.75 13.70 139.63 33.88 114.49 23.15

Chicago 2.73 7.72 11.55 1.85 5.87 2.16 0.06 2.52 32.96 5.80 17.28

Kitchen Atlanta 0.24 3.25 7.65 1.99 5.67 3.15 0.13 0.68 42.56 10.91

Houston 0.80 4.23 9.05 1.42 4.25 1.89 4.57 1.33 52.72 14.55

Chicago 0.11 4.11 7.29 1.45 4.67 1.92 0.03 0.28 29.37 414.10 7.65
4-10

 Figure 4.3-1 illustrates the effect of fuel and mode (N-normal, F-malfunction) on 

mean garage values averaged across vehicle and season. Figure 4.3-2 shows the kitchen 

values. Both figures report relatively high 1,3-BD values for the Houston fuel high 

emitter mode. Since both are also associated with high MTBE values, these 1,3-BD 

values are suspect as discussed earlier and in Chapter 1. The same caveat applies to 

Figures 4.3-3 and 4.3-4. 

0

10

20

30

40

50

60

70

80

Budi13

Benze

Tolue

Etbz

Mp_xyl

O_xyl

MTBE

CO,ppm

Formal

EtOH

Acetal

compound

ppbv

Atlanta-N

Atlanta-F

Houston-N

Houston-F

Chicago-N

Chicago-F

Figure 4.3-1. Effect of fuel and mode on observed concentrations in the garage. The 

legend “N” is normal and “F” is malfunction. The 1,3-BD value for Houston-F is suspect. 
4-11

0

5

10

15

20

25

30

35

40

45

50

Budi13

Benze

Tolue

Etbz

Mp_xyl

O_xylMTBE

CO,ppm

Formal

EtOH

Acetal

compound

ppbv

Atlanta-N

Atlanta-F

Houston-N

Houston-F

Chicago-N

Chicago-F

339,542

Figure 4.3-2. Effect of fuel and mode on observed concentrations in the kitchen. The 

legend “N” is normal and “F” is malfunction. The 1,3-BD value for Houston-F is suspect.

The kitchen concentrations are dominated by HCHO and EtOH, but high 

background levels indicate kitchen sources rather than the garaged vehicles. 

The effect in the garage is expected to be more directly correlated with the 

vehicle. Figure 4.3-3 shows the concentrations seen in the garage only for the sedan, 

looking at the effect of the fuel and operational mode. The same presentation for the truck 

only is in Figure 4.3-4. 
4-12

0

10

20

30

40

50

60

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

compound

Garage, ppbv

Atlanta-N

Atlanta-F

Houston-N

Houston-F

Chicago-N

Chicago-F

Figure 4.3-3. Effect of fuel and mode on observed sedan garage levels. The legend “N” is 

normal and “F” is malfunction. The 1,3-BD level for Houston-F is suspect, see text.

0

20

40

60

80

100

120

140

160

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO,ppm Formal EtOH Acetal

compound

Garage, ppbv

Atlanta-N

Atlanta-F

Houston-N

Houston-F

Chicago-N

Chicago-F

Figure 4.3-4. Effect of fuel and mode on observed truck garage levels. The legend “N” is 

normal and “F” is malfunction. The 1,3-BD level for Houston-F is suspect, see text.
4-13

Comparison of 1,3-BD, BTEX and CO background concentrations with garage 

and kitchen concentrations for each test is shown in Figure 4.3-5 and Figure 4.3-6 for 

Summer 2002 and Winter 2005, respectively. In general, these figures indicate 

compound range rankings of garage » kitchen ~ background, especially for vehicle in the 

normal mode. For vehicles in high emitting mode, the increase in kitchen levels could be 

seen. In Winter 2005, a few high background samples were observed, possibly due to a 

prolonged storage of a plastic gasoline container in the garage. 
4-14

0

50

100

150

200

250

300

350

400

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

K-BACKG

G-BACKG

K-TEST

G-TEST

ppbv

0

5

10

15

20

25

30

35

CO (ppm)

budi13 mtbe benze tolue etbz mp_xyl o_xyl CO

Toyota, 

normal 

Toyota, 

malfunction

Atlanta (Baseline) Fuel

Truck, 

normal 

Truck, 

malfunction 

Toyota, 

normal 

Toyota, 

normal 

Truck, 

malfunction Toyota, 

malfunction

Toyota, 

malfunctio

Truck, 

normal 

Houston (MTBE) Fuel

Truck, 

malfunction Truck, 

normal 

Chicago (Ethanol) Fuel

Figure 4.3-5. Concentrations of 1,3-butadiene, MTBE and BTEX and CO as measured from canisters in the garage and the adjacent 

kitchen in Summer 2002 
4-15

0

50

100

150

200

250

300

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

K-TEST

G-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

G-BACKG

K-BACKG

G-TEST

K-TEST

ppbv

0

5

10

15

20

25

30

35

40

45

CO (ppm)

budi13 mtbe benze tolue etbz mp_xyl o_xyl CO_ppm

Atlanta (Baseline) Fuel

Toyota, 

normal Toyota, 

malfunction

Truck, 

normal 

Truck, 

malfunction 

Houston (MTBE) Fuel

Toyota, 

normal 

Toyota, 

malfunction Truck, 

normal 

Truck, 

malfunction 

Chicago (Ethanol) Fuel

Toyota, 

normal Toyota, 

malfunction Truck, 

normal 

Truck, 

malfunctio

M

M

A

Figure 4.3-6. Concentrations of 1,3-butadiene, MTBE and BTEX (A) and CO (B) as measured from canisters in the garage and the 

adjacent kitchen in Winter 2005. M=sample missing or invalid. 
4-16

4.3.3.4 Comparison with Emissions Data 

There are five distinct garage scenario phases after the background sample as described 

in Table 4.2-2. The first phase, hot soak, is best compared to the hot soak SHED test run by 

SwRI. Benzene canister values are compared in Figure 4.3-7. While there does not appear to be a 

strong correlation, the canister samples collected in the garage average over all five scenarios, 

not only hot soak. The high outlying points come from the truck in high emitter mode and are 

expected to be high. SPME samples taken every half-hour correspond better with the phases of 

the experiment. Benzene winter SPME values for hot soak phase are compared with SHED 

values in Figure 4.3-8A (all samples) and 4.3-8B (outliers removed). Although the correlation is 

not very good for all samples (A), it improves after removing two outliers from the truck in high 

emitter mode (B). The high emitting vehicles are generally not stable and the SHED results may 

be very different from the garage, due to different time and location.

 

0

10

20

30

40

50

60

70

0 20 40 60 80 100 120 140 160

SHED results, mg

Garage, ppbv

Figure 4.3-7. Comparison of SHED results with the observed canister concentration in the garage 

for benzene. 

0

5

10

15

20

25

30

35

0 20 40 60 80 100 120 140 160

SHED, mg

Garage hot soak, ppbv (by SPME)

y = 0.1317x + 4.8305

R2

 = 0.4323

0

5

10

15

20

25

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

SHED, MG

Garage hot soak, ppbv (SPME)

Figure 4.3-8. Comparison of the SHED results with the observed SPME hot soak concentration 

in the garage for benzene A: all data, B: two outliers removed.

A B
4-17

Cold start 1,3-BD and benzene canister values can be compared to the FTP Bag 1 data in Figures 

4.3-9 and 4.3-10, respectively. Garage 1,3-BD values appear insensitive to FTP levels. It is 

possible that this may reflect another 1,3-BD analytical challenge from NO2 scavenging in the 

FTP sample; the high point in Figure 4.3-7 is also suspect since 1,3-BD occurs concurrent with 

high MTBE levels. The Figure 4.3-8 garage benzene scatter is similar to 1,3-BD and also appears 

insensitive to FTP levels; however, benzene is stable in canisters and these values should be 

accurate. Figure 4.3-11 compares garage SPME cold start values to FTP Bag 2 values. This 

comparison trends upwards with garage values increasing with increasing FTP emissions, 

although not strongly. 

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80

FTP Bag 1, mg/mi

Garage, ppbv

Figure 4.3-9. Comparison of FTP Bag 1 emissions and observed garage levels of 1,3-BD.
4-18

0

10

20

30

40

50

60

70

0 50 100 150 200 250

FTP Bag 1, mg/mi

Garage, ppbv

Figure 4.3-10. Comparison of FTP Bag 1 benzene emissions and observed garage levels. 

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100 120 140

FTP Bag 1, mg/mi

Garage, cold start, ppbv (by SPME)

Figure 4.3-11. Comparison of hot soak FTP Bag 1 benzene emissions and observed SPME 

garage values. 
4-19

4.3.3.5 Relationships of Garage and Kitchen Concentrations

Kitchen values would be expected to increase with increasing garage levels from vehicle 

and fuel container sources. Based on their high background levels, EtOH and HCHO would not 

be good candidates for tests. Three other species 1,3-BD, CO, and benzene are plotted in Figures 

4.3-12, 4.3-13 and 4.3-14, respectively. 

 Figure 4.3-12A shows a weak 1,3-BD trend which seems to be driven mostly by outliers 

associated with high level MTBE interference. As explained in Chapter 1 (page 1-6) elevated 

MTBE concentrations biases measured 1,3-BD levels upwards, due to the thermal decomposition 

of MTBE (in the order of 1 to 5 %) in a GC injector. The removal of two outliers (for the truck 

with MTBE fuel in malfunction mode) eliminates any correlation between garage and kitchen 

concentrations (Figure 4.3-12B). 

 Figure 4.3-13 trends toward a CO insensitivity to garage concentrations. The high value 

occurred for the sedan in malfunction mode; the continuous data show a 100 ppm CO spike at 

the beginning of the cold-start phase that may have penetrated through a briefly opened kitchen 

door. Figure 4.3-14 shows that there is no correlations between kitchen and garage benzene 

concentrations. However, it has to be pointed out that these kitchen – benzene correlations are 

shown for the time-integrated canister samples that were collected over 2.5 hr duration of the 

experiment. During this time several 30-min scenarios were executed, as shown in Table 4-2.2. 

The differences in ventilation conditions between garage and kitchen are the most probably 

responsible for the lack of correlations between species measured from canisters. 

y = 0.0298x + 0.2539

R2

 = 0.2034

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 10 20 30 40

Garage Concentration, ppbv

Kitchen Concentration,ppbv

A

y = 0.0141x + 0.2965

R2

 = 0.002

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 1 2 3 4 5 6

Garage Concentrations, ppbv

Kitchen Concentrations, ppbv

B

Figure 4.3-12. Comparison of garage and kitchen concentrations for 1,3-BD. A – all data, Bwith two outliers removed (see text). 
4-20

y = 0.04x + 0.84

R2

 = 0.05

0

2

4

6

8

10

12

0 10 20 30 40 50

Garage Concentration, ppbv

Kitchen Concentration,ppbv

 

Figure 4.3-13. Comparison of garage and kitchen concentrations of carbon monoxide. 

y = 0.04x + 3.61

R2

 = 0.06

0

2

4

6

8

10

12

0 20 40 60 80

Garage Concentration, ppbv

Kitchen Concentration,ppbv

Figure 4.3-14. Comparison of garage and kitchen concentrations of benzene. 
4-21

4.4 Discussion

 The objective of this section was to test the effects of attached garage on indoor home 

levels of fuel and exhaust components. The experiment simulates common activities such as 

coming home with a warm car or leaving home after starting a cold vehicle. 

Various parameters are assessed in section 4.3 to determine their effects on air levels in 

the adjacent room (here a kitchen) connecting to the garage. Two target components, HCHO and 

EtOH, had high kitchen background values indicating indoor sources of these materials. 

Average HCHO levels were higher in summer than winter, consistent with enhanced off-gassing 

of building materials and/or penetration of ambient photochemical HCHO. It has been also 

reported (Reiss et al, 1995; Wang and Morrison, 2006; Weschler, 2006) that a larger fraction of 

indoor HCHO and other oxygenated-low molecular weight hydrocarbons can result from 

heterogeneous processes. Ozone originating from outdoors can be deposited onto indoor surfaces 

and react with different materials to produce low molecular weight organic acids and aldehydes. 

The concentrations of these species are higher during the summer when more ozone penetrates 

indoors. 

 Tables 4.3-8 to 4.3-10 show a seasonal impact where kitchen BTEX, MTBE and CO 

species are higher in winter than summer. The exception is toluene which shows a minimal 

difference that actually averages higher in summer for normal mode vehicles. This is consistent 

with indoor toluene emissions from paints, adhesives, cleaning, and personal care products. 

Tables 4.3-8 and 4.3-9 focus on normal mode vehicles to remove the variability of high emitter 

modes in assessing the seasonal effect. Since many species higher in the winter come from both 

evaporative and exhaust emissions, it is possible that winter enhanced fuel RVP contributes to 

the apparent seasonal effect. In addition, a large number of studies have shown that home air 

exchange rates are typically lower during the winter. This would result in longer residence times 

(thus accumulation) of pollutants generated in the garage and further infiltration to the kitchen 

area.

 Tables 4.3-10 and 4.3-12 show vehicle data separately for each fuel. MTBE and ethanol 

are highest for fuels containing those species, as anticipated. Otherwise, there is not a strong fuel 

effect across vehicles. 

FTP exhaust and SHED evaporative emissions were tested for each vehicle, fuel, and 

emissions mode, and compared to observed levels in the garage. These comparisons are 

challenging in that canisters integrate across hours covering not only hot soak, adjustments to the 

air exchange, and cold start. Concurrent SPME samples are collected for each condition. 

However, neither canister nor SPME samples show strong correlations with hot soak emissions 

(Figures 4.3-5 to 4.3-8), although cold-stabilized FTP Bag 2 benzene appears reasonably 

correlated to the cold-start SPME (Figure 4.3-9). 

 Correlations of kitchen levels with garage concentrations are presented in Figures 4.3-12 

to 4.3-14. These plots evidence weak correlations and could not be used to predict kitchen 

exposures from garage levels. 1,3-BD (Figure 4.3-12) and benzene (Figure 4.3-14) may trend 

weakly upwards, with kitchen levels increasing with garage levels; however CO (Figure 4.3-13) 
4-22

does not. Tables 4.3-6 and 4.3-7 indicate (HCHO & EtOH excepted) compound range rankings 

of garage » kitchen ~ background, especially for vehicle in the normal mode. For vehicles in 

high emitting mode, the increase in kitchen levels is seen from Figures 4.3-5 and 4.3-6. 

4.5 References:

Reiss, R., Ryan, P., Tibbetts, S. E., and Koutrakis, P., Measurement of Organic Acids, 

Aldehydes, and Ketones in Residential Environments and their Relationship to Ozone, Journal of 

the Air and Waste Management Association, 45, 811 (1995). 

Wang, H., G.C. Morrison. Ozone-initiated secondary emission rates of aldehydes from indoor 

surfaces in four homes. ES&T 40: 5262-68 (2006) 

Weschler, C.J. Ozone’s impact on public health: contributions from indoor exposures to ozone 

and products of ozone-initiated chemistry. Environ.Health Perspective 141: 1489-96 (2006). 
5-1

5. Effect of Ventilation, Proximity, and Emission Levels on In-Cabin 

Exposures of Trailing Vehicle. 

5.1 Introduction

This chapter describes experiments designed to determine the relationships 

between ventilation, proximity, fuel, and emission levels of a leading vehicle on in-cabin 

exposures within a trailing vehicle. The same vehicles, fuels and induced malfunctions 

used for this chapter are used for Chapter 4. These measurements are part of the program 

described in the executive summary and Chapter 1. 

 As in the preceding chapter, the vehicles used are a sedan and a pickup truck; the 

fuels used are either a conventional fuel (without oxygenate), an ethanol fuel, or an 

MTBE fuel. The vehicles are tested in a normal and induced-malfunction mode with nonmethane hydrocarbon (NMHC) emissions of about 2 g/mile by Federal Test Procedure 

(FTP).

 The experiments were performed in summer (June-July 2002) and winter 

(February-March 2005). 

5.2 Experimental 

 The Southwest Research Institute (SwRI) procured two test vehicles and 

determined their evaporative/tailpipe emissions in the normal/malfunction modes using 

the three test fuels. The test vehicles, a sedan and full-sized V8 truck, were chosen within 

the 1993-1996 model years from vehicles with 90,000-110,000 odometer miles. The 

chosen 1993 Toyota Camry (2.2L 4-cylinder engine) and 1995 Ford F150 Pickup truck 

(5.0L V8 engine) were operated in normal, as purchased, modes and in “high emitter” 

modes with the catalytic converter removed and emission levels above 2 grams per mile 

NMHC as measured on the FTP driving cycle. While converter removal sufficed for the 

F150 truck, a calibrated manifold leak was also needed to achieve the 2g/mile Camry 

emissions. SwRI determined dynamometer FTP emissions for each vehicle with all three 

fuels in the two emission modes (24 tests). Emission control components could be 

reproducibly adjusted to represent normal and reasonable high-end approximations (2 

g/mile) of real world exhaust emissions. Test vehicle evaporative emissions were also 

measured for test fuels in the two emission modes as reported in Chapter 4. 

 Regulated exhaust emissions (THC, NMHC, CO, NOx), fuel economy, and 

specific VOCs (MTBE, EtOH, BTEX, 1,3-BD, HCHO) were determined in the 

dynamometer FTP tests. During hot-soak SHED tests, THC and specific VOCs (minus 

HCHO) were determined. 

The FTP exhaust emission test uses the 1372 second Urban Dynamometer 

Driving Schedule (UDDS) that is divided into cold/start transient 505 (Bag 1) and cold 

stabilized 867 (Bag 2) second segments. This portion of the FTP is followed by a 10-

minute soak and a hot/start transient 505 (Bag 3) test. The FTP evaporative emission test 
5-2

includes one hour Diurnal Heat Build (DHB) and Hot Soak Loss (HSL) tests. THC/VOC 

emissions are recorded during the HSL segment of the test. Prior to the FTP cold-start 

exhaust test, the DHB is conducted by fueling the test vehicle to 40 percent of tank 

capacity with fuel < 55°F, attaching a heating blanket outside the fuel tank, placing a 

thermocouple in the tank fuel, hooking it up to computer control, and beginning the test 

as fuel reaches 60°F (increasing at 0.4°F per minute for the 60-minute test to a 84°F final 

temperature).

In the HSL segment, conducted immediately following exhaust emission testing, 

the vehicle is driven into an evaporative emission enclosure and allowed to “soak” in the 

enclosure for one hour. THC/VOC emissions are measured at the beginning and end of 

the one-hour segment and hot soak evaporative emissions are calculated. 

5.2.1 Fuel Testing

Test fuel samples were subject to standard tests for Reid Vapor Pressure (RVP), 

distillation range, Specific Gravity, Sulfur, Benzene, HC Category (saturates, olefins, 

aromatics), Oxygenated species (MTBE/EtOH), carbon weight percent, hydrogen weight 

percent, oxygen weight percent, and octane number. These results are presented in 

Chapter 4, Table 4.3-1. 

5.2.2 Relationship between Exhaust Emission Rates and In-Cabin Exposure - 

Trailing Vehicle Test

5.2.2.1 Test Protocol 

The two test vehicles were used as characterized sources of measured in-cabin 

exposures for an instrumented trailing vehicle. SwRI procured a 1996 Chrysler Minivan 

which DRI instrumented as the trailing vehicle (described in Chapter 1) that was driven 

behind the test vehicles over a remote, paved, two-lane, farm-to-market roadway loop 

(described below) for test periods up to 3 hours. Initial measurements made absent the 

test vehicles established background levels. Trailing vehicle tests then implemented far, 

near, and passing scenarios at low (30 mph) and high speeds (60 mph) as noted in Table 

5.2-1. During 'far' scenarios, ‘safe’ vehicle spacing (defined as one car length - 10 feet - 

for each 10 mph) was maintained. During the 'near' scenario, the trailing vehicle 

tailgated the lead vehicle, following at a close distance deemed 'safe' by the professional 

drivers under prevailing traffic and meteorological conditions. During the “passing” 

scenario, the trailing vehicle split its time between tailgating the lead vehicle and 

‘passing,’ immediately behind the lead vehicle but in the adjacent lane. A final idling test 

was conducted while the trailing vehicle was parked on the road shoulder downwind and 

closely behind the parked idling lead vehicle. High (10 min) and low (10 min) ventilation 

conditions were used during all (including idling) tests. 

 Table 5.2-1 details the trailing vehicle protocol. Trailing vehicle in-cabin TVOC 

[ppbRAE-PID (photoionization detector)], CO (Langan T15), BTEX (Kore200MS), and 

HCHO (A-Ω) were continuously monitored. Integrated VOC/NMHC (canister), 
5-3

HCHO/CH3CHO (DNPH cartridge), and EtOH (sorbent tube – EtOH fuel only) samples 

were also collected. SPME BTEX samples were collected every 10 min. Appendix B 

describes sampling and analytical methods in detail. 

 The trailing vehicle tests were conducted south of San Antonio, TX on county 

roads 462 and 2779 off IH 35 in the vicinity of Moore, Big Foot, and Jones Mound, 

Texas. The position of the trailing vehicle was recorded continuously by a Garmin 12XL 

GPS unit recording in UTM using NAD83/WGS84. Speed and direction of the vehicle 

between any two points can be located on a map as illustrated in the June 19, 2002 test 

Figures 5.2-1, -2. The mapping software also contains a digital elevation model that 

creates elevation profiles as shown in Figure 5.2-3. The change in elevation over the 

14.5-mile driving route is approximately 100 feet. 

Table 5.2-1. Protocol for Trailing Vehicle Tests 

Time

Min.

Speed

Mph

Ventilation

Setting Distance Notes

Continuous

Instruments

SPME Time

Integrated

10 high high background Y 1 1

10 low high far

Vehicles:Toyota 

Camry and Ford 

Pick-up truck, in 

normal and 

malfunction mode. 

Fuels: Atlanta 

(conventional), 

Houston (MTBE), 

Chicago (ethanol)

Y 1

One sample 

in Summer 

2002. 

Two 

samples, at 

high/low 

ventilation, 

for Winter 

2005. 

10 low high near Y 1

10 low high passing Y 1

10 high high far Y 1

10 high high near Y 1

10 high high passing Y 1

10 low low far Y 1

10 low low near Y 1

10 low low passing Y 1

10 high low far Y 1

10 high low near Y 1

10 high low passing Y 1

10 idle low adjacent Y 1 1

10 idle high adjacent Y 1
5-4

Figure 5.2-1. Map of Driving Test Location near San Antonio. The blue markers indicate 

the location of the driving tests.
5-5

Figure 5.2-2. Map of Driving Test Location near Moore, TX. 

Figure 5.2-3. Elevation Profile of the Driving Route near Moore, TX. 
5-6

5.3 Results

An initial summary of the trailing vehicle study findings, averaging across all 

vehicles, emission modes, and fuels, is presented below. The lead vehicles and fuels are 

the same as described in Chapter 4; Section 4.3.1 presents the fuel analyses and Section 

4.3.2 the FTP exhaust and evaporative vehicle emissions tests. 

 Note the protocol changes between Summer 2002 and Winter 2005 tests: in the 

Summer tests only half the sample days were begun with a background sample; in the 

Winter tests separate in-cabin samples were taken for the high ventilation and low 

ventilation measurements as detailed in Table 5.2-1. 

5.3.1 Background and Overall Concentrations 

 The background sample results from the summer and winter samples are 

presented in Table 5.3-1. The percent standard deviations are relatively low, suggesting 

that the backgrounds are relatively stable. The MTBE deviations are highest likely 

because this compound is principally present only in the Houston fuel. Background 

MTBE ranged from 0 to 0.21 ppbv. There was only one EtOH background measurement 

for the Summer 2002 (261 ppb) and three valid measurements for Winter 2005. The high 

2002 EtOH value could be connected with the presence of four people in the vehicle 

cabin and/or the presence of the continuous formaldehyde analyzer. The winter values 

range from 9 to 44 ppb and seem to be more reliable. 

Table 5.3-1. Summary of Summer and Winter Background Concentrations. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal EtOH Acetal

Mean Summer (n=6) 0.02 0.27 0.44 0.07 0.17 0.11 0.06 0.13 5.80 261 2.80

% std dev 54% 26% 15% 24% 46% 48% 131% 18% 84% (n=1) 90%

Mean Winter (n=12) 0.03 0.32 0.52 0.11 0.38 0.16 0.08 0.21 5.62 22.07 4.05

% std dev 46% 46% 67% 61% 63% 62% 101% 38% 63% 88% 42%

Mean all 0.03 0.31 0.49 0.10 0.31 0.14 0.07 0.19 5.68 81.81 3.64

% std dev 50% 42% 58% 59% 72% 63% 107% 41% 68% 147% 56%

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

 In Figure 5.3-1 the values for formaldehyde are divided by 10 to fit on the same 

scale as the rest of the species and the EtOH values are not shown. Generally speaking 

the in-cabin background values are < 1 ppbv, with the exception of HCHO and EtOH, 

and relatively consistent from summer to winter. 

In-cabin HCHO measurements likely included contributions from photochemical 

formation from ambient VOCs and in-cabin fabric component degassing of this species. 

As mentioned in Chapter 1 and 4, EtOH may be emitted from people (as a metabolic 

product for certain food types), foods, cleaning& personal care products, etc. 
5-7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal/10 Acetal/10

Concentrations (ppbv or ppmv)

Mean Summer (n=6) Mean Winter (n=12)

Figure 5.3-1. Comparison of Summer and Winter Background Concentrations with 

Standard Deviations. Formaldehyde and acetaldehyde divided by 10 for scale. 

Mean concentrations over all tests are presented in Table 5.3-2. Standard 

deviations are expressed as a percent of test value. As with the background 

concentrations, MTBE likely shows the greatest variability since it was prominent in only 

one fuel. Also, EtOH Summer 2002 measurements (3 values) are most probably artifact, 

whereas Winter 2005 data (6 measurements) seem to be much more reliable.

Table 5.3-2. Summary of Test Concentrations for Summer, Winter and Overall. Units are 

ppbv, except CO as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal EtOH

Mean Summer (n=12) 0.69 1.40 2.32 0.43 1.25 0.59 0.44 1.00 6.84 5.61 2308.07

% std dev 103% 69% 56% 65% 62% 63% 230% 72% 47% 71% 102%

Mean Winter (n=24) 0.59 1.20 1.99 0.37 1.30 0.50 0.83 1.72 4.82 2.54 1.70

% std dev 96% 76% 73% 77% 74% 76% 220% 91% 70% 75% 51%

Mean all 0.62 1.26 2.09 0.39 1.28 0.53 0.70 1.49 5.53 3.63 693.61

% std dev 100% 75% 67% 73% 70% 71% 233% 91% 63% 89% 250%

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

 Figure 5.3-2 and 5.3-3 shows the CO, MTBE and BTEX concentrations for each 

test in the Summer 2002 and Winter 2005, respectively. 
5-8

0

10

20

30

40

50

60

BACKG.

TEST

IDLE

TEST

IDLE

TEST

IDLE

BACKG.

TEST

IDLE

BACKG.

TEST

IDLE

TEST

IDLE

TEST

IDLE

TEST

IDLE

BACKG.

TEST

IDLE

BACKG.

TEST

IDLE

BACKG.

TEST

IDLE

TEST

IDLE

ppbv

0

2

4

6

8

10

12

CO (ppm)

budi13 mtbe benze tolue etbz mp_xyl o_xyl CO

Truck, 

malfunction

Toyota, 

normal 

Toyta, 

malfunction

Truck, 

normal 

Toyota 

malfunction 

Truck 

malfunctio

Toyota 

normal 

Toyota, 

malfunction Track 

normal

Toyota, 

normal 

(M)

Truck 

malfunction

Truck, 

normal 

Atlanta (Baseline) Fuel Houston (MTBE) Fuel Chicago (Ethanol) Fuel

Figure 5.3-2. Concentrations of 1,3-BD, MTBE and BTEX (A) and CO (B) as measured in the cabin of the trailing vehicle, Summer 

2002 
5-9

0

5

10

15

20

25

30

35

40

45

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

BACKG

TEST_HV

TEST_LV

IDLE

ppbv

0

2

4

6

8

10

12

CO (ppm)

budi13 mtbe benze tolue etbz mp_xyl o_xyl CO_ppm

Atlanta (Baseline) Fuel

Toyota, 

normal 

Toyota, 

malfunctio

Truck 

normal

Truck 

malfunction

Toyota, 

normal 

Toyota, 

malfunctio

M

Truck 

normal

Truck 

malfunction

Houston (MTBE) Fuel

Toyota, 

normal 

Toyota, 

malfunction

Truck 

normal

Tr 

ma

Chicago (Ethanol) Fu

Figure 5.3-3. Concentrations of 1,3-BD, MTBE and BTEX and CO as measured in the cabin of the trailing vehicle, Winter 2005 
5-10

Figure 5.3-4 compares summer and winter concentrations which, like background, are 

similar (EtOH data not shown). 

0

1

2

3

4

5

6

7

8

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

Concentrations (ppbv or ppmv)

Mean Summer (n=12) Mean Winter (n=24)

Figure 5.3-4. Comparison of Summer and Winter Concentrations for the Trailing tests.

 Summer background and test values, excluding HCHO and EtOH, are compared 

in Figure 5.3-5. Test values show a substantial increase over background. Correlating all 

summer species except HCHO and EtOH against their background values gives a slope 

of 0.24 (r-square = 0.93). 

 Winter background and test values are presented in Figure 5.3-6, omitting HCHO 

and EtOH. The observation that the winter HCHO values were, on average, lower than 

background values suggests that most of the HCHO observed was not coming from the 

lead vehicle but possibly from photochemical or off-gassing sources (e.g., fabrics) inside 

the trailing vehicle. EtOH background values were higher than test values, which suggest 

some initial off-gassing of EtOH in the vehicle cabin (since background sample was 

collected at the beginning of each experiment). The correlation of all winter species 

values except HCHO and EtOH against their background values had a slope of 0.31 (rsquare = 0.73). 
5-11

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm

Concentration, ppbv or ppm

Summer Background Summer Tests

Figure 5.3-5. Comparison of Summer Background and Test Values. 

0

1

1

2

2

3

3

4

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm

Concentration, ppbv or ppm

Winter Background Winter Tests

Figure 5.3-6. Comparison of Winter Background and Test Values. 

 
5-12

 Table 5.3-3 presents the concentrations and percent standard deviations observed 

during the idle tests. These values showed more of a range and larger deviations than 

either the background or the driving tests. HCHO again appears to be an outlier with the 

lowest deviation of any of the species, likely indicating that this species is not coming 

predominantly from the upwind lead vehicle. EtOH values for Summer 2002 (3 

measurements) are most probably artifact and the Winter 2005 values (4 measurements) 

are more realistic. Since the main difference between the Summer 2002 and Winter 2005 

experiments was the absence of the continuous formaldehyde and MS200 KORE mass 

spectrometer in the trailing vehicle, it is possible that one of these instruments (most 

probably the continuous formaldehyde analyzer, since it is based on the wet method) was 

out-gassing EtOH. 

Table 5.3-3. Summary of Concentrations Observed During Idle Tests. Units are ppbv 

except CO as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal EtOH Acetal

Mean Summer (n=11) 1.50 3.77 4.96 0.80 2.45 0.99 1.54 2.16 9.61 1030.68 9.04

% std dev 149% 116% 103% 110% 109% 104% 195% 160% 43% 59% 65%

Mean Winter (n=12) 0.66 2.57 3.01 0.48 1.71 0.65 0.54 3.06 6.53 3.86 3.37

% std dev 156% 137% 136% 111% 111% 96% 169% 118% 40% 61% 28%

Mean all 1.08 3.17 3.99 0.64 2.08 0.82 1.04 2.61 8.00 517.27 6.08

% std dev 163% 124% 116% 114% 110% 103% 214% 133% 46% 131% 81%

Budi13 = 1,3BD; Benze = benzene; Tolue = toluene, Mp_xyl = m,p-xylene; o_xyl = o-xylene, 

Formal = formaldehyde; EtOH = ethanol, Acetal = acetaldehyde

5.3.2 Vehicle and Fuel Effects

 The preceding section assessed overall mean concentrations in the trailing vehicle 

cabin, averaging across vehicles, emission modes and fuels; this section will separately 

consider these parameters. 

 Table 5.3-4 details the effects of changing vehicle, fuel, and emission mode. 

 The first two rows distinguish the truck and the car, averaged over all fuels and 

modes. These values are very similar, showing little effect of the vehicle by itself. 

 The next three rows distinguish the fuels, averaging over the vehicles and modes. 

The Atlanta fuel results in higher BTEX concentrations in the trailing vehicle cabin, 

which is consistent with higher aromatic contents of Atlanta fuel, especially in summer

(see Table 4.3-1). 

 The next two rows distinguish the normal and high emitter modes, averaging over 

the vehicles and fuels. The values clearly differ, with the high emitter mode values much 

higher than for the normal emitter mode. 

 The last line in this table presents the percent standard deviations of the high 

emitter values that are very similar, with the anticipated exception of MTBE which is 

larger due to its predominant occurrence in only one of the three fuels. 
5-13

 Figure 5.3-7 presents the effect of normal versus high emitter vehicle on the 

trailing vehicle in-cabin concentrations in a scatter plot for all species except HCHO and 

EtOH. Cabin levels of HCHO and EtOH were omitted since in-cabin upholstery and 

occupant sources of these compounds predominate penetration of outdoor levels. The 

slope indicates that in-cabin values measured during trailing the vehicle in high emitter 

mode are about twice those found for the normal mode. Since lead vehicles in these tests 

are converted between ‘normal’ and ‘high emitter’ states by disabling control devices, not 

by mis-tuning the engines or opening fuel line leaks, exhaust emissions should remain 

roughly proportionate between both operational modes. 

Table 5.3.4. Effect of Vehicle, Fuel, and Operational Mode. Units are ppbv, except CO as 

noted. Number of measurements = n

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

Truck only (n=12) 0.64 1.40 2.32 0.45 1.46 0.61 0.87 1.56 4.55 3.67

Car only (n=12) 0.59 1.13 1.87 0.33 1.11 0.45 0.53 1.42 5.90 3.59

Atl fuel only (n=8) 0.53 1.44 2.79 0.51 1.66 0.68 0.14 1.41 5.99 3.39

Hou fuel only (n=8) 0.89 1.52 2.20 0.48 1.58 0.66 2.17 1.91 5.61 4.37

Chi fuel only (n=8) 0.48 0.87 1.32 0.20 0.66 0.28 0.03 1.22 4.20 3.19

Normal only (n=12) 0.06 0.46 1.05 0.21 0.73 0.31 0.16 0.41 5.21 3.26

High emitter only (n=12) 1.06 1.95 2.99 0.55 1.77 0.71 1.21 2.50 5.37 3.37

St Dev high emitter only 28% 36% 38% 41% 44% 44% 177% 52% 52% 64%

y = 2.2228x + 0.4798

R2 = 0.6929

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Normal Emitter

High Emitter

Figure 5.3-7. Scatter plot of Normal Emitter and High Emitter Mean In-cabin Values for 

all species except HCHO and EtOH. 

 Looking at the high emitter mode only, Table 5.3-5 presents high emitter mean incabin values for each fuel separately. MTBE values present the clearest difference. This 

is expected based on the fuel composition. The other species show relatively little 

difference. EtOH values are not shown, due to the Summer 2002 artifact. 
5-14

Table 5.3-5. Influence of high emitting vehicles and each fuel on trailing vehicle in-cabin 

concentrations. Units are ppbv except CO as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

High Emiter, Atl (n=4) 1.02 2.35 3.97 0.67 2.12 0.85 0.03 2.48 5.04 2.80

High Emiter, Hou (n=4) 1.43 2.18 3.08 0.69 2.24 0.93 3.45 2.81 6.00 5.77

High Emiter, Chi (n=4) 0.91 1.40 2.02 0.31 0.98 0.42 0.06 2.08 5.42 3.90

 The high emitter values, averaged across fuels, are presented in Table 5.3-6 

separated by season. HCHO has the largest difference, summer > winter, which is likely 

due to more rapid photochemical reactions or in-cabin off gassing rates during the 

summer. In addition, BTEX concentrations are consistently higher during the summer, 

which is consistent with higher aromatic contents of summer fuels, especially for Atlanta

(see Table 4.3-1). 

Table 5.3-6. Summary of Seasonal Differences in the High Emitter Samples. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

Summer High 1.23 2.15 3.33 0.61 1.79 0.82 0.76 1.52 8.02 7.66

Winter High 1.06 1.89 2.86 0.53 1.78 0.69 1.39 2.92 4.22 2.27

5.3.3 Trailing Vehicle Effects

 In the winter 2005 tests, separate canisters were collected for the high and low 

cabin ventilation portions of the tests; in the summer 2002 tests, only a single canister 

was collected integrating these two periods. Table 5.3-7 shows the average values from 

the high and low ventilation winter 2005 canisters. Their values are similar across 

seasons. Table 5.3-7 shows that although mean canister (integrated) in-cabin values were 

similar under high and low ventilation conditions, the range of concentrations observed 

by continuous PID monitor was much larger under high ventilation conditions, as 

illustrated in Figure 5.3-8. The high ventilation condition continues up to 60 min and is 

then switched to low ventilation for the remaining 60 min. The outdoor ppbRAE-PID 

shows generally lower values and the two indoor peaks in the first 60 min are associated 

with the “near” tailgating portion of the driving sequence. The outdoor PID2 shows 

generally lower values that the indoor PID1, since it was mounted on the aerial on the 

right side of the van, thus its inlet was mostly opposite to the truck’s tailpipe (that was 

situated on the left side of the truck). 
5-15

ME0 - IN-CABIN TRUCK MAL BASE HV TEST 2/25 8:56

0

10

20

30

40

50

60

70

80

0 30 60 90 120

elapsed time (min)

PID

PID1 PID2

Figure 5.3-8. Time Series of In-Cabin (PID1) and Outside (PID2) PID Values. The first 

60 min are under high ventilation conditions (0-60 min) and the next 60 min (60-120 

min) are under low ventilation conditions. 

Table 5.3-7. Comparison of High and Low In-cabin Ventilation Conditions, Winter 2005 

only. Units are ppbv except CO as noted. 

Budi13 Benze Tolue Etbz Mp_xyl O_xyl MTBE CO, ppm Formal Acetal

High Vent only 0.52 1.15 2.07 0.40 1.35 0.54 0.74 1.54 4.38 2.13

Low Vent only 0.64 1.24 1.91 0.35 1.25 0.47 0.91 1.89 4.65 3.08
5-16

5.3.4 Comparison with FTP Data 

The driving tests were all conducted while the vehicle was in a hot stabilized 

operating condition. The FTP test phase most comparable is phase 2 (Bag 2) and this 

section will examine the correlation of the Bag 2 components with observed values in the 

driving tests. 

 Figure 5.3-9 correlates Bag 2 and the trailing vehicle benzene values. There is a 

trend of increasing cabin benzene concentrations with increasing benzene FTP emissions 

(R2=0.64). Figure 5.3-10 presents the same correlation for MTBE although there are 

fewer data points since only the Houston fuel contained substantial concentrations of 

MTBE. Figure 5.3-11 illustrates the same correlation for 1,3-BD. Unlike benzene and 

MTBE, 1,3-BD is primarily an exhaust component. The 1,3-BD plot shows the same 

correlation (R2

 

 =0.62) between the FTP emission level and the resulting trailing vehicle 

cabin concentration as benzene. The correlations are driven mostly by the vehicles in 

malfunction modes, since only these vehicle emissions result in significant concentrations 

in the trailing vehicle cabin.

y = 0.02x + 0.55

R2

 = 0.64

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 20 40 60 80 100 120 140

FTP Bag 2 mg/mi

Trailing Veh, ppbv

Malfunction

Normal

Figure 5.3-9. Comparison of FTP Bag 2 Benzene Emissions to In-cabin Concentration in 

the Trailing Vehicle. 
5-17

y = 0.0367x + 0.5247

R2

 = 0.5041

0

1

2

3

4

5

6

7

0 20 40 60 80 100 120 140

FTP Bag 2 mg/mi

Trailing Veh, ppbv

Malfunction

Normal

Figure 5.3-10. Comparison of FTP Bag 2 MTBE emissions to in-cabin concentrations in 

the trailing vehicle. 

y = 0.02x + 0.26

R2

 = 0.62

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0 10 20 30 40 50

FTP Bag 2 mg/mi

Trailing Veh, ppbv

Malfunction

Normal

Figure 5.3-11. Comparison of FTP Bag 2 1,3-BD Emissions to In-cabin Concentrations 

in the Trailing Vehicle. 
5-18

5.4 Discussion

 The overall objective of this section is to assess the various effects that might 

impact trailing vehicle in-cabin levels of leading vehicle emissions. A rural test site with 

very little traffic was chosen to minimize non-lead vehicle influences on measured incabin values. Background samples were taken prior to the driving tests to quantify other 

possible sources. Measured component backgrounds were low and consistent from 

summer to winter although HCHO backgrounds were relatively high, suggesting in-cabin 

sources. 

Summer and winter in-cabin values were similar in magnitude with the exception 

of HCHO which was higher in the summer, possibly due to higher photochemical activity 

and higher temperatures that led to more HCHO off-gassing of the vehicle cabin interior. 

EtOH values in Summer 2002 are much higher than in Winter 2005, most probably due 

to the off-gassing effect of the continuous formaldehyde analyzer that was located in the 

trailing vehicle cabin for Summer 2002 measurements. 

 Trailing vehicle cabin values were substantially larger than background values 

except for HCHO which was actually lower than background in winter tests. Idle test 

sample values were on average twice those encountered in driving tests, suggesting that 

proximity and proximity duration may substantially impact in-cabin trailing vehicle 

concentrations. 

Average in-cabin levels were little affected by different vehicles or fuels except 

for an MTBE fuel effect. However, averaging over the fuels and vehicles, the high 

emitter mode resulted in much higher trailing vehicle in-cabin values than the normal 

emitter mode, on average 2.2 times higher; except for HCHO which was relatively 

unchanged from background. Similarly, the season had no strong effect upon the trailing 

vehicle concentrations. 

Trailing vehicle ventilation status also affected in-cabin values. Although mean 

canister (integrated) in-cabin values were similar under high and low ventilation 

conditions, the range of concentrations observed by continuous PID and CO monitors 

was much larger under high ventilation. This may be rationalized as the vehicle moving 

into and out of the exhaust plume of the leading vehicle with in-cabin values changing 

rapidly under high ventilation; whereas under low ventilation, in-cabin concentrations 

trapped as the vents were closed stayed relatively constant during the remainder of low 

ventilation conditions. 

Trailing vehicle tests indicated that the largest impact on in-cabin values came 

from the emissions mode of the leading vehicle. Emissions observed in Bag 2 of the FTP 

tests were compared to the observed trailing vehicle levels of benzene, MTBE and 1,3-

BD. Benzene and MTBE have both exhaust and evaporative emissions while 1,3-BD is 

only emitted in exhaust. In-cabin benzene and MTBE levels appear to correlate with FTP 

emissions, however, 1,3-BD does not but correlates with other in-cabin species. 
Appendix A 

Exposure Protocol and Study Plan for the Section 211(B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline 

 
APPENDIX A 

Exposure Protocol and Study Plan for the Section 211(B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

Barbara Zielinska, Eric M. Fujita, John C. Sagebiel, and David E. Campbell 

Desert Research Institute 

2215 Raggio Parkway 

Reno, NV 89512 

Lawrence R. Smith 

Southwest Research Institute 

6220 Culebra Road 

San Antonio, TX 78228-0510 

Ted Johnson 

TRJ Environmental, Inc. 

713 Shadylawn Road 

Chapel Hill, NC 27514 

Revised: October 1, 2003 
ACKNOWLEDGMENT 

This work is supported by the American Petroleum Institute. We gratefully acknowledge the administrative 

and technical support provide by Dr. Will Ollison of API. We acknowledge Darryl Joseph and Thomas Kelly of 

Battelle for their assistance with the continuous formaldehyde measurements during the pilot study phase of the 

project. 

ii 
TABLE OF CONTENTS

ACKNOWLEDGMENT................................................................................................................. ii 

LIST OF TABLES......................................................................................................................... iv 

LIST OF FIGURES ....................................................................................................................... iv 

LIST OF APPENDICES..................................................................................................................v 

1. INTRODUCTION ................................................................................................................... 1-1 

2. MEASUREMENT METHODS AND PROTOCOLS............................................................. 2-1 

2.1 Biomarker Measurements..................................................................................................... 2-7 

2.1.1 Breath Sample Collection ........................................................................................... 2-8 

2.1.2 VOC Analysis in Breath Samples................................................................................. 2-8 

2.2 Instrument Measurement Protocol.......................................................................................... 2-8 

2.2.1 Kore MS200 ............................................................................................................ 2-9 

2.2.2 CO Instruments ........................................................................................................ 2-9 

2.2.3 Continuous ppbRAE Photoionization Detector (PID)..................................................... 2-11 

2.2.4 Continuous Formaldehyde Monitor ............................................................................ 2-11 

2.2.5 BTEX by Solid Phase Microextraction (SPME)............................................................ 2-11 

2.2.6 Time-Integrated Air Sample Collection and Analysis..................................................... 2-12 

3. EXPERIMENTAL Protocol .................................................................................................... 3-1 

3.1 San Antonio Controlled In-Cabin and Residential Garage Exposure Measurements.............. 3-1 

3.1.1 Procurement of Test Fuels from Houston, Chicago and Atlanta.......................................... 3-1 

3.1.2 Determination of Tailpipe and Evaporative Emissions of Test Vehicles............................... 3-5 

3.1.3 Relationship Between Exhaust Emission Rates and In-Cabin Exposure ............................... 3-7 

3.1.4 Relationship Between Evaporative Emission Rates and Exposure in a Residence With an 

Attached Garage ....................................................................................................... 3-8 

3.2 Microenvironmental Exposure Measurements in Atlanta, Chicago, and Houston........................... 3-10 

3.2.1 Exposure Diary and Script Development ..................................................................... 3-12 

3.2.2 In-cabin Exposures in Urban Microenvironments.......................................................... 3-12 

3.2.3 Technician Biomarker Analysis................................................................................. 3-13 

3.2.4 Criteria for Selecting High End Microenvironments....................................................... 3-13 

3.3 Meteorology.................................................................................................................... 3-17 

3.4 Data Analysis .................................................................................................................. 3-17 

3.5 Reporting........................................................................................................................ 3-19 

4. PROJECT SCHEDULE AND DELIVERABLES .................................................................. 4-1 

5. REFERENCES ........................................................................................................................ 5-1 

iii 
 LIST OF TABLES 

Table No. Page No.

Table 3-1. Collection of Time-Integrated Samples for Chemical Analysis – San Antonio ....... 3-4 

Table 3-2. Test Plan for Each Vehicle ........................................................................................ 3-6 

Table 3-3. Summary of the FTP Driving Cycle.......................................................................... 3-7 

Table 3-4. Protocol for trailing vehicle tests............................................................................... 3-8 

Table 3-5.Protocol for attached garage experiments. The same vehicles and fuels as for 

trailing vehicle experiment are used..................................................................................... 3-9 

Table 3-6. Microenvironment Listing........................................................................................ 3-10 

Table 3-7. The Number of Samples for Each Microenvironment for Three Cities and 

Two Seasons....................................................................................................................... 3-11 

LIST OF FIGURES 

Figure No. Page No.

Figure 2-1..................................................................................................................................... 2-2 

Figure 2-2..................................................................................................................................... 2-2 

Figure 2-3..................................................................................................................................... 2-3 

Figure 2-4..................................................................................................................................... 2-3 

Figure 2-5. Variability of CO Electrochemical Cell Response with Temperature.................... 2-10 

Figure 3-1: Overall Structure of 211(b) Monitoring Requirements............................................ 3-3 

Figure 3-2. Monitoring Requirements for San Antonio Study ................................................... 3-3 

Figure 3-3. FTP Driving Cycle. ................................................................................................... 3-7 

iv 
LIST OF APPENDICES 

APPENDIX A............................................................................................................................. A-1 

APPENDIX B ..............................................................................................................................B-1 

APPENDIX C ..............................................................................................................................C-1 

APPENDIX D............................................................................................................................. D-1 

APPENDIX E ..............................................................................................................................E-1 

v 
1. INTRODUCTION 

The U.S. Environmental Protection Agency (EPA) has recently issued requirements for a test program in accordance 

with the Alternative Tier 2 provisions of the fuels and fuel additives (F/FA) health effects testing regulations, which 

are required pursuant to Section 211(b) of the Clean Air Act. In response to these requirements, the American 

Petroleum Institute (API) contracted with a research team consisting of the Desert Research Institute (DRI), 

Southwest Research Institute (SwRI), Lovelace Respiratory Research Institute (LRRI), and TRJ Environmental, Inc 

(TRJ) to conduct a screening study of the high-end distribution of inhalation exposures to evaporative and 

combustion emissions of baseline- and oxygenated gasoline. This study plan describes the exposure protocols and 

specifies the measurement methods, sampling & analytical procedures, and quality assurance protocols that will be 

used in the study. 

The goal of this research program is to screen potential high-end inhalation exposure microenvironments dominated 

by evaporative and exhaust emissions of baseline- and oxygenated-gasoline. The specific objectives are to provide 

information allowing the Agency to: 

• Quantify personal exposures to motor vehicle oxygenated and non-oxygenated gasoline evaporative and 

exhaust emissions in microenvironments (MEs) representing the upper end of the exposure frequency 

distribution of such exposures; 

• Determine the quantitative relationships between personal exposures in selected MEs with fixed site 

measurements in these MEs and at nearby air monitoring stations; 

• Determine how personal exposures differ in cities and seasons in which methyl tertiary butyl ether 

(MTBE)-oxygenated, ethanol (EtOH)-oxygenated, and baseline gasolines are in use; 

• Extrapolate to other sites and, if possible, other oxygenated fuels; 

• Determine the relative contributions of vehicle fuel exhaust and evaporative emissions to personal 

exposures from oxygenated and non-oxygenated gasoline. 

The overall approach for the exposure study is based upon the draft June 29, 2001 S211b Tier 2 Exposure Study 

Protocol that was developed in May 2001 by the API Section 211(b) Research Group and reviewed by the U.S. 

Environmental Protection Agency (EPA). The main study protocol has changed significantly from the original 

version based on the results from the first Reno pilot study (submitted to EPA April 25, 2002) and recommendations 

made by EPA during the summer Atlanta site visit in August 2002, specifically in relation to the measurement 

methods approach. These changes were incorporated into the second Reno pilot study in April 2003 (submitted to 

EPA June 13, 2003). Additional protocol adjustments incorporated into this September 4, 2003 draft have been the 

result of continuous dialog between EPA and DRI. 

The main exposure study consists of gathering data under controlled and field conditions. First, DRI and SwRI will 

conduct exposure measurements under controlled conditions in order to establish quantitative relationships between 

vehicle tailpipe and evaporative emissions to exposure levels in two specific microenvironments, a trailing vehicle 

cabin and an attached residential garage. In the field, DRI and LRRI will monitor microenvironmental and personal 

exposures in various potential high-end microenvironments in Houston, Chicago, and Atlanta during summer (July 

to September) and winter (January to March). These cities have ongoing ambient monitoring programs and have 

MTBE-RFG, EtOH-RFG, and baseline gasoline formulations, respectively. A number of key variables will be 

measured in ambient air within microenvironments, in subjects’ personal breathing zones and in breath. Section 3 

specifies the microenvironments and exposure protocols. The results of this study will provide information to 

quantify the upper-end personal exposure to gasoline and oxygenated gasoline emissions and extrapolations to other 

cities using oxygenated fuels. The information from this study will permit sensitivity analyses to determine the range 

of these exposures, especially during heavy traffic, in residential and public parking garages and during refueling. 

1-1
2. MEASUREMENT METHODS AND PROTOCOLS 

The exposure screening study uses three approaches to measure the targeted air toxics in high-end 

microenvironments: (1) reference method time-integrated samplers to quantify concentrations over 5-60 minute 

sampling periods; (2) continuous surrogate method monitors to determine short-term concentration variations over 

10-60 second sampling periods; and (3) supplementary methods to provide additional short-term surrogate 

concentration estimates over intermediate time frames of one to several minutes. It should be noted that the 

supplemental methods are newer methods that, in many cases, utilize instruments that have not been fully adapted 

for field use. These methods are independent checks on the surrogate approach, providing periodic corroboration 

under differing conditions and locations encountered during the tests. The supplementary method data are not 

required to conform to the CAA requirements and therefore should not to be used in regulatory decision making. 

1. The reference methods include pumped whole-air canister samplers used for CO, CO2, benzene, toluene, 

ethylbenzene, xylenes (BTEX), MTBE and 1,3 butadiene (BD), acidified 2,4-diphenylhydrazine (DNPH) 

cartridges for formaldehyde (HCHO) & acetaldehyde (CH3CHO) and a multi-bed (TenaxTA-CarbotrapCarbosieve) solid adsorbent tube for EtOH. Canister CO and CO2 are converted to methane for analysis by 

gas chromatography with flame ionization detection (GC/FID) and BTEX, MTBE, 1,3 BD are quantified 

by capillary GC/FID, or GC/MS for breath samples, using separate analysis. The aldehyde cartridges are 

eluted with acetonitrile and analyzed by high performance liquid chromatography with photodiode array 

UV detection of their hydrazone derivatives. The multi-bed tubes are thermally desorbed into a gas 

chromatograph and quantified by mass spectrometric detection (GC/MS). In addition, the multi-bed tubes 

provide the opportunity to compare the values for toluene, ethylbenzene and xylenes obtained by the 

canister method with those obtained by the tube method. These methods are basically standard TO-15, -

11A, and -17 EPA procedures with improvements incorporated by the Desert Research Institute (DRI), as 

described in Section 2.3.5. .

2. The surrogate methods include both active non-dispersive infrared (NDIR) and passive T-15 Langan 

electrochemical cell devices for CO and an active photo-ionization detector (PID) for volatile organic 

compounds with an ionization potential below 10.6 eV (principally olefins and aromatic species). These 

continuous instruments respond to concentration changes of a few seconds and provide sensitive 

proportionate measures of the short-term variability of target exhaust and evaporative species quantified by 

the time-integrated reference methods. These methods are used to generate the short-term time-series of 

concentrations for BTEX, MTBE, EtOH, 1,3 BD, and the aldehydes quantified by the reference methods.

3. The supplemental methods include both active continuous instruments with one to several minute time 

responses, respectively, for BTEX and HCHO and a passive sorbent fiber sampling of a flowing analyte 

stream for BTEX over a 10-minute period. The continuous BTEX monitor quantifies species diffusing 

through a semi-permeable membrane by ionizing them at 70 eV by electron impact and pulsing them into a 

time-of-flight (TOF) mass spectrometer. The HCHO instrument bubbles ambient HCHO into a flowing 

aqueous 2,4-pentanedione reagent to produce a formaldehyde-specific product, 3,5-diacetyl-1, 4-

dihydrolutidene that is quantified by ultra-violet fluorescence. The 75 um solid phase 

(carboxen/polydimethylsiloxane) (SPME- CAR/PDMS) fiber is passively exposed for ten minutes, 

retracted into its syringe holder, and promptly injected into a GC with PID/FID detection optimized for 

BTEX quantification. 

The surrogate approach is used to generate short-term time-series values for the target species (MTBE, EtOH, 1,3 

BD, CH3CHO) for which there are no continuous measures. In microenvironments with running engines exhaust 

emissions may dominate and either CO or PID surrogates should provide comparable time-series measures of shortterm values, as shown in Figure 2-1. In engine-off microenvironments, evaporative species should dominate and the 

PID surrogate should provide the time-series measure since CO isn’t emitted, as shown in Figure 2-2. 

2-1
Continuous Measurements

0.0

5.0

10.0

15.0

20.0

25.0

17:0017:1017:2017:3017:4017:50

CO (ppm) 

0

200

400

600

800

1000

PID

API CO DRI T15 CO PID (ppb)

Reconstructed BTEX

0

50

100

150

200

250

17:0017:1017:2017:3017:4017:50

BTEX (ppbv)

BTEX (PID) BTEX (T-15 CO) BTEX (API CO)

Figure 2-1 

Since collocated contemporaneous reference measurements are paired with surrogate measures during each 

sampling period, each time-series generated is individually calibrated to the specific target compound/CO or target 

compound/PID relationship determined by the vehicles, fuels, and conditions measured during that period. The area 

under the continuous surrogate trace is normalized to that of the integrated reference measurement which is assumed 

to be relatively constant over the 20-40 minute period of measurement. 

Continuous Measurements

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

17:0017:1017:2017:3017:4017:50

CO (ppm) 

0

2000

4000

6000

8000

PID

DRI T15 CO PID (ppb)

Reconstructed BTEX

0

100

200

300

400

500

600

700

800

17:0017:1017:2017:3017:4017:50

BTEX (ppbv)

BTEX (PID) BTEX (T-15 CO)

Figure 2-2 

A constant compound/surrogate ratio is required during the period of measurement to provide reliable time-series 

values. However, where continuous monitors are available (although of different time resolutions), such values 

(e.g., BTEX, HCHO) may be compared to surrogate time series results as backup confirmatory data reducing 

uncertainties in the measurements, as shown in Figures 2-3 and 2-4. 

2-2
Figure 2-3 

0

4

8

12

16

20

12:0012:0312:0612:0912:1212:1512:1812:2112:2412:2712:3012:3312:3612:3912:4212:4512:4812:5112:5412:57

Time

Battelle HCHO, ppb

0

4

8

12

16

20

Recon HCHO, ppb

Measured HCHO (ppb) Reconstructed HCHO from CO and DNPH

0

100

200

300

400

7:05 7:15 7:25 7:35 7:45 7:55 Time

PID Concentration (ppbv)

0

100

200

300

400

SPME Concentration (ppbv)

PID (ppb) avgPID SPME

Figure 2-4 

2-3
Analytical method descriptions and data quality objectives are tabulated below. Note that in the Measurement Data 

Quality Objectives table, the Time Resolution row reflects the time resolution logged in this study rather than the 

higher time resolution capabilities typical of specific instruments noted in the Continuous Methods table. 

Integrated and Semi-Continuous Methods

Integrated Semi-Cont.

Method Canister DNPH Adsorbent SPME

Applicable 

Environments all all all all

Time Resolution 5-60 min 20-60 min 20-60 min 10 min

Detection Limits 0.05 ppbC 0.1 ppbv 0.2 ppbv 0.2 ppbv

Data Application Reference (R) Reference (R) Reference (R) Confirmatory (C)

CO R

PID

BTEX R C

1,3-Butadiene R

MTBE R C

Formaldehyde R

Acetaldehye R

Ethanol R

NMHC R

2-4
Continuous Methods

Continuous

Method T15 CO NDIR CO ppbRAE MS200 HCHO

Applicable Environments outdoor and incabin all all higher end stationary

Time Resolution seconds seconds seconds 1 min 1 min

Detection Limits 0.1 ppm 0.04 ppm 1 ppb 1-3 ppbv 1 ppbv

Data Application Surrogate (S) Surrogate (S) Surrogate (S) Confirmatory (C) Confirmatory (C)

CO Surrogate Surrogate

PID Surrogate

BTEX S (a) S (a) SC (c) C

1,3-Butadiene S (a) S (a) S (c)

MTBE S (a) S (a) S (c)

Formaldehyde S (b) S (b) S (d) C

Acetaldehye S (b) S (b) S (d) S (g)

Ethanol S (e) S (e) S (f)

NMHC S (a) S (a) S (c)

S (a). Time series reconstructed from canister/CO ratio for exhaust-dominated samples.

S (b). Time series reconstructed from DNPH/CO ratio for exhaust-dominated samples except outdoor daytime samples.

S (c). Time series reconstructed from canister/PID ratio for exhaust- or evap-dominated samples in outdoor MEs.

S (d). Time series reconstructed from DNPH/PID ratio for exhaust-dominated samples except outdoor daytime samples.

S (e). Time series reconstructed from solid adsorbent/CO ratio for exhaust-dominated samples.

S (f). Time series reconstructed from solid adsorbent/PID ratio for exhaust and evap-dominated samples.

S (g). Time series reconstructed from CH3CHODNPH/HCHOCont ratio for exhaust dominated samples.

2-5
Measurement Data Quality Objectives

Instrument Canister DNPH SPME CO-T15 CO-NDIR PID HCHO (1) MS-200

Accuracy <5% <5% 3-50% +/- 1 ppm (2) <0.1 ppm or 

0.5% NA <25% <8%

Precision <3% <3% 2-15% +/-0.1 ppm +/-0.1 ppm or 

1% 0.1 <25% <5%

Detection 

Limit 0.05 ppbC 0.1 ppbv 0.2 ppbv 0.1 ppm 0.05 ppm 1 ppb 1 ppb 1-3 ppbv

Time 

Resolution (3) variable variable variable 10 sec 10 sec 10 sec 1 min 1 min

Artifacts None None None H2, very high 

humidity

CO2>10-4 

H2O>4x10-5

plastics,very 

high humidity None None

Method GC/FID

HPLC/ 

Photodiode 

array

GC/FID 

& PID 

Electrochemical 

Detector

NDIR 10.6 eV 

lamp PID

Hantzch rxn 

fluorescence

Mass 

spectrometer

Source

DRI QA/QC 

Ext Audits 

Comparisons

DRI QA/QC 

Ext Audits 

Comparisons

DRI 

Use/intercomp

arisons

Manufacturer 

literature

Manufacturer 

literature

Manufacturer 

literature

DRI 

Use/intercomp

arisons

DRI 

Use/intercomp

arisons

(1) HCHO performance paramters based on Alpha Omega instrument's performance in the 2nd Reno pilot study.

(2) Based on DRI test

(3) Time resolution for continuous instruments designates data logging resolution used in the study rather than instrument time resolution

2-6
The continuous Kore MS200 will be used to monitor BTEX on a one-minute basis, sampling during the initial 10 

second portion of each 60 second period. This instrument uses a time-of-flight mass spectrometer to separate 

compounds of interest. Rather than using a gas chromatograph, this instrument uses a software solution to apportion 

the contribution of each component of interest to the time-of-flight (TOF) mass spectrum seen by the instrument. 

The software does not distinguish between specific isomers, thus xylenes and ethylbenzene are reported together. 

The inlet uses a polydimethylsiloxane membrane preferentially to allow non-polar organic compounds into the 

analyzer while maintaining the vacuum inside the analyzer chamber. This membrane inlet does limit the types of 

compounds that can be analyzed, however. Common air constituents and polar organic molecules do not pass the 

membrane quickly. The instrument performed well during the pilot studies, comparing favorably with the canister 

measurements for most samples. Although we have attempted to secure the availability of another Kore MS200, 

which Horiba Instruments, Inc. in Irvine, CA, maintains, repeated shipping damage to this only other MS200 in the 

US has made its availability problematic. Given the periodic corroborative use proposed for this device, we do not 

believe the information provided by this instrument, while desirable, is necessary to fulfill the goals of the screening 

study. In the unlikely event this device goes out of service in the field, we will attempt to access the Horiba backup 

unit. Due to interferences from the vehicle’s ignition system, likely the result of occasional resonances set up 

between engine electrical radio-frequency noise and MS200 circuits, this instrument may not provide full data 

capture during the mobile ME. Use of alternative instrument grounding and engine ignition filters will be 

investigated to remedy this occasional nuisance. Since the MS200 runs directly off isolated 12V AGM battery 

power, it should also be isolated from battery inverter electrical noise 

Carbon monoxide will be monitored continuously by the Langan T15 CO monitor and by the ML 9830 (Monitor 

Lab) NDIR instrument. Langan T15 is an electrochemical monitor for CO. The response time of this instrument is 

somewhat slower than the response of the infrared-based instruments. 

A Continuous Formaldehyde Monitor was purchased from Alpha-Omega Power Technology, Ltd. (Albuquerque, 

NM). The Alpha-Omega (AO) instrument utilizes the Hantzch reaction - it absorbs formaldehyde in acidified water, 

reacting it with 2,4-pentanedione and ammonia to form a cyclized product, 3,5-diacetyl-1, and 4-dihydrolutidene, 

which is continuously detected by fluorescence. The method is highly specific for formaldehyde and very sensitive. 

The AO device has been extensively modified by DRI to enhance its field reliability and ruggedness to vibration and 

shock and is designated as the DRI-formaldehyde instrument in subsequent discussion. However, its use is limited 

to stationary microenvironments in the present study since sensitivity to motion remains. 

2.1 Biomarker Measurements 

During the 1st Reno pilot study both urinary and breath concentrations of MTBE and the BTEX compounds were 

measured in two subjects after three separate scripted exposures. Breath measurements showed an exposure effect 

(post-exposure concentration in breath higher than pre-exposure concentration) when samples were collected soon 

after exposure (within ~2-3 minutes). Breath samples collected after longer post-exposure durations showed no 

increase relative to pre-exposure breath concentrations, most likely due to the short 1-3 minute half lives of these 

compounds in breath (Lindstrom and Pleil, 1996). The short half-life of absorbed volatile vapors such as BTEX in 

breath will require fast, precise timing for sample collection. 

Urinary measurements from the pilot study showed little exposure effect from most compounds for 2 of the three 

exposures. In all cases the urinary concentrations of MTBE, toluene, ethyl benzene, and xylene were below 

detection limits. In most cases the concentrations of benzene (the only observed compound) post-exposure were 

similar to pre-exposure due to the fact that the exposure concentrations were low in most cases. After the highest 

exposure in the pilot study (refueling a vehicle - hourly canister average of about 10 ppbv benzene) there was a 

relatively strong exposure effect observed in one subject and a lesser exposure effect observed in a second subject. 

There was a time course in the elimination of benzene that showed urinary benzene concentrations increasing with 

time. This is similar to the results reported by Lee and Weisel (1998) on the behavior of MTBE in urine. Because of 

an inability to see the decay of urinary benzene 3 hours post exposure, a second scripted refueling exposure was 

conducted in Reno, NV, to repeat this peak exposure and see if the urinary VOC concentration data can be linked to 

an exposure effect at these levels and to follow the full time course of elimination. The measurements of urinary 

MTBE/BTEX from the second refueling experiment were successful, but demonstrated no differences between preand post-exposure. 

2-7
Based on the pilot study results, since it was not possible to discriminate urinary benzene concentrations in postexposure as compared to pre-exposure, it was decided not to conduct urinary measurements. 

Based on results from the 2nd Reno pilot study, breath sampling will be conducted in three microenvironments; 

outdoor refueling, trailing high emitting vehicles (or roadway tunnel in Chicago and Houston), and underground 

garages. Three 1 liter breath canister samples will be collected for each experiment: before the exposure in the 

isolated subject, and 10 seconds (timed with a stopwatch) immediately after active refueling or a measured peak 

exposure in the other MEs. In addition, a third backup breath sample will be collected immediately after the second 

sample for these three microenvironments, in case there is a problem with the second sample. 

2.1.1 Breath Sample Collection 

Breath samples will be collected from technicians who participate in a scripted exposure. Since this study requires 

the use of human subjects, the final protocol was reviewed by an Institutional Review Board certified with NIH. 

Technicians will be instructed to avoid exposure to material that may compromise the exposure assessment prior to 

and during the scripted exposures. This will include avoiding alcohol ingestion (ethanol) and first-hand or secondhand cigarette smoke for at least 3 days prior to the scripted exposures. Breath samples collected before the 

exposure will be used to assess background levels in the technician. 

The test subject technician will take the three breath samples. One sample is taken before initiating ME sampling; 

the second, ten seconds (timed with a stopwatch) immediately after completing active refueling task or experiencing 

a measured peak exposure in another ME, and the third one immediately following the second. The 3rd sample will 

be analyzed only in case there is a problem with the second sample. The technician takes a 1-liter canister, places 

the tube in his mouth, and breathes smoothly and regularly through the mouth around the tube until a resting breath 

pattern is established. At the end of a normal exhalation, the technician closes the mouth, opens the canister valve, 

and continues to expel the expiratory reserve. The canister vacuum will collect 1 L of the expiratory reserve. When 

the flow stops, the technician closes the canister valve to capture the sample (Pleil and Lindstrom, 1995; 2002). 

2.1.2 VOC Analysis in Breath Samples 

The analysis of VOC in breath samples will be conducted as described by Pleil and Lindstrom (1995, 2002) Prior to 

the commencement of the study, the CO2 level in alveolar breath of all technicians performing breath sample 

collection will be measured using GC/FID. Since the FID does not respond to CO2, this species is converted to 

methane by a methanator, positioned after the GC column, but ahead of the FID. Three breath samples will be 

collected and analyzed, and the mean CO2 value will be used for further comparison. After breath sample 

collection, the CO2 will be measured using the same method. The target VOC (MTBE, 1,3-butadiene, ethanol, 

BTEX) will be measured using a GC/MS technique. The GC/MS system includes: Entech 7100 preconcentrator, 

Varian 3800 gas chromatograph with FID and column switching valve, and Varian Saturn 2000 ion trap mass 

spectrometer. Breath canister samples are pressurized with laboratory-grade zero air and a dilution factor is 

calculated based on initial and final pressures. An additional normalization factor could be determined for samples 

that deviate significantly from the expected CO2 level (subject-specific CO2 level/dilution factor). Approximately 

200 to 300 ml of the breath sample is concentrated and injected at the head of a 60 m x 0.32 mm polymethylsiloxane 

column (CPSil-5, Varian, Inc.) held at 30 °C. This column is connected to the switching valve leading into a 30 m x 

0.53 mm GS-GasPro column (J&W Scientific). After approximately 7 min the valve is switched so that the effluent 

from the first column elute onto a second 15 m x 0.32 mm polymethylsiloxane column connected to the mass 

spectrometer. The column switch is timed so that the C2 and C3 compounds elute on the FID and all C4 and higher 

compounds elute on the mass spectrometer. 

2.2 Instrument Measurement Protocol 

This section describes protocols that will be applied for each method and applicable quality assurance procedures. 

2-8
2.2.1 Kore MS200 

The Kore MS200 will be used to measure BTEX in select MEs. The protocol for use includes the following 

calibration and operational procedures. 

Calibration Procedures:

1. Start instrument and establish zero. 

2. Apply span gas and allow 2 minutes to stabilize response. 

3. Collect at least 5 spectra 

4. Using calibration section in software, confirm calibration response or enter new calibration values as 

needed. 

Daily Startup Procedures: 

1. Check Battery Status (or plug in). 

2. Inlet valve: Middle position (heater). 

3. Inlet pump: On 

4. Wait until inlet vacuum is less than 3x102

 pa and inlet temperature LED is green 

5. Sample pump On 

6. TOF MS: On 

7. TDC: On (unless you are on battery, then wait as this draws a lot of current.) 

Once you are ready to sample: 

1. Inlet Valve Down position (confirm that vacuum is ok and heat is still ok) 

2. Apply zero air and allow it to flow for at least 1 minute. 

3. Collect 5 spectra of background air to assess variability. 

4. Begin sampling 

If possible, during a run perform a zero check as follows: 

Apply zero air for 15 to 30 seconds, allowing the instrument to collect one spectrum. 

After a sampling run, perform a zero check as follows: 

Apply zero air and immediately collect at least 5 spectra. Allow the zero air to remain on the instrument for 

5 minutes and collect another 5 spectra. 

During sampling runs, keep track of the main analyzer chamber vacuum. If the vacuum is regularly getting above 20 

x10-6 Pa, the instrument may need baking out. Follow the written procedures for bakeout. 

2.2.2 CO Instruments 

Two CO monitoring instruments will be used for the field study: a high sensitivity, fast response gas-correlation unit 

(Monitor Labs 9830) as a reference device, and a portable, battery-powered passive electrochemical unit (Langan 

T15). Prior to each period of field measurements both instruments will be calibrated using a zero-air generator and 

span gas (10.5 ppm) to provide two reference points encompassing the expected range of concentrations anticipated 

during actual testing. The two-point calibration procedure is as follows: 

1. Collocate instruments and warm up for a minimum of 45 minutes. During the study the CO units will be 

powered 24/7 since the van is on AC power overnight to recharge the batteries and the passive 

Langan unit draws little power from its long-lasting batteries. Collocated Langans will be tested 

for calibration stability in high CO MEs and paired during runs if found to be unstable. 

2. Record ambient concentration as determined by each instrument. 

3. Connect inlet lines from both instruments to a zero-air source (for passive sampler use flooder cap 

provided by manufacturer) and check for positive flow rate of >1 lpm with rotometer. 

4. Let instruments stabilize, record current baseline, then adjust zero. 

5. Connect inlet lines to a tank of span gas with appropriate CO concentration for anticipated range and 

verify flow rate 

6. Let instruments stabilize, record current reading, and adjust span to correct value. 

2-9
7. Re-connect zero-air source, let stabilize and check baseline zero readings. 

8. Repeat steps 4-7 if necessary. 

9. Check third concentration level with span gas if available. 

During field measurement periods the passive sampler will be checked against the reference unit, which has an 

automatic baseline stabilization and internal zero-air source, at the beginning and end of each sampling day and 

baseline readings will be recorded. If any significant deviations are observed a re-calibration will be performed. 

The electrochemical cell in the Langan instruments exhibits a significant response to temperature variations as 

shown in Figure 2.2-1. Note that these variations are due to changes in the temperature of the electrolyte in the cell, 

not in the ambient air temperature. Prior to field use, the temperature response will be characterized at realistic CO 

levels in the laboratory. If the response appears to be sufficiently reproducible, the resulting concentration data will 

be adjusted based on the units internal temperature sensor, which has an accuracy of +/- 2 C. If the temperature 

compensation approach does not appear feasible, the instrument will be thermally isolated and maintained as close 

to calibration temperature (typically 20 C) as possible during use. 

Our initial evaluation indicated that the lead-acid batteries are a source of hydrogen that interferes with the Langan 

CO monitor. This was confirmed by observing the Langan CO monitor in the presence of the batteries when both 

were removed from the vehicle. In order to eliminate this source of interference, the wet-cell lead acid batteries were 

replaced with AGM batteries that are sealed and hence do not outgas. We have currently installed 4 large AGM 

batteries and two new battery chargers in the van along with two new power inverters providing a total of 

approximately 3000 Watts of continuous power at 110V AC. The power system will be permanently installed so that 

we will not need to remove the batteries to charge them, they will simply be plugged in to charge. To handle the 

additional load, we have installed overload springs on the van. Furthermore, racks have been installed to secure 

instruments from movement and vibration; instrument & sampler inlet mounts have been installed to collocate inlets 

further within driver’s breathing zone (including one PID inlet with the other PID sampling outside the vehicle on 

the radio antenna at least six inches above the hood); a remote switch was installed to allow cabin on/off control of 

the integrated samplers; and a hitch-mounted rack was installed to transport the instrument cart. We will continue to 

use the other batteries for the cart experiments since the lack of a trapped space means we will not encounter 

interferences. We will also use the NDIR-based CO instrument, which does not suffer from the same artifact as the 

Langan, inside the vehicle cabin. 

Figure 2-5. Variability of CO Electrochemical Cell Response with Temperature. 

2-10
2.2.3 Continuous ppbRAE Photoionization Detector (PID) 

A RAE Systems Model PGM-7240 (ppbRAE) portable PID monitor is used to continuously monitor ambient VOC 

levels in the microenvironments. The monitor is equipped with a 10.6 eV photoionization (PID) detector and 

responds to organic and inorganic gases that have an ionization potential of less than 10.6 eV, which includes most 

compounds of interest in this study. It does not respond to light hydrocarbons such as methane, ethane, propane or to 

acetylene, CO, or formaldehyde. . 

2.2.4 Continuous Formaldehyde Monitor 

The continuous monitor for gaseous formaldehyde was purchased from Alpha-Omega Power Technologies. This 

instrument uses Hantzsch reaction to produce a fluorescent derivative from HCHO that is monitored with a 

fluorescent detector. An aqueous calibration standard in the 10-7 to 10-6 M range made by serial dilution of 37% 

formalin solution in the 0.1 N H2SO4 scrubber solution is used for the daily instrument calibration (Kelly and 

Fortune, 1994). This daily calibration standard is compared with the gaseous formaldehyde standard, purchased 

from Apel-Riemer Environmental, Inc. The monitor is zeroed by supplying high-purity air to the inlet. Span and 

zero samples are provided to the monitor at regular intervals using automated valving. We’ve completed reengineering the Alpha Omega HCHO instrument to make it more field-rugged and reliable. 

The modified Alpha-Omega HCHO instrument was evaluated during the 2nd Reno Pilot study. One of the most 

significant limitations of the formaldehyde monitor was an apparent sensitivity to moving environments. It has been 

observed that when the formaldehyde instrument was warmed up and operated in a stationary environment, such as 

a parking garage, and then subjected to transport while still operating, response at the detector oscillated and 

increased overall. Another limitation of this continuous instrument was the long stabilization time required for the 

fluorescence detector upon instrument start-up. In some cases, response at the detector was still stabilizing when the 

sampling period began. Thus, the supplemental continuous formaldehyde analyzer will be used for monitoring 

stationary microenvironments only. 

2.2.5 BTEX by Solid Phase Microextraction (SPME) 

Carboxen/(poly)dimethylsiloxane (CAR/PDMS) coated (75 μm) quartz fibers are used for 10 min BTEX sampling. 

All SPME samples are analyzed in a mobile laboratory with a Model 8610C SRI Instruments GC equipped with a 

heated injection port suitable for SPME desorption and a CP-Sil 5 (Varian, Inc.) capillary column (60m, 0.32mm 

i.d.) and a PID detector. The heated flash vaporization injector is maintained at 250°C and PID at 150°C. The 

column temperature program was 60°C for 2 min, 8°C/min to 165°C and held for 1 min, and then 45°C/min to 

240°C and held for 2 min. Helium carrier gas flow rate was 3 ml/min. 

Blanks and calibration checks are performed daily on the SRI GC in order to determine the performance of the 

instrument and quality of the data. Fibers are kept in the injector port throughout the sample run to guarantee that 

the entire sample was desorbed and to begin the conditioning of the fiber. In addition, fibers are cleaned in a fiber 

conditioner at 300°C for at least one hour. One fiber per batch of 5 is checked for purity after conditioning. The 

fiber conditioner consisted of a 70 cm x 16 cm stainless steel box with 5 ports machined to fit the needle size and a 

Watlow heater/temperature controller capable of maintaining the temperature in the 200-300° C range. A helium 

flow of approximately 10 ml/min is maintained during fiber conditioning. Testing showed that the same fiber can be 

subsequently reused up to 40 times for collecting additional samples, unless breakage of the fiber or failure of the 

fiber mounting mechanism occurs. 

The SRI GC is calibrated with 1 μl injection of liquid standards prepared in pentane with BTEX at different 

concentrations (1, 5, 10, 20, 40, 50, and 100 ng/μl). Carboxen/PDMS fibers are calibrated by introducing the SPME 

for a defined time to a flowing standard gas containing the calibration component, which loads a known mass of 

standard onto the fiber. The fiber is then introduced to the analytical instrument for calibration. SPME gas 

calibrations are done initially and throughout the study when necessary. BTEX calibration is performed with 

certified gas standards at different concentrations (20, 80, 100 and/or 200 ppbv for each compound). 

SPME is a passive method, thus the rate of the fiber uptake is controlled by the diffusion rate of the analytes to the 

fiber. In a stationary environment without any air movement, the gradient of concentration is formed in the 

boundary layer between the fiber and surrounding environment. This is a situation that occurs during the fiber 

2-11
calibration in a static system, such as a Tedlar bag. However, in an outdoor environment there is always some air 

movement, so the air is passing continuously across the surface of the fiber. The sorption rate will be higher in this 

situation, since the thickness of the boundary layer will be somewhat smaller. 

We tested the fiber uptake in the dynamic (flow-through) conditions, in the apparatus shown in Figure 2.3-1, page 2-

9 of the 2nd Reno Pilot Study Report (Zielinska et al., 2003) When the BTEX standard mixture was flowing through 

the system with the rate of 100 ml/min, the fiber uptake was approximately three times higher than in static (no 

flow) conditions. In addition, the dynamic calibration was more reproducible and more precise. For the summer 

study we will employ flow-through sampling conditions for the fiber. The calibration of the fiber will be performed 

in the identical flow-through conditions, using the same flow rate. 

Sampling temperature is an important parameter affecting the SPME data. Temperature corrections are obtained in 

the laboratory with an experimental set up that consists of a 1L glass bulb that has two stopcocks in each side to let 

the calibration gas flow through and an injection port covered with a sleeve septum to allow a SPME fiber to be 

introduced. The bulb is temperature controlled with a cooling/heating system. Temperature inside the glass bulb is 

measured with a thermocouple. For introducing humidity, a heated injection port is added before the glass bulb 

entrance in order to inject water with a syringe pump (Harvard Apparatus) to produce the desired relative humidity 

(Tuduri, Ludovic et al., 2001; Nelson, 1992; Martos, P. and J. Pawliszyn, 1997, and Lodge 1984). 

SPME Carboxen/PDMS coated (75 μm) fibers are used with portable or manual samplers. When manual samplers 

are used, the tip of the needle is closed with a septum or Teflon tape (Martos and Pawliszyn, 1997 and Chai and 

Pawliszyn, 1995). Prior to sampling, the pre-cleaned fibers will be kept at ambient temperature with an activated 

charcoal protector. This storage method has been tested in the laboratory and we have not seen any increases in the 

BTEX background up to 48 hours of storage following cleaning (the longest tested period). After sampling, fibers 

are kept in sealed Mylar bags inside a cooler with dry ice. Samples are analyzed 4-10 hours post-sampling, on 

average, with a minimum of 1 hour and a maximum of 20 hours between sampling and analysis. 

2.2.6 Time-Integrated Air Sample Collection and Analysis 

Time-integrated monitoring methods are used primarily for quantification of the responses of continuous surrogate 

instruments. The methods include canister sampling for VOC (BTEX, 1,3-butadiene, MTBE), solid adsorbent 

sampling (for ethanol) and DNPH-coated Sep Pak cartridges sampling for carbonyl compounds. The DRI Organic 

Analytical Laboratory (OAL) routinely uses these methods and DRI standard operating procedures (SOPs) for 

sampling and analysis are available upon request. Five to sixty minute samples will be collected depending on the 

ME sampled. 

Sampling. The DRI custom built sampler that can sample simultaneously a canister, solid adsorbent cartridges (two 

in parallel) and DNPH-impregnated Sep-Pac cartridge, is used for this study. The sampler is compact; it can be setup in a vehicle cabin and run from the battery. Prior to use the sampler is checked for cleanliness by sampling zero 

air through the canister inlet. If the concentration of any targeted compound exceeds 0.1 ppb, the sampler is 

thoroughly cleaned and re-tested. As noted earlier, a remote switch was installed to allow cabin on/off control of the 

sampler (no longer requiring access through the van tailgate) and the protocol was modified to require that the van 

engine be off during changes of sampler media. 

 The canister sampler uses a differential pressure flow controller to supply air to the sampler canister. A calibrated 

mass flow controller will check the flow rate. Since the actual flow rate is less important than the fact that the flow 

rate remains constant, additional quality assurance checks on the flow controllers is not necessary. For the 5-min 

canister samples, an additional battery-operated sampler will be used, allowing up to 3 L/min flow rates to 

pressurize the 3 L canister. 

Both the solid adsorbent and DNPH samplers use the same vacuum pump controlled by mass flow controllers. 

These controllers will be calibrated at the start of the field program by using a primary flow device (e.g. Gillibrator) 

and then will be periodically checked while in the field to confirm that the flow rates are accurate. 

Canister samples. Prior to sampling, the canisters are cleaned by repeated evacuation and pressurization with 

humidified zero air, as described in the EPA document "Technical Assistance Document for Sampling and Analysis 

of Ozone Precursors" (October 1991, EPA/600-8-91/215). Six repeatable cycles of evacuation to ~0.5 mm Hg 

2-12
absolute pressure, followed by pressurization with ultra-high-purity (UHP) humid zero air to ~20 psig are used. The 

differences between the DRI procedure and the EPA recommended method are that, in the DRI method, canisters 

are heated to 140°C during the vacuum cycle and more cycles of pressure and vacuum are used. According to our 

experience and that of others (Rasmussen, 1992), heating is essential to achieve the desired canister cleanliness. 

Also, the canisters are kept longer under vacuum cycles, about one hour in the DRI method, as opposed to half an 

hour in the EPA method. At the end of the cleaning procedure, one canister out of 12 in a lot is filled with 

humidified UHP zero air and analyzed by the gas chromatograph/flame ionization detection (GC/FID) method. The 

canisters are considered clean if the total non-methane organic compound (NMOC) concentration is less than 20 

ppbC. The actual concentrations of blank-check canisters are typically below 10 ppbC. 

Canister samples are analyzed for speciated VOC concentrations promptly upon receipt of samples from the field, 

using gas chromatography with flame ionization detection (GC/FID, Hewlett Packard) according to guidance 

provided by the EPA Method TO-15. The GC/FID response is calibrated in ppbC, using NIST Standard Reference 

Materials (SRM) 1805 (254 ppb of benzene in nitrogen). Based on the carbon response of the FID to hydrocarbons, 

the response factors determined from these calibration standards are used to convert area counts into concentration 

units (ppbC) for every peak in the chromatogram. Identification of individual compounds in an air sample is based 

on the comparison of linear retention indices (RI) with those RI values of authentic standard compounds. A DB-1 

column (60 m long 0.32 mm i.d., 1 μm film thickness) is used for these analyses. Breath canisters will be quantified 

for CO2, MTBE, and BTEX by the method of Pleil & Lindstrom using GC/MS. 

Blanks are performed once daily, while performance standards are executed three times per week. Our analysis plan 

and data processing standards call for the replicate analysis of approximately 10% of the samples. For canisters the 

replicate analysis is conducted at least 24 hours after the initial analysis to allow re-equilibration of the compounds 

within the canister. The replicate analyses are flagged in our database and the programs we have for data processing 

extract these replicates and determine a replicate precision. Replicate analysis is important because it provides us 

with a continuous check on all aspects of each analysis, and indicates problems with the analysis before they become 

significant. A portion (5%) of the canisters will also be analyzed by a second independent laboratory (negotiations 

with Battelle-Columbus are currently underway). 

Solid adsorbent samples. Ethanol will be quantified using solid adsorbent cartridges, in addition to canister method. 

Although MTBE is stable in SUMMA canisters and can be quantified with high precision and accuracy, ethanol is 

relatively unstable and the replicate analyses of canister samples show a high degree of scatter (Goliff and Zielinska, 

2001). Thus, the solid adsorbent samples are only necessary for quantification of ethanol, although TEX data may be 

obtained from the solid adsorbent samples to serve as a comparison with canister data for QA purposes. For sample 

collection we will use multibed adsorbent cartridges consisting of Tenax TA, Carbotrap (or Carboxen) and 

Carbosieve (Shire et al., 1996; Tsai and Weisel. 2000; Vayghani et al., 1999). Prior to use, the Tenax-TA solid 

adsorbent is cleaned by Soxhlet extraction with hexane/acetone mixture (4/1 v/v) overnight, and dried in a vacuum 

oven at ~80 °C. The dry Tenax is packed into Pyrex glass tubes together with Carbotrap and Carbosieve and 

thermally conditioned for four hours by heating in an oven at 300 °C under nitrogen purge. Approximately 10% of 

the precleaned tubes are tested by GC/FID for purity prior to sampling. After cleaning, the tubes are capped tightly 

using clean Swagelok caps (brass) with graphite/vespel ferrules, placed in metal containers with activated charcoal 

on the bottom, and kept in a clean environment at room temperature until use. 

After sampling at nominal monitored flows of 200-300 ml/minute, tube samples are analyzed by the thermal desorptioncryogenic preconcentration method, followed by high-resolution gas chromatographic separation and mass spectrometric 

detection (MSD) of individual compounds. The Chrompack Thermal Desorption-Cold Trap Injection (TCT) unit is used 

for the purpose of sample desorption and cryogenic preconcentration. The compounds are quantified by MS, using the 

response factors of authentic standards, prepared at five different concentrations with a static dilution bulb. 

Carbonyl compounds. Formaldehyde and acetaldehyde will be collected with Sep-Pak cartridges that have been 

impregnated with an acidified 2,4-dinitrophenylhydrazine (DNPH) reagent (Waters, Inc), according to the EPA 

Method TO-11A. When ambient air is drawn through the cartridge at nominal flow rates of 1 L/min, carbonyls in 

the air sample are captured by reacting with DNPH to form hydrazones, which are separated and quantified using 

HPLC in the laboratory (Fung and Grosjean, 1981). Depending on the type of sorbent (C18 or silica gel) in the 

cartridge, the ambient measurement results are subject to various artifacts due to interaction with ozone, thus the 

ozone denuder is recommended for sample collection. We will use a honeycomb denuder coated with sodium 

2-13
carbonate/sodium nitrite/glycerol mixture (Koutrakis, et al., 1993). After sampling, the cartridges will be eluted 

with acetonitrile. An aliquot of the eluent will be transferred into a 1-ml septum vial and injected with an 

autosampler into a high performance liquid chromatograph (Waters Alliance System) for separation and 

quantization of the hydrazones (Fung and Grosjean 1981). A portion (5%) of these aliquots will also be analyzed by 

a second independent laboratory (negotiations with Battelle-Columbus are currently underway).Liquid fuel samples. 

Liquid gasoline samples will be collected for each service station (if more than one is used per city) after ME 3/7 

refueling measurements during subsequent off-loading of the van fuel tank at the mobile lab site. Composition of 

these fuels will be determined by GC/FID for comparison to measured species (benzene & oxygenates) reported in 

summer and winter gasoline surveys conducted for the three cities being sampled and for determining relative 

exhaust/evaporative emissions sources in measured MEs. Relative exhaust and evaporative emissions may be 

estimated from fuel component ratios as noted in Graboski et al., 1998.

2-14
3-1

3. EXPERIMENTAL PROTOCOL 

This section specifies the tasks required to meet the objectives for the S211 (b) Tier 2 Exposure Study and how each 

element of the proposed testing protocol will be carried out. Details of the methods and procedures and quality 

assurance program are described in Section 2. The exposure studies have two components. First, Desert Research 

Institute (DRI) and Southwest Research Institute (SwRI) will conduct exposure measurements in San Antonio under 

controlled conditions in order to establish quantitative relationships between vehicle tailpipe and evaporative 

emissions to exposure levels in a trailing vehicle cabin and in a residence with an attached garage. Second, DRI will 

monitor microenvironmental and personal exposures in 12 high-end exposure microenvironments in Atlanta, 

Chicago, and Houston during summer and winter conditions. Selection of the high-end microenvironments was 

made in consultation with EPA and independent peer reviewers. Figures 3-1 and 3-2 show the monitoring 

requirements for the overall study and for the controlled San Antonio studies, respectively. 

3.1 San Antonio Controlled In-Cabin and Residential Garage Exposure Measurements 

DRI and SwRI will determine the quantitative relationships between evaporative and tailpipe emission from 

characterized test vehicles to exposure in (1) a cabin of a trailing vehicle under normal operation and with induced 

malfunctions and (2) a residence with an attached garage. The exposure measurements were made in San Antonio 

during June 2002 for summer fuels and will be made during January 2005 for winter fuels according to the 

following protocol. Part of the measurements made in June 2002 may be repeated in June 2004 after review of the 

entire San Antonio database by EPA. Table 3-1 shows the exposure matrix and the number of samples and hours of 

measurements for controlled in-cabin trailing vehicle and residential garage studies. 

3.1.1 Procurement of Test Fuels from Houston, Chicago and Atlanta 

With API and DRI guidance, SwRI will procure six test fuels (a summer regular grade and winter regular grade 

fuels in each of the three cities – Houston, Atlanta, and Chicago) for the study. SwRI will procure two 55-gallon 

drums of each fuel from a major supplier in each city to conduct the work in San Antonio. Three summer fuels were 

procured and evaluated during May 2002 and the three winter fuels will be procured during December 2004. SwRI 

will test fuels for bulk properties and DRI will speciate the chemical composition of each of the six blended fuels. 
Figure 3-1: Overall Structure of 211(b) Monitoring Requirements 

Segment N

Leading

vehicle

Trailing

vehicle

Segment 1

Cabin

Tests

FTP

Emission Tests

Garage Adjacent

room

Test 1 Test N

Garage

Tests

Normal Malfunctioning

Sedan Truck

RFG-MTBE RFG-EtOH Baseline

Summer Winter

San Antonio

MEASUREMENTSReference integrated (20-40 min) canister-1,3 BD, MTBE, BTEX, VOC

(20-40 min) DNPH cartridge - HCHO, CH3CHO(20-40 min) Multibed tube - EtOH

Continuous surrogate (1 min) Langan-CO, ML-NDIR CO, ppbRAE-VOCSupplemental corroborative (1-5; 10 min): KORE-BTEX, DRI-HCHO

SPME - BTEX

OTHER DATA

Diary (ME/event)Location: GPS (lat/long, min)Meteorology: W S/W D, RH, T (min); surface roughness; stability classLocal air quality: sampling day monitoring station data (60 min)

MEASUREMENTS

Semi-continuous (10 min): SPME - MTBE, EtOH, BTEX

OTHER DATA

Diary (ME/event)Location: GPS (lat/long, min)Meteorology: W S/W D, RH, T (min); surface roughness; stab. class Local air quality: sampling day monitoring station data (60 min)

Segments for Cabin Tests

1 Initial background -- no test vehicles2 Idling, close spacing3 Moderate speed, moderate spacing4 High speed, greater spacing5 Final background - no test vehicles

Garage Tests

1 Background, garage empty2 Car in garage, kitchen door

open f or 1 min

3 Car in garage, kitchen door 

open for entire test

4 Car in garage, kitchen door

closed -- window open

5 Car in garage idling, garage

door open, kitchen door openfor 1 min

6 Back car out and close garage

door

3-3

Figure 3-2. Monitoring Requirements for San Antonio Study 
3-4

San A

Table 3-1. Collection of Time-Integrated Samples for Chemical Analysis – San Antonio 

Test 

Duration 

(min)

Sample time 

SPME (min) SPME Cans DNPH

Solid Adsorb. 

a

No. of 

Tests SPME 

ntonio - Trailing Vehicle

kground 10 10 1 1 1 1 24 24 

ure Measurements 120 10 12 1 1 1 24 288 

20 10 2 1 1 1 24 48 

15 3 3 3 360 

ntonio - Residential Gara

 Initial bac  Expos  Idle  SubtotalSan A ge Exposure

age (baseline) 30 30 1 1 1 1 24 24 

age (during exposure) 150 30 5 1 1 1 24 120 

ent room (baseline) (b) 30 1 1 1 1 24 24 

ent room (during exposure) (b) 30 5 1 1 1 24 120 

30 12 4 4 4 288 

 In-gar  In-gar  adjc  adjc  Subtotal
3.1.2 Determination of Tailpipe and Evaporative Emissions of Test Vehicles 

SwRI will procure two test vehicles and determine evaporative and tailpipe emissions for the vehicles with and 

without malfunctions using the six test fuels. The two test vehicles will be 1993 to 1996 model year vehicles with 90 

to 110K odometer miles. One vehicle will be a sedan, and the second a full sized pickup truck with a V-8 engine. 

The SWRI will measure the vehicle’s exhaust emissions on a dynamometer according to the Federal Test 

Procedures (FTP). SwRI will modify these vehicles so that emission control system components (e.g., ECU, O2

sensor, catalyst) can be reversibly disconnected to represent normal and reasonable high-end approximations (e.g., ≥

2 gm HC/mile exhaust) of real world exhaust emissions. SwRI will determine exhaust emission rates for the two test 

vehicles, with and without malfunction, using three regional fuels during each of two seasons (with seasonal fuels). 

This will result in 12 combinations for each season. SwRI also will measure evaporative emissions using the same 

test vehicles with and without induced malfunction (e.g., disconnecting fuel line to carbon canister). Hydrocarbon 

samples will be collected in canisters and analyzed by DRI for complete hydrocarbon speciation. The data will be 

used to apportion the relative contributions of exhaust and evaporative emissions by applying these source 

composition profiles to the microenvironmental measurements from the three cities using Chemical Mass Balance 

(CMB) receptor modeling. 

The emission tests will be coordinated with the trailing vehicle tests described in Section 3.1.3 and the residential 

garage exposure tests describes in Section 3.1.4. SwRI will install the reversible malfunction on the two test vehicles 

and perform all emission testing prior to start of the exposure measurements. Two days will be required for the 

trailing vehicle and residential garage exposure measurements described in Tasks 2c and 2d for each of six 

combinations of vehicle and test fuel per season. The trailing vehicle exposure measurements will be scheduled in 

the morning, followed by garage exposure measurements in the afternoon. Measurements will be made on the first 

day with normal emissions and on the second day with induced malfunctions. During the exposure tests of one 

vehicle, SwRI will switch the fuel in the other vehicle and condition the vehicles with the new fuel prior to the 

exposure measurements. 

For the dynamometer FTP exhaust emissions testing, regulated exhaust emissions (total hydrocarbons, THC; nonmethane hydrocarbons, NMHC; carbon monoxide, CO; and oxides of nitrogen, NOx, carbon dioxide, CO2; and 

speciated VOC emissions (to include MTBE, ethanol, benzene, toluene, ethyl benzene, xylene, 1,3-butadiene, 

formaldehyde, and acetaldehyde) will be determined for each test. During hot soak SHED tests, total hydrocarbon 

and VOC emissions (as above except without aldehyde/ketone measurements) will be determined. Table 3-2 

presents a suggested test plan for the emissions testing at SwRI. 

The exhaust emission portion of the FTP utilizes the Urban Dynamometer Driving Schedule (UDDS), which is 1372 

seconds in duration. The UDDS is divided into two segments; the first consisting of 505 seconds, and the second 

consisting of 867 seconds. An FTP is composed of a 505-second cold transient (bag 1) portion and an 867-second 

cold stabilized (bag 2) portion, followed by a ten-minute soak and then a 505-second hot transient (bag 3) portion. 

A summary of the cycle duration, driving distance, and average speed is given in Table 3-3. The FTP driving 

schedule with the cold- and hot-transient test segments identified is given in Figure 3-1. 

The evaporative emission portion of the FTP will consist of a one-hour Diurnal Heat Build (DHB) and a one-hour 

Hot Soak Loss Test (HSL). Total hydrocarbons and VOC emissions will be recorded only during the HSL segment 

of the test. Prior to the cold-start exhaust portion of the FTP, the DHB evaporative segment of the FTP will be 

conducted by fueling the test vehicle to 40 percent of tank capacity with test fuel at a temperature below 55°F. A 

heating blanket will be attached to the outside of the fuel tank, and a thermocouple placed in the fuel inside the fuel 

tank will be connected to the computer controller. The fuel inside the tank will be raised to a nominal temperature 

of 60°F, at which point the DHB segment of the test will begin. The fuel temperature will be raised at a linear rate 

of 0.4°F per minute for the 60-minute test. The final nominal temperature will be 84°F. 

The HSL segment of the evaporative emission test will be conducted immediately following exhaust emission 

testing. For the HSL segment, the vehicle will be driven into the evaporative emission enclosure immediately after 

the exhaust emission portion of the FTP has been completed. The vehicle will be allowed to “soak” in the enclosure 

3-5 
for one hour. Total hydrocarbon and VOC emissions will be measured at the beginning and end of the one-hour 

segment to permit calculation of hot soak evaporative emissions. 

Table 3-2. Test Plan for Each Vehicle

STEP DESCRIPTION

1 Obtain test vehicle. Verify proper mechanical operation.

2 Determine malfunction condition to achieve 2 or more grams/mile total 

hydrocarbons.

3 Equip vehicle to allow switching between normal and malfunction conditions. 

Return vehicle to normal operating condition.

4 Remove canister from test vehicle.

5 Purge canister with 300°F zero nitrogen at 20L/min for five hours, reattach canister.

6 Drain fuel tank and fill to 40 percent capacity with test fuel.

7 Perform a 2-hour diurnal heat build from 70 to 120°F at a ramp rate of 0.4°F/min.

8 Operate vehicle on chassis dynamometer over one UDDS cycle.

9 Turn engine off for five minutes.

10 Start engine and idle for one minute.

11 Turn engine off for one minute.

12 Start engine and idle for one minute.

13 Remove canister from vehicle and purge canister with zero air for 60 minutes.

14 Reattach canister, drain fuel from tank, and fill to 40 percent capacity with chilled 

test fuel.

15 Conduct one hour DHB (no emission measurements).

16 Operate vehicle on chassis dynamometer over one UDDS.

17 Soak vehicle overnight.

18 Next day prior to the cold-start exhaust portion of the FTP, conduct one-hour Diurnal 

Heat Build (DHB). No emission measurements.

19 Conduct 3-bag FTP exhaust emission test. Measure regulated gaseous emissions 

and VOC emissions.

20 Conduct the Hot Soak segment of the SHED test immediately following the exhaust 

emissions testing. Measure total hydrocarbons and VOC emissions (same as with 

exhaust except no aldehyde emissions).

21 Switch vehicle to malfunction per Step 2, and disconnect evaporative canister.

22 Repeat Steps 8 through 12 and Steps 16 through 20.

23 Repeat Steps 3 through 22 for each of the remaining five test fuels. 

3-6 
Table 3-3. Summary of the FTP Driving Cycle 

Duration, Distance, Average 

Speed,

Segment Seconds Miles Miles/Hr.

Transient Phase 505 3.6 25.7

Stabilized Phase 867 3.9 16.2

UDDS 1372 7.5 19.7

F 

Figure 3-3. FTP Driving Cycle. 

Figure 3-3. FTP Driving Cycle. 

3.1.3 Relationship Between Exhaust Emission Rates and In-Cabin Exposure 

DRI and SwRI will use the two test vehicles in normal operation and with induced malfunction to determine 

exposure in a cabin of a third vehicle that is trailing the test vehicles. In addition to the two test vehicles, SwRI will 

procure a third vehicle that will be used as the trailing vehicle. DRI will install the instrument and sampling systems 

on board the trailing vehicle. This trailing vehicle will be towed to the three cities and used to conduct the exposure 

measurements described in Tasks Section 3.2. The trailing vehicle tests will be conducted on a remote road upwind 

of San Antonio, Texas. The test matrix will mirror the dynamometer tests - two test vehicles with and without 

malfunction, three regional fuels, and two seasonal fuels for 12 combinations per season. Tests using summer and 

winter fuels will be conducted in June and January, respectively. 

3-7 
During each test, the trailing vehicle will be driven behind the test vehicle over a travel loop of several miles for a 

period of up to 3 hours. Measurements will be made during the first 10 minutes without the test vehicles in order to 

establish background exposure levels. The trailing vehicle study will implement three scenarios (far, near, and 

passing) for each low or high speed (30 and 60 mph) as scheduled in the table below. During each 'far' scenario, the 

trailing vehicle will follow continuously at the conventional 'safe' following distance for the indicated speed, defined 

as one car length (about 10 feet) for each 10 mph. During the 'near' scenario, the vehicle will 'tailgate' the leading 

vehicle continuously following at a closer distance deemed 'safe' for professional drivers under low-traffic density 

and prevailing meteorological conditions by SwRI and DRI staff. During the “passing” scenario, the trailing vehicle 

will spend 10 min at “tailgating” distance, i.e., as close as safety permits, and 10 min at “passing” distance at an 

adjacent lane position that maximizes potential cabin penetration (based on maximal hood TVOC). 

Table 3-4 details the trailing vehicle protocol. We are continuously monitoring total VOC (with ppbRAE PID) 

inside the cabin and outside the cabin, with the inlet mounted on the radio antenna 6 inches above the hood of the 

vehicle. In addition, we measure TNMHC from time-integrated canister samples. 

Table 3-4. Protocol for trailing vehicle tests 

Time 

Min. 

Speed 

Mph 

Ventilation 

Setting Distance Notes 

Continuous 

Instruments 

SPME Time 

Integrated 

10 high high background Y 1 1 

10 low high far Y 1 

10 low high near Y 1 

10 low high passing Y 1 

10 high high far Y 1 

10 high high near Y 1 

10 high high passing Y 1 

10 low low far Y 1 

10 low low near Y 1 

10 low low passing Y 1 

10 high low far Y 1 

10 high low near Y 1 

10 high low passing Y 1 

1 

10 idle low adjacent Y 1 

10 idle high adjacent 

Vehicles: 

Toyota Camry 

and 

Pick-up truck, 

in normal and 

malfunction 

mode. 

Fuels: baseline, 

MTBE, ethanol

Y 1 

1 

3.1.4 Relationship Between Evaporative Emission Rates and Exposure in a Residence With an Attached 

Garage 

The two test vehicles (with and without malfunctions) will be used to determine indoor exposures in homes with 

attached residential garages. The same test vehicles will be used to measure indoor exposures in a residence with an 

attached garage using the following testing matrix. The vehicles will be parked in a closed residential garage also 

containing a gasoline powered lawnmower and gas container with in-garage and adjacent room monitoring 

conducted before, during and after the vehicle cool-down period. Door openings between the garage and adjacent 

room and room window openings will be monitored. The vehicle will also be ‘warmed up’, idling in the garage 

(with the garage door open) during a period of the 3-hour monitoring process. The measurements will be made in 

3-8 
San Antonio at the residence of a SWRI employee who has agreed to provide access to the house during the study. 

The test procedure will be similar to those described by Tsai and Weisel (2000). We propose to collect two timeintegrated samples of each kind per test (one in the garage and one in the adjacent room). A set of continuous and 

semi-continuous methods will be operated during the vehicle exposure period of approximately two hours. 

The attached garage study will implement six scenarios as described in the Table 3-5. Measurements will be taken 

over 30-minute periods with the collocated sampling inlets located at breathing height (1.5 m) at least three feet 

away from nearby walls in both the unvented garage and adjacent indoor room (kitchen). The two PID instruments 

will sample continuously both before (background) and during the tests with one unit each having its collocated inlet 

in the garage and adjacent room. Langan CO and/or NDIR CO instruments will sample continuously in the garage 

and adjacent room. The MS200 BTEX and DRI aldehyde monitors will sample continuously from collocated inlets 

in the adjacent room for corroborative purposes. A half-filled two gallon standard plastic gasoline storage container 

with vent open will be placed with a lawnmower with gas tank half filled against the center of the garage wall 

common to the adjacent room. The appropriate fuel (i.e. from Houston, Atlanta or Chicago) will be placed in the 

garage one day before the series of tests for this fuel and left there over the duration of these tests. Scenario 

conditions will be changed every 30 minutes over the 3-hour protocol as described in the table. 

The ambient garage temperature will be recorded every 30 min during each experiment and the tests will be 

conducted every day (excluding weekends) over the period of two weeks. 

Table 3-5.Protocol for attached garage experiments. The same vehicles and fuels as for trailing vehicle experiment 

are used. 

Condition Time 

 (min) 

Garage 

Door 

Kitchen 

Door 

Kitchen 

Window 

Inlet 

Location 

Continuous SPME Integrated 

Samples 

garage Langan CO 

PID1 

Background 

30 closed closed closed kitchen MS200 

DRI 

PID2 

NDIR CO 

2 2 

garage Langan CO 

PID1 

Hot soak 30 closed open 1min 

& closed 

closed kitchen MS200 

AO 

PID2 

NDIR CO 

2 

garage Langan CO 

Maximal PID1 

AER to 

indoors 

30 closed closed closed kitchen MS200 

DRI 

PID2 

NDIR CO 

2 

garage Langan CO 

Maximal PID1 

AER to 

outdoors 

30 closed closed open kitchen MS200 

DRI 

PID2 

NDIR CO 

2 

garage Langan CO 

PID1 

Cold start 30 open open 1 min 

& closed 

closed kitchen MS200 

DRI 

PID2 

NDIR CO 

2 

2 

3-9 
3-10

3.2 Microenvironmental Exposure Measurements in Atlanta, Chicago, and Houston 

One of the overall goals of the project is to sample high-end microenvironments (MEs), plausibly characterized in 

the upper 90th centiles of exposure that result from the impacts of exhaust/evaporative emissions from gasolinefueled vehicles. Selection of high-end microenvironments was made in consultation with EPA and independent peer 

reviewers. 

DRI will determine in-cabin exposure in urban roadway and other high-end exposure microenvironments in 

Houston, Chicago, and Atlanta over several weeks in each city and season during July-September (summer test) and 

January-March (winter test). Exposure measurements will be made for thirteen different microenvironments with 

three replicate measurements for microenvironments with low variability and five replicate measures for highly 

variable MEs including trailing high emitting vehicles (ME 13), underground garages (ME 11), and outdoor 

refueling (ME 7). Measurements in each of the microenvironments will be taken over a period of 20-60 minutes and 

completed within the hour where possible to facilitate comparisons with local ambient monitoring values. Sampling 

durations will depend on the event and may range from 20 to 60 minutes in the discretion of DRI as necessary to 

obtain a typical sample. For example, refueling events and clearing of parking garages after sporting events usually 

occur over periods substantially less than an hour and do not start at the top of the hour. Continuous measurements 

of carbon monoxide, benzene, toluene, ethyl benzene, xylenes, photoionizable (10.6 eV) VOC, and formaldehyde 

will be taken during the entire sampling period. Time-integrated canister, DNPH cartridge, and solid adsorbent (in 

Chicago) samples will also be collected over the full sampling period unless the next sample will be collected during 

a consecutive hour. In such cases, 60-minute samples will be collected during the first 50 minutes to allow time for 

replacement of sampling media. In addition, four SPME samples (for BTEX) will be collected during consecutive 

10 -minute periods during each sampling period. Liquid fuel samples will be collected after ME3/7 measurements 

(during off-loading of the van fuel tank) for each service station (if more than one is used per city) sampled for this 

ME. Video tapes of ME sampling will be conducted as advisable considering local privacy and security concerns; at 

least one videotape will be provided to EPA for each ME sampled in each city. 

Table 3-6. Microenvironment Listing. 

ME # ME Description Replicates Biomarker 5 min Canister Sampling Time 

(min) 

1 In-Cabin Congested Freeway 5 40 

2 In-Cabin Urban Canyon 3 40 

3 In-Cabin Refueling 5 20 

4 In-Cabin Underground Garage 5 40 

5 In-Cabin Toll Plaza 3 40 

6* Roadway Tunnel 5 yes yes 40 

7 Outdoor Refueling 5 yes yes 20 

8 Sidewalk 3 40 

8/9 Sidewalk/Bus Stop 3 40 

10 Outdoor Surface Parking 3 40 

11 Outdoor Underground Garage 5 yes yes 40 

12 Outdoor Toll Plaza 3 40 

13* In-cabin Trailing High-Emitting Vehicles 5 yes yes 40 

*ME6 will be sampled in Houston & Chicago and ME13 in Atlanta.. 

Table 3.6 displays the planned exposure matrix with the number of replicates, and the location of biomarker and 5-

minute canister peak sampling. Table 3.7 lists the number of samples for each microenvironment. 
3-11 

Urban 

 1. I 2. I 3. I 4. I 5. In 6. Ro 13 Su

Urban nts

 7. Outdoor Refueling4 5 20 10 10 10 5 10 30 60 

 8. Sidewalk 3 40 10 20 3 3 6 18 120  8/9. Sidewalkl/Bus Stop 3 40 10 20 3 3 6 18 120  10. Outdoor Surface Parking 3 40 10 20 3 3 6 18 120 

 11. Outdoor Underground Garage4 5 40 10 20 10 5 10 30 120 

 12. Outdoor Toll Plaza 3 40 10 20 3 3 6 18 120  Subtotal 22 110 32 22 44 132 660 

Biomarker Breath Samples

 6. Roadway Tunnel 1 5 40 15 20 0 

 7. Outdoor Refueling 5 20 15 30 0  11. Outdoor Underground Garage 5 40 15 30 0 

 13. In-cabin Trailing High-Emitting Vehicles2 5 40 15 10 0 

 Subtotal5 15 45 90 0 

 Total 63 220 108 48 96 378 1320 

1ME6 will be done in Houston and Chicago.2ME13 will be done in Atlanta only.3Chicago only.4Includes 5 minute canister.5Only one ME counted for ME6 and ME13 for Total No. of Samples Per Site.

Total No. of Samples Per Site Total No. of Samples f

Table 3-7. The Number of Samples for Each Microenvironment for Three Cities and Two Seasons 

e

Replicates

Test 

Duration 

(min)

Sample time 

SPME (min) SPME Cans DNPH

Solid Adsorb. 

A&B3

Total No. of 

Tests

Total No. 

SPME

Exposures in Vehicle Cabin 

n-Cabin Congested Freeway 5 40 10 20 5 5 10 30 120 

n-Cabin Urban Canyons 3 40 10 20 3 3 6 18 120 

n-Cabin Refueling 5 20 10 10 5 5 10 30 60 

n-Cabin Underground Garage 5 40 10 20 5 5 10 30 120 

-Cabin Toll plaza 3 40 10 20 3 3 6 18 120 

adway Tunnel1,4 5 40 10 20 10 5 10 20 80 

. In-cabin Trailing High-Emitting Vehicles2,4 5 40 10 20 10 5 0 10 40 

btotal5 26 110 31 26 52 156 660 

Exposures in Other Microenvironm
3.2.1 Exposure Diary and Script Development 

Scripted activities will be used during the exposure measurements. This methodology, referred to as the indirect 

approach, has the advantage of providing estimates of exposure over a range of scenarios based on a limited sample 

size (Klepeis, 1999). This approach involves the following steps: (1) micro environmental identification, (2) 

quantification of time spent performing activities in a given microenvironment, and (3) measurements of pollutant 

concentrations during a specified activity. By multiplying the total time spent during each activity by the pollutant 

concentrations, activity-specific exposure can be estimated. Using EPA human activity patterns, exposure from 

these activities can be estimated for the total population (EPA, 1996). 

One of the key aspects of the indirect approach is an accurate measure of the time spent performing a specified 

activity. In order to define exposure time in a reproducible manner, scripted activities are developed for this study by 

Ted Johnson of TRJ Environmental Inc. for various high-end exposure microenvironments. In this manner, 

different subjects can reproduce the total time required for a specified activity and an accurate estimate of exposure 

time can be determined. Scripted activity diaries are developed and completed by field personnel during the 

exposure measurements to document more detailed information about the sampling location and activities during 

each monitoring period. Examples of a diary pages are included in Appendix D. 

We also will compare personal exposures with ambient measurements from nearby local and state monitoring sites. 

This can be facilitated by scheduling activities to begin on the hour and end on the hour, enabling a direct 

comparison with ambient network data. However, many high-end microenvironmental activities take less than an 

hour (e.g., refueling, transiting a tunnel, leaving a parking garage) so scheduling of start and stop times within the 

same clock hour will be attempted as an alternative to increase correlation with ambient monitor sampling periods. 

Ambient monitor locations are provided to allow estimates of distance and directional relationships to ME 

measures. 

3.2.2 In-cabin Exposures in Urban Microenvironments 

The trailing vehicle from the controlled exposure tests in San Antonio will be transported to each of the three cities 

and used for the in-cabin exposure measurements in each of the three cities in both summer and winter. A driving 

route will be developed for each city, which includes the urban roadway microenvironments and trailing high 

emitting vehicles encountered in these roadways. 

ME#1 – Freeway traffic under stop-and-go conditions (40 minutes) 

ME#2 – Downtown surface street loop characterized by an urban canyon effect (40 minutes) 

ME#3 – Refueling (20 minutes) 

ME#4 – Parking garage (40 minutes) 

ME#5 – Toll plaza (40 minutes) 

ME#6 – Tunnel or covered roadway (40 minutes) 

ME#13 – Trailing high-emitting vehicles (40 minutes) 

In addition to continuous measurements, one integrated sample will be collected during each 20-40 minute exposure. 

Table 3-6 shows the proposed exposure matrix. We will use GPS on board the vehicle to record the location and 

time during the entire test. Testing over the driving route will be made three – five times for each city and season on 

rush-hour weekdays with both high ventilation (e.g., window and vent open during the summer) and lower 

ventilation (i.e., windows and vent closed with AC or heater on during the summer/winter). 

3-12
We will use scripted technicians and measure breathing zone and ME air levels in the following outdoor and indoor 

microenvironments: self-service refueling stations, sidewalks near high-density traffic, underground parking garage, 

bus stop, toll booth, and an above ground parking garage. Technicians will follow the activity scripts developed and 

will use diaries and/or GPS monitors to document actual exposure locations and conditions. 

The exposures in each microenvironment will be monitored for 20-40 minutes. We propose to repeat the 

measurements in each microenvironment three to five times and collect time-integrated canister, DNPH and solid 

adsorbent (for Chicago only) samples during each exposure period (see Table 3-7). For all tests the inlet for 

portable and time-integrated instruments will be collocated at breathing zone height (i.e. 1.5 m above the ground) 

and in the breathing zone of the technician as appropriate. 

3.2.3 Technician Biomarker Analysis 

Breath measurement will be used as the biomarker of choice. Since we were not able to distinguish background 

benzene concentrations from low-level exposures (e.g. walking down street), we propose only to conduct biomonitoring experiments for projected “high-end” exposures such as outdoor refueling, trailing high emitters on 

congested roadways, and exiting an underground parking garage. Breath sampling will be conducted similar to the 

2nd pilot study, with pre- and post-exposure collections (plus a backup sample) of the subject’s breath. Samples 

will be collected and analyzed according to the protocols described in detail in Section 2. 

3.2.4 Criteria for Selecting High End Microenvironments 

General selection criteria for the 13 high-end MEs are listed below. These selection criteria were developed to bias 

selection towards sampling ME locations and conditions with higher levels of accumulated emissions. Survey 

technicians will also use pollutant sniffers (e.g., Langan CO and ppbRAE VOC monitors) to sense relative peak 

pollutant levels within and among these candidate locations, choosing the ME locations with the highest levels in 

each category for inclusion in the city-specific sampling scripts. Detailed descriptions of the Houston, Atlanta and 

Chicago microenvironments are presented in the city plans appended to the protocol. 

1. Congested (stop-and-go) freeway (vehicle cabin) 

• Rush hour sampling on roadway parallel to wind direction 

• Locally known choke points & signaled intersections on high density routes 

• Locations most shielded from air dispersion by local topography 

• Lane reductions due to ongoing construction or breakdowns/accidents 

• Downwind direction from traffic density centroid 

• Trailing high emitting vehicles encountered 

Protocol: Prior to test, identify roadway segment that best satisfies above conditions and confirm high potential 

concentrations using sniffer. Drive back and forth on the segment continuously during the 40-minute rush-hour 

test period. Drive in most congested (slowest) lane. Maintain a safe following distance, about one car length 

(10 feet) per 10 mph speed, closing to within 3 feet during stopped conditions. Sample alternative 20-minute 

periods under high- and low-ventilation (vehicle windows & vents open and windows & vents closed). Trail 

high emitting vehicles where encountered. 

2. Urban canyon (vehicle cabin) 

• Rush hour sampling on roadway perpendicular to wind direction 

• Greatest contiguous length & height of high-rise buildings 

• Narrowest canyon width 

• Highest traffic density 

• Mid-block sampling most shielded from air dispersion 

Protocol: Urban canyons are streets edged by tall buildings that were selected to be deep as possible 

generally with height/width ratios > 1. Prior to test, identify roadway segment that best satisfies above 

conditions and confirm high potential concentrations using sniffer. Drive back and forth on the segment 

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continuously during the 40-minute rush-hour test period (an around-the-block downtown loop may be used 

if entire loop is associated with high canyon concentrations). Drive in most congested (slowest) lane. 

Maintain a safe following distance, about one car length (10 feet) per 10 mph speed, closing to within 3 feet 

during stopped conditions. Sample alternative 20-minute periods under high- and low-ventilation (vehicle 

windows & vents open and windows & vents closed). Trail high emitting vehicles where encountered. 

Note that GPS data are often unavailable or unreliable in tall urban canyons as the satellite signals are 

blocked. 

3. Refueling (vehicle cabin) 

• Peak refueling period for station 

• Largest number of pumps 

• Downwind direction from centroid of pump locations 

• Location most shielded from air dispersion by topography 

• Period with the lowest achievable wind speeds 

• Protocol: Prior to test, identify service station that best satisfies above conditions and use sniffer to 

locate refueling stations associated with highest concentrations. Drive van sufficiently to elevate 

measured fuel tank temperature prior to the refueling test. Park car at refueling location and sample 

alternative 10-minute periods under high- and low-ventilation (vehicle windows & vents open and 

windows & vents closed). Refuel car over a 1 to 2-minute active refueling period at mid-point of highventilation sampling period, spilling a few drops of fuel (whose volume is estimated by spot diameter) 

as the nozzle is withdrawn from the fuel tank inlet. The number of gallons dispensed will be recorded 

along with number and diameters of spill spots; the start and stop times of active fueling will be 

recorded on monitor charts. Endeavor to sample the same service station at the same time of day on 

different days as is possible. 

4. Parking garage (vehicle cabin) underground 

• Rush hour exit sampling 

• High capacity & usage 

• Near internal entrance/exit lanes 

• Location with smallest external openings & most shielded from air dispersion by topography 

• Downwind direction from centroid on most occupied parking level 

Protocol: Prior to test, identify aboveground parking lot that best satisfies above conditions and use sniffer to locate 

parking area within lot associated with highest concentrations. Park car at the location and sample alternative 40-

minute periods under high- and low-ventilation (vehicle windows & vents open and windows & vents closed), 

during most active period of vehicles exiting. 

5. Toll plaza apron (vehicle cabin) 

• Rush hour sampling 

• General location of idling traffic queue (e.g., at road toll, parking garage entrance/exit, emissions 

testing facility, controlled on-ramp, multi-road signal-controlled intersection) 

• Location most shielded from air dispersion by topography 

• High use location 

• Downwind direction from centroid of traffic mass 

Protocol: Prior to test, identify toll plaza apron that best satisfies above conditions and use sniffer to locate parking 

area within plaza associated with highest concentrations. Park car at the location, if feasible, and sample alternative 

20-minute periods under high- and low-ventilation (vehicle windows & vents open and windows & vents closed). If 

not, repeatedly traverse the plaza queue during the 40-minute test period, sampling as above, trailing any high 

emitting vehicles encountered. 

6. Tunnel/Covered Roadway (vehicle cabin) 

• Rush hour sampling 

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• Stop-n-go traffic flow 

• Highest traffic density 

• Lack of mechanical ventilation, if available 

• Smallest enclosed volume 

Protocol: Prior to test, identify tunnel or covered roadway that best satisfies above conditions and use 

sniffer to confirm high concentrations. Drive back and forth on enclosed roadway during the 40-minute 

test period maximizing time spent in the enclosed environment. Drive in slowest, most congested lane. 

Maintain a safe following distance, about one car length (10 feet) per 10 mph speed, closing to within 3 feet 

during stopped conditions. Note that GPS data are unavailable inside the tunnel as the satellite signals are 

blocked. Sample alternative 20-minute periods under high- and low-ventilation (vehicle windows & vents 

open and windows & vents closed). Trail high emitting vehicles where encountered. Collect 5-minute 

canister sample during tunnel transit of peak concentration. Biomarker samples (breath) will be collected 

from the technician, who will be isolated from further exposure before performing this task. 

7. Outdoor Refueling (self-service) 

• Peak refueling period for station 

• Largest number of pumps 

• Downwind direction from centroid of pump locations 

• Location most shielded from air dispersion by topography 

• Period with lowest achievable wind speeds 

• Protocol: Prior to test, identify service station that best satisfies above conditions and use sniffer to 

locate refueling area associated with highest concentrations. After driving car sufficiently to elevate 

measured temperature of fuel tank, park car at refueling location and sample alternative 10-minute 

background (at pump) and refueling periods. With collocated sampling inlets in the breathing zone, 

refuel the vehicle over a 1 to 2-minute active refueling period at the mid-point of the second 10 min 

sampling period. A 5-minute canister sample is taken to include the active refueling period. Return to 

the vehicle cabin for the rest of the 10-minute sampling period. During active refueling, maintain 

manual control of the nozzle (i.e., use an unlatched nozzle) and stand downwind of the vehicle fuel 

tank inlet, spilling a few drops of fuel (whose volume is estimated by spot diameter) as the nozzle is 

removed from the fuel tank inlet. The number of gallons dispensed will be recorded along with 

number and diameters of spill spots; the start and stop times of active fueling will be recorded on 

monitor charts. Endeavor to sample the same service station at the same time of day on different days 

as is possible. Liquid fuel samples will be collected after ME7 measurements (during off-loading of 

the van fuel tank) for each service station (if more than one is used per city) sampled for this ME. 

 Biomarker samples (breath) will be collected from the technician, who will be isolated from further 

exposure before and after performing this task. 

8. Sidewalk/crosswalk near high density traffic 

• Rush hour sampling on roadway parallel to wind direction 

• Downwind direction from traffic mass centroid 

• Location most shielded from air dispersion by topography 

• Highest traffic density 

• In urban canyon 

Protocol: Prior to test, identify roadway segment with sidewalks that best satisfies above conditions and 

identify the highest concentration area using sniffer. With cart sampler inlet in breathing zone, walk along 

loop route on both sides of roadway using crosswalks to cross roadway during the 40-minute sampling 

period. Walk within three feet of curb. 

9. Bus stop 

• Rush hour sampling on roadway parallel to wind direction 

• High traffic density route 

• Located on traffic island/median strip 

3-15
• Downwind direction near high density traffic intersection 

• In urban canyon 

Protocol: Prior to test, identify bus stop (or cab stand) satisfies above conditions and confirm high 

concentrations using sniffer. With cart inlet in breathing zone, stand/sit at this location (within three feet of 

curb) for the entire 40-minute test. 

10. Outdoor Surface Parking 

• Rush hour/maximal usage sampling 

• High capacity & usage location 

• Near internal entrance/exit lanes 

• Downwind direction from centroid of traffic mass 

• Location most shielded from air dispersion by topography 

Protocol: Prior to test, identify stadium parking lot that best satisfies above conditions and locate parking 

area within lot where vehicles will queue as they attempt to exit. Identify approximate time that the 

game/event ends. Sample during 40-minute test, approximately dividing the time to see the peak number of 

vehicles leaving the lot. Sample with front windows down, sliding doors open and vents open, as 

appropriate. 

11. Outdoor Underground Parking Garage 

• Rush hour sampling 

• High capacity & usage 

• Near internal entrance/exit lanes 

• Lowest level with high capacity usage 

• Lack of mechanical ventilation, or away from fans & vents if present 

Protocol: Prior to test, identify underground parking lot that best satisfies above conditions and use sniffer 

to locate parking area within garage associated with highest concentrations. Park car at location during 40-

minute rush-hour test with front windows down and vents open. Maximize number of vehicles passing the 

sampling point as they exit the garage. Collect a 5-minute canister sample during a period of peak 

concentration. Biomarker samples (breath) will be collected from the technician, who will be isolated from 

further exposure before performing this task. 

12. Outdoor Toll booth 

• Rush hour/maximal usage sampling 

• Lack of mechanical ventilation, if available 

• Enclosed queues (e.g., from parking garages, tunnels, testing facilities) 

• Central booth & location most shielded from air dispersion by topography 

• Downwind direction from centroid of traffic mass 

Protocol: Prior to test, identify tollbooth area that best satisfies above conditions and confirm highest 

concentrations using sniffer. With cart inlet in the breathing zone, sample a location representative of the 

tollbooth operator’s exposure during the 40-minute test. 

13. Trailing High Emitters 

• Rush hour sampling on roadway perpendicular to wind direction 

• Greatest contiguous length & height of high-rise buildings 

• Narrowest canyon widths 

• Highest traffic density 

Protocol: Prior to test, identify roadways which have the most high emitters using sniffers. Acquire 

candidate high emitters from PID/CO sensors and follow as closely as is prudent. Maintain a safe 

following distance, about one car length per 10 mph speed, closing to within 3 feet during stopped 

conditions. Sample alternative 20-minute periods under high- and low-ventilation (vehicle windows & 

3-16
vents open and windows & vents closed). Trail high emitting vehicles as long as possible or until a higher 

emitter is encountered. Collect a 5-minute canister sample during a peak concentrations period. Biomarker 

samples (breath) will be collected from the technician, who will be isolated from further exposure before 

performing this task. 

Appendices A, B and C contain the specific city plans for sampling in Houston, Atlanta, and Chicago, 

respectively. 

3.3 Meteorology 

For portions of the sampling periods involving stationary activities, local meteorological variables such as wind 

speed and direction, temperature and relative humidity will be taken periodically with a handheld monitoring station. 

During both these and mobile sampling periods, additional information representing regional conditions will be 

obtained from nearby NOAA/FAA sites, or other agencies if available. Stability information requires upper air data. 

The closest locations to the selected cities of San Antonio, Houston, Atlanta, and Chicago, that take routine 

radiosonde measurements, are at Corpus Christi TX, Lake Charles LA, Peachtree City GA, and Davenport IA or 

Lincoln IL. Sections of two of the cities, Houston and Chicago, can also be affected by land/ocean breezes. 

Although in situ surface-based observations are preferable, diagnostic output from operational numerical models can 

also be analyzed. 

Field participants in the experiment will make the local on-site measurements using a portable meteorological 

station. Dr. Kelly Redmond, Regional Climatologist, of the Western Regional Climate Center (WRCC), will 

undertake remaining phases. A principal role of this NOAA-funded facility, housed within DRI's Division of 

Atmospheric Sciences, is to acquire, store, summarize, distribute, and interpret atmospheric data. The Climate 

Center has excellent access to past data nationwide through its own considerable in-house capabilities, as well as 

strong programmatic ties to the other five Regional Climate Centers and to the National Climate Data Center. (The 

entire national program is funded through DRI.) Each day WRCC processes approximately 100-200 MB of weather 

and climate data from the national distribution circuits, and saves indefinitely the entire feed containing observations 

from all NOAA/FAA sites in North America. The Climate Center has a wide variety of software for producing 

climatological summaries of differing degrees of sophistication, depending on the need. 

3.4 Data Analysis 

Compile summary statistics of the data, perform consistency checks, and identify outliers. 

The data validation process consists of procedures that identify deviations from measurement assumptions and 

procedures. We will apply the following tests to evaluate the internal, spatial, temporal, and physical consistency of 

each data set and identify invalid data and outliers. DRI will compile and validate the data from Tasks 2 through 4 

and prepare statistical summaries of the data and perform the following validation checks. 

• Compare averages derived from continuous and semi-continuous measurements with data from timeintegrated samples. Determine systematic biases. 

• Derive summary statistics (mean, maximum, standard deviation) for all species, sort the concentrations and 

note any unusually high or low concentrations. 

• Determine variations in fractions of benzene, toluene, ethyl benzene, xylenes, MTBE, and ethanol, 

formaldehyde, acetaldehyde to TNMHC and significant differences in the ratios among 

microenvironments. 

• Prepare scatter plots of mean CO and PID with BTEX from canister and MS200), 1,3-butadiene and MTBE 

from canisters, ethanol from adsorbent cartridges, formaldehyde and acetaldehyde from DNPH cartridges, 

and formaldehyde from continuous measurements. 

3-17
• Determine ratios of the sum of formaldehyde and acetaldehyde to CO, and relate variations in the ratios 

with MEs and time of day with expectations in the relative contributions of direct emissions versus 

photochemical formation. 

Evaluate the suitability of candidate measurement methods for use in the main exposure study. 

• Summarize results of laboratory evaluations of continuous and semi-continuous methods. 

• Compare time-averaged continuous data from the pilot study with corresponding semi-continuous and 

time-integrated measurements over the same time intervals. Determine significant biases among methods 

and determine whether continuous measurements will be suitable for determining time-integrated exposure 

or for documenting peak exposures only. 

• For continuous and semi-continuous measurement methods, characterize the effect of time resolution on 

measurement of peak exposures. 

Determine quantitative relationships between tailpipe emission rates and variations in fuel formulations with 

exposures in the cabin of a trailing vehicle. 

• Quantify the variations in the background values for BTEX, MTBE, 1,3-butadiene, HCHO, CH3CHO, 

EtOH, TVOC and CO during the initial and final loops without the test vehicle. 

• Subtract the average time-integrated background values from the corresponding time integrated exposure 

levels for the default driving condition for each of the 24 test combinations (i.e., two test vehicles, two 

emission conditions, three fuels, and two season) and four replicates. 

• Quantify separately for each of the two vehicles, the specific differences due to emission condition, fuel 

and season. Quantify absolute differences for each designated species and differences normalized to 

concurrent CO data. 

• Variations in MTBE/benzene and EtOH/benzene ratios (or other HC species) will be related to extent of the 

potential contribution of tailpipe and evaporative emissions. 

• Determine the effect on cabin exposure of varying speed, spacing between test and trailing vehicle, and 

degree of ventilation. 

• Determine variations of the in-cabin exposures within the test and trailing vehicle due to variation in 

normal/malfunction test vehicle emission rates under idle. 

Determine quantitative relationships between evaporative emission rates and variations in fuel formulations with 

exposures in a residence with an attached garage. 

• Subtract the time-integrated background values of BTEX, MTBE, and TVOC from the corresponding time 

integrated exposure levels in the garage and in the adjacent room and determine the increased exposure due 

to hot-soak evaporative emissions for the vehicle and fuel combinations that were tested. 

• Determine the time-evolution in the levels of the BTEX, MTBE, and TVOC above background levels and 

determine the penetration of evaporative emissions from the garage to the adjacent room for the vehicle and 

fuel combinations that were tested. 

Quantify exposures to conventional and oxygenated evaporative and exhaust emission in microenvironments. 

• Process GPS data and develop a log of exposure measurements with respect time, location, and speed. 

3-18
• Compare time-integrated exposure levels measured in the microenvironments that were investigated among 

the three cities by season. Develop correlations of individual toxic species from time-integrated 

measurements with CO or PID measurements as appropriate for microenvironments dominated by vehicle 

exhaust or fuel evaporative emissions. 

• Evaluate the consistency in time-series among continuous CO, PID, MS200, and HCHO measurements in 

each microenvironment by city and season. 

• Reconstruct the time-series of individual air toxics using the surrogate CO and PID measurements and their 

correlations to time-integrated measurements. 

• Determine the differences in mean and peak exposures by city and season for each microenvironment and 

characterize the variability of replicate tests for each microenvironment. 

• Characterize the extremes in exposure levels for each microenvironment using the reconstructed 1-minute 

data. 

• Determine the effect of varying cabin ventilation conditions on exposure levels using the ratios of in cabin 

CO concentrations to ambient CO (measured in the mobile laboratory). 

• Compare CO/BTEX/HCHO/NMHC levels that were measured during the exposure study with nearby 

values from the local ambient air monitoring station. 

• Estimate the relative importance of tailpipe and evaporative emissions on exposure using the ratio of 

MTBE to benzene as described in the RFP. 

• Determine the levels of the designated species in the urine and breath of technicians carrying out the 

scripted behaviors and determine significant differences due to varying fuel formulation. 

3.5 Reporting 

This task will require completion of the following: 

• Report after completion of the 1st Reno Pilot Study (complete) 

• Detailed preliminary protocol (peer-reviewed by API and submitted for EPA approval prior to initiating the 

main exposure measurements) (complete) 

• Interim Data Report after 2002 summer field study (complete) 

• Atlanta Summer Field Study report (complete) 

• Report after completion of the 2nd Reno Pilot Study (complete) 

• Final protocol (after incorporating protocol changes) (this document) 

• Comprehensive draft report (including the hypotheses, descriptions of statistical analyses, and 

interpretations of the findings)Final report incorporating reviewers’ comments (submitted to EPA for 

review and approval together with the reviewers’ comments and a statement of the disposition of the 

reviewers’ comment) 

3-19
4. PROJECT SCHEDULE AND DELIVERABLES 

o 10/03 Final protocol submitted to EPA for formal approval 

o 11/03 Send summer 2002 San Antonio & Houston data report to EPA 

o 12/03 Send summer 2003 Chicago & Atlanta data report to EPA 

o 1/04 EPA approves San Antonio and/or Houston re-sampling plan 

o 2/04 DRI begins winter Atlanta sampling 

o 3/04 DRI completes winter Chicago sampling 

o 7/04 DRI begins summer re-sampling in San Antonio (if required) 

o 8/04 DRI completes summer re-sampling in Houston 

o 1/05 DRI begins winter San Antonio sampling 

o 2/05 DRI completes winter Houston sampling 

o 5/05 Send draft report to EPA & peer reviewers 

o 6/05 Revise draft report incorporating peer reviewer comments 

o 7/05 Send draft final report to EPA 

o 9//05 Receive EPA comments 

o 1/06 Address EPA comments, send final report to EPA, & archive results 

 

4-1 
5. REFERENCES 

Cardin, D. and T. Robinson (2002). Formaldehyde and VOCs in air-quality determinations by GC-MS. American 

Laboratory. 32-34 

Chai, M. and J. Pawliszyn (1995) Analysis of Environmental Air Samples by Solid Phase Microextraction and Gas 

Chromatography/Ion Trap Mass Spectrometry, Environmental Science and Technology, Vol. 29, No. 3. 

Environmental Protection Agency (EPA) (1991). "Technical Assistance Document for Sampling and Analysis of 

Ozone Precursors." Document No. EPA/600-8-91/215, U.S. Environmental Protection Agency, Research 

Triangle Park, NC. 

Environmental Protection Agency (EPA) (1996). Descriptive Statistics from a Detailed Analysis of the National 

Human Activity Pattern Survey (NHAPS) Data. Document no. EPA/600/R-96/148, U.S. Environmental 

Protection Agency, Office of Research and Development, Washington, DC, July 1996. 

Fung, K., and D. Grosjean (1981). "Determination of Nanogram Amounts of Carbonyls as 2,4-

Dinitrophenylhydrazones by High Performance Liquid Chromatography." Anal. Chem., 53, 168-171. 

Graboski, M.S., D.L. Mowery, J. McClelland (1998). Microenvironmental Exposure Analysis Evaluation of the 

Toxicity of Conventional and Oxygenated Motor Fuels, SAE International Fall Fuels and Lubricants 

Meeting and Exposition, San Francisco, October 19-22, 1998, in Alternative Fuels 1998 (SP-1319), SAE 

Technical Paper 982535. 

Goliff, W.S. and B. Zielinska (2001). Long-Term Stability of Oxygenated Compounds inElectropolished Canisters, 

Paper #403, presented at the 94th Annual A&WMA Conference and Exhibition, June 24-28, 2001, in 

Orlando, Florida. 

Kelly, T.J. and C.R. Fortune (1994). Continuous Monitoring of Gaseous Formaldehyde Using an Improved 

Fluorescence Approach. Intern. J. Environ. Anal. Chem., 54: 249-263 

Klepeis, N.E. (1999). An Introduction to the Indirect Exposure Assessment Approach: Modeling Human Exposure 

Using Microenvironmental Measurements and the recent National Human Activity Pattern Survey, 

Environmental Health Perspectives, 107, 365-374. 

Koutrakis, P., J.M. Wolfson, A. Bunyaviroch, S.E. Froehlich, K. Hirano, J.D. Mulik (1993). Measurement of 

Ambient Ozone Using a Nitrite-Coated Filter. Anal Chem 65, 209-214. 

Lee, C.W. and C.P. Weisel (2001). Toxicokinetics of Human Exposure to Methyl tertiary-butyl ether (MTBE) 

Following Short-Term Controlled Exposures. JEAEE ., 11, 67-78 

Lindstrom, A.B., and J.D. Pleil (1996). Alveolar Breath Sampling and Analysis to Assess Exposures to Methyl 

Tertiary Butyl Ether (MTBE) During Motor Vehicle Refueling., JAWMA . 46, p. 676-682 

Martos, P. and J. Pawliszyn (1998). Sampling and Determination of Formaldehyde Using Solid-Phases 

Microextraction with On-Fiber Derivation, Analytical Chemistry, 70, 2311-2320. 

Pleil, J. and A. Lindstrom (2002). A review of the USEPA’s single breath canister (SBC) method for exhaled 

volatile organic biomarkers. Biomarkers, 7, 189-208 

Rasmussen, R.A. (1992). “The ABCs of stainless steel canister clean-up and certification.” Presented at the 1992 

U.S. EPA/A&WMA International Symposium on Measurement of Toxic and Related Air Pollutants, 

Durham, NC, May 1992. 

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Shire, J.; Harshfield, G.; Zielinska, B.; Pasek, R. “A Comparison of Analytical Methods for Oxygenated Volatile 

Organic Compounds in Ambient Air,” In: Proceeding of the U.S. EPA/A&WMA International Symposium 

on Measurements of Toxic and Related Air Pollutants: Durham, NC May 1996. 

Tsai, P. and C.P. Weisel (2000). Penetration of Evaporative Emissions into a Home from an M85-Fueled Vehicle 

Parked in an Attached Garage, JAWMA , 50:371-377. 

Vayghani, S. A., C. Weisel, (1999) The MTBE air concentrations in the cabin of automobiles while fueling, JEAEE 

9, 261-267. 

5-2 
6. APPENDICIES 

 A-1
APPENDIX A 

Exposure Protocol and Study Plan for the Section 211(B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline 

- Summer/Winter Sampling Plan for Houston 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

DESERT RESEARCH INSTITUTE 

2215 Raggio Parkway 

Reno, NV 89512 

October 1, 2003 

 A-1
INTRODUCTION 

This sampling plan specifies the details for the field measurement program that will be carried out in Houston, Texas 

during the summer of 2004 and winter of 2005 as part of a screening study of the high-end exposures to baseline and 

oxygenated gasoline. It specifies example dates, times and measurement locations for the twelve categories of 

microenvironments and explains the selections with respect to the objective of capturing the upper-end of the 

distribution of exposures for each microenvironment. This document is an addendum to the Exposure Protocol and 

Study Plan, which describes the proposed measurement methods and rationale for their selection. 

Exposure levels are directly related to the activity and emission rates of sources in the microenvironment and 

inversely related to the distances between sources of emissions and the measurement location and the extent of 

dilution of emissions, which is a function of meteorological conditions and the presence of physical obstruction that 

inhibit dispersion. The API and EPA have prescribed a goal to capture the 99th percentile exposure levels within 

each type of microenvironment. Due to the scope of this study, it will not be possible to fully characterize (by 

measurements) the range of exposures that include the 99th percentile. However, we considered available surrogate 

parameters for emission levels and dispersion to select sampling times and locations with the greatest potential for 

higher exposures. These emission surrogates include traffic counts, and diurnal variations in average highway 

speeds, length of queues at toll plazas, number of cars refueling or entering and exiting parking garages. Surrogates 

for dispersion include wind roses and diurnal variations in temperature. Measurements in microenvironments with 

unrestricted dispersion will be made in the early morning or evening during calm conditions and minimal vertical 

mixing. In moderate wind conditions, we will drive parallel to the prevailing wind to reduce the impact of cross 

winds. Our sampling strategy also recognizes that vehicle exhaust emission levels are significantly higher for high 

emitters and are higher for all vehicles during cold starts and accelerations. All of these factors are important in 

understanding the large temporal and spatial variations that are likely to exist within each of the microenvironments. 

We plan to examine available hourly CO data and PAMS BTEX and 1,3-butadiene data for June through September 

2003 to place the field measurement data in context with seasonal variations. 

Desert Research Institute personnel, accompanied by the API project officer, surveyed potential microenvironments 

in Houston on June 20-22, 2002 (Thursday to Saturday). The objectives of the survey were to ascertain the 

suitability of sampling locations with respect to access and potential for higher-end exposures, and to determine the 

variations in air pollutant levels in several of the microenvironments with a portable gas analyzer. We visited the 

following locations: I-10 during the morning commute period, urban canyons in downtown Houston, Washburn 

Tunnel, various toll plazas on the Sam Houston Tollway and Hardy Toll Road, toll plaza at the Ship Channel 

Bridge, covered terminals at the Bush International and Hobby Airports, parking garages in downtown Houston and 

the Texas Medical Center, underground parking garages at the City Hall Annex and Greenway Plaza (Compaq 

Center), and parking lots at Minute Maid Park after a Houston Astros baseball game. A RAE Systems Model PGM7240 (ppbRAE) portable PID monitor was used to continuously monitor ambient VOC levels in several of the 

microenvironments. The monitor is equipped with a 10.6 eV photoionization (PID) detector and responds to certain 

organic and inorganic gases that have an ionization potential of less than 10.6 eV, which includes most compounds 

of interest in this study. It does not respond to light hydrocarbons such as methane, ethane, and propane or to 

acetylene, formaldehyde or methanol. For the purposes of the survey of microenvironments in Houston, the PID 

detector was used to measure variations rather than absolute VOC levels. 

SURVEY RESULTS

Figures 1 through 5 show the time-series plots of the PID response in several microenvironments. Data are plotted 

for the 10-second average and maximum PID response during each 10-second interval. Because we inspected many 

sampling locations within a short time, many of the PID measurements do not coincide with periods of highest 

emissions. Coupled with expected variations in emission activity levels, these measurements may be used to assess 

the potential for the highest exposures. Figure 6 shows the historic mean wind speed and direction in Houston for 

July. 

 Figure 1 shows the PID response for a one-hour trip during the morning commute period on eastbound I-10 from 

Barker-Cypress Rd. to downtown Houston via southbound I-45. The trip ended south of the downtown area at the 

Fannin St. exit off westbound SR-59. The trip was made on Thursday, June 20, 2002 from 7:27 to 8:27 a.m. The 

 A-2
first 40 minutes of the trip was in congested traffic (average speed of 20-25 mph). For most of this period, the 

maximum PID response hovered around 100 ppb with occasional excursions to up to 200 ppb. The maximum PID 

response increased to between 400 and 600 ppb during a three-minute period in the first ten minutes of the trip. 

These high values were associated with a suspected high emitter. The vehicle was a landscape service truck, which 

was towing a trailer containing lawn and garden equipment. Three spikes in the PID response coincided with slow 

downs in traffic followed by accelerations. Without concurrent CO data, we cannot rule out evaporative emissions 

from the lawn and garden equipment. However, we followed one other landscape service truck with no increase in 

the PID response. From the I-610 loop to I-45, the traffic moved near the speed limit and the PID response was 

consistently at or below 100 ppb. VOC concentrations were higher during the last ten minutes of the trip when we 

encountered congested traffic in downtown Houston and substantial backup at the junction of southbound I-45 and 

westbound SR-59. This trip demonstrates what we have observed with similar measurements. A great majority of 

the on-road vehicle fleet are relatively low emitters that have little impact on in-cabin exposure levels at highway 

speed. Congested stop-and-go conditions result in some increase in exposure levels due to shorter gap between 

vehicles and due to intermittent accelerations. Higher exposures are anticipated when following high emitters. 

Figure 2 shows the time-series of the PID response during a 1.3-hour tour through downtown Houston. The first half 

of the tour covered the west side of downtown with potential urban canyons. The PID response varied with traffic in 

the area, which was relatively light during this period. We sampled in an above-ground parking garage at about 9:00 

a.m. for about five minutes. The VOC levels measured in the garage were not significantly above the surrounding 

urban background. The second half of the tour covered the eastside of downtown near Minute Maid Park (Houston 

Astros baseball stadium). The large parking lot east of the stadium is a potential sampling site during ballgames (see 

Figure 4). 

Congested Freeway

0

100

200

300

400

500

600

700

072707320737074207470752075708020807081208170822

Time, CDT

PID Response (ppb)

Average

Maximum

Figure 1. Eastbound I-10 from Barker-Cypress Rd. through downtown Houston via southbound I-45 and westbound 

SR-59 and ending at Fannin exit. 

 A-3
Downtown Houston

0

100

200

300

400

500

600

08300835084008450850085509000905091009150920092509300935094009450950

Time, CDT

PID Response (ppb)

Average

Maximum

Figure 2. Tour of downtown Houston. 

Bush Int. Airport, Highways 8, 59, and 10, and Washburn Tunnel

0

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12401245125012551300130513101315132013251330133513401345

Time, CDT

PID Response (ppb)

Average

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Figure 3. George Bush International Airport and drive to Washburn Tunnel. 

 A-4
Minute Maid Stadium Parking Lot After Houston Astros Baseball Game

0

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700

2145215021552200220522102215

Time, CDT

PID Response (ppb)

Average

Maximum

Figure 4. Minute Maid Park at the end of a ballgame on evening of June 21, 2002. 

Wahburn Tunnel and Ship Channel Bridge Toll Plaza

0

100

200

300

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13451350135514001405141014151420

Time, CDT

PID Response (ppb)

Average

Maximum

Figure 5. Tour of Washburn Tunnel and the Ship Channel Toll Plaza on the Sam Houston Tollway. 

 A-5
The first 20 minutes in Figure 3 show the variations in PID response at the George Bush International Airport. The 

road through the airport is split into two levels at each of the four terminals with passenger pick-up being the lower, 

covered level. Terminal C appeared to have the greatest length of covered roadway in front of the terminal. Traffic 

was light during this time and we observed about a 50 to 100 percent increase in PID response while driving past 

Terminal C. We expect significantly higher VOC levels during peak periods. We also visited the Hobby Airport 

(data not shown), which also has a two-level road at the terminal. The length of covered roadway is greater at Hobby 

and adjacent parking garage is larger. We propose to sample in-cabin exposure at the Hobby Airport terminal during 

peak periods. 

Figure 3 also shows the variations in PID response during three trips through the Washburn Tunnel. The first three 

spikes in Figure 5 correspond to trips through the tunnel on another day. Travel time through the tunnel is 52 

seconds at 35 mph from portal to portal. The tunnel is book ended on each side by a rotary. Passage through the 

tunnel is controlled during peak periods to avoid congestion within the tunnel. A queue of vehicles develops during 

these controlled periods. We propose to sample during peak periods in order to measure exposure while in the queue 

as well as in the tunnel. 

Figure 4 shows the time-series of the PID response at Minute Maid Park at the end of a ballgame on the evening of 

June 21, 2002. We were parked in the middle of Lot C and made 

 

Figure 6. Frequencies of wind speed and direction in Houston during July. 

 A-6
measurements at this location for about ten minutes while vehicles began to leave the lot. The 

PID response was nearly constant during this period. We then walked to the parking lot exit and made measurements 

there. The spikes in the PID coincide with the passage of vehicles accelerating out the parking lot, while presumably 

still in cold-start mode. We then walked along the sidewalk towards the park. These measurements were lower than 

at the parking lot exit but higher and more variable than at the center of the parking lot. Based upon these results, we 

propose to sample with a sampling cart for a one-hour period at the end of the game with 15-minute sampling times 

alternating between a fixed location at the exit of the parking lot and a walk along the sidewalk. 

The second half of the time-series in Figure 5 shows the variations in the PID response at the toll plaza at the Sam 

Houston Tollway Ship Channel Bridge. The speed limit on the Tollway is 70 mph. As the vehicles leave the toll 

plaza, they accelerate rapidly leaving a puff of higher emissions at the tollbooth. The emissions of vehicles are 

typically much higher under hard accelerations. The spikes in PID response in Figure 5 coincide with vehicles 

accelerating rapidly from the tollbooth. Based on these results, we propose to sample with a sampling cart as close 

to a tollbooth as allowed by the Harris County Tollway Authority. Prior to setup, we will make one pass through the 

toll plaza to measure in-cabin exposure with continuous instruments only. We will endeavor to use the same ME 

locations during both the winter and summer studies. 

DESCRIPTIONS OF MICROENVIRONMENTS (ME) AND SAMPLING PROTOCOL 

1. In vehicle: commuter rush hour in stop-and-go traffic (ME1) 

Make one to two 20-minute roundtrips (depending on traffic conditions) on a segment of freeway during peak 

weekday morning commuter traffic (Option A or B depending upon wind speed and direction) from 7:00 to 

8:00 a.m. Use high ventilation conditions (window and vent open, AC on during summer and heater on during 

winter) during the first half and low ventilation (windows and vent closed, AC on during summer and heater on 

during winter) during the second half of the ME. Maintain a safe following distance, about one car length (15 

feet) per 10 mph speed, closing to within 3 feet during stopped conditions. Use the middle lane and do not 

follow the same vehicle for more than two minutes. Attempt to get behind at least one high-emitter. 

Sample in-cabin air at driver’s breathing zone continuously with Langan T15 CO monitor, NDIR CO 

instrument, and ppbRAE, r and collect one set of canister and DNPH samples integrated over the entire sample. 

Collect four SPME samples, one every 10 minutes. Sample the outside air with the second portable PID monitor 

during the entire period without compromising the ventilation condition in the cabin. Monitor and record the 

van’s position (GPS), and in-cabin temperature and relative humidity. A forward facing camcorder will record 

roadway activities and locations for this and other in-cabin MEs during the sampling run. Other relevant data 

collected by the City of Houston include CO and meteorological data at the Lang (C408) monitoring station in 

west Houston at 4401 1⁄2 Lang. Check wind speed and direction at the mobile laboratory and traffic conditions 

(radio reports of any accidents on sampling routes) prior to sampling run and select the appropriate sampling 

route from the following options. If accidents, other hazards, or local conditions change, substitute other, 

equivalent routes with similar distances and speeds as needed. 

a. Option A (use for calm wind conditions or winds from west or east). A six-mile segment of I-10 between 

Dairy Ashford Rd. (2 mile west of the Sam Houston Tollway) and Voss Rd. (4 miles east of the SH 

Tollway). Start with the inbound (east) direction at Dairy Ashford Rd. Average speeds in the inbound and 

outbound directions are 20-25 mph and 50-60 mph, respectively. 

b. Option B (use for moderate winds from south-southeast or north-northwest). An eight-mile segment of US290 between N. Eldridge Parkway (3 miles northwest of SH Tollway) to Bingle Rd (5 miles southeast of 

SH Tollway). Start with inbound (southeast) direction from N. Eldridge Parkway. Average speeds in the 

inbound and outbound directions are about 30 mph and 65-70 mph, respectively. 

2. In vehicle: urban street canyons (ME2) 

The greatest volume of traffic in the downtown Houston occurs during the morning and afternoon commute 

periods and to a lesser extent during the noon hour. We propose the weekday afternoon commute period from 

4:00 to 5:00 p.m. because the vehicles exiting the parking garages may still be in cold-start mode and because 

ME1 precludes ME2 during the morning commute period. 

 A-7
Make multiple trips during a 40-minute period along a four by one block surface street loop in downtown 

Houston. The loop consists of four one-way streets and four left turns. Starting from the intersection of 

Louisiana and Clay, go northeast on Louisiana for four blocks, turn left on Walker, left on Smith, left on Clay, 

and left on Louisiana to complete the loop. Use high ventilation conditions (window and vent open, AC on 

during summer and heater on during winter) during first 20 minutes and low ventilation (windows and vent 

closed, AC on during summer and heater on during winter) during second 20 minutes. Drive at or near the end 

of a pack of vehicles as much as possible. 

Sample in-cabin air at driver’s breathing zone continuously with the Langan T15 CO, NDIR CO, and ppbRAE 

analyzer and collect one set of canister and DNPH samples integrated over the entire period. Collect four SPME 

samples, one every 10 minutes Sample the outside air with the second portable PID monitor during the entire 

period without compromising the ventilation condition in the cabin. Monitor and record the van’s position 

(GPS), and in-cabin temperature and relative humidity. Note that GPS data is often unavailable or unreliable 

during this ME as the tall buildings block satellite signals. A forward-facing camcorder will record roadway 

activities and locations during the run. Other relevant data collected by the City of Houston include CO and 

meteorological data at the Houston Texas Avenue (C411) monitoring station in downtown Houston at 2311 

Texas Avenue. 

3. In vehicle: refueling (ME3) 

Select appropriate refueling location(s) and sampling times based on the following guidance. The fuel pump 

islands should be located on the lee side of the service station building or other large obstruction such as the 

raised section of highway. Given the prevailing southerly to southeasterly winds, the turnarounds at the north 

sides of I-10, South I-610 loop, or SR 59 are potential areas for the search. Conduct sampling during the peak or 

near-peak refueling periods for the station as indicated by service station personnel. 

After driving to elevate measured fuel tank temperatures, park sampling van at refueling location and sample 

alternate 10-minute periods under background (parked at pump) and refueling conditions Park the van 

downwind from the centroid of the pump locations. Sample in-cabin air at driver’s breathing zone continuously 

with a KORE MS 200, Langan T15 CO, NDIR CO, and ppbRAE PID, and collect one set of canister and 

DNPH samples integrated over the sampling period. Collect two SPME samples, one 10-minute sample during 

the background sampling period and one 10-minute sample during the refueling period. Sample both the outside 

and in-cabin air with the two portable PID monitors during the entire sampling period. Monitor and record the 

outside wind speed, and direction, as well as the sampling location temperature and relative humidity. A 

camcorder will be positioned to record the sampling scene from outside the van; a pan of the sampling site will 

also be provided to record details of the location. Van windows are to be down and doors open as appropriate 

during this ME 

4. In vehicle: parking garage (ME4) 

Drive within a parking garage for 40 minutes. Use high ventilation conditions (window and vent open, AC on 

during summer and heater on during winter) during first 20 minutes and low ventilation (windows and vent 

closed, AC on during summer and heater on during winter) during second 20 minutes. Potential garages include 

the Houston City Hall Annex, Greenway Plaza, and Hobby Airport (covered road in front of terminal and 

adjacent parking structure). 

Sample in-cabin air at driver’s breathing zone continuously with a KORE MS 200, Langan T15 CO, NDIR CO, 

ppbRAE, and DRI HCHO analyzer and collect one set of canister and DNPH samples integrated over the entire 

hour. Collect six SPME samples, one every 10 minutes. Sample both the outside and in-cabin air with the two 

portable PID monitors during the entire hour without compromising the ventilation condition in the cabin. 

Monitor outside wind speed and direction (if any) and record the in-cabin temperature and relative humidity. A 

camcorder will be positioned to record the sampling scene from outside the van; a pan of the sampling site will 

also be provided to record details of the location. 

5. In vehicle: toll plaza (ME5) 

 A-8
Measurements for this microenvironment are combined with the tunnel and tollbooth microenvironments. See 

ME6 and ME12. 

6. In vehicle: tunnel (ME6)

Make several trips though the Washburn Tunnel for one hour during peak periods when traffic through the 

tunnel is controlled. Use high ventilation conditions (window and vent open, AC on during summer and heater 

on during winter) during first 20 minutes and low ventilation (windows and vent closed, AC on during summer 

and heater on during winter) during second 20 minutes. 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO, and ppbRAE, 

and collect one set of canister and DNPH samples integrated over the entire period. Collect a 5-minute canister 

sample during a peak concentration period. Collect four SPME samples, one every 10 minutes. Biomarker 

samples (breath) will be collected from the technician, who will be isolated from further exposure before 

performing this task. Sample the outside and in-cabin air with the two portable PID monitors during the entire 

hour without compromising the ventilation condition in the cabin. Monitor and record the van’s position (GPS), 

and in-cabin temperature and relative humidity. Note that the GPS data will be unavailable for the period the 

van is inside the tunnel as the tunnel blocks the satellite signals. A front-facing camcorder will record the 

roadway activities and also, when stopped, provide a pan of the sampling site location. 

7. Outdoor: refueling vehicle (ME7) 

Select appropriate refueling location(s) and sampling times based on the following guidance. The fuel pump 

islands should be located on the lee side of the service station building or other large obstruction such as the 

raised section of highway. Given the prevailing southerly to southeasterly winds, the turnarounds at the north 

sides of I-10, South I-610 loop, or SR 59 are potential areas for the search. Conduct sampling during the peak or 

near-peak refueling periods for the station as indicated by service station personnel if possible and strive for as 

low wind speed (< 5 mph) as possible. Conduct sampling in the morning to accommodate the collection of 

biomarker samples and presence of low wind speeds. 

Park the van downwind from the centroid of the pump locations after driving it sufficiently to elevate measured 

fuel tank temperatures. With sampling inlets in the breathing zone, refuel the vehicle over a 1 to 2 minute active 

refueling interval within the second 10-minute sampling period. During refueling, maintain manual control of 

the nozzle and stand downwind of the vehicle fuel tank inlet, spilling a few drops of fuel after removing the 

nozzle from the fuel tank. Sample the breathing zone continuously with a KORE MS 200, NDIR CO, and 

ppbRAE and collect one set of canister and DNPH samples integrated over the entire 20-minute period. Collect 

a 5-minute canister sample that includes the active refueling period. Biomarker samples (breath) will be 

collected from the technician, who will be isolated from further exposure before performing this task. Collect 

two SPME (background and refueling) samples during the initial background and final refueling periods. 

Record the ambient temperature and relative humidity. A camcorder will be positioned to record the sampling 

scene from outside the van; a pan of the sampling site will also be provided to record details of the location. 

Local wind speed, direction, temperature and humidity will be collected with the hand held meteorological 

monitor. A liquid fuel samples will be collected after ME7 measurements (during off-loading of the van fuel 

tank) for each service station (if more than one is used per city) sampled for this ME. 

8. Outdoor: sidewalk near high-density traffic (ME8) 

Conduct sidewalk sampling by cart in downtown Houston along the city block bordered by Polk, Louisiana, 

Clay and Smith. A portion of Polk St. is covered and several eating establishment are located there with outdoor 

seating. After the first trip around the block, remain in the covered section of Polk Street for at least 10 minutes, 

and then continue the walk around the block. Sampling should be conducted during the morning and afternoon 

commute periods and during the noon hour. A camcorder will be positioned to record the sampling scene from 

the cart; a pan of the sampling site will also be provided to record details of the location. 

Sample the breathing zone continuously with Langan T15 CO, and ppbRAE portable PID monitor and collect 

one set of canister and DNPH samples integrated over the entire 40 minute period. Collect four SPME samples, 

 A-9
one every 10 minutes. Record the local wind speed, direction, ambient temperature and relative humidity with 

the hand held meteorological device. 

9. Outdoor: bus stop (ME9) 

Sample the ambient air at a bus stop by cart in downtown Houston during the morning and/or afternoon 

commute periods. Conduct as described in ME8 above. 

10 Outdoor: stadium parking lot (ME10) 

Sample for 40 minutes at the end of Houston Astros baseball games. Attempt to determine the end of the game 

time by listening to the radio to determine the progress of the game. Park the van near the exit of the parking lot 

where vehicles will queue up as they exit, down wind of the exhaust. Sample the breathing zone continuously 

with a KORE MS 200, Langan T15 CO, DRI HCHO analyzer, and portable PID monitor and collect one set of 

canister and DNPH samples integrated over the entire period. Collect four SPME samples one every 10 

minutes. A camcorder will be positioned to record the sampling scene outside the van; a pan of the sampling 

site will also be provided to record details of the location. 

11. Outside underground parking garage (ME11) 

Sample the ambient air in an underground parking garage for one hour. Potential garages include the Houston 

City Hall Annex and the Greenway Plaza. The Greenway Plaza is preferable for several reasons. The Greenway 

Plaza is a business complex of ten office towers, the Renaissance Hotel and the Compaq center, home to the 

NBA Houston Rockets and the WNBA Comets. The complex includes 13,000 parking spaces. A large fraction 

of the parking is underground. During our study period in Houston, the Comets are scheduled to play. We 

propose three separate 40-minute sampling periods. The first will start about 4:00 p.m. when the office workers 

leave the complex (cold start emissions). The second starts about 7:00 p.m. when the basketball fans arrive for 

the game (hot stabilized exhaust and hot soak emissions) and the final sampling period will be after the game 

(cold start emissions). 

Sample the breathing zone continuously with a KORE MS 200, Langan T15, DRI HCHO analyzer, and portable 

PID monitor and collect one set of canister and DNPH samples integrated over the entire period. Collect a 5-

minute canister sample that includes a peak period during the crowd exit after the game. Biomarker samples 

(breath) will be collected from the technician, who will be isolated from further exposure before performing this 

task Collect four SPME samples, one every 10 minutes. Collect breath biomarker samples after a peak period 

encountered early during the sampling event. Record the local ambient wind speed, direction (if any), 

temperature and relative humidity with the hand held meteorological instrument. A camcorder will be 

positioned to record the sampling scene outside the van; a pan of the sampling site will also be provided to 

record details of the location. 

12, Outdoors: toll booth (ME12) 

Sample the ambient air at the Ship Channel Bridge toll plaza for 40 minutes. Locate the sampling cart behind 

the concrete barrier on the west end of the plaza as close to the tollbooth as possible. Notify Patricia Watson of 

the Harris County Tollway Authority (281/875-1400) of the Harris County Tollway Authority at least 24 hours 

prior to sampling. 

Sample the breathing zone continuously with a KORE MS 200, Langan T15 CO, and portable PID monitor and 

collect one set of canister and DNPH samples integrated over the entire hour. Collect six SPME samples with 

each sampling period lasting 10 minutes. Record the ambient wind speed, direction, temperature and relative 

humidity with the hand held meteorological instrument. A camcorder will be positioned to record the sampling 

scene from the cart; a pan of the sampling site will also be provided to record details of the location. 

 A-10
If time permits before or after the sampling period and sufficient traffic exist, conduct measurement of in-cabin 

exposure during one pass through the toll plaza. Collect one SPME sample during this sampling period. 

DAILY SAMPLING SCHEDULE 

The daily schedules for the Houston summer and winter sampling program will be finalized prior to 

summer 2004 and winter 2005 studies. In order to stay on project schedule as much as possible, sampling will be 

conducted on Saturdays in case we encounter unsuitable meteorological conditions on scheduled sampling days. 

 A-11
APPENDIX B 

Exposure Protocol and Study Plan for the Section 211(B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline 

Addendum B – Summer/Winter Sampling Plan for Atlanta 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

DESERT RESEARCH INSTITUTE 

2215 Raggio Parkway 

Reno, NV 89512 

October 1, 2003 

 B-1 
INTRODUCTION 

This sampling plan specifies the details for the field measurement program that will be carried out in Atlanta, GA 

during the summer as part of a screening study of the high-end exposures to baseline and oxygenated gasoline. It 

specifies example dates, times and measurement locations for the twelve categories of microenvironments and 

explains the selections with respect to the objective of capturing the upper-end of the distribution of exposures for 

each microenvironment. This document is an addendum to the Exposure Protocol and Study Plan, which describes 

the proposed measurement methods and rationale for their selection. We will endeavor to use the same ME locations 

during both the winter and summer studies. 

Desert Research Institute personnel, accompanied by the API project officer, surveyed potential microenvironments 

in Atlanta on July 24-26, 2002. The objectives of the survey were to ascertain the suitability of sampling locations 

with respect to access and potential for higher-end exposures, and to determine the variations in air pollutant levels 

in several of the microenvironments with a portable gas analyzer. We visited the following locations: I-20 W and I75 NW during the morning commute period, urban canyons in downtown Atlanta, Justus C. Martin Jr. Tunnel, 

GA400 toll road plaza, parking garages in downtown and midtown Atlanta and in Buckhead, service stations, 

parking garage at the Georgia Dome and parking lots at Turner Field. A RAE Systems Model PGM-7240 (ppbRAE) 

portable PID monitor was used to continuously monitor ambient VOC levels in several of the microenvironments. 

The monitor is equipped with a 10.6 eV photoionization (PID) detector and responds to certain organic and 

inorganic gases that have an ionization potential of less than 10.6 eV, which includes most compounds of interest in 

this study. It does not respond to light hydrocarbons such as methane, ethane, and propane or to acetylene, 

formaldehyde or methanol. For the purposes of the survey of microenvironments in Atlanta, the PID detector was 

used to measure relative variations rather than absolute VOC levels. 

Information for the survey were obtained from the following Atlanta web sites: 

Air Quality Agencies

http://www.dnr.state.ga.us/environ/ Georgia Environmental Protection Division 

http://www.air.dnr.state.ga.us/amp/index.html Current air quality 

http://www.cleanairforce.com/ Vehicle inspection program 

http://www.atlreg.com/ Atlanta Regional Commission 

http://www.atlanta-airport.com/ Atlanta Airport 

http://www.dot.state.ga.us/ Georgia Dept. of Transportation 

http://www.accessatlanta.com/autos/special/roadwords.html Road works 

http://www.georgia-navigator.com/traffic/ Real-time traffic map 

http://www2.georgianavigator.com/links.html Atlanta Visitor Links 

http://www.itsmarta.com/ Metro Atlanta Rapid Transit Authority 

http://www.metrogirl.com/dna/links.htm Downtown Atlanta Links 

http://www.atlantadowntown.com/downtownlivedirectory.htm Downtown Events 

http://www.gadome.com/ Georgia Dome/World Congress Center, Falcons 

http://braves.mlb.com/NASApp/mlb/atl/ballpark/atl_ballpark_history.jsp Turner Field, Braves 

http://www.atlantaarena.com/st0300/main/main.shtml Phillips Arena, Hawks 

http://www.aaaparking.com/property2.htm parking garages 

http://www.accessatlanta.com/shopping/guides/mallguide.html Mall Guide 

DESCRIPTIONS OF MICROENVIRONMENTS (ME) AND SAMPLING PROTOCOL 

1. In vehicle: commuter rush hour in stop-and-go traffic (ME1) 

Drive for 40 minutes in congested freeway traffic during weekday morning rush hour from 0700 to 0800, local 

time or evening rush hour from 1700 to 1800. During the morning, drive southbound on I-75 beginning at S. 

 B-2 
Marietta Parkway to downtown Atlanta. Drive the opposite direction during the evening rush hour. A forward 

facing camcorder will record roadway activities and locations for this and other in-cabin MEs during the 

sampling run. Use high ventilation conditions (window and vent open, AC on during summer and heater on 

during winter) during the first 20 minutes and low ventilation (windows and vent closed, AC on during summer 

and heater on during winter) during the second 20 minutes. Maintain a safe following distance, about one car 

length (15 feet) per 10 mph speed, closing to within 3 feet during stopped conditions. Use the middle lane and 

do not follow the same vehicle for more than two minutes. Attempt to get behind at least one high-emitter 

during each of the two ventilation conditions. If accidents, other hazards, or local conditions change, substitute 

other, equivalent routes with similar distances and speeds as needed. 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO, and ppbRAE 

PID analyzer and collect one set of canister and DNPH samples integrated over the entire hour. Collect four 

SPME samples, one every 10 minutes. Sample the outside air with a second portable PID monitor during the 

entire hour without compromising the ventilation condition in the cabin. Monitor and record the van’s position 

(GPS), and sampling point temperature and relative humidity. Other relevant data collected by the City of 

Atlanta include CO and meteorological data at the Roswell monitoring station at 4434 Roswell Rd. and the PM 

Super site at 829 Jefferson St. NW. 

2. In vehicle: urban street canyons (ME2) 

Make multiple trips during a 40-minute period along a surface-street loop in downtown Atlanta bordered by 

Peachtree Street NW, Forsyth/Carnegie, Spring Street NW, and Harris Street (four right turns). Make the 

measurements during either the morning commute period from 0700 to 0800 or evening commute period from 

1700 to 1800. Use high ventilation conditions (window and vent open, AC on during summer and heater on 

during winter) during first half and low ventilation (windows and vent closed, AC on during summer and heater 

on during winter) during second half. Drive at or near the end of a pack of vehicles at stoplights as much as 

possible and attempt to get behind at least one high-emitter during each of the two ventilation conditions. 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO, ppbRAE PID 

analyzer and collect one set of canister and DNPH samples integrated over the entire hour. Collect four SPME 

samples, one every 10 minutes. Sample the outside air with a second portable PID monitor during the entire 

hour without compromising the ventilation condition in the cabin. Monitor and record the van’s position (GPS), 

and sampling point temperature and relative humidity. Note that GPS data are often unavailable or unreliable in 

urban canyons as the tall buildings block satellite signals. 

3. In vehicle: refueling (ME3) 

Sample for 20 minutes at the Racetrak or Quicktrip (QT) service station located north of the Thornton Rd exit 

off I-20. Conduct sampling during the peak or near-peak refueling periods for the station as indicated by service 

station personnel. 

After driving to elevate measured fuel tank temperatures, park sampling van at refueling location and sample 

alternate 10-minute periods under background (parked at pump) and refueling conditions Park the van 

downwind from the centroid of the pump locations. Sample in-cabin air at driver’s breathing zone continuously 

with a KORE MS 200, Langan T15 CO, NDIR CO, and ppbRAE PID, and collect one set of canister and 

DNPH samples integrated over the sampling period. Collect two SPME samples, one 10-minute sample during 

the background sampling period and one 10-minute sample during the refueling period. Sample both the outside 

and in-cabin air with the two portable PID monitors during the entire sampling period. Monitor and record the 

outside wind speed, and direction as well as the sampling location temperature and relative humidity. A 

camcorder will be positioned to record the sampling scene from outside the van; a pan of the sampling site will 

also be provided to record details of the location. Van windows are to be down and doors open as appropriate 

during this ME. 

4. In vehicle: parking garage (ME4) 

 B-3 
Drive within a parking garage for 40 minutes. Use high ventilation conditions (window and vent open, AC on 

during summer and heater on during winter) during the first half and low ventilation (windows and vent closed, 

AC on during summer and heater on during winter) during the second half. Potential garages include Colony 

Square parking garage at Peachtree Street and 14th Street in Midtown Atlanta during the morning and evening 

commute period and prior to and after the Atlanta Falcons’ pre-season football games if possible 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO, ppbRAE, and 

DRI HCHO analyzer and collect one set of canister and DNPH samples integrated over the entire period Collect 

four SPME samples, one every 10 minutes. Sample both the outside and in-cabin air with the two portable PID 

monitors during the entire period without compromising the ventilation condition in the cabin. Monitor outside 

wind speed and direction (if any) and record the in-cabin temperature and relative humidity. A camcorder will 

be positioned to record the sampling scene from outside the van; a pan of the sampling site will also be provided 

to record details of the location. 

5. In vehicle: toll plaza (ME5) 

Sample during the morning commute period for 40 minutes at the toll plaza between exit 2 and 3 on the GA 400 

toll road. 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO and ppbRAE 

PID analyzer and collect one set of canister and DNPH samples integrated over the entire period Collect four 

SPME samples, one every 10 minutes. Sample the outside air with a second portable PID monitor during the 

entire period without compromising the ventilation condition in the cabin. Monitor and record the van’s position 

(GPS), and sampling point temperature and relative humidity. 

6. In vehicle: tunnel (ME6)

The Justus C. Martin Jr. Tunnel is the only roadway tunnel in Atlanta. It is located less than two miles south of 

the toll plaza on GA 400. The tunnel consists of separate bores for the northbound and southbound direction 

consisting of four lanes each. The tunnel is very short and is unlikely to restrict dilution of emissions to any 

significant degree. Traffic in both directions remains uncongested during the evening commute period. No 

sampling is planned for this microenvironment in Atlanta. 

7. Outdoor: refueling vehicle (ME7) 

Sample at the Racetrak or Quicktrip (QT) service station located north of the Thornton Rd exit off I-20. 

Conduct sampling during the peak or near-peak refueling periods for the station as indicated by service station 

personnel. 

Park the van downwind from the centroid of the pump locations after driving it sufficiently to elevate measured 

fuel tank temperatures. Collect biomarker samples during refueling periods with low (< 5 mph) local wind 

speed. Breath samples are taken before and 10 seconds immediately after active refueling. A backup breath 

samples is taken immediately after the second breath sample. With sampling inlets in the breathing zone, refuel 

the vehicle over a 1 to 2 minute active refueling interval within the second 10-minute sampling period. During 

refueling, maintain manual control of the nozzle and stand downwind of the vehicle fuel tank inlet, spilling a 

few drops of fuel after removing the nozzle from the fuel tank. Sample the breathing zone continuously with a 

KORE MS 200, NDIR CO, and ppbRAE and collect one set of canister and DNPH samples integrated over the 

entire 20-minute period. Collect a 5-minute canister sample that includes the active refueling period. Collect 

two SPME (background and refueling) samples during the initial background and final refueling periods. 

Record the ambient temperature and relative humidity. A camcorder will be positioned to record the sampling 

scene from outside the van; a pan of the sampling site will also be provided to record details of the location. 

Local wind speed, direction, temperature and humidity will be collected with the hand held meteorological 

monitor. A liquid fuel samples will be collected after ME7 measurements (during off-loading of the van fuel 

tank) for each service station (if more than one is used per city) sampled for this ME. 

 B-4 
8. Outdoor: sidewalk near high-density traffic (ME8) 

Conduct sidewalk sampling in downtown Atlanta along the city block bordered by Peachtree Street NE, 

Andrew Young International, Spring Street NW, and Harris Street NW. Sampling should be conducted during 

the morning and afternoon commute periods and during the noon hour. 

Sample the breathing zone continuously with a Langan T15 CO, and portable PID monitor and collect one set 

of canister and DNPH samples integrated over the entire 40 minute period. Collect four SPME samples, one 

every 10 minutes. Record the ambient temperature and relative humidity. 

9. Outdoor: bus stop (ME9) 

Combined with ME8. 

10. Outdoor: stadium parking lot (ME10) 

Sample for 40 minutes at the end of an Atlanta Braves baseball game. Because the atmosphere is more stable in 

the evening, night games are preferable to day games. Attempt to determine the end of the game time by 

listening to the radio to determine the progress of the game. Park the van near the exit of the parking lot where 

vehicles will queue up as they exit, down wind of the exhaust. 

Sample the breathing zone continuously with a KORE MS 200, Langan T15 CO, DRI HCHO analyzer, and 

portable PID monitor and collect one set of canister and DNPH samples integrated over the entire period. 

Collect six SPME samples one every 10 minutes. A camcorder will be positioned to record the sampling scene 

outside the van; a pan of the sampling site will also be provided to record details of the location. 

11. Underground parking garage (ME11) 

Sample the ambient air in the Colony Square underground parking garage (Peachtree and 14th Streets) for 40 

minutes starting about 5:00 p.m. when office workers leave the complex (cold start emissions). Sample at exit 

queues and ramps. 

Sample the breathing zone continuously with a KORE MS 200, Langan T15, DRI HCHO analyzer, and portable 

PID monitor and collect one set of canister and DNPH samples integrated over the entire period. Collect a 5-

minute canister sample after a peak exposure encountered during the sampling period. Breath biomarker 

samples are collected before and within 10 seconds after a similar peak exposure and followed immediately by 

backup breath canister sample. Collect four SPME samples, one every 10 minutes. Record the local ambient 

wind speed, direction (if any), temperature and relative humidity with the hand held meteorological instrument. 

A camcorder will be positioned to record the sampling scene; a pan of the sampling site will also be provided to 

record details of the location. 

12. Outdoors: toll booth (ME12) 

Make the measurement on the northbound side of the toll plaza. Access to the toll plaza is from the northbound 

direction. This is an employee parking lot on the eastside of the plaza. An underground tunnel accesses the 

southbound lanes. There is an elevator down to the tunnel. Contact the John Leonard, deputy director at the 

Georgia Department of Transportation, 24 hours prior to sampling (404/463-8766). On-site supervisor at the toll 

plaza is Robert Smith. Clarice Boone is another on-site contact (404/760-5893). 

Sample the breathing zone continuously with a KORE MS 200, Langan T15, DRI HCHO analyzer, and portable 

PID monitor and collect one set of canister and DNPH samples integrated over the entire 40 minute period. . 

Collect four SPME samples, one every 10 minutes. Record the ambient temperature and relative humidity. 

If time permits before or after the sampling period and sufficient traffic exist, conduct measurement of in-cabin 

exposure during one pass through the toll plaza. Collect one SPME sample during this sampling period. 

 B-5 
13. Trailing high emitters (ME13) 

Attempt to trail high emitters in Atlanta locations with higher fractions of high emitters. Protocol will follow 

ME2 except there will be no limits placed on what streets may be driven. Collect a 5-minute canister sample 

after a peak exposure encountered during the sampling period. Breath biomarker samples are collected before 

and within 10 seconds after a similar peak exposure and followed immediately by backup breath canister 

sample. 

DAILY SAMPLING SCHEDULE 

The prospective summer 2003 schedule for the Atlanta summer sampling program is summarized in Table 1. The 

sampling schedule is subject to change due to field conditions encountered. Actual summer and winter schedules 

will appear in the draft/final reports. In order to stay on project schedule as much as possible, sampling will be 

conducted on Saturdays in case we encounter unsuitable meteorological conditions on scheduled sampling days. 

However, this daily schedule doesn’t take into consideration the potential for prolonged weather delays. The winter 

daily sampling schedule for Atlanta will be finalized prior to the 2004 winter study. 

Table 1 

Prospective Summer 2003 Daily Sampling Schedule for Atlanta

August/September 2003

Sunday Monday Tuesday Wednesday Thursday Friday Saturday 

24 25 26 27 28 29 30

Arrival/ 

Setup 

7am ME1 7am ME1 7am ME1 7am ME1 7am ME1 10am 

ME3/ME7 

8am ME13 8am ME13 8am ME13 8am ME13 8am ME13 

5pm ME11 5pm ME11 5pm ME11 5pm ME11 5pm ME11 

31 1 2 3 4 5 6

8am ME3/7 8am ME3/7 8am ME3/7 8am ME3/7 

5pm ME4 5pm ME4 5pm ME4 5pm ME4 5pm ME4 

7 8 9 10 11 12 13

Packing Leave 

for Reno 

 B-6 
APPENDIX C 

Exposure Protocol and Study Plan for the Section 211(B) Tier 2 High End Exposure 

Screening Study of Baseline and Oxygenated Gasoline 

Addendum C – Summer/Winter Sampling Plan for Chicago 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

DESERT RESEARCH INSTITUTE 

2215 Raggio Parkway 

Reno, NV 89512 

October 1, 2003 

 C-1 
INTRODUCTION 

This sampling plan specifies the details for the field measurement program that will be carried out in Chicago, IL 

during the summer of 2003 and winter 2004 as part of a screening study of the high-end exposures to baseline and 

oxygenated gasoline. It specifies the measurement locations for the twelve categories of microenvironments and 

explains the selections with respect to the objective of capturing the upper-end of the distribution of exposures for 

each microenvironment. This document is an addendum to the Exposure Protocol and Study Plan, which describes 

the proposed measurement methods and rationale for their selection. We will endeavor to use the same ME locations 

during both the winter and summer studies. 

Desert Research Institute personnel surveyed potential microenvironments in Chicago on August 14-16, 2002. The 

objectives of the survey were to ascertain the suitability of sampling locations with respect to access and potential 

for higher-end exposures, and to determine the variations in air pollutant levels in several of the microenvironments 

with a portable gas analyzer. We visited the following locations: I-57 and I-94 during the morning commute period, 

urban canyons in downtown Chicago (particularly under the elevated trains), Tri-State Tollway ((I-294) toll plazas, 

parking garages in downtown Chicago (Millennium, Monroe St and Grant Park underground garages), service 

stations (Gas City in Tinley Park), parking lots at United Center (Chicago Bulls and Blackhawks) and Comiskey 

Park (White Sox), and three centralized vehicle inspection stations (#14, 27 and 28). A RAE Systems Model PGM7240 (ppbRAE) portable PID monitor and Langan Products Inc. T15 were used to continuously monitor ambient 

VOC and CO levels, respectively, in several of the microenvironments. For purposes of the survey of 

microenvironments in Chicago, the PID was used to measure relative variations rather than absolute VOC levels.

The location of the mobile laboratory is a significant logistical consideration in the selection of some of the 

microenvironments. Accordingly, selecting a base of operations for the mobile laboratory was the initial task during 

the survey trip. A suitable RV park is located in Tinley Park (Windy City Campground at 18701 South 80th

Avenue), which is about 20 miles southeast of Downtown Chicago. Our search for some microenvironments such as 

service stations, vehicle inspection stations, and congested freeway was focused in this general area. 

DESCRIPTIONS OF MICROENVIRONMENTS (ME) AND PROPOSED SAMPLING PROTOCOL 

1. In vehicle: commuter rush hour in stop-and-go traffic (ME1) 

Begin the run at 0700 in South Chicago near the I-57 and I-94 interchange and drive north on I-94 towards 

Downtown Chicago. The ten miles to the I-290 (Eisenhower Expressway) and I-94 interchange will take 

roughly 20 minutes. Use high ventilation conditions (window and vent open, AC on during summer and heater 

on during winter) during the first half of the run. Continue north on I-94 and turn around about 5 miles north of 

the I-290 and I-94 interchange. Reenter the I-94 going south and exit the freeway after the second 20 minutes. 

This stretch of freeway includes a series of overpasses, with the longest about a quarter of a mile. Use low 

ventilation (windows and vent closed, AC on during summer and heater on during winter) during the second 

half. Maintain a safe following distance, about one car length (15 feet) per 10 mph speed, closing to within 3 

feet during stopped conditions. Use the middle lane and do not follow the same vehicle for more than two 

minutes. Attempt to get behind at least one high-emitter during each of the two ventilation conditions. If 

accidents, other hazards, or local conditions change, substitute other, equivalent routes with similar distances 

and speeds as needed. 

Sample in-cabin air at driver’s breathing zone continuously with: Langan T15 CO monitor, NDIR CO 

instrument, and ppbRAE, and collect one set of canister and DNPH samples integrated over the entire sample. 

Collect four SPME samples, one every 10 minutes. Sample the outside air with the second portable PID during 

the entire period without compromising the cabin ventilation condition. Monitor and record the van’s position 

(GPS), and in-cabin temperature and relative humidity. A forward facing camcorder will record roadway 

activities and locations for this and other in-cabin MEs during the sampling run. Relevant data collected by the 

Illinois EPA include CO and meteorological data at the CTA Building monitoring station at 320 S. Franklin. 

 C-2 
2. In vehicle: urban street canyons (ME2) 

Make multiple trips during a 40-minute period along a surface-street loop in downtown Chicago bordered by 

Lake Street, Wabash Avenue, Van Buren Street, and State Street (four right turns). The elevated train covers 

three sides of this loop. Make the measurements during either the morning commute period from 0700 to 0800 

or evening commute period from 1700 to 1800. Use high ventilation conditions (window and vent open, AC on 

during summer and heater on during winter) during first 20 minutes and low ventilation (windows and vent 

closed, AC on during summer and heater on during winter) during second 20 minutes. Drive at or near the end 

of a pack of vehicles at stoplights as much as possible and attempt to get behind at least one high-emitter during 

each of the two ventilation conditions. 

Sample in-cabin air at driver’s breathing zone continuously with the Langan T15 CO, NDIR CO, and ppbRAE 

analyzer and collect one set of canister and DNPH samples integrated over the entire period. Collect four SPME 

samples, one every 10 minutes. Sample the outside air with the second portable PID monitor during the entire 

period without compromising the ventilation condition in the cabin. Monitor and record the van’s position 

(GPS), and in-cabin temperature and relative humidity. Note that GPS data is often unavailable or unreliable 

during this ME as the tall buildings block satellite signals. A forward-facing camcorder will record roadway 

activities and locations during the run. 

3. In vehicle: refueling (ME3) 

Sample at the Gas City (80th Avenue just north of I-80) or Speedway (Harlem Avenue just north of I-80) service 

stations in Tinley Park. Conduct sampling during the peak or near-peak refueling periods for the station as 

indicated by service station personnel. 

After driving to elevate measured fuel tank temperatures, park sampling van at refueling location and sample 

alternate 10-minute periods under background (parked at pump) and refueling conditions Park the van 

downwind from the centroid of the pump locations. Sample in-cabin air at driver’s breathing zone continuously 

with a KORE MS 200, Langan T15 CO, NDIR CO, and ppbRAE PID, and collect one set of canister and 

DNPH samples integrated over the sampling period. Collect two SPME samples, one 10-minute sample during 

the background sampling period and one 10-minute sample during the refueling period. Sample both the outside 

and in-cabin air with the two portable PID monitors during the entire sampling period. Monitor and record the 

outside wind speed, and direction, as well as the sampling location temperature and relative humidity. A 

camcorder will be positioned to record the sampling scene from outside the van; a pan of the sampling site will 

also be provided to record details of the location. Van windows are to be down and doors open as appropriate 

during this ME. A liquid fuel sample will be collected after ME3 measurements (during off-loading of the van 

fuel tank) for each service station (if more than one is used per city) sampled for this ME. 

 In vehicle: parking garage (ME4) 

Drive within a parking garage. Use high ventilation conditions (window and vent open, AC on during summer 

and heater on during winter) during the first half and low ventilation (windows and vent closed, AC on during 

summer and heater on during winter) during the second half. Potential garages include Millennium, Monroe 

Street, or Grant Park underground parking garages in Downtown Chicago. Millennium and Monroe Street 

garages use the same access. Millennium is to the left after entering the underground garage complex, and the 

Monroe Street garage is to the right. Millennium is closer to the downtown office building and has many more 

parked cars than the Monroe St garage, which is located closer to the Michigan Lake shoreline. Monroe St. 

garage was mostly empty during the weekday, but may see for use during the weekends. Grant Park garage was 

nearly full and appears to have high fraction of commuters. Park adjacent to the northbound pay station. We 

observed 150 to 500 ppbC on PID and 8 to 26 ppm CO at this location during the 1700 to 1800 period. 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO, ppbRAE, and 

DRI HCHO analyzer and collect one set of canister and DNPH samples integrated over the entire 40 minute 

period. Collect four SPME samples, one every 10 minutes. Sample both the outside and in-cabin air with the 

two portable PID monitors during the entire period without compromising the ventilation condition in the cabin. 

Monitor outside wind speed and direction (if any) and record the in-cabin temperature and relative humidity. A 

 C-3 
camcorder will be positioned to record the sampling scene from outside the van; a pan of the sampling site will 

also be provided to record details of the location. 

 5. In vehicle: toll plaza (ME5) 

Sample during the morning commute period 0700-0800 on tollways with high traffic volume with higher 

fraction of time spent at toll plazas (e.g., exit on ramps in both directions within short distances before and after 

the toll plaza). Potential plazas include 82nd Street (southbound)/83rd Street (northbound) and Cermak Road (all 

traffic) on the Tri-State Tollway (I-294) and the York Road (all traffic) on the East-West Tollway (I-88). 

Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, NDIR CO and ppbRAE 

PID analyzer and collect one set of canister and DNPH samples integrated over the entire 40 minute period. 

Collect four SPME samples, one every 10 minutes. Sample the outside air with a second portable PID monitor 

during the entire period without compromising the ventilation condition in the cabin. Monitor and record the 

van’s position (GPS), and sampling point temperature and relative humidity. 

6. In vehicle: tunnel (ME6)

The tunnel in Chicago is a covered roadway with no mechanical ventilation and very limited opportunity for 

natural ventilation. The route is from West Congress Parkway (Eisenhower Freeway) eastbound, enter Lower 

Wacker Drive via the off ramp from Congress parkway. Begin sampling anytime after entering the underground 

portion of the roadway. Proceed north on Lower Wacker Drive; immediately after Lower Wacker Drive turns 

east, use Orleans Street to turn around and proceed back south on Lower Wacker Drive. Just before exiting 

Lower Wacker Drive at the south end of the street, there is a turn-around through the center divider that allows 

you to return northbound again. 

Make several trips though the Lower Wacker Drive route for 40 minutes during peak traffic periods. Use high 

ventilation conditions (window and vent open, AC on during summer and heater on during winter) during first 

20 minutes and low ventilation (windows and vent closed, AC on during summer and heater on during winter) 

during second 20 minutes. Sample in-cabin air at driver’s breathing zone continuously with a Langan T15 CO, 

NDIR CO, and ppbRAE, and collect one set of canister and DNPH samples integrated over the entire period. 

Collect a 5-minute canister sample during a peak concentration period. Collect four SPME samples, one every 

10 minutes. Biomarker samples (breath) will be collected from the technician, who will be isolated from further 

exposure before performing this task. Sample the outside and in-cabin air with the two portable PID monitors 

during the entire hour without compromising the ventilation condition in the cabin. Monitor and record the 

van’s position (GPS), and in-cabin temperature and relative humidity. Note that the GPS data will be 

unavailable for the period the van is inside the tunnel as the tunnel blocks the satellite signals. A front-facing 

camcorder will record the roadway activities and provide a stopped pan of the sampling site location. 

7. Outdoor: refueling vehicle (ME7) 

Sample at the Gas City (80th Avenue just north of I-80) or Speedway (Harlem Avenue just north of I-80) service 

stations in Tinley Park. Conduct sampling during the peak or near-peak refueling periods for the station as 

indicated by service station personnel. 

Park the van downwind from the centroid of the pump locations after driving it sufficiently to elevate measured 

fuel tank temperatures. Refueling sampling will be conducted during periods with local wind speed below 5 

mph. With sampling inlets in the breathing zone, refuel the vehicle over a 1 to 2 minute active refueling 

interval within the second 10-minute sampling period. During refueling, maintain manual control of the nozzle 

and stand downwind of the vehicle fuel tank inlet, spilling a few drops of fuel after removing the nozzle from 

the fuel tank. Sample the breathing zone continuously with a KORE MS 200, NDIR CO, and ppbRAE and 

collect one set of canister and DNPH samples integrated over the entire 20-minute period. Collect a 5-minute 

canister that includes the active refueling period. Collect breath biomarker samples, including breath prerefueling and immediately after refueling (10 second) samples and a backup breath sample immediately after 

the second breath sample. Collect two SPME (background and refueling) samples during the initial background 

 C-4 
and final refueling periods. Record the ambient temperature and relative humidity. A camcorder will be 

positioned to record the sampling scene from outside the van; a pan of the sampling site will also be provided to 

record details of the location. Local wind speed, direction, temperature and humidity will be collected with the 

hand held meteorological monitor. A liquid fuel sample will be collected after ME7 measurements (during offloading of the van fuel tank) for each service station (if more than one is used per city) sampled for this ME. 

8. Outdoor: sidewalk near high-density traffic (ME8) 

Conduct sidewalk sampling in downtown Chicago along the city block bordered by Monroe Street, Wabash 

Avenue, Adams Street, and State Street. Sampling is conducted during the morning periods and at noon. 

Sample the breathing zone continuously with Langan T15 CO, and ppbRAE portable PID monitor and collect 

one set of canister and DNPH samples integrated over the entire 40 minute period. Collect four SPME samples, 

one every 10 minutes. Record the local wind speed, direction, ambient temperature and relative humidity with 

the hand held meteorological device. 

9. Outdoor: bus stop (ME9) 

Combined with ME8. 

10. Outdoor: stadium parking lot (ME10) 

Sample at the end of a Chicago White Sox baseball game at Comiskey Park during the summer and after a 

Chicago Bulls or Blackhawks game at the United Center. Because the atmosphere is more stable in the evening, 

night games are preferable to day games. 

Attempt to determine the end of the game time by listening to the radio to determine the progress of the game. 

Park the van near the exit of the parking lot where vehicles will queue up as they exit, down wind of the 

exhaust. Sample the breathing zone continuously with a KORE MS 200, Langan T15 CO, DRI HCHO 

analyzer, and portable PID monitor and collect one set of canister and DNPH samples integrated over the entire 

40 minute period. Collect four SPME samples one every 10 minutes. A camcorder will be positioned to record 

the sampling scene from the cart outside the van; a pan of the sampling site will record details of the location. 

11. Underground parking garage (ME11) 

Sample underground parking garage starting about 5:00 p.m. when office workers leave the complex (cold start 

emissions). Sample at exit queue and ramps. Measure temperature, humidity and ventilation velocities. Potential 

garages include Millennium, Monroe Street, or Grant Park underground parking garages in Downtown Chicago. 

Sample the breathing zone continuously with a KORE MS 200, Langan T15, DRI HCHO analyzer, and portable 

PID monitor and collect one set of canister and DNPH samples integrated over the entire 40 minute period. 

Collect a 5-minute canister that includes an exposure peak encountered during the sampling period. Collect 

biomarker samples with breath samples taken before and immediately after (10-seconds) a peak exposure; a 

backup breath sample will be taken immediately after this second sample. Collect four SPME samples, one 

every 10 minutes. Record the local ambient wind speed, direction (if any), temperature and relative humidity 

with the hand held meteorological instrument. A camcorder will be positioned to record the sampling scene; a 

pan of the sampling site will also be provided to record details of the location. 

12. Outdoors: toll booth (ME12) 

Two possible locations for this microenvironment are tollbooths on tollways or one of the centralize vehicle 

inspection stations. The vehicle inspection station at 3824 159th Place is reasonably close to the RV Park and 

has good access. Sampling at the toll plaza would be conducted behind the tollbooth similar to arrangement in 

Atlanta. For the vehicle inspection station, we would sample near the dynamometers. We will need to obtain 

permission from the Illinois EPA to conduct sampling at the inspection station. 

 C-5 
Sample the breathing zone continuously with a KORE MS 200, Langan T15, and portable PID monitor and 

collect one set of canister and DNPH samples integrated over the entire 40 minute period. Collect four SPME 

samples, one every 10 minutes. Record the ambient temperature and relative humidity. If time permits before or 

after the sampling period and sufficient traffic exist, conduct measurement of in-cabin exposure during one pass 

through the toll plaza. Collect one SPME sample during this sampling period. 

13. Trailing high emitters (ME12) 

Since we’ll be sampling the Wacker Drive ‘tunnel’ (ME6), there are no plans to sample ME13 in Chicago. 

DAILY SAMPLING SCHEDULE 

The prospective daily schedule for the Summer 2003 Chicago sampling program is summarized in Table 1. The 

sampling schedule is subject to change due to field conditions encountered. Actual summer and winter schedules 

will appear in the draft/final reports. In order to stay on project schedule as much as possible, sampling will be 

conducted on Saturdays in case we encounter unsuitable meteorological conditions on scheduled sampling days. 

However, this daily schedule doesn’t take into consideration the potential for prolonged weather delays. The winter 

daily sampling schedule for Chicago will be finalized prior to the 2004 winter study. 

Table 1 

Prospective Summer 2003 Daily Sampling Schedule for Atlanta

 

July/August 2003 

Sunday Monday Tuesday Wednesday Thursday Friday Saturday 

31 

Leave Reno 

1 2

3 4 5 6 7 8 9

Arrival/ 

Setup 

Setup Final 

preparations

7am ME1 7am ME1 7am ME1 10am ME3, 

ME7 

Calibrate 8am ME13 12/1pm ME3/7 8am ME13 

Familiarize 5pm ME4 

5pm ME4 5pm ME4 5pm ME4 10 pm ME10 10 pm ME10 

10 11 12 13 14 15 16

7am ME1 7am ME1 7 am ME8/9 7 am ME5 7am ME5 10am ME3, 

ME7 

8am ME13 8am ME13 8am ME2 8am ME2 

12pm ME8/9 12pm ME3/7 

5pm ME11 5pm ME11 5pm ME8/9 5pm ME11 5pm ME11 

17 18 19 20 21 22 23

7am ME5 7am ME12 7am ME12 Leave for Arrive 

8am ME2 8am ME3/7 Packing Atlanta Atlanta 

5pm ME4 

5pm ME11 5pm ME12 10pm ME10 

24 25 26 27 28 29 30

 C-6 
APPENDIX D 

Example of a Diary Page 

 

 D-1 
P027 API ME Diary Page 

(Not for Refueling) 

Circle One: ME1 In-Cabin Freeway; ME2 In-Cabin Urban Canyon; ME4 InCabin Under-Ground Garage; ME5 In-Cabin Toll Plaza; ME6 In-Cabin Tunnel; 

ME8 Outdoor Sidewalk; ME9 Outdoor Bus-Stop; ME10 Outdoor Surface 

Parking; ME11 Outdoor Under-Ground Garage; ME12 Outdoor Toll Plaza; ME13 

Following Hi-Emitter. 

Date: Start Time: Location: 

Any Possible Pre-Exposure by Breath Technician? 

Weather Description: 

First 10 min: SPME 1. PMI: 

Time Traffic Level Windspeed 

Direction 

Unusual Events? Vent 

High 

Med 

Low 

HI 

LO 

Outside 

Second 10 min: SPME 2. PMI: 

Time Traffic Level Windspeed 

Direction 

Unusual Events? Vent 

High 

Med 

Low 

HI 

LO 

Outside 

Third 10 min: SPME 3. PMI: 

Time Traffic Level Windspeed 

Direction 

Unusual Events? Vent 

High 

Med 

Low 

HI 

LO 

Outside 

Fourth 10 min: SPME 4. PMI: 

Time Traffic Level Windspeed 

Direction 

Unusual Events? Vent 

High 

Med 

Low 

HI 

LO 

Outside 

 D-2 
Notes:

 D-3 
P027 API ME Diary Page 

(Refueling) 

Circle One: ME3 In-Cabin Refueling ME7 Outdoor Self-Serve Refueling 

Date: Start Time: Location: 

Any Possible Pre-Exposure by Breath Technician? 

Station Description: Total # of Pumps: Van at Pump #? 

Draw sketch of station with location of van (North is up). 

Weather Description: 

First 10 min: SPME 1. PMI: 

Time # Cars in Station Windspeed 

Direction 

Unusual Events? Vent 

HI 

LO 

Outside 

Second: SPME 2 PMI: 

Time # Cars in Station Windspeed 

Direction 

Unusual Events? Vent 

HI 

LO 

Outside 

Refueling: Time: Start: Stop: 

 # Gallons: # Drops (diameters) spilled: 

Notes: 

 D-4 
APPENDIX E 

Quality Assurance 

 E-1
APPENDIX E 

1.0 Quality Assurance

The Desert Research Institute maintains a very complete quality assurance and quality control program that is 

detailed in this section. This section addresses all the required components from the RFP. These include: 

a. Daily calibration. All instruments to be used in this study have calibration checks run each day. 

These checks will confirm both response factors and retention times for both continuous and timeintegrated instruments. 

b. Daily instrument blank. An appropriate blank will be run daily for each instrument. Generally this 

is run after the calibration check and before any samples are analyzed. This confirms that there is 

no carryover from the calibration check as well as confirming the blank or zero level of the 

instrument. 

c. Duplicate analysis for every 10 samples. Our protocols generally call for 10% replicate analyses. 

These are an important part of our QA/QC program since these are applied to determine replicate 

precision that allows us to calculate sample uncertainty. 

d. Control samples. DRI labs analyze a variety of control samples for QA/QC purposes. These 

include calibration, replicate, collocated and blind QA samples. 

e. Recovery tests for selected analytes. For DNPH analyses internal standards are also added. 

Recovery for NMHC samples in internally determined by calibration standards. 

f. Determine and report minimum trapping efficiency. For solid adsorbent samples, the backup traps 

are used for approximately 5 % of samples to confirm that no quantifiable levels of compounds are 

getting through the first trap. 

Every measurement consists of four attributes: a value, a precision, an accuracy, and a validity (e.g., Hidy, 1985). 

The measurement methods described in the previous section are used to obtain the value. Quality assurance is the 

complementary part of the measurement process which provides the precision, accuracy, and validity estimates and 

guarantees that these attributes are within acceptable limits. 

Quality assurance for the project is the joint responsibility of the laboratory manager and the quality assurance 

manager. The QA manager must ensure that the program design contains adequate quality control procedures and 

adequate external checks to assure that the data obtained will be adequate for their intended purposes. It is the 

responsibility of the laboratory manager to monitor the quality assurance activities during the project and to make 

certain that problems are rapidly identified and solved. 

The quality assurance program includes two types of activities: quality control (QC), and quality assurance (QA). 

The QC activities are on-going activities of measurement and data processing personnel. QC activities consist of 

written standard operating procedures to be followed during sample collection, sample analysis, and data processing. 

These procedures define schedules for periodic calibrations and performance tests (including blank and replicate 

analyses). They specify pre-defined tolerances that are not to be exceeded by performance tests and the actions to 

be taken when they are exceeded. The QC activities also include equipment maintenance and acceptance testing, 

and operator training, supervision, and support. 

Quality assurance is a project management responsibility that integrates quality control, quality auditing, 

measurement method validation, and sample validation into the measurement process. Quality auditing is an 

external function performed by personnel who are not involved in normal operations An independent auditor will 

be contracted by API to conduct a quality audit during a one week period in a single city. The purpose of quality 

 E-2
audits is to determine whether the QC procedures are adequate and are being followed and whether the tolerances 

for accuracy and precision are being achieved in practice. The quality auditing function consists of two 

components: systems audits and performance audits. Systems audits include review of the operational and QC 

procedures to assess whether they are adequate to assure valid data that meet the specified levels of accuracy and 

precision. All phases of the measurement and data processing activities are examined during the systems audit to 

determine whether the procedures are being followed and the operating personnel are properly trained. Performance 

audits establish whether the predetermined specifications for accuracy are being achieved in practice. For 

measurements, the performance audit involves challenging the measurement/analysis system with a known standard 

sample that is traceable to a primary standard. Performance audits of data processing involve independent 

processing of raw data and comparing the results with reports generated by routine data processing. 

1.1 Quality Assurance Objectives 

The objectives of our quality assurance measures are: 

1. To maintain a continuing assessment of the quality of data generated by analysts working in the laboratory. 

2. To provide a permanent record of instrument performance as a basis for validating data and projecting 

repairs and replacement needs. 

3. To ensure sample integrity. 

4. To improve record keeping. 

5. To produce analytical results that can withstand scientific and legal scrutiny. 

2.0 Organization and Responsibility 

The general structure of the organization of the Desert Research Institute, Division of Atmospheric Sciences (DAS), 

Organic Analytical Laboratory is indicated on the Figure 2-2. For an effective quality assurance program, all 

individuals must take personal responsibility for monitoring, recording, and reporting all measures that relate to the 

quality assurance program. Specific responsibilities include the following: 

DRI DAS

Executive Director

Dr. Kent Hoekman

DRI OAL

QA Manager

Ms. Nancy Peneff

DRI OAL

Director

Dr. Barbara Zielinska

DRI OAL

Laboratory Operations

Dr. Wendy Goliff and Dr. John Sagebiel

DRI OAL

Field Operations

Mr. Larry Sheetz

DRI OAL

Laboratory Technicians

Ms. Anna Cunningham, Mr. Michael Keith, Mr. Mark McDaniel, Ms. Katrzyna Rempala

Organizational Structure of OAL

DRI DAS

Executive Director

Dr. Kent Hoekman

DRI OAL

QA Manager

Ms. Nancy Peneff

DRI OAL

Director

Dr. Barbara Zielinska

DRI OAL

Laboratory Operations

Dr. Wendy Goliff and Dr. John Sagebiel

DRI OAL

Field Operations

Mr. Larry Sheetz

DRI OAL

Laboratory Technicians

Ms. Anna Cunningham, Mr. Michael Keith, Mr. Mark McDaniel, Ms. Katrzyna Rempala

Organizational Structure of OAL

Figure 2-2. Organization of the Desert Research Institute – Division of Atmospheric Sciences, Organic 

Analytical Laboratory. 

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DAS Director (Dr. S. Kent Hoekman): Overall management and supervision of the Division of Atmospheric 

Sciences. 

QA Manger (Ms. Nancy Peneff): Responsible for internal audits and checks of laboratory QA program, operations, 

and procedures. Requests performance audits, and reviews procedures and protocols. Reviews data reduction and 

handling procedures. 

Laboratory Director (Dr. Barbara Zielinska): Responsible for direct supervision of laboratory and field operations. 

Supervises QA program at the operational level. Approves analytical and sampling methods, and practices. 

Reviews and approves all SOPs. Reviews and approves sampling media and sampling equipment certification 

procedures. Reviews and approves all laboratory-generated data. Reviews and ensures continued calibration of 

instruments. 

Laboratory Operations (Dr. John Sagebiel and Dr. Wendy Goliff): Responsible for Laboratory Information 

Management System (LIMS), data management software and operations. Reviews and approves data. Under 

general supervision from Laboratory Manager, reviews laboratory practices and corrects as needed. Performs 

general maintenance on analytical instruments and LIMS computers. Performs Level I validation of data and 

participates in general review of all laboratory-generated data. Performs general maintenance on laboratory 

analytical instruments. 

Field Operations (Mr. Larry Sheetz): Responsible for assembly, cleaning, maintenance, and certification of all 

sampling equipment. Maintains records of use of each sampler, including any modifications made. Certifies proper 

operation of samplers including leak checks, and calibration of flow controlling equipment. Orders certification of 

flow controllers as needed. Orders certification of cleanliness of sampling equipment as needed. Maintains records 

of sampler maintenance and cleaning. Responsible for training of field personnel in proper operation, record 

keeping and maintenance of sampling equipment. Performs general maintenance on laboratory analytical 

instruments. 

Laboratory Technicians (Mr. Michael Keith and Mark McDaniel, Mrs. Anna Cunningham, Ms. Katarzyna 

Rempala). Perform calibration of analytical instruments. Perform regular calibration checks and recalibrate if 

calibration does not meet specified parameters. Log in samples in project logbooks upon receipt. Properly store 

samples in possession. Perform analysis of samples. Perform analysis of media, canisters, and sampling equipment 

to ensure cleanliness. Responsible for record keeping. Participate in internal and external audits and checks of 

methodology. Perform other tasks as directed by Laboratory Operations, Field Operations, Laboratory 

Management, Laboratory QA or Center Director. Performs general maintenance on laboratory analytical 

instruments. 

3.0 Sample Custody 

For our quality assurance plan, a sample is considered in custody when it is received by the DRI-DAS receiving 

department from an official package courier. At this time it is logged into the general receiving department's 

logbook and the Organic Analytical Laboratory is notified of the package's arrival. A representative of the 

laboratory signs for the package and returns with it to the laboratory room, where he opens it. The samples are 

logged into the Organic Analytical Laboratory’s LIMS system in lieu of updating the chain-of-custody form (if 

supplied), and the samples are stored appropriately for the sample type. At this time any unusual situations 

(damaged shipping container, evidence of damage and/or tampering, etc.) are brought to the attention of the 

laboratory manager. If necessary, a review will be initiated to determine if the damage compromised the integrity 

and/or quality of the sample. 

Samples are stored in the Organic Analytical Laboratory, inside the DRI Northern Nevada Science Center (2215 

Raggio Parkway, Reno, NV). All condensed phase samples and sample extracts are stored in the freezers. The 

rooms are locked when not in use and the building has limited access (i.e., it is locked from 1730 to 0730 weekdays 

and all weekend to ensure access only to authorized personnel). 

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When a sample is analyzed, its identification number (sample number) is recorded both in the written logbook for 

each instrument and in the LIMS file created for that analysis. The sample number serves as a tracking number, as 

does the LIMS file itself. Canisters will not be cleaned until each sample has passed initial validation. 

Condensed phase samples and sample extracts will be maintained for at least one year following the completion of 

the project. Samples will be stored in refrigerators or freezers. 

4.0 Laboratory Records 

Several forms of laboratory records are routinely maintained. Written records include receiving logbooks, shipping 

log books, chain-of-custody forms, project log books, instrument log books, instrument service logbooks, calibration 

records which include a calibration standard logbook and graphs of response factors vs. time, a canister cleaning 

logbook, and sampler maintenance and cleaning logbooks. Computerized records include method files, calibration 

files, raw data files, processed data files, and combined data files. 

Written records are maintained in the appropriate location in the laboratory. Written records are always maintained 

in non-erasable ink so that any alteration is easily noted. Project logbooks record sample arrival and other 

information about the sample. Instrument logbooks record each sample run, including all pertinent information. All 

calibration runs are also recorded here. Other calibration records include the calibration logbook where all standard 

solutions made in the laboratory are logged, a graph of all calibration checks, and the computerized calibration files. 

Service logbooks show services and/or modifications done to the instruments. The canister cleaning logbook 

records each canister number, the project the canister was used for, date of last cleaning, and certification 

information. 

Computerized records are maintained on a central computer (the LIMS file server). Our data collection system 

includes a history record that maintains lists of files created or modified and the name of the person creating or 

modifying the file. Each sample has an original report printed at the time the sample run is completed and this 

report indicates which method and calibration file are used, including the last modification date of the file. Backups 

of computerized records, including but not limited to removable media (floppy disks) and tapes are stored in the 

LIMS manager's office as an off-site storage area. 

5.0 Standard Operating Procedures 

Standard operating procedures (SOPs) codify the actions taken to implement a measurement process over a specified 

time period. State-of-the-art scientific information is incorporated into the SOP with each revision. SOPs include 

the following elements: 

1. A brief summary of the measurement method, its principles of operation, its expected accuracy and 

precision, and the assumptions which must be met for it to be valid. 

2. A list of materials, equipment, reagents and suppliers. Specifications are given for each expendable item 

and its storage location. 

3. A general traceability path, the designation of primary standards or reference materials, tolerances for 

transfer standards, and a schedule for transfer standard verification. 

4. Start-up, routine, and shutdown operating procedures and an abbreviated checklist. 

5. Copies of data forms with examples of filled out forms. 

6. Routine maintenance schedules, maintenance procedures, and troubleshooting tips. 

7. Internal calibration and performance testing procedures and schedules. 

8. External performance auditing schedules. 

9. References to relevant literature and related standard operating procedures. 

The standard operating procedures for all analyses will be provided upon request. 

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5.1 Sampling Media Preparation and Certification 

For commercial cartridges, e.g. Waters Si-DNPH, DRI shall analyze 5% of the purchase initially to ascertain the 

blank variability. Another 5% will be analyzed if the initial data show that the blank variability is marginally 

acceptable (at or slightly higher than 1/3 of the desired lower quantifiable limits (LQL)). This is necessary because, 

unless cartridges are prepared in-house, there is no other indication of the quality of the product, such as how pure 

the reagent or the blank cartridges are. In carbonyl measurement, the blank variability is the single most important 

factor in determining the lower quantifiable limit of the measurement. The other factors, such as flow rate and 

analytical variability are secondary in importance. 

Tenax-TA solid adsorbent is cleaned by Soxhlet extraction with hexane/acetone mixture (4/1 v/v) overnight, and 

dried in a vacuum oven at ~80 °C. The dry Tenax is packed into Pyrex glass tubes (4 mm i.d. x 15 cm long, each 

tube containing 0.2 g of Tenax) and thermally conditioned for four hours by heating in an oven at 300 °C under 

nitrogen purge (25 ml/min nitrogen flow). Approximately 10% of the precleaned Tenax cartridges are tested by 

GC/FID for purity prior to sampling. If Carbotrab, Carboxen and/or Carbosieve are used, the amount of Tenax is 

reduced as necessary. After cleaning, the Tenax cartridges are capped tightly using clean Swagelok caps (brass) 

with graphite/vespel ferrules, placed in metal containers with activated charcoal on the bottom, and kept in a clean 

environment at room temperature until use. 

5.2 Analytical Systems 

Prior to analysis all analytical systems (i.e., GC/ECD/FID, HPLC, GC/MS, and GC/IRD/MSD) are checked for 

purity and are certified clean (less than 0.1 ppbv of targeted compound). Quality control in the laboratory includes 

instrument calibration for each batch of samples analyzed, replicates of standards, and reanalysis of approximately 

10% of the samples for estimation of analytical precision, which historically has been less than 6%. In past 

programs, field blanks were at the 0.5-1 ppb levels, based on the air volume of the samples. Coefficients of 

variation (CV) calculated from observed differences between duplicate sample pairs were under 10%. The data 

quality in this program is likely to be similar. 

5.3 Standards and Materials 

Primary reference standards are traceable to an NIST Standard Reference Material (SRM). For canister 

hydrocarbon speciation by GC/FID, we use NIST SRM 1805, which consists of 254 ppb of benzene in nitrogen. In 

addition, NIST SRM 2764 (245 ppb of propane in N2), is used for calibrating the light hydrocarbon analytical 

system. For halogenated compound measurements, an NIST-traceable standard mixture of 39 compounds is 

purchased from Scott Specialty Gases and diluted by DRI scientists for calibration. For VOC measurements by 

GC/MS system, 74 compound mixture in low ppb level (Air Environmental, Inc., Denver, CO), traceable to the 

NIST SRM 1805, is used for calibration. For PAH measurements NIST SRM 1647, with the addition of other 

compounds not present in the mixture, is used. 

Gas cylinders of helium, nitrogen, hydrogen and ultra zero air (all UHP grade) — from the best sources available — 

are used for the GC/FID, GC/MS and GC/IRD/MSD. From a single analysis, the GC/IRD/MSD system gives three 

dimensions of data for positive compound identification: retention times, infrared spectra, and mass spectra. 

Identification of individual compounds is based upon matching corresponding data for authentic samples. The 

current inventory of reference samples at DRI's Organic Analytical Laboratory consists of over 250 single- and 

multi-component reference samples, and includes most of the compounds of interest in this project. 

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5.4 Calibrations 

The GC/FID, HPLC, GC/MS and GC/IRD/MSD systems are calibrated initially by multipoint calibration (i.e., three 

levels plus humid zero air), and regularly checked by a one-point calibration, using appropriate NIST SRM or other 

standard. The day-to-day reproducibility of ±10% is acceptable for either standard. Control charts are used for 

assessing analytical system performance. 

Samples that fall outside the calibration range are diluted until bracketed by the calibration curve. Instrument 

responses to calibration standards for each parameter are analyzed using a least squares linear regression. The 

calibration must generate a correlation co-efficient (R2) of 0.99 to be acceptable. 

During the course of analysis, calibration standards are routinely analyzed to ensure that the instrument response has 

not changed. The criterion of 10% of expected response is used by the analyst to determine whether the instrument 

must be recalibrated. 

Retention time windows for each analyte will be established prior to analysis and re-established continuously 

throughout the course of the analytical period. 

5.5 Relative Accuracy and Precision of Sampling and Analysis 

Accuracy involves the closeness of a measurement to a reference value and reflects elements of both bias and 

precision. Percent relative accuracy is calculated: 

 

 % Relative Accuracy = (X - Y)/X x 100 

 

where: Y = concentration of the targeted compound, as determined by the analytical instrument, 

and 

X = concentration of the targeted compound in the NIST standard. 

If the relative accuracy does not fall within the ± 10% range, the instrument is recalibrated. 

Precision is a measure of the repeatability of the results. The overall precision of sampling and analysis is 

determined by the analysis of collocated or equivalent samples. These precision tests will depend upon available 

resources, and we will develop the protocol in consultation with the project officer. 

5.6 Internal Quality Control Checks 

Our entire quality assurance program is organized around providing continuing internal quality control checks. This 

begins with proper training of the laboratory technicians so that they can identify problems with analyses and point 

these out to the Laboratory Operations Manager or Laboratory Manager for resolution. Other internal quality 

control checks include our blank checks, certification of sampling media, and our data analysis system. The ability 

of our data analysis system to merge multiple samples into a single database allows for rapid and accurate crosscomparisons among the samples. 

Other internal quality control checks consist of those ordered by the QA officer and required by our standard 

operations. Standard operation quality control checks include the calibration procedures, the regular calibration 

checks, and the duplicate analyses. Duplicate analyses are essential for determining precision of analyses and give 

us information about the stability of the system over time. The QA officer may, at his discretion, order performance 

checks at any time. These may include verification of response factors, blank checks of sampling media, and 

participation in interlaboratory comparisons (see below). 

 E-7
5.7 Preventative Maintenance 

All of our equipment is on a preventative maintenance schedule. We have found that the most important 

preventative maintenance tool is our systematic performance checks. When an instrument is not performing up to 

standards, we investigate and in this way find most problems before they become significant. 

All of our major equipment (the GC/MS:s and HPLC) is on a service contract with the original manufacturer 

(Hewlett-Packard and Varian). This contract calls for biannual routine service by a Hewlett-Packard or Varian 

service technician, and immediate response to any service call. Our contract specifically states that any problem will 

be corrected within 48 hours of notification of the manufacturer. 

Several laboratory personnel have extensive experience working with all the major laboratory equipment and DRI 

has extensive support facilities (electronics and machine shops, QA lab with standard reference materials, etc.). 

These personnel and facilities ensure the continued smooth operation of all analytical instruments in the Organic 

Analytical Laboratory. 

5.8 Corrective Action 

A need for corrective action can be triggered by a number of activities, including the assessments of precision, 

accuracy, and completeness listed above. The most important corrective action trigger is the response factor chart 

mentioned above. This is the graph of our daily response factor check and it requires a full multi-point recalibration 

if the response factor differs by more than ±10% from the original calibration. Other triggers can include an 

instrument not meeting basic performance criteria, observations by any laboratory personnel of unusual performance 

by an instrument, or error messages displayed by the controlling computers or the LIMS system. 

Once a need for corrective action has been identified, two basic steps follow: identification of the problem, and 

correction of the problem. Exactly what action is taken depends on what is determined to be wrong. Actions can 

include replacement of a defective part, correction of an incorrect flow, resetting or adjusting of tuning parameters, 

and contacting manufacturer service personnel for corrective action through our service contract. 

5.9 Laboratory Data Processing 

The goal of our data processing is to provide accurate data combined into a single database for each analysis type 

and to include calculations of replicate precision, mean blank values, and blank variability, and blank-corrected 

concentrations and standard errors for each reported value based on combined volume (for carbonyl and semivolatile compounds), replicate (for hydrocarbon, SVOC and carbonyl data), and blank uncertainties (for carbonyl 

and SVOC data only; substitute minimum detection limits for hydrocarbon data). The uncertainty analysis allows us 

to present our data with absolute uncertainties associated with each number in the report. 

5.10 Laboratory Data Management 

The primary functions of laboratory data management are to have data stored in a consistent fashion that is both 

secure and available. To serve this need we have established a file server system that provides a central storage area 

for all laboratory and field data. The databases have defined structures that are maintained in one area so that all 

field names will be consistent, which permits easy merging and comparison of the various databases. Locating all 

data on a central file server prevents the problems associated with having multiple copies of the same data set, and 

allows the individuals charged with data processing, security, validation, and QA access to the same database. 

 E-8
5.11 External Quality Assurance 

The DRI Organic Analytical Laboratory (OAL) participated in the International Hydrocarbon Intercomparison 

Experiment, organized by National Center for Atmospheric Research (NCAR). The results of Tasks I, II, and III of 

this intercomparison have been published (Apel et al., 1994; 1999). The first task involved the circulation of a twocomponent hydrocarbon mixture of known composition and unknown concentration, prepared by NIST. The DRI 

values were within the acceptable range of 5% of the nominal values provided by NIST. In task II the participating 

laboratories were asked to identify and quantify 16 components present, in the ppb range, in a mixture prepared by 

NIST. The agreement between the DRI values and the NCAR values, as well as with nominal values provided by 

NIST, were within acceptable ranges (15%). Task III was more complex - it involved the analysis of 60 commonly 

observed hydrocarbons in low ppbv concentrations in a mixture prepared and analyzed by Scott-Marrin, Inc., NCAR 

and U.S. EPA laboratory. The next tasks, IV and V, which were carried out in 1996 -1997, involved the analysis of 

ambient air samples in the ppbv and pptv concentration ranges, respectively. The DRI has successfully completed 

these tasks — the agreement between the DRI values and the NCAR values were within acceptable ranges (10%). 

In the summers of 1995 and 1996 the DRI OAL participated in the NARSTO-Northeast hydrocarbon 

intercomparison study, involving the analysis of two ambient air samples by participating laboratories. Participants 

included Biospheric Research Corporation (BRC), State University of New York at Albany (SUNYA), EPA Region 

I, DRI, and 8 of the PAMS networks in the northeastern U.S. The DRI laboratory performed the best in comparison 

with all other participants (Fujita et al., 1997). In the summer of 1997, the DRI OAL participated in the SCOS97-

NARSTO performance audit and laboratory comparisons involving speciated non-methane hydrocarbons (NMHC), 

carbonyl compounds, halogenated compounds and biogenic hydrocarbons (Fujita et al., 2003). 

During the last six years, the DRI laboratory participated in non-methane hydrocarbon laboratory performance 

audits, organized by the Quality Assurance Section, Monitoring and Laboratory Division, CARB. The last 

intercomparison studies, organized in 1999-2002, involved the analysis of ambient air samples by California district 

laboratories and the DRI laboratory. 

6.0 REFERENCES 

Apel, E.C., J.G. Calvert, and F.C. Fehsenfeld (1994). The Nonmethane Hydrocarbon Intercomparison Experiment 

(NOMHICE): Tasks 1 and 2. J. Geophys. Res. 99: 16,651-16,664 

Apel, E.C., J.G. Calvert, T.M. Gilpin, F.C. Fehsenfeld, D.D. Parrish, W. A. Lonneman (1999). The Nonmethane 

Hydrocarbon Intercomparison Experiment (NOMHICE): Task 3. Journal of Geophysical Research, 104: 

20,069-26,086 

Fujita, E., G. Harshfield, L. Sheetz (2003). Performance Audits and Laboratory Comparisons for SCOS97-

NARSTO Measurements of Speciated Volatile Organic Compounds. In press. 

Fujita, E., Z. Lu, G. Harshfield, and B. Zielinska (1997). NARSTO-Northeast: Hydrocarbon and Carbonyl 

Measurement Audits for the 1995 Field Study. Final Report prepared for the Electric Power Research 

Institute, Palo Alto, CA, July 1997 

Hidy, G.M. (1985). "NMOG in California's South Coast Air Basin." Doctoral dissertation, University of California, 

Los Angeles, CA, University Microfilms International, Ann Arbor, MI. 

 E-9
Appendix B 

Sampling and Analysis Methods 

 
Appendix B. Sampling and Analysis Methods 

Table of Contents 

1.1 Time-Integrated Air Sample Collection and Analysis ................................................2 

1.2 BTEX by Solid Phase Microextraction (SPME).........................................................4 

1.2.1 Sampling ............................................................................................................4 

1.2.2 Analysis..............................................................................................................5 

1.3 Continuous Methods....................................................................................................8 

1.4 Breath Collection and Analysis.................................................................................10 

1
1.1 Time-Integrated Air Sample Collection and Analysis 

Time-integrated monitoring methods are used for quantification of the responses of 

continuous surrogate instruments. The methods include canister sampling for VOC (BTEX, 

1,3-butadiene, MTBE), solid adsorbent sampling (for ethanol) and DNPH-coated Sep Pak 

cartridges sampling for carbonyl compounds. The DRI Organic Analytical Laboratory (OAL) 

routinely uses these methods and DRI standard operating procedures (SOPs) for sampling 

and analysis are available upon request. Five to forty minute samples are collected 

depending on the ME sampled. 

Sampling. The DRI custom built sampler used for this study can sample 

simultaneously a canister, solid adsorbent cartridges (two in parallel), and a DNPHimpregnated Sep-Pac cartridge. The sampler is compact and can be set-up in a vehicle cabin 

and run from a battery. Prior to use, the sampler is checked for cleanliness by sampling zero 

air. If the concentration of any targeted compound exceeds 0.1 ppb, the sampler is 

thoroughly cleaned and re-tested. As noted earlier, a remote switch is installed to allow 

cabin on/off control of the sampler, no longer requiring access through the van tailgate. The 

protocol requires that the van engine be off during changes of sampler media. 

 The canister sampler uses a differential pressure flow controller to supply air to the 

sampler canister and a calibrated mass flow controller to check the flow rate. Since the actual 

flow rate is less important than that the flow rate remain constant, additional quality 

assurance checks on the flow controllers is not necessary. For the 5-minute canister samples 

an additional battery-operated sampler is used that allows flows up to 3 L/minute to 

pressurize the 3 L canister. 

 Both the solid adsorbent and DNPH samplers use a common vacuum pump controlled 

by mass flow controllers. These controllers are calibrated at the start of the field program by 

using a primary flow device (e.g. Gillibrator) and then periodically checked in the field to 

confirm that the flow rates are accurate. 

Canister samples. Prior to sampling, the canisters are cleaned by repeated evacuation 

and pressurization with humidified zero air, as described in the EPA document "Technical 

Assistance Document for Sampling and Analysis of Ozone Precursors" (October 1991, 

EPA/600-8-91/215). Six sequential cycles of evacuation to ~ 0.5 torr absolute pressure, 

followed by pressurization with ultra-high-purity (UHP) humid zero air to ~ 20 psig are used. 

The differences between the DRI procedure and the EPA recommended method are that the 

canisters are heated in the DRI method to 140°C during the vacuum cycle and that more 

cycles of pressure and vacuum are used. According to our experience and that of others 

(Rasmussen, 1992), heating is essential to achieve the desired canister cleanliness. Also, the 

canisters are kept longer under vacuum cycles, about one hour in the DRI method, as 

opposed to half an hour in the EPA method. At the end of the cleaning procedure, one 

canister out of 12 in a batch is filled with humidified UHP zero air and analyzed by the gas 

chromatograph/flame ionization detection (GC/FID) method. The canisters are considered 

clean if the total non-methane organic compound (NMOC) concentration is less than 20 

ppbC. The actual concentrations of blank-check canisters are typically below 10 ppbC. 

2
Canister samples are analyzed promptly upon receipt of samples from the field, using 

GC/FID according to guidance provided by the EPA Method TO-15. The GC/FID response 

is calibrated in ppbC, using NIST Standard Reference Materials (SRM) 1805 (254 ppb of 

benzene in nitrogen). Based on the carbon response of the FID to hydrocarbons, the response 

factors determined from these calibration standards are used to convert area counts into 

concentration units (ppbC) for every peak in the chromatogram. Identification of individual 

compounds in an air sample is based on the comparison of linear retention indices (RI) with 

those RI values of authentic standard compounds. A DB-1 column (60 m long 0.32 mm i.d., 

1 μm film thickness) is used for these analyses. Breath canisters are quantified for CO2, 

MTBE, and BTEX by the method of Pleil & Lindstrom using GC/MS. 

Blank checks are performed once daily, while performance standards are executed 

three times per week. Our analysis plan and data processing standards call for the replicate 

analysis of approximately 10% of the samples. For canisters the replicate analysis is 

conducted at least 24 hours after the initial analysis to allow for re-equilibration of the 

compounds within the canister. The replicate analyses are flagged in our database and the 

programs we have for data processing extract these replicates and determine a replicate 

precision. Replicate analysis is important because it provides us with a continuous check on 

all aspects of each analysis, and indicates problems with the analysis before they become 

significant. A portion (5%) of the canisters is also analyzed by a second independent 

laboratory (Battelle-Columbus). 

Solid adsorbent samples. Ethanol is quantified from solid adsorbent cartridges as 

well as canister methods. Although MTBE is stable in SUMMA canisters and can be 

quantified with high precision and accuracy, ethanol is relatively unstable and the replicate 

analyses of canister samples show a high degree of scatter (Goliff and Zielinska, 2001). 

Thus, the solid adsorbent samples are necessary for quantification of ethanol. For sample 

collection we use multibed adsorbent cartridges consisting of Tenax-TA, Carbotrap (or 

Carboxen) and Carbosieve (Shire et al., 1996; Tsai and Weisel. 2000; Vayghani et al., 1999). 

Prior to use the Tenax-TA solid adsorbent is cleaned by Soxhlet extraction with 

hexane/acetone (4/1 v/v) overnight and dried in a vacuum oven at ~ 80 °C. The dry Tenax is 

packed into Pyrex glass tubes together with Carbotrap and Carbosieve and thermally 

conditioned for four hours in an oven at 300 °C under nitrogen purge. Approximately 10% 

of the precleaned tubes are tested by GC/FID prior to sampling. After cleaning, the tubes are 

sealed with clean Swagelok caps (brass) with graphite/Vespel ferrules, placed in metal 

containers with activated charcoal on the bottom, and kept in a clean environment at room 

temperature until use. 

After sampling at monitored flows of 200-300 ml/minute, tube samples are analyzed by 

a thermal desorption-cryogenic preconcentration method, followed by high-resolution GC/MS. 

A Chrompack Thermal Desorption-Cold Trap Injection (TCT) unit is used for sample 

desorption and cryogenic preconcentration. The compounds of interest are quantified by MS, 

using the response factors of authentic standards, prepared at five different concentrations 

with a static dilution bulb. 

Carbonyl compounds. Formaldehyde and acetaldehyde are collected with Sep-Pak 

cartridges that have been impregnated with an acidified 2,4-dinitrophenylhydrazine (DNPH) 

3
reagent (Waters, Inc), according to the EPA Method TO-11A. When ambient air is drawn 

through the cartridge at nominal flow rates of 1 L/min, carbonyls are captured by reaction 

with DNPH to form hydrazones, which are separated and quantified in the laboratory using 

HPLC (Fung and Grosjean, 1981). The ambient measurement results are subject to various 

artifacts due to sorbent interactions with ozone so ozone is removed with a honeycomb 

denuder coated with sodium carbonate/sodium nitrite/glycerol mixture (Koutrakis, et al., 

1993). After sampling, the cartridges are eluted with acetonitrile. An aliquot of the eluent is 

transferred into a 1-ml septum vial and injected by autosampler into a high performance 

liquid chromatograph (Waters Alliance System) for separation and quantization of the 

hydrazones (Fung and Grosjean 1981). 

1.2 BTEX by Solid Phase Microextraction (SPME) 

1.2.1 Sampling 

 Carboxen/(poly)dimethylsiloxane (CAR/PDMS) coated (75 μm) quartz fibers are 

used for 10-minute BTEX sampling. SPME is a passive method, thus the rate of the fiber 

uptake is controlled by the diffusion rate of the analytes to the fiber. In a stationary 

environment without air movement, a concentration gradient is formed in the boundary layer 

between the fiber and the surrounding environment. This situation occurs during fiber 

calibration in a static system, such as a Tedlar bag. However, in an outdoor environment 

there is always some air movement and the sorption rate will be higher in this situation, since 

the thickness of the boundary layer will be smaller. This phenomenon explains some of the 

differences observed between canister and SPME samples collected in summer 2002. To 

improve the agreement between these methods the Summer 2003 SPME samples were 

obtained using the experimental set up in Figure 1. The outlet of the SPME sampling bulb 

was connected to the Tenax media sampling pump. Active sampling at low constant air 

flows was a suitable solution of outdoor field sampling variability on windy days. With these 

modifications, wind speed influence is avoided and a common air stream is being sampled by 

all instruments. The SPME was exposed to the air stream at a fixed flow rate of about 300 

ml/min. The sampling bulb temperature is not controlled. 

4
Figure 1. SPME Sampling System Set Up 

1.2.2 Analysis 

All SPME BTEX samples are analyzed in a mobile laboratory with a Model 8610C SRI 

Instruments GC equipped with a heated injection port suitable for SPME desorption, a CP-Sil 

5 (Varian, Inc.) capillary column (60m, 0.32mm i.d.), and a PID detector. The heated flash 

vaporization injector is maintained at 250°C and the PID at 150°C. The column temperature 

was programmed at 60°C for 2 min, 8°C/min to 165°C (held for one minute), and then 

45°C/min to 240°C. The helium carrier gas flow rate was 3 ml/min. 

Blanks and calibration checks are performed daily on the SRI GC in order to determine the 

performance of the instrument. Fibers are kept in the injector port throughout the sample run 

to guarantee that the entire sample was desorbed and to begin the conditioning of the fiber. 

Fibers are further cleaned in a fiber conditioner at 300°C for at least one hour. One fiber per 

batch of 5 is checked for cleanliness after conditioning. The fiber conditioner consisted of a 

70 cm x 16 cm stainless steel container with 5 ports and a Watlow heater/temperature 

controller capable of maintaining temperatures in the 200-300° C range. A helium flow of 

approximately 10 ml/min is maintained during fiber conditioning. Testing showed that the 

same fiber can be reused up to 40 times absent breakage of the fiber or failure of the fiber 

mounting mechanism. 

The SRI GC is calibrated with 1 μl injections of liquid standards prepared in pentane with 

BTEX at different concentrations (1, 5, 10, 20, 40, 50, and 100 ng/μl). Carboxen/PDMS 

fibers are calibrated by introducing the SPME fiber for a defined time into a flowing standard 

gas containing the calibration component under the same flow-through conditions used for 

field sampling). The fiber is then analyzed by GC/PID. SPME gas calibrations are done 

throughout the study as necessary. BTEX calibration is performed with certified gas 

standards at different concentrations (20, 80, 100 and/or 200 ppbv for each compound). 

5
The dependence of the SPME uptake rate on the sample flow rate is shown in Figure 2. The 

response changes logarithmically and reaches a plateau region after approximately 0.038 

cm/s when changing flow has a lesser effect on the amount of extracted mass. Optimal flow 

was determined to be 0.038 cm/s. The linear velocities studied were low (0.0044-0.1126 

cm/s) enough to characterize a “quasi static” environment. The flow profile showed two 

distinctive zones in Figure 2. In the first zone (0-0.0665 cm/s) mass transfer is controlled 

by diffusion through the well-developed fiber boundary layer; in the second zone (0.0665 

cm/s and higher) transfer is controlled by diffusion through the fiber pores. 

Sampling was performed within the plateau region where the SPME response is not greatly 

affected by changes in the flow. 

Figure 2. SPME Flow Profile 

Sampling temperature and humidity are also important parameters affecting the SPME data. 

Temperature correction factors are obtained in the laboratory. The sampling bulb is 

temperature controlled with a cooling/heating system. Temperature inside the glass bulb is 

measured with a thermocouple. For introducing humidity, a heated injection port is added 

before the glass bulb entrance in order to inject water with a syringe pump to produce the 

desired relative humidity (Tuduri, et al., 2001; Nelson, 1992; Martos, P. and J. Pawliszyn, 

1997, and Lodge 1989). 

6
Chai and Pawliszyn, 1995, performed several experiments to determine the influence of 

relative humidity (RH) on the 100 μm PDMS partition coefficient (Boy-Boland, 1998). RH 

usually decreases the response factor (Kfg) of each individual compound. The decrease of 

the response is dependent on temperature. At lower temperatures humidity has a larger effect 

on the response factor. The highest effect of humidity was observed for a 0°C-10°C 

temperature range for 0% to 25% RH. Changes in the area counts at 0°C-25°C for 25%-75% 

RH were almost negligible. It is understood that humidity affects the fiber response because 

water at high concentrations competitively adsorbs into the coating of the fiber. Some 

compounds are less affected by humidity than others. 

The 75 μm Carboxen/PDMS fiber showed no effect with RH at 100 ppbv of BTEX 

concentration. Experiments at 25°C and 12.5°C determined that RH does not affect the fiber 

uptake of BTEX compounds significantly. Figure 3 shows toluene response at 100 ppbv for 

different RH. All the other BTEX species behaved similarly. Data for BTEX showed a 

standard deviation between 5 to 13% for the range of humidity analyzed, 10% to 80% RH. 

Sensors are accurate as long as there is no condensation of water, which may happen above 

85% RH). These differences in the response of the fiber are within the precision of the 

method. Low RH effects on the fiber sensitivity may be due to the low concentration ranges 

used for calibration. At low BTEX concentrations, water is probably not an important 

competitive molecule. More research in this area is suggested. 

SPME Carboxen/PDMS coated (75 μm) fibers are used with portable or manual samplers. 

When manual samplers are used, the tip of the needle is closed with a septum or Teflon tape 

(Martos and Pawliszyn, 1997 and Chai and Pawliszyn, 1995). Prior to sampling, the precleaned fibers are kept at ambient temperature within an activated charcoal protector. This 

storage method has been tested in the laboratory and BTEX backgrounds are stable up to 48 

hours in storage following cleaning (the longest tested period). After sampling, fibers are 

kept in sealed Mylar bags inside a cooler with dry ice. Samples are analyzed 4-10 hours after 

sampling, on average, with a minimum of 1 hour and a maximum of 20 hours between 

sampling and analysis. 

7
0

5000

10000

15000

20000

25000

0 10 20 30 40 50 60 70 80 90

Relative Humidity (%)

Area Counts

Toluene 25C Toluene 12.5C Avg 25C Avg 12.5C

Figure 3. Humidity Effect in GC/PID response for a 100 ppbv BTEX standard at 25oC and 

12.5oC (with a standard deviation of 5% for the 12.5 °C and 8% for 25 °C from the respective 

mean) 

1.3 Continuous Methods 

The continuous Kore MS200 is used to monitor BTEX on a one-minute basis, sampling 

during the initial 10 second portion of each 60 second period. This instrument uses a time-offlight mass spectrometer to separate compounds of interest. Rather than using a gas 

chromatograph, this instrument uses a software solution and a library of 70 eV electron 

ionization fragmentation patterns to apportion the contribution of each parent species to the 

time-of-flight (TOF) mass spectrum recorded by the instrument. The software program does 

not distinguish between specific isomers so xylenes and ethylbenzene are reported together. 

The inlet uses a polydimethylsiloxane membrane preferentially to allow non-polar organic 

compounds into the analyzer while impeding polar species and air components to maintain 

the vacuum inside the analyzer chamber. The instrument performed well during the pilot 

studies and early field work, comparing favorably with the canister measurements for most 

samples, although it became increasingly unreliable in subsequent field studies. Given the 

corroborative role proposed for this device, we do not believe the information provided by 

this instrument, while desirable, is necessary to fulfill the goals of the screening study. 

Carbon monoxide is monitored continuously by the Langan T15 electrochemical 

monitor for CO and by a nondispersive infrared (NDIR) analyzer. The response time of 

Langan T15 instrument is slower than the response of the infrared-based instruments. Prior to 

each period of field measurement the instrument is calibrated using a zero-air generator and 

8
span gas to provide two reference points encompassing the expected range of concentrations 

anticipated during actual testing. The two-point calibration procedure is as follows: 

1. Allow instrument to stabilize for a minimum of 15 minutes. 

2. Record ambient concentration as determined by the instrument. 

3. Connect inlet lines from the instrument to a zero-air source (for a passive sampler 

use the flooder cap provided by manufacturer) and check for a flow rate of >1 

lpm with rotometer. 

4. Let instrument stabilize, record current baseline, then adjust zero. 

5. Connect inlet lines to a tank of span gas with an appropriate CO concentration for 

anticipated range and verify flow rate 

6. Let instrument stabilize, record current reading, and adjust span to correct value. 

7. Re-connect instrument to zero-air source, let stabilize and check baseline zero 

reading. 

8. Repeat steps 4-7 if necessary. 

9. Check a third concentration level with span gas if available. 

During field measurements the passive sampler is checked against the reference unit, which 

has automatic baseline stabilization and an internal zero-air source. Baseline readings will be 

recorded at the beginning and end of each sampling day. If significant deviations are 

observed a re-calibration will be performed. 

RAE Systems Model PGM-7240 (ppbRAE) portable PID monitors are used to continuously 

monitor ambient VOC levels in high end microenvironments. The monitor is sensitive to 

organic and inorganic gases that have an ionization potential of less than 10.6 eV, which 

includes most compounds of interest in this study. It does not respond to light hydrocarbons 

such as methane, ethane, propane, and acetyleneor to CO or formaldehyde. 

A Continuous Formaldehyde Monitor was purchased from Alpha-Omega Power Technology, 

Ltd. (Albuquerque, NM). The Alpha-Omega (AO) a wet instrument that utilizes the Hantzch 

reaction, absorbing formaldehyde in acidified water, reacting it with 2,4-pentanedione and 

ammonia to form a cyclized product, 3,5-diacetyl-1, and 4-dihydrolutidene, which is 

continuously detected by fluorescence. The method is sensitive and highly specific for 

formaldehyde. 

9
1.4 Breath Collection and Analysis 

Breath is collected from technicians who participate in a scripted exposure. Since this study 

requires the use of human subjects, the final protocol was reviewed by an Institutional 

Review Board that is certified with the National Institute of Health. 

Technicians were instructed to avoid exposure to materials that may compromise the 

exposure assessment prior to and during the scripted exposures. This includes avoiding 

alcohol ingestion (ethanol) and cigarette smoke for at least 3 days prior to the scripted 

exposures. Breath samples collected before the exposure were used to assess background 

levels in the technician. 

The test subject takes the three breath samples. One sample is taken before initiating ME 

sampling for background purposes; the second sample, ten seconds (timed with a stopwatch) 

immediately after completing an active refueling task or experiencing a measured peak 

exposure in another ME, and the third sample 1 minute immediately following the second 

sample. The 3rd backup sample is analyzed in case there is a problem with the second 

sample. The technician takes a 1-liter canister, places the tube in his mouth, and breathes 

smoothly and regularly through the mouth around the tube until a resting breath pattern is 

established. At the end of a normal exhalation, the technician closes the mouth, opens the 

canister valve, and continues to expel the expiratory reserve. The canister vacuum will 

collect 1 L of the expiratory reserve. When the flow stops, the technician closes the canister 

valve to capture the sample (Pleil and Lindstrom, 1995; 2002). Breath samples are collected 

in 1 L silico-steel steel canisters (Restek, Inc). . 

Gas Chromatography-Mass Spectrometry. The analysis of VOC in breath samples is 

conducted as described by Pleil and Lindstrom (1995, 2002). Prior to the commencement of 

sampling, the CO2 level in alveolar breath of all technician subjects is measured using 

GC/FID. Since the FID does not respond to CO2, this species is converted to methane by a 

methanator, positioned after the GC column, but ahead of the FID. Three breath samples are 

collected and analyzed, and the mean CO2 value is used for further comparison. After breath 

sample collection, the CO2 is measured using the same method. The target VOC (MTBE, 

1,3-butadiene, ethanol, BTEX) is measured using a GC/MS technique. The GC/MS system 

includes an Entech 7100 preconcentrator, a Varian 3800 gas chromatograph with FID and 

column switching valve, and a Varian Saturn 2000 ion trap mass spectrometer. 

10
References: 

Boy-Boland, A. (1998). SPME – Solvent-free sample preparation for GC and HPLC. 

Chemistry in Australia, 65: 10-12 

Chai, M. and J. Pawliszyn (1995) Analysis of Environmental Air Samples by Solid-Phase

Microextraction and Gas Chromatography/Ion Trap Mass Spectrometry, Environmental 

Science and Technology, Vol. 29, No. 3: 693-701. 

Fung, K., and D. Grosjean (1981). "Determination of Nanogram Amounts of Carbonyls as 

2,4-Dinitrophenylhydrazones by High Performance Liquid Chromatography." Anal. 

Chem., 53: 168-171. 

Goliff, W.S. and B. Zielinska (2001). Long-Term Stability of Oxygenated Compounds in 

Electropolished Canisters, Paper #403, presented at the 94 Annual A&WMA 

Conference and Exhibition, June 24-28, 2001, in Orlando, Florida. 

th

Koutrakis, P., J.M. Wolfson, A. Bunyaviroch, S.E. Froehlich, K. Hirano, J.D. Mulik (1993). 

Measurement of Ambient Ozone Using a Nitrite-Coated Filter. Anal Chem 65: 209-

214. 

Li, K., A. Santilli, M. Goldthorp, S. Whiticar, P. Lambert, M. Fingas (2001). Solvent vapour 

monitoring in work space by solid phase micro extraction. Journal of Hazardous 

Materials 83: 83-91 

Lodge, J. P. (1989). Methods of Air Sampling and Analysis. Third edition, Lewis publishers. 

Intersociety committee, Michigan, p. 15-16 

Martos, P. and J. Pawliszyn, (1997) Calibration of Solid Phase Microextraction for Air 

Analysis Based on Physical Chemical Properties of the Coating. Analytical 

Chemistry, 69: 206-215. 

Nelson, G. O. (1992). Gas Mixtures: Preparation and Control. Lewis Publishers, CRC Press, 

Chelsea, MI 

Pleil, J. and A. Lindstrom (1995). Measurement of volatile organic compounds in exhaled 

breath as collected in evacuated electropolished canisters. J. of Chromatography B: 

Biomedical Applications, 665: 271-279. 

Pleil, J. and A. Lindstrom (2002). A review of the US EPA’s single breath canister (SBC) 

method for exhaled volatile organic biomarkers. Biomarkers, 7: 189-208 

Rasmussen, R.A. (1992). “The ABCs of stainless steel canister clean-up and certification.” 

Presented at the 1992 U.S. EPA/A&WMA International Symposium on Measurement 

of Toxic and Related Air Pollutants, Durham, NC, May 1992. 

11
Shire, J.; Harshfield, G.; Zielinska, B.; Pasek, R. (1996). “A Comparison of Analytical 

Methods for Oxygenated Volatile Organic Compounds in Ambient Air,” In: 

Proceeding of the U.S. EPA/A&WMA International Symposium on Measurements of 

Toxic and Related Air Pollutants: Durham, NC, May 1996. p. 740-747. 

Tsai, P. and C.P. Weisel (2000). Penetration of Evaporative Emissions into a Home from an 

M85-Fueled Vehicle Parked in an Attached Garage, Journal of the Air & Waste 

Management Association, 50: 371-377. 

Tuduri, L.; Desauziers, V.; and Fanlo, J. L. (2001). Potential of Solid-Phase Microextraction 

fibers for the Analysis of VOC in air. Journal of Chromatographic Science, 39: 521-

529 

U.S. Environmental Protection Agency (1991). "Technical Assistance Document for 

Sampling and Analysis of Ozone Precursors." Document No. EPA/600-8-91/215, 

U.S. Environmental Protection Agency, Research Triangle Park, NC. 

US EPA Method TO-11A Determination of Formaldehyde in Ambient Air Using Adsorbent 

Cartridge Followed by High Performance Liquid Chromatography (HPLC) in 

Compendium of Methods for the Determination of Toxic Organic Compounds in 

Ambient Air – Second Edition, EPA/625/R-96/010b, January 1999. 

US EPA Method TO-15. Determination of Volatile Organic Compounds (VOCs) In Air 

Collected In Specially-Prepared Canisters And Analyzed By Gas 

Chromatography/Mass Spectrometry (GC/MS)-Second Edition, EPA/625/R-96/010b, 

January 1997. 

Vayghani, S. A. and Weisel, C. (1999). The MTBE air concentrations in the cabin of 

automobiles while fueling. Journal of Exposure Analysis and Environmental 

Epidemiology, 9, 261-267 

12
Appendix C 

Characterization of Solid-Phase Microextraction and Gas Chromatography for the 

Analysis of Gasoline Tracers in Different Microenvironments 

(Celballos, D., Zielinska, B., Fujita, E., Sagebiel, J. (2007) J. Air & Waste Manage. Assoc. 57: 355-365) 

Link to JAWMA article: http://216.92.182.36/gsearch/journal/2007/3/ceballos.pdf

 
APPENDIX D 

Section 211(B) Tier 2 High-End Exposure Screening Study Of 

Baseline and Oxygenated Gasoline – 1st Reno Pilot Study 

 
APPENDIX D 

First Reno Pilot Study 

Section 211(B) Tier 2 High-End Exposure Screening Study Of 

Baseline and Oxygenated Gasoline – Pilot Study 

Final Report 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

Barbara Zielinska, John Sagebiel, Eric Fujita and Dave Campbell 

Desert Research Institute 

2215 Raggio Pkwy. 

Reno, NV 89512 

Jake McDonald 

Lovelace Respiratory Research Institute 

Inhalation Toxicology Laboratory 

P.O. Box 5890 

Albuquerque, NM 87185 

Tomas J.Kelly and Darrell W. Joseph 

Battelle 

505 King Avenue, 

Columbus, Ohio 43201 

June 13, 2002 
ii
ACKNOWLEDGMENT 

This work was supported by the American Petroleum Institute (API) and was conducted 

in coordination with the U.S. Environmental Protection Agency. We gratefully acknowledge the 

technical support provided by Dr. Will Ollison of the API and Dr. Ted Johnson of TRJ 

Environmental during the pilot study. 

iii
TABLE OF CONTENTS 

Acknowledgment ............................................................................................................................ ii 

List of Tables ................................................................................................................................. iii 

List of Figures................................................................................................................................ iv 

1. INTRODUCTION ................................................................................................................... 1-1 

1.1 Measurement Methods......................................................................................... 1-1 

1.2 Description of Microenvironments and Sampling Procedures............................1-2 

2. RESULTS ................................................................................................................................ 2-1 

2.1 Continuous Instruments.......................................................................................2-1 

2.2 Integrated Samples............................................................................................... 2-2 

2.3 Solid Phase Microextraction (SPME).................................................................. 2-5 

2.4 Biological Samples .............................................................................................. 2-6 

2.4.1 Breath VOC Concentrations.................................................................... 2-6 

2.4.2 Urine VOC Concentrations...................................................................... 2-8 

2.5 Results of Additional Refueling Experiment (June 4, 2002, Reno) ..................2-10 

2.5.1 MS200 and Canister Results.................................................................. 2-11 

2.5.2 Breath Sample Results........................................................................... 2-11 

2.5.3 Analysis of Urinary VOC Concentrations............................................. 2-12 

3. RECOMMENDATIONS......................................................................................................... 3-1 

3.1 Exposure Measurements...................................................................................... 3-1 

3.2 Recommendations for Measurements of VOC in Breath ....................................3-2 

3.3 Recommendations for Measurement of VOC in Urine ....................................... 3-3 

4. REFERENCES ........................................................................................................................ 4-1 

iv
LIST OF TABLES 

Table 1.1 API S211 (b) Exposure Study-Reno Pilot Study ........................................................ 1-2 

Table 2.1 Canister and Tenax/Carbotrap Data............................................................................ 2-3 

Table 2.2 Comparison of MS200 with Canisters ........................................................................ 2-4 

Table 2.3 Comparison of Formaldehyde Data ............................................................................ 2-4 

Table 2.4 Concentrations (ppbv) of volatile organic compounds in breath and 

 microenvironments...................................................................................................... 2-7

Table 2.5 Urinary benzene concentrations in two subjects exposed to three 

 Microenvironments ................................................................................................... 2-10 

Table 2.6 Breath Data (ppbC) ................................................................................................... 2-13 

Table 2.7 Concentrations of Ethanol, MTBE & BTEX in urine samples (ng/L)...................... 2-16 

Table 3.1 Recommendation Summary........................................................................................ 3-1 

v
LIST OF FIGURES 

Figure 2-1 Concentration Time Series, Freeway AM ...........................................................F-1 

Figure 2-2 Concentration Time Series, Surface Streets.........................................................F-2 

Figure 2-3 Concentration Time Series, Freeway PM ............................................................F-3 

Figure 2-4 Concentration Time Series, Refueling In-Cabin..................................................F-4 

Figure 2-5 Concentration Time Series, Refueling out of cabin.............................................F-5 

Figure 2-6 Concentration Time Series, Walking Downtown ................................................F-6 

Figure 2-7 Concentration Time Series, Underground Garage...............................................F-7 

Figure 2-8 Concentration Time Series, Residential Garage Background A..........................F-8 

Figure 2-9 oncentration Time Series, Residential Garage Background B.............................F-9 

Figure 2-10 Concentration Time Series, Residential Garage Sample C ...............................F-10 

Figure 2-11 Concentration Time Series, Residential Garage Sample D ...............................F-11 

Figure 2-12 Concentration Time Series, Residential Garage Sample E................................F-12 

Figure 2-13 Concentration Time Series, Residential Garage Sample F................................F-13 

Figure 2-14 Concentration Time Series, Residential Garage Sample G ...............................F-14 

Figure 2-15 Concentration Time Series, Generator...............................................................F-15 

Figure 2-16 MS200 Raw and Corrected Data .......................................................................F-16 

Figure 2-17 MS200 Corrected Data Only .............................................................................F-17 

Figure 2-18 Correlation between CO by T15 and by Innova ................................................F-18 

Figure 2-19 Correlation between Innova and TEI for total hydrocarbons ............................F-19 

Figure 2-20 Innova vs. TEI for total hydrocarbons with three outliers removed..................F-20 

Figure 2-21 Correlation between CO and formaldehyde ......................................................F-21 

Figure 2-22 Correlation between DNPH and continuous formaldehyde...............................F-22 

Figure 2-23 Pre and post exposure breath samples during refueling.....................................F-23 

Figure 2-24 Pre and post exposure breath samples during in-cabin fueling..........................F-24 

Figure 2-25 Pre and post exposure breath samples during walk ...........................................F-25 

Figure 2-26 Relationship between full and alveolar breath...................................................F-26 

Figure 2-27 The three traces; benzene, toluene and sun of xylenes and 

 ethylbenzene ......................................................................................................F-27 

Figure 2-28 Data for BTEX and MTBE................................................................................F-28 

vi
1. INTRODUCTION 

 This report summarized the results of a pilot study that was conducted in Reno, NV, from 

February 25 through March 1, 2002 as part of a screening study of the high-end exposures to 

baseline and oxygenated gasoline. The study is being conducted for the American Petroleum 

Institute pursuant to Section 211(b) of the Clean Air Act. The objectives of the pilot study were 

to evaluate various monitoring methods under realistic field sampling conditions and to 

determine their suitability for use in the main exposure study to be conducted in Atlanta, 

Chicago, and Houston during the upcoming summer and winter seasons. We also evaluated 

biological sampling methods (breath and urine) for their applicability to the final study. In 

addition to DRI, personnel from Lovelace Respiratory Research Institute and Battelle 

participated in the pilot study. The refueling experiment was repeated on June 4, 2002 to 

evaluate the response of the portable mass spectrometer, which was not available for the 

refueling experiment during the pilot study. This report includes the results of the second 

refueling experiment. 

1.1 Measurement Methods 

 During the pilot phase of the study, we evaluated the sensitivity, precision, accuracy, 

selectivity, power requirements, and portability of sampling and monitoring devices to be used in 

the main study. The evaluations included methods for continuous measurement of carbon 

monoxide (CO), methyl tertiary butyl ether (MTBE), formaldehyde (HCHO), benzene, toluene, 

ethylbenzene, and xylenes (BTEX), with time integration of 1-5 minutes, and time-integrated 

measurements of ethanol (EtOH), 1,3-butadiene, and acetaldehyde (CH3CHO). The following 

continuous analyzers were used during the pilot study: 

Background CO, Monitor Labs. Research-grade non-dispersive infrared detection for carbon 

monoxide. This was maintained in the mobile lab and measured CO during our runs. Property of 

DRI. 

T15 CO, Langan products. Electrochemical monitor for CO. Quite small and portable, but it is 

temperature dependant. Property of DRI 

Photoacoustic Gas Monitor, Innova. A photoacoustic instrument that uses infrared light to 

detect CO and total hydrocarbons (calibrated as propane). In addition, this instrument could 

provide CO2 and water vapor (relative humidity). Property of Lovelace. 

Continuous Formaldehyde Monitor, Battelle. This instrument monitors formaldehyde in a 

continuous mode via a reaction to a fluorescent species and detection in a fluorimeter. Property 

of Battelle. 

Model TVA1000 FID, Thermo Environmental Instruments. This is a flame ionization based

instrument for total hydrocarbons on a continuous basis. Sold primarily for leak detection at 

petrochemical plants. Property of TEI, on loan to DRI for the pilot study only. 

MS200, Kore Technologies. An electron impact ionization time-of-flight mass spectrometer 

was used for the detection of VOC species. Rather than using a GC to separate species, this 

1-1
1-2

instrument uses software to quantify species by apportionment of their mass fragmentation 

patterns. Property of DRI. 

In addition to the continuous instruments, time-integrated samples were collected in 

stainless steel canisters and on 2,4-dinitrophenylhydrazine (DNPH)-impregnated silica gel 

cartridges and Tenax/Carbotrap solid adsorbent traps. These samples were collected over a onehour exposure period. The DNPH cartridges were sampled with a potassium iodide coated 

denuder to remove ozone. The canisters were analyzed by gas chromatography with flame 

ionization detection for BTEX, MTBE, 1,3-butadiene, and total nonmethane hydrocarbons. The 

extracts of the DNPH cartridges were analyzed by HPLC/UV for formaldehyde and 

acetaldehyde. The Tenax/Carbotrap samples were analyzed for EtOH. 

We also tested the solid phase microextraction (SPME) technique during the pilot study 

for the collection and analysis of BTEX, MTBE, ethanol, formaldehyde, and acetaldehyde. A 

100 μm (poly)dimethylsiloxane (PDMS) fibers and 75 μm Carboxen/(poly)dimethylsiloxane 

(CAR/PDMS) fibers were used for BTEX, MTBE, and ethanol and 65 μm 

PDMS/divinylbenzene (DVB) fiber that was impregnated with o-(2,3,4,5,6-pentafluorobenzyl) 

hydroxylamine hydrochloride (PFBHA) was used for carbonyl compound collection. The fibers 

were exposed in parallel for 15 to 30 min and were analyzed on a gas chromatograph with both 

FID and photoionization detector (PID). Some of the fibers were also analyzed by GC/MS. 

1.2 Description of Microenvironments and Sampling Procedures 

A summary of the samples collected is presented in Table 1-1. This table details the 

samples that were taken and a brief summary of the conditions at the time of sampling. In 

addition, the following notes detail the experiments. For the three driving exposures, we also 

collected GPS data showing location and time. Unless noted otherwise, each run last one hour. 

These are presented in the appendix. 

In-cabin Freeway (R02022607), Run #1

 For the first 15 minutes, the sampling van drove south on US 395 from Parr Boulevard to 

south Reno. This was a stretch of high rush hour traffic. The second 15 minutes, the van drove 

north from south Reno to Parr Boulevard. This was a stretch of low rush hour traffic. This loop 

was repeated for the third and fourth 15-minute periods. Data were not collected for the Innova 

photoacoustic instrument due to a failure of the pump. Only limited, hand logged, data were 

available for the TEI FID because of a failure of the internal memory of that instrument. A few 

data points are missing due to power problems at the beginning of the run. 

In-cabin Surface Streets (R02022612), Run #2

 For the first 15 minutes, the sampling van drove within the “urban canyon” loop, 

consisting of south on Sierra, east on 4th, north on Virginia, west on 5th. (This made a total of 4 

left turns around the Silver Legacy Hotel/Casino.). The second 15 minutes, the van drove a 

surface street loop, consisting of going east on 4th to Wells, north on Wells to Oddie, south on 

Sutro, and west on 4th. The third 15 minutes began at 4th, went north on Center, stopped at 

 
Table 1-1. API S211(b) Exposure Study - Reno Pilot Study 

Run 

# Test ID Date 

Start 

Time 

End 

Time

Microenvironment Exposure Level Location/Activity Ventila

R02022607 02/26/02 0710 0810 In-cabin - freeway 395 from Parr to south Reno 

R02022607a 02/26/02 0710 0725 higher -stop & go SB 395 from Parr to south Reno R02022607b 02/26/02 0725 0740 lower - free flow South Reno to DRI via 395 

R02022607c 02/26/02 0740 0755 higher -stop & go SB 395 from Parr to south Reno 

1 

R02022607d 02/26/02 0755 0810 lower - free flow South Reno to DRI via 395 

D&P-siinch, heoutside

betwee

R02022612 02/26/02 1200 1300 In-cabin -surface streets

R02022612a 02/26/02 1200 1215 higher - urban canyon S on Sierra, E on 4th, N on Virginia, W on 

5th (4 left turns around Silver Legacy) 

R02022612b 02/26/02 1215 1230 mixed - cross I-80 w/o 

stopping) 

From urban canyon loop, go E on 4th to Wells, N on Wells to Oddie, S on Sutro, W on 4th 

R02022612c 02/26/02 1230 1245 transect across I-80 with 

10-min stop at bridge 

From 4th, N on Center, stop at bridge over I80 for 10 minutes, then go back to urban 

canyon loop 

2 

R02022612d 02/26/02 1245 1300 higher - urban canyon S on Sierra, E on 4th, N on Virginia, W on 

5th (4 left t

urns around Silver Legacy) 

D&P-siinch, heoutside

betwee

R02022616 02/26/02 1600 1700 In-cabin - freeway 395 from Parr to south Reno 

R02022616a 02/26/02 1600 1615 lower - free flow SB 395 from Parr to south Reno 

R02022616b 02/26/02 1615 1630 higher -stop & go South Reno to DRI via 395 

R02022616c 02/26/02 1630 1645 lower - free flow SB 395 from Parr to south Reno 

3 

R02022616d 02/26/02 1645 1700 higher -stop & go South Reno to DRI via 395 

D&P-siinch, he

outside

betwee

R02022708 02/27/02 0810 0910 Refueling/in-cabin 

R02022708a 02/27/02 0810 0825 baseline Frontage Road just south of Gold Ranch window 

R02022708b 02/27/02 0825 0840 refueling/in cabin Gold Ranch Pump #10 window 

door on

R02022708c 02/27/02 0840 0855 refueling/in cabin Gold Ranch Pump #10 window 

once 

4 

R02022708d 02/27/02 0855 0910 refueling/in cabin Gold Ranch Pump #10 window 

1-3
Run 

# Test ID Date 

Start 

Time 

End 

Time

Microenvironment Exposure Level Location/Activity Ventila

R02022712 02/27/02 1200 1300 Refueling/outside 

R02022712a 02/27/02 1200 1215 baseline Trailer park south of Gold Ranch window 

R02022712b 02/27/02 1215 1230 refueling/outside Van at Gold Ranch Pump #10, filled Suburu 

with midgrade gas on Pump #9 

samplin

R02022712c 02/27/02 1230 1245 refueling/outside Van at Gold Ranch Pump #10, filled Corolla 

with regular on Pump #9, collected gasoline 

sample 

samplin

5 

R02022712d 02/27/02 1245 1300 refueling/outside Van at Gold Ranch Pump #10, filled Volvo 

with premium gas on Pump #9, collected 

gasoline sample 

samplin

R02022811 02/28/02 1100 1200 Pedestrian walk 1 square block around Silver Legacy 

R02022811a 02/28/02 1100 1115 Virginia St between 4th and 5th (southbound)

R02022811b 02/28/02 1115 1130 4th between Virginia and Sierra (westbound)

R02022811c 02/28/02 1130 1145 Sierra between 4th and 5th (northbound) 

6 

R02022811d 02/28/02 1145 1200 5th between Sierra and Virginia (eastbound) R02022815 02/28/02 

1500 1600 Garage underground 

R02022815a 02/28/02 1500 1515R02022815b 02/28/02 1515 1530

R02022815c 02/28/02 1530 1545

7 

R02022815d 02/28/02 1545 1600

Survey surrounding area, enter garage and survey upper level. Paused for 15 min to 

allow traffic to build up, then sampled for 1 hour. 

D&P-siwith hevent opgaraged

inside gopen w

R02030109 03/01/02 0935 1340 Garage residential 

R02030109a 03/01/02 0935 1005 Background 1 R02030109b 03/01/02 1005 1035 Background 2 R02030109c 03/01/02 

1110 1140

Pull car in gar. open kitchen door 1 min and close 

R02030109d 03/01/02 1140 1210 Kitchen door open. R02030109e 03/01/02 1210 1240 Kitchen door closed, windows open 

8 

R02030109f 03/01/02 1240 1310 Open garage door and let icar dle for 30 min. 

open door to kitchen for 1 minute and keep 

close for remainder of period. 

Use houof room 

garage continumin cycand kitcthrough 

1-4
1-5

R02030109g 03/01/02 1310 1340 Post Exposure, back car out and close garage 

door 

Run 

# Test ID Date 

Start 

Time 

End 

Time

Microenvironment Exposure Level Location/Activity Ventila

R02030116 03/01/02 1600 1630 Generator Exhaust R02030116a 03/01/02 1600 1605 Exhaust downwind (CO ~ 2-3 ppm) 

R02030116b 03/01/02 1605 1610 Exhaust upwind (CO peak of 150 ppm) 

R02030116c 03/01/02 1610 1615 Exhaust downwind (CO <10 ppm) 

R02030116d 03/01/02 1615 1620 Exhaust upwind (CO 10-50 ppm) 

R02030116e 03/01/02 1620 1625 Exhaust upwind (CO 20-150 ppm) 

9 

R02030116f 03/01/02 1625 1630 Exhaust downwind (CO <5 ppm) 

10 R02060410 06/04/02 1010 1101 Refueling/outside 

R02060410a 1010 1025 Parking west of Gold Ranch- background Samplin

R02060410b 1031 1046 At Gold Ranch Pump#10, refueling Volvo (4 

min) with premium gas on Pump #10 Samplin

R02060410c 1047 1101 At Gold Ranch Pump#10, refueling Corolla 

(2 min) with regular on Pump#9 Samplin
bridge over I-80 for 10 minutes, then went back to the urban canyon loop. The van door was 

open during the stop at the freeway overpass. For the fourth 15 minutes, the sampling van drove 

the “urban canyon” loop again, completing another 4 turns around the Silver Legacy 

Hotel/Casino. Data were collected from all instruments , but the MS200 instrument shut down 

during the run due to vacuum becoming too low. 

In-cabin Freeway (R02022616), Run #3

 For the first 15 minutes, the sampling van drove south on US 395 from Parr Boulevard to 

south Reno. This was a stretch of low rush hour traffic. The second 15 minutes, the van drove 

north from south Reno to Parr Boulevard. This was a stretch of high rush hour traffic. This loop 

was repeated for the third and fourth 15-minute periods. Data were collected from all 

instruments, but a few data points are missing due to power problems at the beginning of the run. 

In-cabin Refueling (R02022708), Run #4

 For both refueling experiments a rural but high volume service station was used. The 

station is located near a major interstate (I-80), but is otherwise in a rural area. The station has 18 

fueling pumps and sells between 20,000 and 40,000 gallons of gasoline per day. The mangers 

indicated they are the largest gasoline seller in northern Nevada. 

For the first 15 minutes, the sampling van parked on the frontage road, near the I-80 

freeway, away from the filling station to collect a background sample. The goal was to be 

approximately the same distance from the freeway as we would be at the fueling station. For the 

next 50 minutes, samples were collected while the van was parked at pump number 10, the 

center pump of the center island. Most equipment worked well, except that the MS200 had 

vacuum problems and had to be shut down. 

Refueling at Pump (R02022712), Run #5

 Similarly as with the first experiment, during the first 15 minutes, the sampling van 

parked on the frontage road, near the I-80 freeway, away from the filling station to collect a 

background sample. For the next 45 minutes, samples were collected in the breathing zone while 

the van was parked at pump 10, center of the center island. Breathing zone was at pump 9 

(opposite side of a dual-side pump), while three cars were filled with fuel. First was a Subaru 

that was filled with regular. Next came a Toyota that was filled with mid-grade, and finally was a 

Volvo filled with super. No formaldehyde data were collected due to power failure. In addition, 

the MS200 was not run due to vacuum problems. 

Refueling at Pump, Repeated (R02060410), Run #10

During the first 15 min the vehicle with sampling equipment was park on the quiet 

parking area, west of Gold Ranch and away from the filling station to collect a background 

sample. Only MS and SPME samples were collected. For the next 30 minutes, samples were 

collected in the breathing zone while the vehicle with sampling equipment was parked at pump 

10, center of the center island. Breathing zone was either at pump 10 or at pump 9 (opposite side 

of a dual-side pump), while two cars were filled with fuel. First was a Volvo filled with super, 

1-6
and next came a Toyota Corolla that was filled with regular grade. During 30 min one canister 

sample and two 15 min SPME samples were collected. MS200 was operating in a continuous 

mode. 

Pedestrian Walk (R02022811), Run #6

 All the monitoring equipment was placed on two mobile carts with batteries and 

inverters. For one hour, monitoring was conducted while the carts were slowly pushed around a 

large one square block area of central downtown Reno (the Silver Legacy Casino). The block 

was split roughly into equal times with approximately 15 minutes spent on each leg of the block. 

We started at 4th and Virginia, went south on Virginia, then west on 5th to Sierra, then north to 4th

and back to the starting point. 

 Data was collected from all instruments, except that for the first 15 minutes, no 

formaldehyde data was collected possibly due to a light leak in the fluorescence detector. In 

addition, the TEI FID did not collect data, although it appeared to be on the entire time. The 

reason for this failure was never determined. 

Underground Public Parking Garage (R02022815), Run#7

 The van was parked in an underground parking garage for one and a half hours during the 

period of maximum car departure. This garage has two underground levels, however the van 

remained on the upper of these two levels for two reasons. The first is that this level was nearly 

full while the lower level had only a few vehicles. The second reason is that the traffic ramps in 

the garage would allow travel from the first underground level down to the second, but from the 

second level the van could only go up to the surface, not back to the first underground level. The 

van’s position was relocated several times to try and capture the cold start exhaust from 

departing vehicles. Data were collected for the first 15 minutes, followed by a 15 minute zeroing, 

and then data collection for the next hour. 

Residential Kitchen and Garage without Car (R02030109a,b), Run #8

 For both residential exposures a home was used that had an attached two-car garage. The 

home and the garage share a common wall and there is a door from the garage into the kitchen. 

For the duration of these experiments a vented 2.5 gallon gasoline storage container was also 

present in the garage during the sampling period, located in the front center portion of the garage, 

closest to the house. The can was approximately half-full and the vent on the gas can was open. 

The sampling equipment was set up in a residential kitchen next to the door of the attached 

garage. For the first hour, the sampling was done with the garage door closed and no car. 

Samples were taken alternately for 10 minutes in the kitchen followed by 10 minutes in the 

garage for one hour. 

Residential Kitchen and Garage with Car (R02030109c-g), Run #8

 For these experiments the car used was a 1984 Honda Accord with a four-cylinder engine 

and it is carbureted. The vehicle is normally fueled with regular gasoline and annually passes the

state smog check with no problems. Prior to parking the car in the garage, it was driven 

approximately 5 miles to warm the engine up. Once parked in the garage, the air cleaner cover 

1-7
was removed, exposing the inlet of the carburetor and the oil filler cap on the valve cover was 

removed to allow additional evaporative emissions. 

The sampling equipment had the same setup as the background samples. Separate 

integrated samples were collected in the garage and in the kitchen. The continuous instruments 

were switched between the garage and the kitchen at 10-minute intervals for 2.5 hours. The 

sequence of activities was as followed: 

 

Time Activity 

1110 1140 Pull car in gar. open kitchen door 1 min and close 

1140 1210 Kitchen door open. 

1210 1240 Kitchen door closed, windows open 

1240 1310 Open garage door and let car idle for 30 min. Open door to kitchen for 1 

minute and keep closed for remainder of period. 

1310 1340 Post Exposure, back car out and close garage door 

Sample probe was on the following sequence: 

garage 11:10-11:20 

kitchen 11:20-11:30 

garage 11:30-11:40 

kitchen 11:40-11:50 

garage 11:50-12:00 

kitchen 12:00-12:10 

kitchen 12:10-12:20 

garage 12:20-12:30 

kitchen 12:30-12:40 

garage 12:40-12:50 

kitchen 12:50-13:00 

garage 13:00-13:10 

garage 13:10-13:20 

kitchen 13:20-13:30 

garage 13:30-13:40 

Generator Exhaust (R02030115), Run #9

 In the DRI staging lot, the exhaust hose of a gasoline powered electrical generator was 

operated near the inlet of the sampling equipment. The generator exhaust hose was moved to a 

different location every 5 minutes. Adjusting its position relative to the instrument inlets; first 

downwind, then upwind, downwind, upwind, upwind closer to exhaust, and finally downwind. 

1-8
2. RESULTS 

 The results from this study are presented in four parts: 1) continuous (or semicontinuous) instruments; 2) integrated samples; 3) SPME samples; and 4) biological samples. 

Where appropriate, comparisons are made between the continuous and the integrated samples. 

Results from the additional refueling experiment performed in June 2002 in Reno are 

summarized in Section 2.5. 

2.1 Continuous Instruments 

Figures 2-1 through 2-15 present the time series for the continuous analyzers. For the 

residential garage exposures (2-8 through 2-15) the plots are only 30 minutes, not 60 minutes as 

for the rest of the plots. This is because of the number of changes that took place during these 

exposures. Also, during the residential garage exposures, the sample probe was moved to 

measure the kitchen area and the garage area as per the schedule listed above in the description 

of the runs. This accounts for the sudden changes in concentration seen in the data. 

The MS200 data is not presented in these time series. When we examined the raw MS 

data, without background correction, we found very high concentration levels being reported. 

The MS200 data appear high during all runs, especially compared to the integrated canister data, 

however, the structure of the data suggests that the MS200 is accurately responding to changes in 

ambient concentrations. Additional work was conducted with this instrument to help explain this 

effect. As a result of this work and discussions with the manufacturer (Kore), we have been able 

to better understand these data. The data that the MS200 reports is very dependent on the blank 

level. In addition, the membrane-based inlet and the relatively slow pumping mechanism appear 

to have the effect of slowing the 2-3 minute recovery time of the instrument, especially when the 

instrument is challenged with a high concentration. To test this we alternatively applied a high 

concentration standard and a zero air to the inlet of the MS200. On the basis of these 

experiments, we applied a correction that consisted of subtracting a background value consisting 

of a linearly sloping zero to the data, based on our experiments with the standards. This was 

difficult in the case of the residential garage where the instrument was switched every 10 

minutes between the relatively high concentrations in the garage with the much lower levels seen 

in the kitchen. However, once these backgrounds were subtracted, the MS200 data generally 

showed agreement (within a factor of 2 at ppb levels) with the canister data, which will be 

discussed later. We are still working with Kore to develop a pre-concentrator inlet that will allow 

for a much lower detection limit, however, this will sacrifice time resolution. 

An example of the correction applied is in chart 2-16 which shows the original benzene 

concentration, the zero function applied and the resulting corrected benzene concentration. The 

next figure, 2-17 shows the corrected data from this run for benzene, toluene, and the xylenes. In 

this chart, it is clear that the corrected plots track each other in structure, as we expected. The 

other data sets were similarly corrected and are summarized in Table 2-1 with the canister data. 

The comparison with the canister is quite favorable, except in the case of benzene at very low 

concentrations and in some runs where limited data was available. This was generally due to 

problems with the vacuum system in the MS200. 

2-1
2-2

 To compare the responses of the various instruments, we produced scatter plots, Figures 

2-18 through 2-21. Figure 2-18 shows the comparison between the Innova CO and the T15 CO. 

There is reasonable agreement, but especially at lower concentrations, we find that the Innova

occasionally is much higher than the T15. This may be due to the method the Innova uses, which 

is to take a grab sample into its internal chamber, measure the components of interest and then 

evacuate the chamber. If this grab sample is during a particularly high brief instant, this may 

result in the higher response seen. 

 Figure 2-19 compares the two continuous hydrocarbon (HC) measuring devices, the

Innova and the TEI. There are two very high values from the Innova, which Figure 2-20 

removes. The Innova data are adjusted upward by 10 to account for the expected difference in 

response from the photoacoustic vs. the FID. These two instruments use fundamentally different 

methods to measure hydrocarbons and may be hard to compare. In general, the two are tightly 

correlated, despite the different response factors. 

 The correlation between the Battelle continuous formaldehyde monitor and the T15 CO is 

presented in Figure 2-21, without the data from the generator which was significantly higher and 

dominated the plot. This shows a weak correlation, but includes some very high values. At more 

ambient concentrations, they are slightly better correlated. We should expect that these two 

would be correlated as they both are combustion-derived. 

2.2 Integrated Samples 

 Integrated samples consist of canisters, DNPH cartridges (for aldehydes) and 

Tenax/Carbotrap solid adsorbent traps. Canister data and Tenax/Carbotrap data for ethanol are 

presented in Table 2-1. In addition to the values measured, we show the sum of the BTEX 

compounds. Of interest was to compare these values to the MS200; this comparison is presented 

in Table 2-2. In this table, the average values (canister) from the various exposures are presented 

along with the corrected MS200 values for these same exposures. The corrected data are 

calculated as described above (Section 2.1). Generally the averages agree better at higher 

concentrations, but lower concentrations are quite reasonable, considering we are working at or 

near the detection limit of the MS200. In the case of the residential garage exposures this was 

further complicated by the 10-minute cycle time between the garage (at high concentrations) and 

the kitchen (at much lower concentrations). In spite of all this, the correlations between the 

canister and the MS200 were on the order of r2 ~ 0.87 and the slopes were ~0.75, with the 

MS200 reporting less than the canisters. 

 The DNPH samples were compared with the averaged data from the Battelle continuous 

formaldehyde sampler. This comparison is presented in Table 2-3 and Figure 2-22. The 

agreement is excellent for the 10 samples that are comparable. The correlation suggests that the 

Battelle unit is reading about 15% less than the DNPH cartridges are reporting. 
Table 2-1: Canister and Tenax/Carbotrap Data (concentrations in ppbv) 

Test ID Date Location 

1,3-

butadiene

Ethanol 

(T/C) MTBE benzene toluene

ethyl 

benzene

m/p

xylen

R02022607 2/26/02 

Morning Freeway Commute 1.02 0.79 0.07 4.32 10.77 0.95 3.65 

R02022612 2/26/02 

Urban canyon, surface 0.55 0.13 0.04 1.79 6.08 0.63 2.35 

R02022616 2/26/02 

Afternoon Freeway Commute 0.68 Missing 0.04 2.24 5.82 0.53 1.94 

R02022708 2/27/02 In van, gas station 0.16 nd 0.12 1.14 6.72 0.63 2.63 

R02022712 2/27/02 

Gas station, refueling 1.58 nd 2.06 10.37 53.38 2.93 12.0

R02022811 2/28/02 pedestrian walk 0.16 0.47 0.01 0.69 2.29 0.22 0.85 

R02030109a 3/1/02 

Res. Garage, background 0.03 Missing 0.03 0.29 1.67 0.31 1.15 

R02030109b 3/1/02 Kitchen, background 0.03 Missing 0.01 0.31 1.25 0.13 0.49 

R02030109c 3/1/02 Residential garage 0.22 0.98 0.95 9.53 164.44 11.18 48.1

R02030109d 3/1/02 Kitchen 0.10 nd 0.36 3.66 55.34 3.60 15.5

R020301016 3/1/02 

Mobile gas generator 17.38 nd 0.58 41.03 123.23 9.95 34.2

2-3

Nd = not detected Missing – missing sample 
2-4

Table 2-

Date

Table 2-3. Comparison of Formaldehyde Data

Date Time Test ID DNPH-HCHO Battelle-HCHO

2/26/02 0710 R02022607 6.66 7.92/26/02 1200 R02022612 9.66 7.92/26/02 1600 R02022616 6.84 6.22/27/02 0810 R02022708 4.13 5.52/27/02 1200 R02022712 4.622/28/02 1100 R02022811 2.30 1.12/28/02 1503 R0202815 4.96 3.5

3/1/02 0935 R02030109a 3.56 4.63/1/02 0935 R02030109b 2.393/1/02 1110 R02030109c 6.27 5.43/1/02 1110 R02030109d 4.15 5.23/1/02 1600 R020301016 23.29 20.7

2. Comparison of MS200 with Canisters

Canisters Summary 

Location benzene toluene ethyl benzem/p-xylene o-xylene Sum Xylenes Benzene 

Morning Freeway Commute 4.32 10.77 0.95 3.65 1.28 4.93 4.38 Urban canyon, surface 1.79 6.08 0.63 2.35 0.86 3.20 9.20 

2/26/022/26/02 2/26/022/27/02 

Afternoon Freeway Commute 2.24 5.82 0.53 1.94 0.70 2.65 12.53 

In van, gas station 1.14 6.72 0.63 2.63 0.99 3.62 9.17 

2/27/02 

2/28/02

3/1/023/1/023/1/023/1/023/1/02

Gas station, refueling 10.37 53.38 2.93 12.00 3.96 15.96 

pedestrian walk 0.69 2.29 0.22 0.85 0.31 1.16 3.11 

Res. Garage, background 0.29 1.67 0.31 1.15 0.50 1.65 2.57 

Kitchen, background 0.31 1.25 0.13 0.49 0.20 0.69 8.69 

Residential garage 9.53 164.44 11.18 48.17 17.39 65.56 9.30 

Kitchen 3.66 55.34 3.60 15.54 5.68 21.22 13.95 

Mobile gas generator 41.03 123.23 9.95 34.21 12.16 46.37 38.33 
2.3 Solid Phase Microextraction (SPME) 

 We tested the SPME technique during the pilot study for the collection and analysis of 

BTEX, MTBE, ethanol, formaldehyde, and acetaldehyde. A 100 μm (poly)dimethylsiloxane 

(PDMS) fibers and 75 μm Carboxen/(poly)dimethylsiloxane (CAR/PDMS) fibers were used for 

BTEX, MTBE, and ethanol and 65 μm PDMS/divinylbenzene (DVB) fiber that was 

impregnated with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was 

used for carbonyl compound collection. The fibers were exposed in parallel for 15 min, with 

exception of the residential garage microenvironment where the fibers were exposed for 30 min. 

The fibers were analyzed by injection into a GC housed in the mobile laboratory. Some of the 

fibers were also analyzed by GC/MS. The analysis was performed immediately after collection, 

when possible. However, some of the fibers had to be stored on dry ice in the cooler for a period 

of several hours. 

The initial SPME results from the pilot study are more qualitative than quantitative. The 

technique is new method for us and requires additional calibration work in the laboratory. Our 

major findings from the pilot study include: 

• 75 μm CAR/PDMS fibers are more sensitive than 100 μm PDMS fibers and are thus 

more suitable for ambient measurements. We will be using 75 μm PDMS fibers in the 

main study for the measurements of MTBE and BTEX. 

• Although ethanol peak was observed in all chromatograms, the ethanol concentrations 

were clearly too high. This is most probably due to the adsorption of ethanol from breath 

into the fibers. We measured up to 200 ppbv of ethanol concentration in the breath 

samples collected during this pilot study. The fibers were situated in the breathing zone 

during each experiment. 

• Formaldehyde and acetaldehyde concentrations are too high as well when compared with 

continuous formaldehyde analyzer data and integrated DNPH cartridge data. This may 

also be due to the presence of acetaldehyde in breath (we measured up to 25 ppbv of 

acetaldehyde in the breath samples). In addition, formaldehyde may be present in the 

mobile lab where the PFBHA impregnation of the PDMS/DVB fibers took place. We are 

getting the continuous formaldehyde analyzed from Battelle, thus we do not see any need 

to monitor formaldehyde with SPME technique and we propose to drop this analysis. 

Acetaldehyde data are less important for this study and we will obtain this data from 

integrated DNPH cartridge method. 

In summary we are still working on the development of the standard procedures for the 

SPME technique. The calibration, storage, and optimal sampling time are being addressed. We 

will be ready for the main study starting in June and we propose to use the SPME method for 

measurements of BTEX and MTBE. 

2-5
2-6

2.4 Biological Samples 

2.4.1 Breath VOC Concentrations 

Breath concentrations are portrayed in Table 2-4 and Figures 2-23 through 2-25 for two 

separate subjects during three separate scripted exposures. For the pilot project the subjects were 

two of the technicians collecting samples for micro-environmental concentrations. The 

objectives of this pilot program for the breath monitoring were to 1) evaluate the ability to 

analyze breath concentrations of VOC’s according to methods developed by Pleil and Lindstrom 

(1995), 2) to see differences between full and alveolar breath collections, 3) to assess breath 

concentrations between two subjects prior to and after scripted environmental exposures, and 4) 

to develop a recommendation for the final sampling protocol and biological monitoring 

technique of choice. All of the samples shown and discussed are “alveolar” samples unless 

designated as “full-breath” samples. Alveolar samples were collected to represent material that 

has undergone gas exchange in the lung. These samples were collected by breathing the end part 

of a breath directly into an evaculated cylinder (1 or 3L). The results of the breath measurements 

are described below. 

Refueling

Subject 7: The out of cabin re-fueling experiment showed the highest average exposure 

concentrations for all of the samples where biological samples were collected, by at least a factor 

of 5 for most analytes. As expected from results published by Philips and Greenberg (1992), all 

of the analytes (except MTBE) show a negative alveolar gradient (concentration in breath lower 

than ambient air) relative to the average exposure concentrations of 60 minutes. Unfortunately 

there is no real time data for these compounds, and the elimination rate via breath is rapid 

enough that real-time levels towards the end of exposure would be most important for these 

compounds. For subject 7 there is an observed exposure effect, with post exposure alveolar 

concentrations higher than pre-exposure concentrations by at least a factor of 2. With the 

exclusion of MTBE and ethyl benzene, this exposure effect was not observed for most 

compounds in subject 3. Exposure for the outside refueling was terminated at 1300 hours. The 

mobile lab was located approximately 1-2 minutes walking distance away from the exposure 

area and the exposure subjects were also responsible for much of the sampling responsibilities. 

Expired breath was not collected from subject 7 until 1302, and not from subject 3 until 1304. 

These short differences in times between samples may explain the lack of an exposure effect 

observed in subject 3. This can be confirmed by the breath elimination half-lives published to be 

between 1 and 3 minutes for MTBE, benzene, and toluene (Lindstrom and Pleil, 1996). 

In-Cabin Refueling

Subject 7 was the only subject sampled for both pre and post samples of the in-cabin 

refueling exposure. With the exception of MTBE, there is no exposure effect. This is most 

likely due to the fact that the post-exposure breath sample was not collected until 0919, 9 

minutes after exposure. This may be enough time to eliminate back down to background levels. 
2-7

Table 2-

micro

Fu

Alv

microenmicro

Fu

Alv

4. Concentrations (ppbv) of volatile organic compounds in breath and micro-environments.

Sample Collection Time Location Subject MTBE benzene toluene ethylbenzen

Breath 800 In Cabin fueling PRE 7 0.32 0.92 2.05 0.33 

Breath 919 In Cabin fueling POST 7 0.79 0.82 1.92 0.33 

environment van, Verdi gas station microenviront conc. 0.12 1.14 6.72 0.63 

Breath 1149 Refueling PRE 7 0.35 0.75 1.74 0.33 

Breath 1302 Refueling POST 7 3.99 1.83 5.73 1.06 Breath 1415 Midday Background 7 0.08 0.58 1.41 0.00 

Breath 1150 Refueling PRE 3 0.22 1.34 2.62 0.00 

ll Breath 1304 Refueling POST 3 1.54 1.52 3.16 0.67 

eolar Breath 1305 Refueling POST 3 1.84 1.24 2.53 0.48 

vironment Verdi gas station, refuel microenviront conc. 2.06 10.37 53.38 2.93 

Breath 1415 Midday Background 3 0.47 1.10 2.26 0.55 

Breath 1422 Midday Background 7 0.80 0.76 1.83 0.00 

environment pedestrian walk microenviront conc. 0.01 0.69 2.29 0.22 

Breath 924 Morning Background 3 0.28 1.18 2.42 0.63 

Breath 1043 Walk PRE 3 0.69 1.56 0.00 0.65 Breath 1201 Walk POST 3 0.31 1.44 3.00 0.73 

Breath 1047 Walk PRE 7 0.79 0.99 2.34 0.41 

Breath 1200 Walk POST 7 0.32 0.84 2.18 1.16 

ll Breath 1623 Direct Exhaust Exposure 3 0.12 1.36 2.73 0.41 

eolar Breath 1623 Direct Exhaust Exposure 3 0.09 1.38 3.79 0.59 
Pedestrian Walk

Again for the pedestrian walk there is very little exposure effect observed from subject 3 

while subject 7 shows at least a factor of 2 increase in alveolar concentrations after exposure for 

ethyl benzene, m/p xylene, and o-xylene. Similar to the refueling samples, subject 3 was did not 

give their sample at the same time as subject 7. There was a one-minute difference between 

subject 3 (1201) and subject 7 (1200). There was a negative exposure effect for MTBE in both 

subjects, suggesting that pre-exposure background or residual subject concentrations are higher 

than the exposure. The un-observable exposure effect for benzene and toluene are not 

explainable, as the exposure to these compounds was actually higher than the compounds where 

an exposure effect was observed. 

Full versus Alveolar Breath

Figure 2-26 shows the relationship between full and alveolar breath. Full and alveolar 

breath are defined here by how the sample was collected. Full is the entire breath blown into the 

canister sample, while the “alveolar” breath consists of partially reserved tidal volume and some 

expiratory reserve. The alveolar sample is collected at the end of a regular breath. As observed 

the agreement between the two breath collection methods are reasonable, but vary slightly by 

analyte. Agreement is between 15-25% for MTBE, benzene and toluene; and about 40% for 

ethyl benzene and the xylenes. In general, the difference is higher for compounds where the 

concentrations are less, indicating some contribution from measurement uncertainty may affect 

observed differences. Since the observed concentrations are higher in the full breath samples 

(with the exception of MTBE), it is obvious that there are levels of these compounds in the 

“dead-space” region of the subject that has not undergone any gas exchange. CO2 measurement 

between the two samples shows a difference of 10%, which is 5% less than the difference 

observed by Pleil and Lindstrom (1995). 15% is the expected amount, based on a 15% dilution 

of a 1 liter tidal volume. The full and alveolar breath sample in this pilot study was taken from a 

3 liter evacuated canister, which is different than the 1 L canister used by the second subject and 

in the Pleil and Lindstrom paper. Additional experiments should be completed comparing 

full/alveolar breath CO2 dilution between the 1 and 3 liter canisters. 

2.4.2 Urine VOC Concentrations 

Urinary concentrations of MTBE, benzene, toluene, ethylbenzene, and the xylenes were 

measured for backgrounds and pre/post exposure levels in two subjects from three scripted 

exposures. Shown in Table 2-5 are the urinary concentrations of benzene, which was the only 

urinary constituent consistently above the analytical limit of quantitation of 100 ng/L. The 

objectives of this pilot study was to apply the technique of 1) Fustinoni (1999) to measure 

urinary volatile organic compounds, 2) to measure concentrations (and variability) in two 

separate subjects, and 3) to evaluate results in terms of their ability to relate to exposure 

concentrations. In the original proposal one objective was also to measure urinary creatinine 

levels. This was not conducted for this report because this is not conducted in the contemporary 

literature to report urinary concentrations of VOC’s. “Older” literature used to measure 

creatinine in order to normalize urinary components for dilution. The current belief is that this is 

not necessary. The benzene results are discussed below for each scripted exposure. 

2-8
In-cabin Refueling

Subject 3 had a high pre-exposure background (208 ng/L) prior to the in-cabin refuel. There was 

a negative exposure effect after the in-cabin exposure (<100 ng/L), and a higher concentration 

one hour after exposure (138 ng/L) than immediately after exposure. This sample was similar to 

the next pre-exposure concentration taken one hour later (120 ng/L). Subject 7 had both pre and 

post exposure levels for the in-cabin re-fuel that were below the detection limit of 100 ng/L (3 x 

baseline). 

Table 2-5. Urinary benzene concentrations in two subjects exposed 

to three micro-environents

Benzene

Time Date subject activity ng/L

520 227 3 background 118.3

520 227 3 background 141.8

755 227 3 preexpos in cabin refuel 208.1

920 227 3 postexpos in cabin refuel 90.4a

1010 227 3 mid background 139.8

1148 227 3 preexpos refuel 118.6

1308 227 3 post expos refuel 3.1a

1417 227 3 post expos refuel 166.3

1524 227 3 post expos refuel 465.8

1645 227 3 post expos refuel 1100.6

950 228 3 pre walk 276.7

1225 228 3 post walk 335.5

445 227 7 background 163.9

752 227 7 preexposin cabin refuel 26.4a

924 227 7 postexpos in cabin refuel 0.0a

1150 227 7 preexpos refuel 15.4a

1312 227 7 post expos refuel 11.4a

1424 227 7 post expos refuel 18.1a

1620 227 7 post expos refuel 101.8

545 228 7 background 0a

1229 228 7 prewalk 106.5

1415 228 7 post walk 131.0

a: below the limit of quantitation of 100ng/L

2-9
Refueling

Subject 3 showed a negative exposure effect immediately after exposure, but saw a 

steady increase in urinary benzene excretion throughout the day. Measurements were made 

approximately every hour until 1645, and the hourly concentrations were 166, 465, and 1100 

ng/L at 1417, 1524, and 1645, respectively. This indicates that for these samples the time course 

for urinary excretion is much slower than it is for breath, and there is a lag in the excretion. The 

exposure concentrations observed for subject 7 were all below 100 ng/L, with the exception of 

the post exposure sample collected at 1620, where the concentration was about 100 ng/L. These 

results are comparable to MTBE data reported by Lee and Weisel (1998) who showed an 

increase in urinary MTBE after exposure (1 ppm for 10 min) at about 1 hour, remaining about 

the same at 3.5 hours and dropping several-fold by 6 hours. 

Pedestrian Walk

There was a slight positive exposure effect for benzene in both subjects from the in-town 

walk. Subject 3 had a pre-exposure urinary benzene concentrations of 276 ng/L and postexposure concentrations of 335 ng/L, while subject 7 had levels of 106 and 135 ng/L. For both 

subjects the starting background was different, and their increase was approximately the same for 

this exposure. 

2.5 Results of Additional Refueling Experiment (June 4, 2002, Reno) 

This experiment was conducted in order to test the response of MS200 (since we were 

not able to operate the instrument during the refueling experiment in February) in this 

microenvironment and to repeat breath and urine testing to confirm the conclusions drawn from 

the pilot study. There were important differences between this refueling and the one conducted 

for the pilot study. Most importantly: 

• We only filled the canister during the actual exposure period of 30 min. During the pilot 

study, we filled the canister over 1 hour, which consisted of 15 min of background plus 

45 min of exposure. 

• Used one exposure subject rather than two. 

• Refueled two vehicles instead of three. 

• The MS200 data output was adjusted to sum the xylenes and ethyl benzene using a single 

library spectra. The reason for this is that there is very little difference between the 

spectra of these four compounds and we found that the software did not do well trying to 

separate them. 

In addition to the MS200 and the canister, we also collected 5 breath samples and 8 urine

samples that were analyzed by LRRI. The five breath samples were: Pre test; 15 min into test; 

approximatelly 2 min post test; 5 min later; and 10 min later. The urine samples included: pretest; approximately15 min post exposure (no urinary output between these two); approximately 

2-10
every hour thereafter for 6 more hours. All the voids from the test subject between the hours of 

0730 and 1800 were collected. 

2.5.1 MS200 and Canister Results 

Figure 2-27 shows the time series of the concentrations of benzene, toluene and the sum 

of xylenes and ethylbenzene in parts per million by volume, ppmv. The data are one-minute 

averages recorded by the MS200. To convert this unit to canister data units (which are parts per 

billion of carbon or ppbC), multiply by the number of carbons and by 1000 to adjust ppm to ppb. 

For example, the highest spike seen (at appx 21 min) is 0.173 ppmv for toluene, which is 

equivalent to 1211 ppbC. Benzene in the same spike is 0.104 ppmv or 624 ppbC. Sum of xylenes 

highest reading at about 22 min is 0.135 ppmv or1080 ppbC. 

The averages of the MS200 data are in good agreement with the canister measurements. 

The data are as follows (units are ppbC): 

Compound MS200 (ppbC) Canister (ppbC) % error 

(difference/can value)

Benzene 128.2 142.1 9.7 

Toluene 413.8 438.4 5.6 

Sum Xyl+EBz 336.6 368.2 8.6 

2.5.2 Breath Sample Results 

As explained above, the breath samples were collected in 1-liter stainless steel canisters 

from one subject. Table 2-6 below lists the results obtained from these samples (the units are 

ppbC): 

Table 2-6 Breath Data in ppbC 

Site/Compound 

Pre refueling 

breath 

Middle of run 

breath 

Post exposure 

breath #1 (2 

min) 

Post exposure 

breath #2 (5 

min) 

Post exposure 

breath #3 (10

min) 

sample_time (hr) 0945 1046 1103 1107 1111 

sample_date 6/4/02 6/4/02 6/4/02 6/4/02 6/4/02 

1,3-butadiene 0.21 0.83 7.46 0.44 0.41 

MTBE 0.00 3.03 1.34 1.91 1.14 

benzene 2.65 14.76 7.82 10.76 9.78 

toluene 5.98 47.32 123.54 27.59 25.17 

ethyl benzene 0.83 1.01 2.77 8.46 7.75 

m/p-xylene 2.61 14.12 18.77 28.75 46.36 

o-xylene 1.66 5.59 3.82 7.03 16.88 

2-11
 These data are consistent with the data obtained during the pilot study, confirming very 

short breath elimination half-lives of the compounds measured. In addition, this elimination time 

is different for every compound. Whereas benzene concentration is the highest in the middle 

point of the exposure, and declines significantly two minutes after exposure, toluene 

concentrations are the highest 2 min after exposure, declining sharply five minutes after the 

exposure. Thus, breath data obtained after an integrated exposure period of an hour will not 

accurately measure the biological uptake that occurs under variable condition during the 

exposure period. 

2.5.3 Analysis of Urinary VOC Concentrations 

Urinary concentrations of MTBE, benzene, toluene, ethyl Benzene, and the xylenes were 

analyzed utilizing the same methods described for the Reno pilot study protocol. In addition, for 

these data we analyzed urinary creatinine values and urinary ethanol. Creatinine values were 

obtained using a standard creatinine analysis kit on a Monarch 2000 clinical chemistry 

instrument. Ethanol data were obtained utilizing the same solid phase extraction fibers that were 

used for the other chemical species. 

 Table 2-7 lists the concentrations of measured species, including creatinine, and Figure 2-

28 shows the data for BTEX and MTBE. Urinary concentrations of all of the measured VOC’s 

except ethanol were present in detectable limits in most of the samples. The absence of ethanol 

may be due to the high detection limits of (0.5 ng/L) relative to the other analytes, which are 

detectable in much lower concentrations. If urinary ethanol is to be monitored in follow on 

studies additional method development will be conducted to decrease the limits of detection on 

this assay. 

Concentrations of the other volatile organics reported here are complicated by the 

relatively high concentration observed in the pre-exposure samples. Concentrations postexposure increased throughout the day for benzene and toluene, which is similar to what was 

observed in the pilot study. However, at their peak, the concentrations of these compounds were 

only slightly larger than the pre-exposure backgrounds. The concentrations observed in the urine 

for benzene were consistent with what was observed during the pilot study and in the literature, 

with values in the range of 100-200 ng/L. The concentrations post-exposure did not increase 

much beyond 200 ng/L for benzene. These low post-exposure concentrations are consistent with 

the results from subject 7. While the highest urinary concentrations for subject 7 in this study do 

not reach levels reported for subject 3 in the pilot study, subject 7 does show an increase in 

urinary benzene and toluene throughout the day, which is consistent with subject 3 in the pilot 

study. The currently reported results do show concentrations of toluene that are increased relative 

to benzene, which is consistent with the higher concentrations of toluene that the subject was 

exposed to. The toluene concentrations do not, however, increase well above the pre-exposure 

background concentrations. 

Creatinine was measured during this follow-on study in response to some criticism from 

an external reviewer that creatinine values would help determine concentration effects resulting 

from dilution. As reported in the pilot study report, the concentrations of urinary VOC’s in the 

contemporary literature are typically not normalized to creatinine concentration. One example of 

the rationale for not using creatinine correction is given in Albertine et al. (2001), where 

2-12
2-13

statistical relationships between exposure and urinary concentrations of butadiene biomarkers 

were more significant when not normalized. 
Table 2-7 

Concentrations of Ethanol, MTBE and BTEX in urine samples (ng/L) 

2-14

Re-do of Refueling Experiment Concentrations in ng/L 

Sample 

# Subject Time Date Description Ethanol MTBE Benzene Toluene 

Eth Benzene 

p/m xylene 

1 7 820 6/4/02 pre exposure-morning nd 0.024 0.165 0.265 0.062 0.05

2 7 1115 6/4/02 post exposure nd 0.052 0.103 0.112 0.039 0.033 7 1215 6/4/02 post exposure nd 0.030 0.135 0.149 0.057 0.054 7 1327 6/4/02 post exposure nd 0.033 0.089 0.135 0.047 0.045 7 1430 6/4/02 post exposure nd 0.021 0.143 0.202 0.051 0.036 7 1522 6/4/02 post exposure nd 0.017 0.203 0.283 0.042 0.047 7 1624 6/4/02 post exposure nd 0.009 0.238 0.279 0.051 0.048 7 1718 6/4/02 post exposure nd 0.013 0.106 0.114 0.046 0.04
3. RECOMMENDATIONS 

 This section describes the equipment and protocols we recommend for this program. We 

first summarize the equipment in Table 3-1 and then discuss each individually. 

Table 3-1 

Recommendation Summary 

Instrument Recommendation Notes 

Battelle HCHO Yes We have requested Battelle build one for DRI. 

Kore MS-200 Yes Needs protocol development and possibly 

preconcentrator. 

TEI TVA1000 No Not sensitive enough. 

Innova 

Photoacoustic 

No Grab sampling method; overlap with other 

instruments. 

Langan T15 CO Yes Need to develop temperature dependence. 

Integrated 

Samples 

Yes 

SPME Yes Would be used only for MTBE and BTEX 

3.1 Exposure Measurements 

Formaldehyde Monitor. The Battelle instrument appears to have performed quite well. We 

evaluated a similar commercial instrument made by Alpha Omega during a three-day evaluation 

period at the end of May 2002. The evaluation consisted of collocated measurements with our 

CO analyzer, Kore MS200 analyzer and integrated DNPH measurements using 

microenvironmental exposures similar to those used during the pilot study. Base upon the results 

of this evaluation, we concluded that the Alpha Omega HCHO monitor would be suitable for the 

main study. 

Kore MS200. The MS200 appears to have performed rather well in the pilot study. We are 

currently refining the protocol for using this instrument, based on the results from the field study 

as well as the results of many experiments we have conducted since that time. We hope to install 

an automated system for zeroing the instrument during the run times to confirm the zero point of 

the instrument as it changes during the day. In addition, we will be standardizing the zeroing 

procedure and are working on methods to automate the background subtraction process. We 

recommend the use of the instrument in the main study. 

TEI TVA1000. The TVA1000 is a FID based detector for total hydrocarbons. As such it 

responds approximately equally to the concentration of oxidizable carbon in the air. In the 

present experiment that means it has the challenge of measuring small amounts of the 

hydrocarbons of interest in the presence of a relatively high concentration of methane. In 

3-1
addition since there is no speciation, we are not obtaining any information about the relative 

contribution of any of the components. Also, the baseline is not very stable and we do not think it 

adds a lot of useful information. Our recommendation is to not use this instrument. 

Innova Photoacoustic. This instrument can measure CO, CO2, total hydrocarbons and water 

vapor (dew point). However, the instrument is not a true “continuous” monitor, but rather it takes 

grab samples, measures that sample and then takes another grab sample. This means that the 

value determined may not accurately represent the average over the time period it is applied to. 

We feel that a better way to obtain total hydrocarbons is to compare CO and BTEX from 

continuous instruments to the same compounds in the canisters. Our recommendation is to not 

use this instrument. 

Langan T15 CO monitor. This instrument appears accurate and easy to use in addition to being 

portable with very low power consumption. It is, however, temperature dependant and we will 

need to develop a temperature based calibration to maintain accuracy. In addition, it appears to 

have a slower response time, especially post-exposure to a high concentration, but this was only 

noticeable in the extreme case of the generator at DRI where concentration changes were over 

100 ppm in less than 1 minute. We do recommend using this instrument. 

Integrated Samples. We recommend collecting integrated samples as a check on the continuous 

samples and to get more detailed speciation of VOCs. The association between the continuous 

CO and BTEX data with the data from time-integrated measurements can provide estimates of 

the time series for species without feasible methods for continuous measurement such as 1,3 

butadiene, acetaldehyde, ethanol, MTBE, and total nonmethane hydrocarbons.. 

SPME. Based on our pilot study, we consider this technique as very promising. We propose to 

use SPME for MTBE and BTEX, but not for ethanol, formaldehyde and acetaldehyde. We are 

currently working on perfecting our calibration procedure. We are also performing the series of 

experiments to determine the optimal exposure time and the dependence of measured 

concentrations on storage conditions. 

3.2 Recommendations for Measurements of VOC in Breath 

During the pilot study breath concentrations of MTBE, benzene, toluene, ethylbenzene, and the 

xylenes was successfully conducted. Analysis of alveolar and full breath showed that the 

sampling technique to target alveolar breath excluded contributions of VOC’s present in the 

“dead-space” air present in a full breath because their concentrations were lower. Breath 

concentrations between the two separate subjects differed in many cases most likely because of 

slight differences in the time of sample collection. This is because the breath elimination halflives of the compounds measured are between 1 and 3 minutes (Lindstrom and Pleil, 1996), so 

slight differences in the time of collection can make large differences in observed breath 

concentrations. This can also explain why for many of the samples there was little or no 

exposure effect observed. These samples were generally collected minutes after the end of the 

exposures, after which much of the target compounds would have been eliminated. This effect 

was observed by Lioy et al. (1991), who saw little correlation with breath benzene concentrations 

and microenvironmental exposure concentrations, and attributed their lack of agreement to the 

short time course of benzene elimination via breath. 

3-2
 When collected in exposure environments where the concentrations are above 

background (e.g. refueling) there is an observable exposure effect when the sample is collected 

very close to the end of exposure. However, these breath concentrations will only reflect what 

the subject is exposed to in the last portion of the exposure, as the majority of the one-hour 

exposure will have been eliminated by the time the samples are collected. Therefore single 

breath measurements at the termination of exposures are not a good index of cumulative onehour exposures. Therefore, we do not recommend breath measurements for urban exposure 

experiments during the main study. 

3.3 Recommendations for Measurement of VOC in Urine 

The method of Fustinoni (1999) based on a sensitive SPME technique was developed for 

application to this study. Work at LRRI was conducted with the same instrument as used in that 

study, but the published quantitation limits of 12-34 ng/L were not attainable. We were able to 

observe good signal/noise for all of the analytes in what would likely be the sensitivity range 

published by Fustinoni (1999). However, the deuterated internal standards utilized for 

quantitation had small amounts of the parent (un-deuterated) compound present that limited the 

limit of detection. The area counts of the parent compound in blanks showed integrated area 

counts from the mass spectrometer of approximately 600 for benzene, when the 100 ng/L 

standard had area counts of about 2500. The use of the internal standards is necessary to reduce 

sample to sample variability in the uptake of the VOC’s by the SPME fiber. 

Because of the low exposure concentrations observed in this study, the amount of urinary 

benzene and other VOC’s were extremely low. Although published excretion rates vary, a 

typical amount of un-metabolized benzene relative to exposure is on the order of 0.1% 

(Waidyanatha et al. (2001)). Fustinoni (1999) showed urinary concentrations of benzene to be 

around 114 ng/L after an approximate 3.5 ppb exposure, and Waidyanatha et al. (2001) have 

shown 145 ng/L concentrations in “non-exposed” subjects from an occupational exposure study. 

Similarly, Ghittori et al (1995) showed background levels of benzene in non-smokers of 

approximately 131 ng/L (geometric mean). Most of the urinary benzene concentrations observed 

in the currently reported pilot study are in the range of the low level exposures from previous 

studies described above. Since the scripted exposures were low there was no strong correlation 

between exposure and urinary benzene in the pilot study. This is slightly in contrast to published 

results of Waidyanatha et al. (2001), who saw an exposure effect with benzene, but the exposure 

concentrations were in the ppm range. 

After the highest exposure there was a relatively strong exposure effect observed in one 

subject and a lesser exposure effect observed in a second subject. There was a time course in the 

elimination of benzene that showed urinary benzene concentrations increasing with time. These 

results are comparable to MTBE data reported by Lee and Weisel (1998) who showed an 

increase in urinary MTBE after exposure (1 ppm for 10 min) at about 1 hour, remaining about 

the same at 3.5 hours and dropping several-fold by 6 hours. Here urinary concentrations were 

only measured 3 hours post exposure, so we were not able to observe the start of elimination 

from the body. Because of an inability to see the decay of urinary benzene after exposures, and 

the slight inconsistency in the two subjects (one showed much higher urinary benzene), we 

repeated this highest end exposure on June 4, 2002, to see if the urinary VOC concentration data 

3-3
can be linked strongly to an exposure effect at these levels and to see the full time course of 

elimination. 

Because the additional measurements of urinary MTBE/BTEX from the second refueling 

experiment were promising, we recommend this measurement as the biomonitoring technique of 

choice. We will pay special attention to the pre-exposure background urine sample collection, 

making sure that the subject is not exposed to gasoline exhaust at least 10 hours prior to sample 

collection. Since we were not able to discriminate urinary benzene concentrations in low-level 

exposures (e.g. walking down street), we propose to only conduct biomonitoring experiments 

from projected “high-end” exposures such as refueling. Monitoring will be conducted similar to 

the pilot study, with pre and post exposure collections of the subject’s urine. 

3-4
4. REFERENCES 

Albertini et al. (2001). Chem. Boil ineract. Vol 135-137, pg 429-453 

Fustinoni, S., R. Giampiccolo, S. Pulvirenti, M. Buratti, and A. Colombi (1999). Headspace 

solid-phase microextraction for the determination of benzene, toluene, ethylbenzene and 

xylenes in urine. J. Chromatogr. B 723: 105-115. 

Ghittori, S., Maestri, L., Fiorentino, M.L. and Imbriani, M. (1995). Evaluation of 

occupational exposure to benzene by urinalysis. Int. Arch. Occup. Environ. 

Health, 67, 195-200 

Lee, C.W. and C.P. Weisel (2001). Toxicokinetics of Human Exposure to Methyl 

tertiary-butyl ether (MTBE) Following Short-Term Controlled Exposures. J. 

Exposure Anal. And Environ. Epi., 11, 67-78 

Lindstrom, A.B., and J.D. Pleil (1996). Alveolar Breath Sampling and Analysis to Assess 

Exposures to Methyl Tertiary Butyl Ether (MTBE) During Motor Vehicle 

Refueling., J. Air and Waste Management, V. 46, p. 676-682 

Lioy, P.J., Wallace, L., and E. Pelizzari (1991). Indoor/Outdoor, and Personal Monitor 

and Breath Analysis Relationships for Selected Volatile Organic Compounds 

Measured at Three Homes During New Jersey Team, J. Exposure Anal. And Envir. Epi., 

Vol. 1, No. 1, pp 45-61 

Philips, M. and J. Greenberg (1992). Ion-Trap Detection of Volatile Organic Compounds 

in Alveolar Breath, Clin. Chem. 38/1, 60-65 

Pleil, J.D., and A.B. Lindstrom (1995). Collection of a Single Alveolar Exhaled Breath 

for Volatile Organic Compound Analysis., American J. Industrial Medicine, 28; 109-121 

Waidyanatha, S., N. Rothman, S. Fustinoni, M. T. Smith, R. B. Hayes, W. Bechtold, M. 

Dosemeci, L. Guilan, S. Yin, and S. M. Rappaport (2001). Urinary benzene as a 

biomarker of exposure among occupationally exposed and unexposed subjects. 

Carcinogenesis 22: 279-286. 

4-1
FIGURE FOR SECTION 2 
Figure 2-1 Concentration Time Series, Freeway AM 

Freeway AM (R02022607)

0.05.0

10.015.020.025.0

7:10

7:15

7:20

7:25

7:30

7:35

7:40

7:45

7:50

7:55

8:00

8:05

CO

HC & HCH

F-1
Figure 2-2 Concentration Time Series, Surface Streets 

Surface Streets (R02022607)

0.02.04.06.08.0

10.012.014.016.018.020.0

12:00

12:05

12:10

12:15

12:20

12:25

12:30

12:35

12:40

12:45

12:50

12:55

CO

0.02.04.06.08.010.012.0

HC & HCHO 

F-2
Figure 2-3 Concentration Time Series, Freeway PM 

Freeway PM (R02022616)

0.05.0

10.015.020.025.0

16:00

16:05

16:10

16:15

16:20

16:25

16:30

16:35

16:40

16:45

16:50

16:55

CO

0.02.04.06.08.010.012.0

HC & HCHO 

F-3
Figure 2-4 Concentration Time Series, Refueling In-Cabin 

Refueling In-Cabin (R02022708)

0.01.02.03.04.05.06.07.08.09.0

10.0

8:10

8:15

8:20

8:25

8:30

8:35

8:40

8:45

8:50

8:55

9:00

9:05

CO

0.01.02.03.04.05.06.07.0

HC & HCHO

F-4
Figure 2-5 Concentration Time Series, Refueling out of cabin 

Refueling Out of Cabin (R02022712)

0.01.02.03.04.05.06.07.0

12:00

12:05

12:10

12:15

12:20

12:25

12:30

12:35

12:40

12:45

12:50

12:55

CO

0.05.010.015.020.025.030.035.040.0

HC & HCHO 

F-5
Figure 2-6 Concentration Time Series, Walking Downtown 

Walking Downtown (R02022811)

0.01.02.03.04.05.06.07.0

11:00

11:05

11:10

11:15

11:20

11:25

11:30

11:35

11:40

11:45

11:50

11:55

CO

0.01.02.03.04.05.06.07.0

HC & HCHO

F-6
Figure 2-7 Concentration Time Series, Underground Garage 

Underground Garage (R02022815)

0.02.04.06.08.0

10.012.0

15:00

15:05

15:10

15:15

15:20

15:25

15:30

15:35

15:40

15:45

15:50

15:55

CO

0.01.02.03.04.05.06.07.08.09.0

HC & HCHO 

F-7
Figure 2-8 Concentration Time Series, Residential Garage Background A 

Residential Garage Background A (R02030109a)

0.00.10.20.30.40.50.6

9:35

9:40

9:45

9:50

9:55

10:00

10:05

CO

0.01.02.03.04.05.06.07.0

HC & HCHO

F-8
Figure 2-9 Concentration Time Series, Residential Garage Background B 

Residential Garage Background B (R02030109b)

0.00.10.10.20.20.30.30.40.40.50.5

10:05

10:10

10:15

10:20

10:25

10:30

10:35

CO

0.01.02.03.04.05.06.07.0

HC & HCHO

F-9
Figure 2-10 Concentration Time Series, Residential Garage Sample C 

Residential Garage Sample (R02030109c)

0.00.10.20.30.40.50.60.70.8

11:10

11:15

11:20

11:25

11:30

11:35

11:40

CO

0246811111

HC &HCHO 

F-10
Figure 2-11 Concentration Time Series, Residential Garage Sample D 

Residential Garage Sample (R02030109d)

0.00.10.20.30.40.50.60.70.80.91.0

11:40

11:45

11:50

11:55

12:00

12:05

12:10

CO

0.02.04.06.08.010.012.014.016.018.0

HC & HCHO 

F-11
Figure 2-12 Concentration Time Series, Residential Garage Sample E 

Residential Garage Sample (R02030109e)

0.00.10.20.30.40.50.6

12:10

12:15

12:20

12:25

12:30

12:35

12:40

CO

0.02.04.06.08.010.012.014.016.0

HC & HCHO

F-12
Figure 2-13 Concentration Time Series, Residential Garage Sample F 

Residential Garage Sample (R02030109f)

0.00.20.40.60.81.01.21.41.61.82.0

12:40

12:45

12:50

12:55

13:00

13:05

13:10

CO

0.02.04.06.08.010.012.014.0

HC & HCHO 

F-13
Figure 2-14 Concentration Time Series, Residential Garage Sample G 

Residential Garage Sample (R02030109g)

0.00.10.20.30.40.50.60.70.80.9

13:10

13:15

13:20

13:25

13:30

13:35

13:40

CO

0.01.02.03.04.05.06.07.0

HC & HCHO 

F-14
Figure 2-15 Concentration Time Series, Generator 

Residential Garage Sample (R02030116)

0.0

100.0200.0300.0400.0500.0600.0700.0800.0900.0

16:00

16:05

16:10

16:15

16:20

16:25

16:30

CO

0.020.040.060.080.0100.0120.0

HC & HCHO

Generator Sample (R02030116)

F-15
Figure 2-16 MS200 Raw and Corrected Data 

Freeway AM

MS200 Raw Benzene, Zero, and Corrected

-0.01

0

0.010.020.030.040.050.060.070.080.09

0.1

0.11

ppmv

0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 0:36:00 0:43:12 0:50:24 0:57:36 

Elapsed time

F-16
Figure 2-17 MS200 Corrected Data Only 

Freeway AM

MS200 Corrected Data Only

-0.01

0

0.010.020.03

ppmv

0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 0:36:00 0:43:12 0:50:24 0:

Elapsed time

F-17
Figure 2-18. Correlation between CO by T15 and by Innova. 

y = 0.8754x + 0.4195

R2 = 0.7709

02468

1012141618

Innova CO (ppm)

0

2

4

6

8 10 12 14 

T15 CO (ppm)

F-18
Figure 2-19 Correlation between Innova and TEI for total hydrocarbons. 

Chart Title

y = 0.0703x + 3.0835

R2 = 0.2878

02468

101214

0 20 40 60 80 100 

Innova HC as propane (ppm*10)

TEI HC as methane (ppm)

F-19
Figure 2-20 Innova vs.TEI for total hydrocarbons with three outliers removed. 

Chart Title

y = 0.209x + 2.4854

R2 = 0.6819

0.002.004.006.008.00

10.0012.0014.0016.0018.00

TEI HC as methane (ppm)

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 

Innova HC as propane (ppm*10)

F-20
F-21

Figure 2-21 Correlation between CO and formaldehyde. 

y = 0.5062x + 4.5338

R2 = 0.2621

02468

10121416

0 5 10 15 20 

T15 CO (ppm)

Battelle HCHO (ppb)
Figure 2-22 Correlation between DNPH and continuous formaldehyde. 

F-22

HCHO

y = 0.8543x + 0.6638

R2

 = 0.9532

15

20

25

25

le-HCHO

0

5

10

0 5 10 15 20

DNPH-HCHO

Battel
Figure 2-23. Pre and post exposure breath samples during refueling. 

Refueling 

01234567

mtbe benze tolue etbz mp_xyl o_xyl

ppbv

F-23
Figure 2-24 Pre and post exposure breath samples during in-cabin fueling. 

In-cabin Fueling

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

mtbe benze tolue etbz mp_xyl o_xyl

ppbvIn Cabi

In Cabi

F-24
Figure 2-25 Pre and post exposure breath samples during walk. 

Walk

0123456789

10

ppbv

mtbe benze tolue etbz mp_xyl o_xyl

F-25
Figure 2-26 Relationship between full and alveolar breath. 

Realationship Between Full and Alveolar Breath

0.000.501.001.502.002.503.003.50

MTBE benzene toluene ethylbenzene m/p xylene o-xylene

ppbvF

A

F-26
Figure 2-27 The three traces; benzene, toluene and sun of xylenes and 

 ethylbenzene 

Refuel

0

0.020.040.060.08

0.1

0.120.140.160.18

0.2

0:00:00 0:07:12 0:14:24 0:21:36 0:28:48 

Elapsed time

ppmv

Benzene Toluene Sum xylenes+ethylbenzene

F-27
Figure 2-28 Data for BTEX and MTBE 

0.0000.0500.1000.1500.2000.2500.300

0 2 4 6 8

Sample Number

ng/L

MTBE Benzene Toluene Eth Benzene p/m xylene 

Pre-exposure Post exposure

F-28
Appendix E 

Section 211(B) Tier 2 High-End Exposure Screening Study of Baseline and Oxygenated 

Gasoline – 2nd Reno Pilot Study 

 
SECTION 211(B) TIER 2 HIGH END EXPOSURE SCREENING STUDY OF BASELINE 

AND OXYGENATED GASOLINE –2ND RENO PILOT STUDY 

DRAFT REPORT 

Prepared for 

AMERICAN PETROLEUM INSTITUTE 

1220 L Street 

Washington, DC 20005-4070 

Prepared by 

Barbara Zielinska, John Sagebiel, David Campbell, Diana Ceballos, Mark McDaniel and Eric 

Fujita 

Desert Research Institute 

2215 Raggio Parkway 

Reno, NV 89512 
TABLE OF CONTENTS 

1. Introduction........................................................................................................................ 1-1 

1.1 Study Overview and Technical Objectives ............................................................. 1-1 

2. Experimental Methods....................................................................................................... 2-1 

2.1 Measurement Approach........................................................................................... 2-1 

2.2 Improvement in Sampling Platform........................................................................ 2-4 

2.3 Analytical Methods ................................................................................................. 2-6 

2.3.1 Breath Samples Analysis ............................................................................... 2-6 

2.3.2 SPME Methodology ...................................................................................... 2-7 

2.4 Data Capture.......................................................................................................... 2-15 

3. Results................................................................................................................................ 3-1 

3.1 Method Comparison of Redundant Data................................................................. 3-1 

3.1.1 PID versus PID .............................................................................................. 3-1 

3.1.2 NDIR vs. Electrochemical CO....................................................................... 3-7 

3.1.3 CO versus Canister CO................................................................................ 3-10 

3.1.4 MS vs. Canister............................................................................................ 3-12 

3.1.5 SPME vs. Canisters...................................................................................... 3-13 

3.1.6 SPME vs. MS............................................................................................... 3-17 

3.1.7 DNPH vs. Formaldehyde............................................................................. 3-21 

3.1.8 Tenax vs. Canisters...................................................................................... 3-21 

3.2 Comparisons of Correlated Data ........................................................................... 3-23 

3.2.1 PID vs. CO................................................................................................... 3-23 

3.2.2 CO vs. Formaldehyde .................................................................................. 3-28 

3.2.3 SPME vs. PID.............................................................................................. 3-32 

3.3 Environmental Factors........................................................................................... 3-35 

3.4 Reconstructed Data................................................................................................ 3-40 

3.5 Breath Data............................................................................................................ 3-46

3.6 Consistency of Microenvironment Conditions...................................................... 3-51 

3.6.1 CO 3-51 

3.6.2 PID 3-53 

4. Conclusions........................................................................................................................ 4-1 

5. References:......................................................................................................................... 5-4 

6. Appendicies........................................................................................................................ 6-1 

6.1 Appendix A: SPME................................................................................................ 6-1 

6.2 Appendix B: Canisters and Tenax.......................................................................... 6-3 

6.3 Appendix C: Breath Samples ................................................................................. 6-9 

6.4 Appendix D: DNPH ............................................................................................. 6-12 

ii
LIST OF FIGURES 

Figure 2.2-1. Van inlets ......................................................................................................... 2-5 

Figure 2.2-2. Inlets mounted on the tripod. ........................................................................... 2-5 

Figure 2.3-1. Set-up for tem perature (upper pane l) and relative hum idity (lower panel) 

dependence measurements.............................................................................................. 2-9 

Figure 2.3-2. Temperature Dependence for 30, 50, and 100 ppb BTEX Concentrations. . 2-10 

Figure 2.3-2–cont’d. Tem perature De pendence for 30, 50, and 100 ppb BTEX 

Concentrations. ............................................................................................................. 2-11 

Figure 2.3-3. Concentration calibration at a given tem perature for the BTEX 

compounds.................................................................................................................... 2-11 

Figure 2.3-3-cont’d. Concentr ation calibration at a given tem perature for the BTEX 

compounds.................................................................................................................... 2-12 

Figure 2.3-4. Dynamic Calibration Temperature Dependence............................................ 2-13 

Figure 2.3-5. Static C alibration T emperature Dependence (By interpolation from 

dynamic system)........................................................................................................... 2-13 

Figure 2.3-6. Hum idity Dependence on SPME response for a 100ppb BTEX standard 

at 25C............................................................................................................................ 2-14 

Figure 2.4-1. Effect of driving on continuous formaldehyde analyzer, during and after 

sampling in ME2-5. ...................................................................................................... 2-16 

Figure 3.1-1a. Comparison of estim ated B TEX concentrations measured by PID 

instruments with inlets collocated w ithin 10 cm . Data are running 1 m inute 

averages. VR = nozzle vapor recovery........................................................................... 3-2 

Figure 3.1-1b – cont’d. Com parison of estim ated BTEX c oncentrations m easured by 

PID instrum ents with in lets collocated within 1 0 cm . Data are runn ing 1 m inute 

averages. VR = nozzle vapor recovery........................................................................... 3-3 

Figure 3.1-2. Com parison of estim ated B TEX concentrations m easured by P ID 

instruments during freeway driving tests. Data are running 1 minute averages............. 3-5 

Figure 3.1-2 –cont’d. C omparison of estimated BTEX concentrations measured by PID 

instruments during freeway driving tests. Data are running 1 minute averages............. 3-6 

Figure 3.1-3. Comparison of NDIR (API m odel 300) and electrochem ical (Langan 

T15v) CO monitors during two freeway driving tests.................................................... 3-8 

iii
Figure 3.1-4. Com parison of two gas-filter correlation NDIR CO analyzers during onroad sampling.................................................................................................................. 3-9 

Figure 3.1-6 Comparison of canister and MS200 data for all measured species................. 3-12 

Figure 3.1-7. Comparison of MS200 and canister for benzene only................................... 3-13 

Figure 3.1-8. Scatter Plots for raw data from SPME vs canister for the Pilot Study 2003. 3-15 

Figure 3.1-9. Scatter Plots for temperature corrected SPME vs canister data for the Pilot 

Study 2003.................................................................................................................... 3-15 

Figure 3.1-10. Scatter plots from SPME vs Canister for the Pilot Study 2003 with two 

outliers removed. .......................................................................................................... 3-16

Figure 3.1-11. 10 m inutes average MS data vs SP ME benzene and toluene 

concentrations: Freeway 5/02 7:35-8:15 am................................................................. 3-18 

Figure 3.1-12. 10 m inutes average MS da ta vs SP ME benzene and toluene 

concentrations: Freeway 4/30, 7:35 am........................................................................ 3-19 

Figure 3.1-13. 10 m inutes average MS data vs SP ME benzene and toluene 

concentrations: Refueling w/o VR 5/02 9:18 am ......................................................... 3-20 

Figure 3.1-14 Comparison of canister and Tenax data for all ME ..................................... 3-22 

Figure 3.2-1. Comparison of CO and BTEX by PID during parking garage tests. ............ 3-24 

Figure 3.2-1 – cont’d. Com parison of CO and BTEX by PID during parking garage 

tests. Data are running 1 minute averages. ................................................................... 3-25 

Figure 3.2-3. Scatter plot of CO vs BTEX by PID during parking garage tests. Data are 

running 1 minute averages............................................................................................ 3-26 

Figure 3.2-4. Comparison of CO and BTEX by PID during freeway driving tests............ 3-27 

Figure 3.2-9. SPME 10 m in total BTEX vs. PID 10 m in averages, Freeway, 5/02, 7:35 

am ................................................................................................................................. 3-32 

Figure 3.2-10. SPME 10 m in total B TEX vs. PID 10 m in averages, Refueling w/o VR 

4/30 9:21am. ................................................................................................................. 3-32 

Figure 3.2-11. SPME 10 m in total BTEX vs. PID 10 min averages, Freeway 4/30, 7:35 

am. ................................................................................................................................ 3-33 

Figure 3.2-12. SPME 10 m in total B TEX vs. PID 10 m in averages, Refueling w/o VR 

5/02 9:18 am. ................................................................................................................ 3-33 

iv
Figure 3.2-13. SPME 10 min total BTEX vs. PID 10 min averages, Parking Garage 5/06, 

16:45 pm. ...................................................................................................................... 3-34 

Figure 3.3-1. Fuel tank te mperatures during freeway ME on 4/29/03. Ambient 

temperature was 4.4 C during this time. ....................................................................... 3-37 

Figure 3.5–1. CO2 values in the breath sam ples of subjects B and J collected in all ME, 

organized by the subject and by microenvironment..................................................... 3-47 

Figure 3.6-1. Range and variability of CO con centration during tests. Statistics for each 

of the five replicate tests are shown for each microenvironment. ................................ 3-52 

Figure 3.6-2. Range and variability of BTEX by PID concentration during tests.............. 3-54 

Figure 3.6-3. Range and variability of m ean CO and mean BTEX by PID concentration 

for four microenvironments.......................................................................................... 3-55 

v
LIST OF TABLES 

Table 2.1-1. Measurement methods used in the 2nd Reno Pilot Study. ................................. 2-3 

Table 2.4-1. Data Capture Summary ................................................................................... 2-16 

Table 3.1-1. Data comparison between SPME and Canister.............................................. 3-14 

Table 3.1-2. Correlation of Scatter Plots from SPME and Canister Comparison............... 3-16 

Table 3.3-1. Environmental Conditions for Freeway Driving MEs. ................................... 3-36 

Table 3.3-2. Environmental Conditions for Garage MEs.................................................... 3-38 

Table 3.3-3. Environmental Conditions for Refueling MEs................................................ 3-39 

vi
1. INTRODUCTION 

The U.S. Environmental Protection Agency (EPA) has recently issued requirements for a test 

program in accordance with the Alternative Tier 2 provisions of the fuels and fuel additives 

(F/FA) health effects testing regulations, which are required pursuant to Section 211(b) of the 

Clean Air Act. In re sponse to th ese requirem ents, the Americ an Petro leum Institu te (API) 

contracted with a research team consisting of the Desert Research Institute (DRI), Southwest 

Research I nstitute (S wRI), Lovelace Respir atory Res earch In stitute (LRRI), and TRJ 

Environmental, Inc (TRJ) to conduct a screen ing study of the high-end distribution of 

inhalation exposures to evapor ative and com bustion emissions of baseline- and oxygenated 

gasoline. T he exposure protocols and m easurement methods, sampling & analytical 

procedures are described in the June 13, 2002 Exposure Protocol and Study Plan. The field 

measurements in San Antonio, Houston , and A tlanta were com pleted in adheren ce to th is 

written protocol during summer 2002. The work in Chicago was postponed pending further 

evaluation of the measurement protocol and assessment of the data collected to date. 

The overall approach for the e xposure study is based upon the draft S211b Tier 2 E xposure 

Study Protocol that was developed in May 2001 by the API Section 211(b) Research Group 

and reviewed by the EP A. DRI and LRRI cond ucted a five-day pilo t study in Reno, NV 

during February 2002 to test alternative m easurement approaches in the field under 

conditions that are sim ilar to those that will be encountered in the m ain study. TRJ and API 

provided input in the design of the pilo t study and rev iewed the results and findings. The 

evaluations included available m easurement methods for continuous and tim e-integrated 

measurements of carbon m onoxide (CO), to tal volatile organic com pounds (TVOC), and 

designated VOC species. DRI and LRRI also evaluated th e stability of the designated VOC 

species in breath and urine sam ples during th e pilot study. Results of the pilot study are 

summarized in our pilot study report (Zielinsk a et al., 2002). The draft exposure protocols 

were appropriately modified based upon the results of the pilot study. 

The work conducted last summ er was summarized in two interim data reports, one reporting 

on data collected in San Antonio, Houston a nd Atlanta, and one conducting detailed data 

analysis from Atlanta. Based on these reports, in order to a ssess and identify th e necessity 

for further refinem ent and adjustm ents to th e study protocol prior to the comm encement of 

the next phase of the study EPA asked to conduct the 2 nd Pilot S tudy in Reno during the 

April – May 2003 time frame. 

1.1 Study Overview and Technical Objectives 

The m ain goal of the 2 nd Reno Pilot Study was to de monstrate proper operation and 

reliability of analytic al ins trumentation and com parability of tim e-integrated, sem icontinuous and continuous m ethods for com pounds of interest. Four m icroenvironments 

were selected for this study, as follows: 

1. Morning rush hour commuter traffic (ME1). This test was conducted on US395. 

Due to the lim ited rush hour period in Reno, a relatively small city, we sam pled for 

1-1
only 40 minutes. The driving route was from Parr Blvd in the north to V illanova Dr. 

in the south. During the test we a ttempted to follow a high e mitting vehicle that was 

supplied by one of our DRI coworkers (Dat sun 280Z, 1975). W e sampled inside the 

van under high (first 20 min) and low (second 20 min) ventilation conditions. In low 

ventilation condition, we used recirculated air, windows closed, fan on high and in 

high ventilation conditions we ha d windows open, with fresh air, recirculated air off. 

During this ME a second PID monitored the air outside the van. 

2. Parking garage (ME2). Due to lack of a suitable be low ground parking structure in 

Reno, we used an above ground parking gara ge. W e selected the Galleria parking 

garage in downtown Re no, a site that is used by county workers in a nearby building 

whose workday ends at 5:00 PM. Consequently, this location had a pulse of cold-start 

traffic emissions at 5:00 PM as workers at tempted to leave at the sam e time. Due to 

our limited city size and m odest traffic de nsity, we anticipated th e evening exit rus h 

from the garage to be over promptly and employed one-half hour of sam pling 

(approximately 1645 to 1715) from the van park ed at a location ne ar the only garage 

exit. Thus, all cars had to pass our sam pling location as they exit the garage. T he 

sampling inlet was located at the breathing zone immediately next to the van. 

3. Outdoor refueling with Stage 2 vapor recovery at the pump (ME3). We 

conducted refueling of one vehicle (our 1996 sam pling minivan) during a 20 m in 

period. The fuel tank of the van was m odified to enable the fuel to be drained from 

the van prior to refueling. Our objective wa s to dispense approxim ately the sam e 

amount of fuel each tim e. The vehicle was driven prior to refu eling to raise the 

monitored temperatures on the outside surf ace of the fuel t ank. The refueling tests 

were performed at the service station in Reno (corner of Sun Valley Dr. and Dandini 

Blv.), which has stage 2 vapor recovery nozzles. While rem oving the nozzle from the 

vehicle filler tube, we spilled a few drops of liquid gasolin e on the ground near th e 

vehicle. The amount of the spill was not ed. The refueling was done under calm wind 

conditions (i.e., wind speed below 5 m ph). W ind was monitored by hand-held 

anemometer. Monitoring was done at the br eathing zone of the person fueling the 

van. 

4. Outdoor refueling without vapor recovery at the pump (ME4). This test was 

conducted at a sm all gas station in Reno th at does not have stage 2 vapor recovery 

nozzles. Because this s tation sells a rela tively low volum e of fuel, it has not been 

required to upgrade to the stage 2. As not ed above, we refueled one vehicle during 

the 20 min test at the gas station. While taking the nozzle from the vehicle filler tube, 

we caused a spill of a few drops of liquid gasoline on the ground near the vehicle. The 

amount of t he spill was noted. The refueling was done under calm wind conditions 

(i.e. wind speed below 5 m ph). M onitoring was done at the breathing zone of the 

person fueling the van. 

Figure 1-1 shows the sampling locations. The US395 driving segment is marked in blue. 

1-2
Copyrighted page/s removed. Copyrighted material is not available in 

Regulations.gov since it may not be reproduced without consent of 

the copyright holder. 

Contact the EPA Docket Center’s Public Reading Room to view 

or receive a copy of this document. 

Requests for copies may be made as follows: 

In person/writing: 

Environmental Protection Agency, Docket Center 

1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov 
2. EXPERIMENTAL METHODS 

2.1 Measurement Approach 

Our sampling strategy consists of a three-tiered approach sh own in Table 2.1-1, which lists 

the overlapping measurement methods used in the Section 211(B) Tier 2 High-End Exposure 

Screening Study and their intended application. The applications are classified in one of three 

tiers: reference, surrogate, and confirmatory. The base s et or “reference” (R) m easurements 

consist of three well-es tablished tim e-integrated m easurements. Thes e include : 1 ) canis ter 

sampling and analysis by gas chromatography with flame ionization detection for methanized 

CO, BTEX, 1,3-butadiene, MTBE, and nonm ethane hydrocarbons (NMHC); 2) 2,4-

dinitrophenylhydrazine (DNPH) cartridge sampling and analysis by high perform ance liquid 

chromatography with UV detection for form aldehyde and acetalde hyde; and 3) solid 

adsorbent sampling and analysis of ethanol by gas chrom atography with m ass spectrometry 

detection. T hese three m ethods combined m easure all species of in terest over the entire 

sampling period with in each m icroenvironment. Although these integrated m ethods do not 

characterize peak exposures in microenvironments with highly varying exposure levels. They 

provide a basis for validating continuous and semi-continuous data. They also provide a basis 

for deriving correlations between the integrated values and continuous “surrogates” (S), such 

as CO and photoionizable VOC (10.6 eV - photoi onization detector) PID data, in order to 

reconstruct their tim e series. For ex ample, data for BTEX, 1,3-butadiene , and MTBE from 

the canister m easurements can be correlated to continuous C O and PID data to reconstruct 

their time series in exh aust-dominated environments. The sam e method is used fo r ethanol 

and NMHC. In a sim ilar manner, the tim e series of acetald ehyde and form aldehyde can be 

reconstructed from the correlation of the integrated DNPH samples with CO or PID. Outdoor 

afternoon samples should be excluded due to possible contributi on of carbonyl compounds 

formed from atmospheric reactions of hydrocarbons. Table 2.1-1 shows the other correlations 

that can be used in this manner. 

Three continuous methods were employed to monitor: 1) the aromatic hydrocarbons benzene, 

toluene, ethylbenzene, and the xylenes (B TEX), 2) carbon monoxide, and 3) for maldehyde. 

These m ethods were also combined with com ponent concentration ratios fr om 

contemporaneous time-integrated samples to rec onstruct the expected tim e series for specie s 

that did not have continuous instrum ents, e.g., 1,3-butadiene (BD), ethanol (E tOH), and 

methyl tert-butyl ether (MTBE). 

The Kore MS200 instrum ent was used to m onitor BTE X on a one-m inute basis. This 

instrument uses a tim e-of-flight mass spectrometer to separate com pounds of interest. This 

instrument also uses a s oftware solution incorporating the 7 0 eV electro n impact ionization 

fragmentation patterns of each compound to apportion the contribution of each component of 

interest to the time-of-flight (TOF) mass spectrum seen by the instrument. The software does 

not distinguish between specific isomers, thus xylenes are reported together. The inlet uses a 

polydimethylsiloxane mem brane preferentially to allow non-polar organic com pounds into 

the analyzer while maintaining the vacuum inside the analyzer chamber. This membrane inlet 

2-1
does limit the types of com pounds that can be analyzed, however. Common air c onstituents 

and polar organic molecules do not pass the membrane quickly. 

Carbon monoxide was monitored by the Langan T15 CO monitor and the API Model 300 

and ML9830 CO NDIR analyzers. The Langan T15 is an electrochemical monitor for CO. 

The response time of this instrument is somewhat slower than infrared-based instruments. 

Both the API and ML instruments are specified in the EPA List of Designated Reference and 

Equivalent Methods (March 24, 2000) as a federal reference method operating at any 

temperature in the range of 15 oC to 35 oC (59 oF to 95 oF). 

(www.epa.gov/ttnamti1/files/ambient/criteria/criteria/0300co.pdf) 

Continuous Form aldehyde Monitor (Alpha-Om ega Power T echnology, Ltd., Albuquerque, 

NM) absorbs form aldehyde in acidified wate r, reacting it with 2,4-pentanedione and 

ammonia to form a cyclized product, 3,5-diacetyl-1,4-dihydrolutidene, which is continuously 

detected by fluorescence. The method is highly specific for formaldehyde and very sensitive. 

However, since this instrum ent did not perform ed well during the summer study we 

introduced several im provements, as follows. The original instrument case, detector, 

electronics, valves, some of the fittings were retained. Major modifications included removal 

of the original four channel peristaltic pump necessary for reagent delivery and fluid flows to 

the detector. This pum p was found to be incapa ble of maintaining consistent flows and was 

susceptible to failure when pum p t ubing woul d rupture or pull away from the connection 

fittings. In addition, flow rates h ad lim ited adjustability, m aking it not suitable for the 

additional modifications that were perform ed on the ins trument. The peris taltic pump was 

replaced with four m illiGAT piston pum ps (Global FIA) with m icroprocessor-controlled 

motors capable of delivering a broad range of precisely metered flow rates. Another m ajor 

modification was replacem ent of the diffusi on scrubber assem bly with a scrubbing coil 

similar to the design described in Kelly and Fortune (1994). The original diffusion scrubber 

was susceptible to m alfunction when scrubbers or driers were heavily used or contam inated 

by the reagents. In contrast, the scrubbing coil is sim ple to operate and m aintain, and is 

reported as being 100% efficient at rem oving gaseous form aldehyde from the air stream 

being sampled. An in-line debubbler (Global FIA) was installed betwee n the heated reaction 

cell and the detector to rem ove any bubbles from the sample stream before entering the 

detector. This was necessary because bubbles m ay be generated elsew here in the system or 

when the sample m obile phase is heated in th e reaction cell. Finally , calibration of the 

instrument was perform ed using a gaseous form aldehyde standard (1 ppm in N 2(g),ApelReimer) diluted to the desired concentration (5 to 250 ppb) with UHP zero air (Airgas) and 

plumbed to the sample inlet of the scrubbi ng coil. Calibration curves were linear (R 2

>0.99). 

The instrument response tim e was determ ined to be 6 m inutes from the tim e of sam ple 

introduction to equilibration at the detector . Instrum ent background was determ ined by 

periodically installing a DNPH car tridge (Waters) on the inlet of scrubbing coil to rem ove 

any formaldehyde from the sample stream in order to observe the detector baseline response. 

 

2-2
Table 2.1-1. Measurement methods used in the 2nd Reno Pilot Study. 

Data applications for specific methods are classified as reference, confirmatory, and surrogate. 

A

1

Continuous Semi-Cont I

Method T15 CO NDIR CO ppbRAE MS200 HCHO SPME Canister 

pplicable Environments all all all higher end all all all 

Time Resolution seconds seconds seconds 1 min 1-2 min 10 min 30 & 40 min 30 Detection Limits 0.1 ppm 0.04 ppm 1 ppb 1-3 ppbv 1 ppbv 0.2 ppbv 0.05 ppbC Data Application 1 SSSCCCR

CO SC SC RPID 2 SC

BTEX S (a) S (a) SC (c) C C R

,3-Butadiene S ( a) S ( a) S (c) R

MTBE S ( a) S ( a) S (c) C RFormaldehyde S (b) S (b) S (d) C Acetaldehye S (b) S (b) S (d) S (g) Ethanol S (e) S (e) S (f) NMHC S ( a) S ( a) S (c) R

1. Category of data application include surrogate (S), confirmatory (C) reference (R), and surrogate compounds or signal (SC)2. Sum of molecules ionizable at 10.6 eV and detected by photoionization detector.

S (a). Time series will be reconstructed from the canister/CO ratio for exhaust-dominated samples.S (b). Time series will be reconstructed from the DNPH/CO ratio for exhaust-dominated samples except outdoor daytime samples.S (c). Time series will be reconstructed from the canister/PID ratio for exhaust- or evap-dominated samples in outdoor MEs.

S (d). Time series will be reconstructed from the DNPH/PID ratio for exhaust-dominated samples except outdoor daytime samples.S (e). Time series will be reconstructed from the solid adsorbent/CO ratio for exhaust-dominated samples.S (f). Time series will be reconstructed from the solid adsorbent/PID ratio for exhaust and evap-dominated samples.S (g). Time series will be reconstructed from CH3CHODNPH/HCHOCont ratio for exhaust dominated samples.

2-3
Photoionization detector (PID) m easured the total signal fr om molecules ionizable at 10.6 

eV. We used two PID monitors for the pilo t study. For the freewa y runs, one PID sampled 

outside air, and the other sam pled in-cabin air. For th e remaining runs, only one PID was 

used, but for comparison purposes we ran both of them side-by-side for selected runs. 

The tim e-integrated and se mi-continuous collection m ethods (canis ters, solid ad sorbent 

cartridges, DNPH-integrated cartridges and SPME) were described in detail before (Zielinska 

et al, 2002, 2003). Depending on the type of sorbent (C18 or silica gel) in the DNPH 

cartridge, the carbonyl com pound a mbient m easurement results are subject to various 

artifacts due to interaction with ozone. Consequently, the ozone denuder is recommended for 

sample collection. For this pilot study, we used a honeycom b denuder coated with sodium 

carbonate/sodium nitrite/glycerol m ixture (m ethod developed by Dr. K outrakis from the

Harvard School of Public Health). For canister sam pling, ambient NO2 is of concern, since 

it might react with 1,3 butadiene. Thus, we were using a honeycom b denuder coated with 

triethanoloamine (TEA) to remove NO2 (a method developed by Dr. Koutrakis). 

In addition, we collected breath samples in all microenvironments. We used 1 liter silicosteel 

canisters (Restek, Inc.) and a collection m ethod described by Pleil and Lindstrom , 1995. 

Breath samples we re c ollected f or the ref ueling MEs imm ediately before and 10 seconds 

after refueling the vehicle to provide an estim ate of the highest cum ulative exposure. For the 

commuter traffic and garage MEs, breath sam ples were collected before, and at 10 seconds 

after a peak exposure indicated by the PID, an d at the end of the ME s ampling time. Two 

breath samples were collected at refueling MEs (total of 20) and three during each co mmuter 

traffic and garage tests. This is a total of 50 breath sam ples. The CO2 level in the breath 

sample of persons conducting the breath test was measured prior to the pilot study. 

2.2 Improvement in Sampling Platform 

The m ost significant ch ange m ade to the sa mpling pla tform was the com bination of all 

sampling inlets at a single location. For the m obile ME (freeway driving), the inlets are all 

located in the breathing zone n ear the driver’s right shoulder. Figure 2.2-1 shows the current 

configuration of the inlets. The line in this figure labeled “Sample Inlet” provides sample to 

the NDIR CO, the MS200, the for maldehyde instrument, one of the two PIDs and all of the 

integrated samplers (canister, DNPH and solid adsorbent). The SPME f iber, the main inlet 

and the temperature and relative humidity sensor are all within 3 cm of each other. The T-15 

(electrochemical) CO instrum ent is also very close. This configuration was designed to 

minimize or eliminate potential variability associated with concentration gradients inside the 

van. In addition, we recorded the fuel tank temperature by way of a tem perature probe 

secured to the outside of the fuel tank and insulated to prev ent influence from the ground or 

air heat. The video camera recorded the view out the front windshield during the driving ME 

and was used to record other significant activ ity a t the other MEs. For exam ple, in the 

garage, the camera was used to record traffic driving by the sampling point. 

2-4
Figure 2.2-1. Van inlets 

For the stationary MEs (refueling and garage), the inlet was mounted on a tripod to allow for 

placement at an appropriate location outside the van. In this case, the temperature and 

relative humidity probe was relocated as well. This was accomplished by an additional piece 

of Teflon tubing for the inlet and an extension cable for the temperature and relative 

humidity probe. This allows the sampling system to be switched from one configuration to 

the other relatively quickly without disturbing the instruments and samplers. Figure 2.2-2 

shows a close-up of the tripod and details the locations of the sample inlet, the T/RH probe, 

and the SPME fiber. The proximity of all three ensures that no small-scale variations in 

concentration are influencing the sample. 

Figure 2.2-2. Inlets mounted on the tripod. 

In addition, there were several other modifications made to the van to improve it for the 

sampling program. Among these were the addition of racks to safely and securely hold the 

equipment, the upgrading of the power supply, and the addition of a pump and lines to 

2-5
withdraw the fuel from the fuel tank in between the refueling MEs. A computer-based data 

acquisition system was also installed to acquire as much of the data as possible in one 

system. This was used to log all temperature and other environmental parameters, analog 

outputs from the CO instruments and the formaldehyde instrument, and position, speed and 

direction information from the GPS unit. 

The power system was significantly upgraded to provide power and to eliminate the 

suspected artifact seen on the T-15 CO under low ventilation conditions. In these 

experiments, no artifact was observed on the T-15 CO monitor, and thus we are confident 

that this potential contamination has been eliminated. However, the power system proved 

incapable of providing enough power for the API NDIR CO monitor. Once we discovered 

what was wrong (the instrument did not give an error message, rather it began giving very 

erratic results), we added a set of lead-acid batteries outside the van to provide the power 

necessary to supply this one instrument. 

2.3 Analytical Methods 

Most of the analytical m ethods e mployed duri ng this pilot study were described in detail 

before (Zielinska et al., 2002a,b; 2003). Th e exceptions are the anal ysis of the breath 

samples that was perform ed si milarly to the m ethod of Pleil and Lindstrom , 1995, by gas 

chromatography/mass spectrom etry (GC/MS), a nd the determ ination of the dependence of 

SPME concentrations o n tem perature and rela tive hum idity. The sections below describe 

these two analytical procedures. 

2.3.1 Breath Samples Analysis 

The GC/MS system included: Entech 7100 prec oncentrator, Varian 3800 gas chrom atograph 

with FID and colum n switching valve, and Vari an Saturn 2000 ion trap m ass spectrometer. 

The Entech preconcen trator consisted of three traps: 50% glass beads/50% Tenax, held at –

100 °C during sample transfer, 100% Tenax held at –40 °C and a final focusing trap (a piece 

of silico-steel capillary) held at –180 °C. The sample is desorbed from the first trap at 10 °C, 

from the second trap at 200 °C and from the third one at approxim ately 70 °C to a transfer 

line heated to 110 °C and connected to the head of the first column. The sample was injected 

at the head of a 60 m x 0.32 mm polymethylsiloxane column (CPSil-5, Varian, Inc.) held at 

30 °C. This column was connected to the switching valve leading into a 30 m x 0.53 mm GSGasPro column (J&W Scientific). After approximately 7 min the valve was switched so that 

the effluent from the first colum n eluted onto a second 15 m x 0.32 mm polymethylsiloxane 

column connected to the mass spectrometer. The column switch was timed so that the C2 and 

C3 com pounds eluted on the FID and all C4 and higher com pounds eluted on the m ass 

spectrometer. The GC program was as follows: 30 °C held for 2 m in, then 8 °C/min up to 

260 °C. 

Calibration of the system was conducted with a mixture that contained the m ost commonly 

found hydrocarbons (75 com pounds from e thane to n-undecane, p urchased from Air 

Environmental), MTBE, and halocarbons (23 co mpounds from F12 to the dichlorobenzenes, 

purchased f rom Scott Specialty Gases). The st andards were prepared in 6 L Silco-Steel 

2-6
canisters (Restek, Bellefonte, PA) by mixing three different standard s through a multi-valve 

manifold us ing a Baratron absolute capacita nce m anometer (MKS Instrum ents, Andover, 

MA) to determ ine the pressu re each standard added to the m ixture. Prior to m ixing, 

approximately 0.2 m l of ultrapure water was ad ded to the canister to hum idify the m ixture 

(for mixture stability). The concentrations in the mixture were in the range of 0.2 to 10 ppbv. 

Three point external calibrations were run pr ior to analysis, and one calibration check was 

run every 24 hours. If the response of individu al compounds were m ore then 10% off, the 

system was recalibrated. 

Carbon dioxide (CO2) f rom breath sam ples was determined using GC/FID. Since the FID 

does not respond to CO and CO2, these species are converted to m ethane by a m ethanator, 

positioned after the GC column, but ahead of the FID. The methanator comprises a firebrick 

powder im pregnated with nickel catalyst, th rough which a stream of hydrogen gas flows 

continuously at ~550 °C. For compound separation, a 20-foot x 1/8-inch inner-diameter (i.d.) 

column, packed with a 60/80 m esh of Carb oxen 1000 (Supelco) is used. This column 

provides sufficient separation between CH4 a nd CO, without retaining CO2. Five m l 

samples were injected using a constant vo lume loop. The minim um detection lim it for both 

CO and CH4 is ~20 ppbv, whereas for CO2 it is ~3 ppmv. The precision of measurements is 

generally better than 10%. 

2.3.2 SPME Methodology 

During the Reno 2nd pilot project, SPME fibers were calibrated and an alyzed as described 

before (Zielinska et al, 2002, 2003). However, the gas calibrat ion had to be corrected for 

temperature, since s tatic (Tedlar b ag) calibration is perform ed at room (25o C) tem perature 

and the sampling tem perature ran ged from 4o C to 30o C (average 16o C). At lower 

temperature the fiber uptake is higher, theref ore SPME values were expected to be higher 

than canister data. The tem perature correction factors were obtained experim entally in the 

laboratory in a dynam ic flow-through system constructed for the control of te mperature and 

humidity of certified BTEX standards. Hum idity corrections are not a ddressed in this report 

because the experimental data obtained so far doesn’t show a significant change in the SPME 

response due to the change in humidity. 

2.3.2.1 Temperature and Humidity Calibration Experimental Setup 

Figure 2.3-1 shows the experim ental setup fo r tem perature and hum idity calibration. It 

consisted of a 1L glass bulb that had two stop cocks on each side to let the calibration gas 

flow through and an injection po rt covered with a sl eeve septum to allow the introduction of 

a SPME fiber. The bulb was tem perature contro lled with a cooling/ heating system. The 

temperature inside the glass bulb was m easured with a therm ocouple. For introducing the 

desired humidity, a heated injection port was added before the gl ass bulb entrance in order to 

inject water with a syringe pum p (Harvard Apparatus), Ludovic et al., 2001; Nelson, 1992; 

McLaren and Zhou, 2000; Martos and Pawlis zyn, 1997). The water-dispensing rate can be 

calculated from the theoretical saturation ratio obtained from a skew T diagram: 

RH = 100 w/ws 

2-7
ws = ws(T,P) 

w is set with the water-dispensing rate as g water/Kg air=RH*ws/100 

The experimental humidity was measured with a humidity sensor (Dickson FH121). 

Data from the static calibration was com pared to the data obtained in the dynam ic system to 

determine a correction factor that could be applied to the sam pling data. Tedlar bag 

calibrations are valid for the type of envir onments we are m easuring where wind should not 

exceed 4 m iles/hour. However, tem perature calibration is a b etter approached in a d ynamic 

system because tem perature is the only variab le that chan ges, while in a static s ystem 

pressure and volum e must be adjusted as explained by the ideal gas law and makes the 

system very imprecise. Some advantages of a dynamic system are greater reproducibility and 

stability of the standards at lower concentration ranges (Nelson, 1992; Lodge 1984). 

2-8
Figure 2.3-1. Set-up for tem perature (upper pane l) and relative hum idity (lower panel) 

dependence measurements 

2-9
2.3.2.2 SPME Temperature Dependence 

PDMS coating has a sm all decrea se in the response of organics for sam ples with relative 

humidity close to 100%. The prim ary experim ental param eter that control the response is 

temperature. In theory , the effect of te mperature on the distribution constant can be 

predicted, since log(Kf g) is linea r with 1/T a nd the heat of vaporization of the pure solvent 

(Kfg – partition coef ficient). In othe r words, Kfg can be calculated f or the given sa mpling 

conditions (Pawliszyn, 2002). This theoretical a pproach is based on th e liquid properties of 

the PDMS coating in th e fiber. However, in practice the theory doesn’t satisfactorily match 

the exper imental va lues. Theref ore, we perf ormed more experim ents and utiliz ed the 

experimental approach. 

Standards were m easured at different tem peratures using the dynamic system described 

above and results were com pared to those obtained in a room temperature static calibration. 

The experiments were performed at different BTEX concentration levels, as shown in figure 

2.3-2. 

Temperature dependence for 30 ppb BTEX

0

2000

4000

6000

8000

10000

12000

14000

0 10 20 30 40 50

Temperature (C)

Area Counts

Benzene Toluene Ethylbenzene m,p-xylene o-xylene

Temperature Dependence for 50 ppb BTEX

0

4000

8000

12000

16000

20000

0 5 10 15 20 25 30 35 40 45

Temperature, C

Area Counts

benzene toluene ethylbenzene m,p-xylene o,xylene

Figure 2.3-2. Temperature Dependence for 30, 50, and 100 ppb BTEX Concentrations. 

2-10
Temperature Dependence for 100 ppb BTEX

0

5000

10000

15000

20000

25000

30000

0 10 20 30 40 50

Temperature, C

Area Counts

bezene toluene ethylbenzene m,p-xylene o-xylene

Figure 2.3-2–cont’d. Tem perature De pendence for 30, 50, and 100 ppb BTEX 

Concentrations. 

These data can be plo tted by tem perature in order to obtain a li near relationship with 

concentration as in Figure 2.3-3. 

Benzene Temperature Dependence

y = 188.38x

R2 = 0.7134

y = 128.92x

R2 = 0.5189

y = 107.17x

R2 = 0.7398 0

5000

10000

15000

20000

25000

0 20 40 60 80 100 120

Concentration, ppb

Area COunts

10 C 25 C 40 C

Linear (10 C) Linear (25 C) Linear (40 C)

Toluene Temperature Dependence

y = 178.81x

R2 = 0.9227

y = 127.49x

R2 = 0.784

y = 99.57x

R2 = 0.5472

0

5000

10000

15000

20000

0 20 40 60 80 100 120

Concentration, ppb

Area COunts

10 C 25 C 40 C

Linear (10 C) Linear (25 C) Linear (40 C)

Figure 2.3-3. Concentration calibration at a given temperature for the BTEX compounds. 

2-11
Ethylbenzene Temperature Dependence

y = 85.481x

R2 = 0.7776

y = 63.1x

R2 = 0.3382

y = 46.488x

R2 = 0.6668

0

2000

4000

6000

8000

10000

0 20 40 60 80 100 120

Concentration, ppb

Area COunts

10 C 25 C 40 C

Linear (10 C) Linear (25 C) Linear (40 C)

m,p-xylene Temperature Dependence

y = 153.11x

R2 = 0.7653

y = 108.77x

R2 = 0.6097

y = 84.309x

R2 = 0.6317

0

5000

10000

15000

20000

25000

30000

35000

0 50 100 150 200 250

Concentration, ppb

Area COunts

10 C 25 C 40 C

Linear (10 C) Linear (25 C) Linear (40 C)

o-xylene Temperature Dependence

y = 230.24x

R2 = 0.8262

y = 148.82x

R2 = 0.8426

y = 116.78x

R2 = 0.8967

0

5000

10000

15000

20000

25000

0 20 40 60 80 100 120

Concentration, ppb

Area COunts

10 C 25 C 40 C

Linear (10 C) Linear (25 C) Linear (40 C)

Figure 2.3-3-cont’d. Concentration calibrati on at a given tem perature for the BTEX 

compounds. 

2-12
Furthermore, we plotted the slope s from this li near relationship vs. te mperature in order to 

analyze the SPME response for a given temp erature. Figure 2.3-4 shows the linear 

relationship between the slopes at different temperatures. 

y = -3.7813x + 259.81

R2

 = 0.9405

y = -2.2933x + 172.73

R2

 = 0.9731

y = -1.2997x + 97.515

R2

 = 0.9928

y = -2.6413x + 201.32

R2

 = 0.9718

y = -2.707x + 209.17

R2

 = 0.9329

0

50

100

150

200

250

0 5 10 15 20 25 30 35 40 45

Temperature (C)

 Slope (AC/Conc)

benzene toluene ehtlybenzene m,p-xylene o-pylene

Linear (o-pylene) Linear (m,p-xylene) Linear (ehtlybenzene) Linear (toluene) Linear (benzene)

Figure 2.3-4. Dynamic Calibration Temperature Dependence 

From this dynam ic temperature calibration we correlated the three variables analyzed (such 

as area cou nts, tem perature, and concentratio n) and calculated the concentration of the 

sample by the area counts from the analysis an d the sampling temperature. Furthermore, we 

compared the 25C dynam ic and static calibrati ons and extrapolated the other temperature 

GC/PID responses in obtaining figure 2.3-5. 

y = -1.1463x + 78.761

R2

 = 0.9405

y = -0.5057x + 37.946

R2

 = 0.9928

y = -0.8207x + 61.813

R2

 = 0.9731

y = -0.7906x + 60.259

R2

 = 0.9718

y = -0.8336x + 64.411

R2

 = 0.9329

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50

Temperature, C

Slope (AC/C)

benzene toluene ethylbenzene m,p-xylene o-xylene

Linear (o-xylene) Linear (ethylbenzene) Linear (m,p-xylene) Linear (toluene) Linear (benzene)

Figure 2.3-5. Static Calibrat ion Temperature Dependence (B y interpolation from dynam ic 

system) 

2-13
The equations that result from these extrapolations are the following: 

STATIC SYSTEM (INTERPOLATED FROM DYNAMIC SYSTEM) 

 

Component equation correl Concentration 

benzene y = -0.8336x + 64.411R2 = 0.9329AC/( -0.8336T+64.411) 

toluene y = -0.7906x + 60.259R2 = 0.9718AC/( -0.7906T+60.259) 

EtBenzene y = -0.5057x + 37.946R2 = 0.9928AC/(-0.5057T+37.946)

m/p-xylene y = -0.8207x + 61.813R2 = 0.9731AC/( -0.8207T+61.813) 

o-xylene y = -1.1463x + 78.761R2 = 0.9405AC/(-1.1463T+78.761)

 

 AC/C=aT+c 

 C=AC/(aT+c) 

2.3.2.3 SPME Humidity Dependence 

Chai and Pawliszyn, 1995, performed several experiments in order to determine the influence 

of humidity for the 100 μm PDMS response factor. Humidity usually decreases the response 

factor of each individual com pound. The lower response depends on temperature. At lower 

temperatures, the humidity has a larger decrease in the response factor of a compound. Some 

compounds are not greatly affected by hum idity. The highest effect of humidity seems to be 

an approxim ately 25% decrease when going fr om dry air at 0C-10C into 25% rela tive 

humidity. Changes of the area counts at rang es of tem perature of 0C-25C for changes in 

relative hum idity from 25%-75% are alm ost ne gligible (also discussed by Parreira et al, 

2002). 

It is understood that hum idity affects the fiber response because water at high concentrations 

is completely adsorbed into the coating of the fiber. 

Initial data from the experimental set up described earlier is shown below: 

0

5000

10000

15000

20000

25000

0 10 20 30 40 50 60 70 80

Relative Humidity (%)

Area Counts

Benzene Toluene ehtylbenzene m,p-xylene o-xylene

Figure 2.3-6. Hum idity Dependence on SPME response for a 100ppb BTEX standard at 

25C. 

2-14
Current experim ents at 25C determined that hum idity in the BTEX compounds does not 

affect the GC/PID respo nse significantly, although is lowers the respon se slightly at RH > 

75% . 

2.4 Data Capture 

The overall data capture rate for all the 2 nd Reno Pilot Study m easurements is provided in 

Table 2.4-1, with the co mplete details for each ME presen ted in Appen dix A. Overall the 

data capture for the in tegrated methods was nearly com plete . Only one solid adorbent tube 

was lost to breakage. The “Refuel Can” in Table 2.4-1 refers to the 5-minute integrated 

canister co llected durin g the actu al refueling event. One canis ter cou ld not be s ampled 

because it was at atm ospheric pressure when opened in the field, and the data obtaine d from 

the other one were invalidated, thus leading to a 80% capture rate for this category. The 

“Breath Can” refers to the breath canisters (2 or 3 per ME) which were all co llected. For the 

continuous and semi-continuous methods, we had very good data captur e with only one run 

missing for the Outside PID (the one m easuring outside the vehicle cabin during the freeway 

ME). This was due to a software difference between this and our older instrum ent that 

resulted in the data logging function being accidentally turned off. The NDIR instrument lost 

some data due to insuf ficient power in a f ew early runs; fortunately the T-15 CO functioned 

perfectly for these runs. For the few runs wher e the T-15 CO data loggi ng had problems, we 

have the NDIR data thus at l east one instrument was functioning for CO during all MEs. The 

MS200 worked very w ell du ring most of the early runs, but som e detector sen sitivity 

problems and other undiagnosed problem s resulted in complete loss of data for the last four 

runs. One freeway run had m ostly good data with 5 m inutes out of the 40 m inute total being 

lost due to electrical noise of undetermined origin. This is a similar problem we had during 

the San Antonio study and m ay be related to the van’s electrical system since proxim ity to 

the other instruments in the refueling MEs did not cause similar noise. 

The formaldehyde instrument showed some good data but overall data capture rate was low , 

mostly due to an electrical shortage in the thermocouple that controls the heated reaction cell. 

This problem was not identified and fixe d until th e afternoon of May 2, 2003. W ithout 

adequate control of the temperature of the heated reaction cell, there is little certainty that the 

formaldehyde collected was actua lly derivatized in a consistent m anner. This m alfunction 

was diagnosed and fixed prior to the parking garage sample ME2-4, and did not reoccur. 

Another major source of m alfunction was the pres ence of air in the sample stream reaching 

the detector. Although an in-line debubbler wo rked well for rem oving air bubbles from the 

sample stream, air m ay still have r eached the detector if pump flow rates were not properly 

balanced among the 4 pum ps and air was accidentally pum ped into the detector. This 

occurred during the freeway (ME1-5) and refuel ing without vapor recovery (ME4-4) tests on 

May 5, 03. Another limitation of this continuou s instrument was the long stabilization time 

required for the fluorescence dete ctor upon instrum ent start-up. In some cases, response at 

the dete ctor was still stabiliz ing when the sampling period began. One of the m ost 

significant lim itations o f the for maldehyde m onitor was an apparen t sensitiv ity to moving 

environments. It has been observed that when the formaldehyde instrument was warmed up 

and operated in a stationary e nvironment, such as a parkin g garage, and then subjected to 

transport w hile still operating, re sponse at the detector oscillat ed and increased in overall. 

2-15
Figure 2.4-1 shows the response of the contin uous for maldehyde analyzer, stabilized and 

“zeroed” with a DNPH cartridge at the inlet, when statio nary and following startup and 

driving of the sampling van where the response of the detector increases and oscillates. (V) pon CHO

H

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

16:40:4816:48:0016:55:1217:02:2417:09:3617:16:4817:24:0017:31:1217:38:2417:45:3617:52:48

Time

 Res se 

installed DNPH on inlet

at 17:22 and continued 

sampling in garage

Started van and drove back to 

DRI, DNPH still on inlet and 

still acquiring

Figure 2.4-1. Effect of driving on continuou s for maldehyde analyzer, during and after 

sampling in ME2-5. 

The environm ental conditions (temperature, relative hum idity, position, speed and other 

parameters) had one run where the logging system apparently locked up about 6 m in into the 

run and gave no further data. This was a 20 min refueling run and does not represent a 

significant loss in data since th e tem peratures and hum idity probably did not change 

appreciably. 

Table 2.4-1. Data Capture Summary 

Parameter Data Capture

Ambient Can 100%

Refuel Can 80%

Breath Can 100%

DNPH 100%

Solid Ads. 95%

SPME 100%

PID In (1) 100%

PID Out (2) 80%

NDIR CO 85%

T-15 CO 85%

MS200 70%

Formaldehyde 10%

Env. Cond. 95%

2-16
3. RESULTS 

 The m ain goal of the 2 nd Reno Pilot Study was to demonstrate proper operation and 

reliability of analytic al ins trumentation and com parability of tim e-integrated, sem icontinuous and continuous methods for compounds of interest. The results section examines 

the consistency between redundant m easurements and co-pollutants, evaluates tem poral and 

spatial variations, and correlations among the vari ous data sets for measured parameters that 

we expect will be correlated. One key aspect of the study des ign was the built-in redundancy 

between the continuous m ethods and the tim e-integrated m ethods. For exam ple, CO was 

measured from the tim e-integrated canis ter sam ples and from the T-15 and NDIR 

instruments. We measured BTEX fr om canisters, continuous MS-200 and semi- continuous 

SPME as well as a surrogate measure in the PID signal. F ormaldehyde was measured by the 

continuous HCHO instrum ent and by the DNPH car tridges. In additio n, we m easured PID 

signal from two independent ppbRAE units p ositioned in -cabin and outside the cabin, o r 

collocated in outdoor microenvironments. 

3.1 Method Comparison of Redundant Data 

3.1.1 PID versus PID 

Two identical ppbRAE continuous PID mon itors were used to estim ate total VOC 

concentrations, ionizable at 10.6 eV, inside and outside the ve hicle cabin. Prior to and after 

the pilot study, both units were ca librated using an activated car bon inlet filter for the zero 

point and a certified BTEX mixture (total concentration 3700 ppb) for span. 

During several tests, the second unit was collocated with its inlet within 10 cm of the inlet of 

the primary unit for quality assurance purposes. The resulting data is s hown in Fig ure 3.1-

1a,b. While the two units track each other accurate ly, after adjusting for differences in in let 

transit tim e, the abso lute concen trations r ecorded differ significantly. The prim ary unit 

(PID1) demonstrated a positiv e offset of 40-50 ppb, which was expected since it w ould not 

read below ~40 ppb eve n when the carbon inlet filter was in place. This behavior is eviden t 

in the tests shown in Figure 3.1-1b. No consis tent bias was observed at the high peak 

concentrations shown in Figure 3.1-1a, with bot h units reading higher at tim es. Since this 

time a dif ference in sof tware was identif ied, and they h ave been h armonized for future 

studies. 

3-1
M E4 - Refueling w/o VR: test4

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 510 15

elaps ed tim e (m in)

BTEX estimated by PID (ppb)

P ID1 PID2

20

M E4 - Refueling w/o VR: test5

0

5000

10000

15000

20000

25000

30000

0 5 10 15 20

ela pse d tim e (m in)

BTEX estimated by PID (ppb)

PID 1 PID2

Figure 3.1-1a. Comparison of estimated BTEX concentrations measured by PID instruments 

with inlets collocated within 10 cm. Data are running 1 minute averages. VR = nozzle vapor 

recovery. 

3-2
ME3 - Refueling w/ VR: test5

0

5 0

100

150

200

250

0 510 15

e la pse d tim e (m in)

BTEX estimated by PID (ppb)

PID1 PID2

20

ME2 - Parking Garage: test5

0

10

20

30

40

50

60

70

80

90

100

0 510 15

e la pse d tim e (m in)

BTEX estimated by PID (ppb)

PID1 PID 2

20

Figure 3.1-1b – cont’d. Com parison of estim ated BTEX c oncentrations measured by PID 

instruments with inle ts collocated within 10 cm . Data are run ning 1 m inute averages. VR = 

nozzle vapor recovery.

3-3
Figure 3.1-2 shows the corresponding total VOC conce ntrations, ionizable at 10.6 eV, 

recorded by the two p pbRAE monitors during four freeway driving tes ts (d ata f or the 

ambient unit during test 2 was lost due to a da ta logger configuration error) where the second 

unit m easured am bient VOC conce ntrations outside the vehicle. As in the collocated unit 

tests, the two monitors track e ach other well during the high ventilati on segment of the test 

(first 20 minutes). The less dynamic variations in concentration recorded by the in-cabin unit 

are consistent with expectations. 

After the switch to low ventilat ion conditions at 20 m inutes elapsed time, the in-cabin unit 

shows very little correl ation to the am bient unit and, while not always stable, shows no 

accumulating drift evidence of interior sources or interferences. 

3-4
ME1 - Freeway: test3

0

100

200

300

400

500

600

700

800

900

0 5 10 1 5 20 2 5 30 35 40

e la psed tim e (m in)

BTE X estim ated by P ID (ppb)

in-cabin PID ambient PID

ME1 - Freeway: test1

0

200

400

600

800

1000

1200

0 5 10 15 2 0 25 30 35 40

elaps ed tim e (m in)

BTEX estim ated by P ID (ppb)

in-cabin PID ambient PID

Figure 3.1-2. Com parison of estimated BTEX concentrations measured by PID instrum ents 

during freeway driving tests. Data are running 1 minute averages. 

3-5
ME1 - Freeway: test4

0

100

200

300

400

500

600

700

0 5 10 1 5 20 25 30 35 40

elapse d tim e (m in)

BTEX estim ated by PID (ppb)

in-cabin PID ambient PID

ME1 - Freeway: test5

0

100

200

300

400

500

600

0 5 10 15 20 25 30 35 40

elaps ed tim e (m in)

BTEX estimated by PID (ppb)

in-cabin PID ambient PID

Figure 3.1-2 –cont’d. Com parison of estim ated BTEX concentrations m easured by PID 

instruments during freeway driving tests. Data are running 1 minute averages. 

3-6
3.1.2 NDIR vs. Electrochemical CO 

Both an EPA-certified gas-filter correlation NDIR optical CO analyzer (API model 300) and 

a portable battery-operated pass ive electrochem ical cell instrum ent (Langan T-15) were 

operated during all tests to measure CO. Although data recovery was less than 100% for each 

method, and the electrochemical instrument was not equipped to sample outside the in-cabin 

breathing zone during the refueling and garage tests, collocated measurements were collected 

during the two tests shown in Figure 3.1-3. 

Although the NDIR instrum ent recorded higher p eak values, due to its faster reponse tim e, 

the measurements are generally consistent to within about 1 ppm. During the low-ventilation, 

half of the tests shown the CO concentrations remain at or decrease towards the lowest level 

measured during the high-vent phase. This beha vior suggests that no in-c abin so urces o r 

interferences are present. 

There was good agreem ent betwe en the two types of CO analyzers, due to the NDIR 

instrument’s internal adaptive filtering. This filter, which is required for EPA certification, is 

intended to adjust the response ra te of the instrum ent with respect to the stability of the raw 

detector signal during a precedi ng time period, to reduce no ise. The len gth of the ‘filtering ’ 

period can range from 10 seconds up to 2 minutes, according to the manufacturer. In practice, 

the adaptive filter effectively averag es the out put data over a variable tim e period, resulting 

in concentration fluctuations that are broader and have a peak th at occurs later in tim e and a 

lower maximum height. This effect can be s een in Figure 3.1-4, whic h shows the measured 

CO concentrations from two si milar instruments drawing air from the sam e inlet ins ide the 

cabin of the test van while driving o n freeway and surface streets with windows open (this 

test was pe rformed later in the d ay than the ME1 tests, concentr ations are low er). The 

API300 was the same instrument used in the pilot study, while the ML9830 (Monitor Labs) 

was an equivalent EPA-certif ied gas -filter co rrelation NDIR instrum ent that was operated 

with the ad aptive filter turned off (a fixe d 10 second filtering period was selected). Both 

instruments have the sa me performance specifications and were calib rated just pr ior to the 

test using zero air and a 10.0 ppm CO standa rd, yet the ML9830 tim e series is m uch more 

dynamic and shows higher peak concentrations. Figure 3.1-4 also shows a tim e series of the 

ML9830 data in which the four minutes preceding each data point were averaged. This series 

matches the API300 data almost exactly, except for the first large peak which was apparently 

steep enough to trigger the API300’s adaptive filter into fast response mode. 

Despite the differences in response rate, the ov erall average concentrat ions recorded for the 

test period shown were very com parable: 1.26 ppm from the ML9830 versus 1.31 ppm from 

the API300. Fast response is desired in order to better characterize the variability of pollutant 

concentrations in a m icroenvironment, so the ML9830 is preferable for the field study. In 

addition to the convenience of front panel conf iguration of t he data filter, the ML9830 also 

uses about 50% less power and has an internal ze ro air generator to allow automatic baseline 

checks. 

3-7
ME1 - Freeway: test3

0

5

10

15

20

25

30

35

40

45

50

0 5 10 15 20 25 30 35 40

elapsed tim e (m in)

CO (ppm)

ND IR_CO Langan_CO

ME1 - Freeway: test4

0

2

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40

elapsed tim e (m in)

CO (ppm)

NDIR_CO Langan_CO

Figure 3.1-3. Com parison of NDIR (API m odel 300) and electrochem ical (Langan T15v) 

CO monitors during two freeway driving tests. 

The NDIR CO data are running 1 m inute averag es, while the electrochem ical instrum ent 

recorded data is in discrete 1 minute averages. In test 3, the NDIR instrument’s analog output 

range (0-20 ppm) was exceeded during the first 4 minutes. 

3-8
0

2468

1012

15:40

15:45

15:50

15:55

16:00

16:05

16:10

CO (ppm )

ML9830 API300 ML9830_4min.Avg

Figure 3.1-4. Comparison of two gas-filter correlation NDIR CO analyzers during on-road sampling. Data from the ML9830 instrument are shown as recorded (10 second averages) and as 4 minute running averages

3-9
3.1.3 CO versus Canister CO 

Average CO concentrations were also m easured by GC analysis of the integ rated canis ter 

samples that were collected for the d uration of each test. Figure 3.1-5 shows a scatter plot of 

the average continuous data from t he NDIR or electrochemical CO i nstruments versus the 

CO from the corresponding canister. The canister CO is generally about 8% higher, but there 

is no consistent bias. The com parison is also made on a test-by-test basis in the second chart 

of this figure, showing that discrepanc ies between the two methods occur in all 

microenvironments and at both high and low co ncentrations. The underestimation of CO by 

the NDIR instrument in the two tests with the highest average concentration (ME1- test 3 and 

ME2 – test 2) is due, at least in part, to exceed ences of the instrum ents output rang e which 

resulted in truncation of peak concentrations above about 23 ppm. This over-ranging problem 

was identified and corrected before the end of the pilot study. 

3-10
y = 1.08x

R2

 = 0.85

0

2

4

6

8

10

12

0 2 4 6 8 10 12

average of continuous CO

Ca nister CO

0

2

4

6

8

10

12

ME1 ME2 ME3 ME4

CO (ppm)

average of continuous CO

Canister CO

Figure 3.1-5. Average CO concentration for each test measured by continuous m onitor and 

GC analysis of integrated canister sample. ME1= morning rush hour commute; 

ME2=parking garage; ME3= refueling with va por recovery; ME4= refueling without vapo r 

recovery. 

3-11
3.1.4 MS vs. Canister 

The MS200 performed well in 16 of the 20 ME test s. For all of those runs we can com pare 

the integrated MS200 response to the caniste r data. Figure 3.1-6 shows the correlation for 

benzene, toluene and the sum of the C8 benzenes (ethylb enzene, o, m, & p-xylene). The C8 

benzenes are presented together because we cannot separate them us ing the MS 200. The 

correlations are all very good, with > 0.9 R-square . The correlation for toluene is the best 

with a 0.99 R-square. B oth toluene and the C8 benzenes show a clos e 1:1 correlation, but 

benzene seems to be overpredicted by the MS200. 

Bz = 1.1537x + 1.0948

R2

 = 0.9016

Tol = 0.9703x + 1.8068

R2

 = 0.9914

C8 = 1.0638x + 0.6664

R2

 = 0.9529

0

10

20

30

40

50

60

70

80

0 20 40 60 80

Canister, ppbv

MS200, ppbv

Benzene

Toluene

C8 Benzenes

Linear (Benzene)

Linear (Toluene)

Linear (C8 Benzenes)

Figure 3.1-6 Comparison of canister and MS200 data for all measured species. 

To further investigate the com parison for benzene, we plotted the benzene concentrations in 

Figure 3.1-7. This figure shows random sca tter around the trend line over the range of 25 

ppbv down to less than 2 ppbv. Overall the MS200 performed very well for runs with valid 

data. We are still inves tigating the causes of the failures of this instru ment and f eel that it 

provides excellent supplemental data but should not be relied upon as a primary method. 

3-12
Bz = 1.1537x + 1.0948

R2

 = 0.9016

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Canister, ppbv

MS200, ppbv

Benzene

Linear (Benzene)

Figure 3.1-7. Comparison of MS200 and canister for benzene only. 

3.1.5 SPME vs. Canisters 

Table 3.1-1 shows the com parison of canister B TEX data with averaged and temperature 

corrected S PME data. In general, SPME BT EX concentrations are higher than canis ter 

concentrations. This is most probably due to the temperature differences between the sta tic 

calibration and sampling conditions and inadequate correction for temperature. However, the 

passive SPME sampling rate could also be affected by the local wind speed, especially if the 

local gusts are close to 5 mph threshold. We observed higher SPME uptake of analytes in the 

dynamic system, if the flow rate of a standard gas mixture was higher than 100 ml/min. 

After clean ing and con ditioning, th e SPME fibers were sto red in the freezer and taken to 

sampling sites in a cooler with dry ice. Although the fibers were taken out of the cooler prior 

to sam pling, we are no t ce rtain if suf ficient tim e was allowed f or f iber equ ilibrations to 

ambient temperature. In retrospect, it was an e rror, since we dete rmined later that the f iber 

uptake is highly dependent on temperature (see Section 2.3.2). For the primary study we will 

change the SPME f iber storage con ditions and w ill store them in m etal cans with activa ted 

charcoal at the bottom (similar to Tenax tubes) at ambient temperature. 

3-13
Table 3.1-1. Data comparison between SPME and Canister 

 can spme can spme can spme can sp

site date strthhmm benze benze tolue tolue etbz etbz mp_xyl m

Freeway 4/29/03742-822 9.10 15.03 45.35 87.42 7.48 18.37 24.92 5Refueling W/Vapor Recovery 4/29/031200-1220 3.38 11.94 9.91 52.85 1.43 10.70 4.82 2Garage 4/29/031642-1712 5.65 19.00 14.67 56.49 3.10 16.11 10.52 4Freeway 4/30/03739-819 10.01 24.01 53.75 127.78 8.69 25.11 29.48 7Refueling W/O Vapor Recovery 4/30/03921-941 9.46 29.04 34.27 112.88 5.50 18.02 19.02 6Refueling W/Vapor Recovery 4/30/031045-1105 1.30 4.66 4.53 20.46 0.97 6.93 3.50 1Refueling W/O Vapor Recovery 4/30/031205-1245 2.13 11.02 7.85 51.68 1.15 14.11 3.96 3Garage 4/30/031645-1715 9.94 37.25 31.92 110.84 6.98 26.43 24.06 8Freeway 5/1/03720-800 18.13 32.60 75.57 146.83 12.28 26.77 40.13 8Refueling W/O Vapor Recovery 5/1/031106-1126 2.34 6.80 10.10 49.24 1.83 14.57 6.48 3Refueling W/Vapor Recovery 5/1/031225-1245 1.61 5.61 6.28 17.02 1.20 4.60 4.21 1Garage 5/1/031642-1717 10.63 20.33 34.25 71.17 7.23 13.91 25.35 4Freeway 5/2/03735-815 7.27 22.62 30.81 114.78 4.77 24.76 15.66 6Refueling W/O Vapor Recovery 5/2/03918-938 20.49 44.77 59.93 154.25 8.13 31.25 28.70 9Refueling W/Vapor Recovery 5/2/031036-1056 2.30 20.44 9.28 67.20 2.10 12.17 7.83 4Garage 5/2/031645-1715 5.29 6.07 17.10 22.80 3.79 5.55 13.53 1Freeway 5/5/03750-830 9.60 19.25 44.69 108.01 8.31 18.21 28.76 6Refueling W/O Vapor Recovery 5/5/03923-943 66.93 52.76 142.14 198.26 11.17 18.30 36.03 6Refueling W/Vapor Recovery 5/5/031045-1105 1.55 5.75 7.23 18.13 1.39 2.49 4.96 9Garage 5/6/031645-1715 4.86 6.29 14.16 22.39 3.25 5.82 11.75 2

3-14
Figure 3.1-8 shows the scatter plots for canis ter and S PME data before temperature 

corrections. 

0

50

100

150

200

250

0 50 100 150 200 250

Canister Concentration (ppb)

SPME Concentration (ppb)

benzene toluene ethylbenzene m,p-xylene o-xylene

Figure 3.1-8. Scatter Plots for raw data from SPME vs canister for the Pilot Study 2003 

Scatter plots after temperature correction. 

0

50

100

150

200

0 50 100 150 200

Canister Con centratio n (p pb)

SPME Con centration (pp b)

benzene toluene ethylbenzene m,p-xylene o-x ylene

Figure 3.1-9. Scatter Plots for temperature corrected SPME vs canister data for the Pilot 

Study 2003 

Figure 3.1-10 and Table 3.1-2 show s the correla tions after removing the two visible outliers 

(benzene and toluene from refueling w/o vapor recovery May 5th at 923-943): 

3-15
0

40

80

120

160

0 40 80 120 160

Canister Con centratio n (p pb)

SPME Con centration (pp b)

benzene toluene ethylbenzene m,p-xylene o-x ylene

Figure 3.1-10. Scatter plots from SPME vs Canister for the Pilot S tudy 2003 with two 

outliers removed. 

Table 3.1-2. Correlation of Scatter Plots from SPME and Canister Comparison 

Compound Equation Correlation 

Benzene y = 1.8365x + 4.9732 R2

 = 0.7291 

Toluene y = 1.9202x + 22.617 R2

 = 0.7936 

Ethylbenzene y = 1.6894x + 7.1997 R2

 = 0.5255 

m,p-xylene y = 1.7814x + 17.323 R2

 = 0.6452 

o-xylene y = 1.6367x + 4.0433 R2

 = 0.6526 

The scatter plots show linearity of the SPME data compared to canister data but the relatively 

low correlation values and the slope in the range of 1.6 – 1.9 can be associated with the 

differences in storage of the c onditioned fibers before sampling. As noted above, m ost fibers 

were not probably stabilized to am bient temperature before sam pling. Since the fibers were 

colder than the environ ment, some variability of the data is expected. This proble m will be 

corrected in the primary study. 

Sampled fibers were s tored an average of 5 hours and all s amples were analyzed the same 

sampling day. 

3-16
3.1.6 SPME vs. MS 

Data from SPME se mi-continuous sam ples compar ed satisfactorily with continuous data 

obtained from the MS 200. In general concentrations are within the same ranges and changes 

in concentration levels track each other most of the time. However, the SPME concentrations 

are higher in m ost cases. As explained before, this may be due to the inadequate c orrection 

for temperature and hu midity differences as co mpared with static calibration conditions and 

cold fiber storage conditions prior to sampling. 

3-17
Ethylbenzene and xylenes

0

40

80

120

160

7:30:43 7:37:55 7:45:07 7:52:19 7:59:31 8:06:43 8:13:55 8:21:07

Time

Concentration, ppb

MS SPME

Benzene

0

10

20

30

7:30:43 7:37:55 7:45:07 7:52:19 7:59:31 8:06:43 8:13:55 8:21:07

Time

Concentration, ppb

MS SPME

Toluene

0

40

80

120

160

7:30:43 7:37:55 7:45:07 7:52:19 7:59:31 8:06:43 8:13:55 8:21:07

Time

Concentration, ppb

MS SPME

Figure 3.1-11. 10 m inutes average MS data vs SPME benzene and toluene concentrations: 

Freeway 5/02 7:35-8:15 am 

3-18
Benzene

0

10

20

30

40

7:33:36 7:40:48 7:48:00 7:55:12 8:02:24 8:09:36 8:16:48 8:24:00

Time

Concentration, ppb

MS SPME

Toluene

40

80

120

160

7:33:36 7:40:48 7:48:00 7:55:12 8:02:24 8:09:36 8:16:48 8:24:00

Time

Concentration, ppb

MS SPME

Ethylbenzene and xylenes

0

40

80

120

160

7:33:36 7:40:48 7:48:00 7:55:12 8:02:24 8:09:36 8:16:48 8:24:00

Time

Concentration, ppb

MS SPME

Figure 3.1-12. 10 m inutes average MS data vs SPME benzene and tolu ene concentrations: 

Freeway 4/30, 7:35 am 

3-19
benzene

0

30

60

90

9:15:50 9:18:43 9:21:36 9:24:29 9:27:22 9:30:14 9:33:07 9:36:00 9:38:53

Time

Concentration, ppb

MS SPME

Toluene

0

50

100

150

200

250

300

9:15:50 9:18:43 9:21:36 9:24:29 9:27:22 9:30:14 9:33:07 9:36:00 9:38:53

Time

Concentration, ppb

MS SPME

Ethylbenzene and xylenes

0

50

100

150

200

250

300

9:15:50 9:18:43 9:21:36 9:24:29 9:27:22 9:30:14 9:33:07 9:36:00 9:38:53

Time

Concentration, ppb

MS SPME

Figure 3.1-13. 10 m inutes average MS data vs SPME benzene and toluene concentrations: 

Refueling w/o VR 5/02 9:18 am 

3-20
3.1.7 DNPH vs. Formaldehyde 

Comparisons of for maldehyde data are few si nce the supplem ental continuous analyzer 

provided little reliable data due to flow fluxuation and unstability during movem ent 

Comparison of formaldehyde data from DNPH with the final garage sampling event (ME2-5) 

shows that average concentration of formaldehyde detected by the continuous instrument was 

11.5 ppb, and the tim e integrated D NPH sample for the sam e event was only 5.41 ppb. I f 

data from the continuous CO m onitor from th e sam e experim ent is used to reconstruct 

concentrations of formaldehyde for the earlier portions of the run, the average form aldehyde 

concentration may be estim ated and compared to the DNPH tim e-integrated formaldehyde 

data (described in 3.2.2.). 

The continuous for maldehyde detector is desi gned for stationary laboratory use, which 

accounts for its poor perfor mance on a m obile platform. Based on these pilot study results, 

continuous formaldehyde measurements will only be made for stationary m easurements in 

the 3 city field studies. 

3.1.8 Tenax vs. Canisters 

Appendix B list the full data sets for canister and Tenax samples. Si nce Tenax and canister 

samples overlap at C8-C12 carbon num bers, it is possible to com pare concentrations for 

toluene, ethylbenzene, m/p-xylene and o-xylene obtained from both methods. Figure 3.1-14 

shows that the correlations between both m ethods are good. The scatte rplots exclude the 

5/5/03 refueling without vapor r ecovery (ME4) sam ples. For th is one ME4 replicate, the 

canister value was m uch higher than the Te nax sam ple, suggestive of a Tenax tube 

breakthrough. for this ME. This c ould be due to the extremely high gasoline concentrations 

encountered in this ME. It is possible that the breakthrough occurred for Tenax sample. One 

issue with the Tenax samples is the accurate determination of the volume sampled. Since the 

flow rate is measured at the beginning and at the end of all sampling periods, and the average 

flow is used for volum e calculation, it is poss ible that the volume is not very pr ecise, if the 

flow drop over the sampling period is substantial and non-linear. We are currently improving 

on the standard m ethod by adding the data logger to the canis ter-Tenax-DNPH cartr idge 

sampling system that will a llow us to continu ously m onitor f low rate s, thus allo wing f or 

accurate volume determination. 

3-21
Toluene

y = 0.8853x + 8.4119

R2

 = 0.8595

0

50

100

150

200

250

300

350

400

450

0 50 100 150 200 250 300 350 400 450

Cans, ppbC

Tenax, ppbC

Ethylbenzene

y = 0.9935x - 3.7545

R2

 = 0.9089

0

10

20

30

40

50

60

70

80

90

0 10 20 30 40 50 60 70 80

Cans, ppbC

Tenax, ppbC

m/p-Xylene

y = 1.1225x - 11.694

R2

 = 0.9236

0

50

100

150

200

250

300

350

0 50 100 150 200 250

Cans, ppbC

Tenax, ppbC

o-Xylene

y = 1.0321x - 6.038

R2

 = 0.9258

0

20

40

60

80

100

120

0 20 40 60 80 1

Cans, ppbC

Tenax, ppbC

00

Figure 3.1-14 Comparison of canister and Tenax data for all ME 

3-22
3.2 Comparisons of Correlated Data 

3.2.1 PID vs. CO 

Since both carbon m onoxide a nd BTEX are produced by gasoline com bustion, they are 

expected to track each other in an automobile exhaust dominated environments. Figure 3.2-1 

shows the two m easurements track well during th e parking garage tests that are focused on 

cold-start emissions, although the ratio is variable as indicate d by the scatter in Figure 3.2-3. 

The apparent time lag for the smaller peaks is an artifact of the API NDIR CO instrum ent’s 

adaptive filtering, described in the previous section, and subsequent averaging of the data. 

During the freeway driving tests, shown in Figure 3.2-4, the correlation between CO and 

VOC is good, but not as high as the parking garage data. 

3-23
ME2 - Parking Garage: test1

0

2

4

6

8

10

12

14

16

18

0 5 10 15 2 0 25 30

elapse d tim e (m in)

CO (ppm)

0

5 0

100

150

200

250

300

350

400

BTEX estimated by PID (ppb)

ND IR_C O PID1

ME2 - Parking Garage: test2

0

5

10

15

20

25

30

0 5 10 15 20 25 30

elapsed tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

BTEX estimated by PID (ppb)

NDIR_CO PID1

Figure 3.2-1. Comparison of CO and BTEX by PID during parking garage tests. 

Data are running 1 m inute averages. The CO instrument’s analog out put range (0-20 ppm ) 

was exceeded briefly during the two large peaks near the end of test 2. 

3-24
ME2 - Parking G arage: test3

0

5

10

15

20

25

0 5 10 15 20 2 5 30

elapse d tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

BTEX estimated by PID (ppb)

ND IR_C O P ID 1

ME2 - Parking G arage: test4

0

2

4

6

8

10

12

14

16

0 5 10 15 20 2 5 30

e lapse d tim e (m in)

CO (ppm)

0

5 0

100

150

200

250

300

350

BTEX estimated by PID (ppb)

N D IR_C O P ID 1

ME2 - Parking G arage: test5

0

5

1 0

1 5

2 0

2 5

0 5 10 1 5 2 0 25 30

e laps e d tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

BTEX estimated by PID (ppb)

ND IR_CO PID 1

Figure 3.2-1 – cont’d. Com parison of CO and BTEX by PID dur ing parking garage tests. 

Data are running 1 minute averages. 

3-25
p arking garage tes ts

y = 17.48x + 13.46

R2 = 0.76

0

100

200

300

400

500

600

0 5 10 15 20 25 30

CO (ppm)

BTEX by PID (ppb)

Figure 3.2-3. Scatter plot of CO vs BTEX by PID during parking gara ge tests. Data are 

running 1 minute averages. 

3-26
ME1 - Freeway: test3

0

5

10

15

20

25

30

0 5 10 1 5 20 2 5 30 35 40

e lap s e d tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

700

800

900

BTEX estimated by PID (ppb)

ND IR_CO PID 1

ME1 - Freeway: test4

0

2

4

6

8

10

12

14

0 5 10 1 5 20 2 5 30 35 40

e lap s e d tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

700

BTEX estimated by PID (ppb)

ND IR_C O P ID 1

ME1 - Freeway: test5

0

1

2

3

4

5

6

7

8

9

10

0 5 10 1 5 20 2 5 30 35 40

e lap s e d tim e (m in)

CO (ppm)

0

100

200

300

400

500

600

BTEX estimated by PID (ppb)

ND IR_CO PID 1

Figure 3.2-4. Comparison of CO and BTEX by PID during freeway driving tests. 

Data are running 1 minute averages. In test 3, the CO instrument’s analog output range (0-20 

ppm) was exceeded during the first 4 minutes. 

3-27
3.2.2 CO vs. Formaldehyde 

For the last two garage sam pling e vents (M E2-4 and ME2-5), tim e series for continuous 

formaldehyde and CO show inconclusive results. Figure 3.2-5 shows time series data for CO 

and for maldehyde for ME2-4. During the ME2- 4 period in which form aldehyde data was 

above the detection limit, both the CO and formaldehyde appear to respond to the same 

event, but the peaks are not in phase with each other. 

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

16:40:4816:48:0016:55:1217:02:2417:09:3617:16:48

Time

HCHO (ppb)

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

NDIR CO (ppm)

HCHO (ppb)

NDIRCO (ppm)

Figure 3.2-5 ME2-4 continuous HCHO and CO tim e series with unexpla ined difference in 

lag between the two instruments. 

Approximately 2.5 minutes separate the instrum ent responses. This indicates that either the 

time lag correction of 6 m inutes is not accura te for this test, or the adaptive s moothing 

feature of the CO instrum ent is caus ing a dela yed peak rise in CO. Figure 3.2-6 shows the 

same ti me series data following adjustm ent of the for maldehyde data by 2.5 minutes t o 

compensate for the undetermined source of error. The data track each other very well. 

3-28
0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

16:40:4816:48:0016:55:1217:02:2417:09:3617:16:48

Time

HCHO (ppb)

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

NDIR CO (ppm)

HCHO (ppb)

NDIRCO (ppm)

Figure 3.2-6. ME2-4 continuous H CHO ti me s eries shifted back 2.5 minutes to match CO 

time series. 

Once this tim e adjustment was m ade, CO an d HCHO concentration s were com pared by 

regression, and the res ulting eq uation ([HCHO] = [CO]*1.2996-1.14587, R 2

 = 0.91) was 

used to estimate HCHO concentrations for the period prior to su ccessful data capture for this 

experiment. The resulting average concentr ation for the estim ated for maldehyde data 

combined with the actual form aldehyde data was 5.414 ppb. The tim e integrated 

formaldehyde data from the DNPH for the ME2-4 experiment was 7.348 ppb. The estimated 

value is 74 % of the o bserved tim e integra ted sam ple. Despite the discrepancy in phase 

between the continuous CO and for maldehyde an alyzers, this experi ment is the best 

indication that the continuous for maldehyde analyzer may work well if properly tuned and 

operated in a suitable environment. It also indicates that CO may serve as a useful surrogate 

for formaldehyde. To explore this relationship further, formaldehyde results from the DNPH 

cartridges were plotted in a scatter plot agains t CO from time integrated canister samples for 

each m icroenvironment. Figure 3.2-7 shows the plot with different m icroenvironments 

having unique symbols on the plot. Formaldehyde from the Freeway microenvironment does 

not correlate with CO sam ples from the sam e environment. The garage and refueling 

microenvironments app ear to have a positive corr elation with CO but clu ster f or each 

microenvironment. Fitting a linear regre ssion through data points for the Garage and 

Refueling m icroenvironments, neglecting th e Freeway m icroenvironment, gives a good 

correlation ([HCHO] = 0.594*[CO] + 0.397, R2

 = 0.793). 

3-29
0

5

10

15

20

25

0 2 4 6 8 10 12 14

Can CO (ppm)

DNPH HCHO (ppb)

Garage

Freeway

Refuel w/o V.R.

Refuel w/ V.R.

Figure 3.2-7. Scatter plot of formaldehyde (from DNPH) and CO for all microenvironments. 

3-30
Finally, comparison of continuous for maldehyde and CO m easurements for the last garage 

sampling event (ME2-5) shows poor correlation in phase and tim ing (Figure 3.2-8). The 

unexplained 2.5 m inute lag that resolved peak s in the ME2-4, did little to help this 

comparison. 

0.00

5.00

10.00

15.00

20.00

25.00

16:4016:4816:5517:0217:0917:16

Time

HCHO (ppb)

0.00

5.00

10.00

15.00

20.00

25.00

NDIR CO (ppm)

HCHO (ppb)

NDIR CO (ppm)

Figure 3.2-8. Formaldehyde and CO time series for ME2-5. 

3-31
3.2.3 SPME vs. PID 

SPME total BTEX se mi-continuous data com pares reasonably with the continuous signal 

obtained from the interior PID situated righ t next to the fiber while sampling. The SPME 

concentrations are with in the rang e of the PID signal and follow the changes in PI D 

concentrations. 

100

200

300

400

7:35 7:41 7:48 7:55 8:01 8:08 8:15

Time

PID Concentration (ppbv)

100

200

300

400

SPME Concentration 

(ppbv)

PID1 SPME tot BTEX

Figure 3.2-9. SPME 10 min total BTEX vs. PID 10 min averages, Freeway, 5/02, 7:35 am 

0

100

200

300

400

500

600

700

9:21 9:27 9:34 9:41

Time

PID Concentration (ppbv)

0

100

200

300

400

500

600

700

SPME Concentration (ppbv)

PID1 SPME tot BTEX

Figure 3.2-10. SPME 10 m in total BTEX vs. PI D 10 m in averages, Refueling w/o VR 4/30 

9:21am. 

3-32
0

100

200

300

400

500

600

700

7:39 7:45 7:52 7:59 8:05

Time

PID Concentration (ppbv)

0

100

200

300

400

500

600

700

SPME Concentration 

(ppbv)

PID1 SPME tot BTEX

Figure 3.2-11. SPME 10 min total BTEX vs. PID 10 min averages, Freeway 4/30, 7:35 am. 

0

200

400

600

800

1000

1200

1400

1600

1800

9:18 9:24 9:31 9:38

Tim e

PID Concentration (ppbv)

0

200

400

600

800

1000

1200

1400

1600

1800

SPME Concentration (ppbv)

P ID 1 S P M E tot B TE X

Figure 3.2-12. SPME 10 m in total BTEX vs. PI D 10 m in averages, Refueling w/o VR 5/02 

9:18 am. 

3-33
0

50

100

150

200

16:45 16:51 16:58 17:05 17:11

Time

PID Concentration (ppbv)

0

50

100

150

200

SPME Concentration (ppbv)

PID1 SPME tot BTEX

Figure 3.2-13. SPME 10 m in total BTEX vs. PI D 10 m in averages, Pa rking Garage 5/06, 

16:45 pm. 

Continuous estimates of total VOC by a PID pp bRAE monitor compared reasonably to the 

semi-continuous measurements of BTEX obtained from analysis of SPME fibers. 

3-34
3.3 Environmental Factors 

The various environm ental conditions m onitored during this study are presented in this 

section by microenvironment. These data were collected once every 10 seconds, to sim plify 

the presentation, we present the average for each 10 m in se gment (to correspond w ith the 

SPME time interval) and the overall average va lue In addition, we present tem perature and 

wind data collected at a weather station on top of DRI’s building. These data are useful as a 

general reference for local c onditions, however, it is im portant to point out that DRI’s 

building is on top of a hill with nothing to block winds for approximately 270 degrees around 

and is noted as being one of the windiest sp ots in th e a rea. Th is is im portant since we 

selected the refueling stations in a location at the bottom of a nearby valley approxim ately 

250 feet lower in elevation with a large ridge blocking the prevailing winds. For all stationary 

MEs we monitored wind with a hand-held anemometer that had a lower-limit of detection of 

approximately 1 mph. 

For the freeway microenvironment (ME1), we measured temperature and relative humidity at 

the driver’s breathing zone which was also the sample inlet location for all equipment except 

the second PID which was m onitoring the air outside the van. The outside PID inlet was 

located on the radio antenna on the right front corner of the van. Since the sampling location 

was inside the van, the tem perature is typicall y higher than the am bient. We also m onitored 

the temperature on the outside surface of the fuel tank. These data are presented in Table 3.3-

1 along with the average conditi ons for the DRI weather stati on. The average temperature in 

the van climbed during the runs partially due to the f act tha t we started low ventilation 

conditions h alfway thro ugh the run. Relativ e hu midities were relativ ely constan t. The fuel 

tank tem perature clim bed steadily during the run, which was interesting considering the 

ambient temperatures did not. This was due to the recirculation of fuel after is passes the fuel 

injectors and picks up heat from the engine. The 10 second data of fuel tank tem peratures for 

an example run are presented in Figure 3.3-1. 

3-35
Table 3.3-1. Environmental Conditions for Freeway Driving MEs. 

Fuel Tank

ME Date Start End Data Set Temp, C Humidity, % Temp, C Wind, mph Temp, C

ME1 - Freeway 4/2904/29/03 7:42 8:22 avg. of 1st 10 minutes: 12 37 5

avg. of 2nd10 minutes: 12 32 7

avg. of 3rd 10 minutes: 16 32 11

avg. of 4th 10 minutes: 21 32 13

Average of all 15 33 9 1.8 4.4

ME1 - Freeway 4/3004/30/03 7:39 8:19 avg. of 1st 10 minutes: 10 42 4

avg. of 2nd10 minutes: 13 34 7

avg. of 3rd 10 minutes: 21 28 11

avg. of 4th 10 minutes: 25 26 14

Average of all 17 33 9 3.0 1.5

ME1 - Freeway 5/0105/01/03 7:20 8:00 avg. of 1st 10 minutes: 11 44 7

avg. of 2nd10 minutes: 16 31 8

avg. of 3rd 10 minutes: 20 30 10

avg. of 4th 10 minutes: 21 34 12

Average of all 17 35 9 1.2 4.4

ME1 - Freeway 5/0205/02/03 7:35 8:15 avg. of 1st 10 minutes: 16 36 11

avg. of 2nd10 minutes: 20 30 12

avg. of 3rd 10 minutes: 23 30 15

avg. of 4th 10 minutes: 23 33 16

Average of all 20 32 14 4.5 7.8

ME1 - Freeway 5/0505/05/03 7:50 8:30 avg. of 1st 10 minutes: 15 39 7

avg. of 2nd10 minutes: 17 33 9

avg. of 3rd 10 minutes: 20 36 12

avg. of 4th 10 minutes: 22 39 16

Average of all 18 37 11 1.8 5.4

Sampling Point Measures

Ambient Conditions

(DRI Weather Station)

3-36
0

2

4

6

8

10

12

14

16

18

7:33 7:40 7:48 7:55 8:02 8:09 8:16 8:24 8:31 8:38

Time

Fuel Tank Temp, C

Start Motor

Start Sampling

End Sampling

Figure 3.3-1. Fuel tank tem peratures during freeway ME on 4/29/03. Ambient temperature 

was 4.4 C during this time. 

For the garage m icroenvironment (ME2) we meas ured temperature and relative humidity at 

the sampling point, which was also the sam ple inlet location for all equipment located on the 

tripod near the van. These da ta are presented in Table 3.3-2 along with the average 

conditions for the DRI weather station. The average temperature and relative humidities were 

relatively constant, as was the fuel tank tem perature as might be expected for this stationary 

and mostly indoor ME. While the average winds at DRI were quite high (twice in excess of 

10 m ph) inside the garage the w inds were calm and undetectab le by the hand-held 

anemometer. The above-ground garage is also approximately 3.5 m iles south and slightly 

west of the DRI building (measured in a straight line). 

3-37
Table 3.3-2. Environmental Conditions for Garage MEs. 

Fuel Tank Local

ME Date Start End Data Set Temp, C Humidity, % Temp, C Wind, mph Temp, C Winds

ME2 - Parking Garage 4/29 04/29/03 16:42 17:12 avg. of 1st 10 minutes: 11 35 15

avg. of 2nd10 minutes: 10 35 15

avg. of 3rd 10 minutes: 10 36 15

Average of all 10 35 15 8.3 9 Calm, not measureabl

ME2 - Parking Garage 4/30 04/30/03 16:45 17:15 avg. of 1st 10 minutes: 12 33 14

avg. of 2nd10 minutes: 11 33 14

avg. of 3rd 10 minutes: 11 33 14

Average of all 11 33 14 10.4 10 Calm, not measureabl

ME2 - Parking Garage 5/01 05/01/03 16:42 17:17 avg. of 1st 10 minutes: 16 24 16

avg. of 2nd10 minutes: 14 25 16

avg. of 3rd 10 minutes: 14 26 16

Average of all 15 26 16 4.9 14 Calm, not measureabl

ME2 - Parking Garage 5/02 05/02/03 16:45 17:15 avg. of 1st 10 minutes: 14 46 15

avg. of 2nd10 minutes: 14 48 15

avg. of 3rd 10 minutes: 14 47 15

Average of all 14 47 15 4.5 12 Calm, not measureabl

ME2 - Parking Garage 5/06 05/06/03 16:45 17:15 avg. of 1st 10 minutes: 14 34 16

avg. of 2nd10 minutes: 13 34 16

avg. of 3rd 10 minutes: 14 35 15

Average of all 14 34 16 11.7 11 Calm, not measureabl

Sampling Point Measures

Ambient Conditions

(DRI Weather Station)

For the ref ueling m icroenvironments (ME3 was with vapor recovery, ME4 w as without 

vapor recovery), we measured temperature and relative humidity at the sampling point which 

was also the sample inlet location for all equipment. This was located on the tripod between 

the van and the fuel pump to allow us to asse ss the conditions at the breathing zone of the 

person refueling the van. These data are presented in Table 3.3-3 along with the average 

conditions for the DRI weather station. The average temperature and relative humidities were 

relatively constant, as was the fuel tank tem perature as might be expected for this 20 m inute 

stationary ME. While the average winds at DRI did go above the 5 mph threshold for three of 

the MEs, the winds at the refueling stations were much lower as monitored by the hand-held 

anemometer. The stations are 1.3 and 1.9 miles from the DRI building (measured in a straight 

line). Also presented in Table 3.3-3 are the maximum numbers of cars seen in the station, the 

amount of fuel dispensed and the amount dropped on the ground following refueling. The 

station with the vapor recovery was a m uch busier station with more than twice the num ber 

of cars as the other station. Th e station used for refueling without vapor recovery (ME4) 

could refuel a m aximum of four vehicles at one time, as it had two p umps and each pum p 

could be used from either side. The station used for refueling with vapor recovery (ME3) 

could refuel a maximum of 8 vehicles at once, as it had two islands with two pumps each and 

each pum p could be approached from either side. For all MEs we managed a relatively 

consistent number of gallons dispensed which was possible since we could unload fuel from 

the van to a nearly cons tant level. For each refueling ME, we filled up until th e automatic 

shutoff stopped the filling process. The num ber of drops spilled was not as co nsistent 

partially due to the difficulty in precisely dropping a fixed amount of fuel out of the nozzle. 

The number in Table 3.3-3 is the number of drops spilled which was an approximate count of 

the number of wet spots noted on the pavem ent. The exception is the fi rst ME where a large 

amount of fuel unexpectedly cam e out of the nozzle and left a single spot approxim ately 5 

cm in diameter. 

3-38
Table 3.3-3. Environmental Conditions for Refueling MEs. 

Fuel Tank Max. Cars Gallons Drops of Local

ME Date Start End Data Set Temp, C Humidity, % Temp, C In Station Dispensed Fuel Spilled Wind, mph Temp, C Winds

ME3 - Refueling w/ VR 4/29 04/29/03 12:00 12:20 avg. of 1st 10 minutes: 11 28 12

avg. of 2nd10 minutes: 11 28 13

Average of all 11 28 13 6 16.50 5 cm pool 5.9 7.4 1 - 2 mph

ME3 - Refueling w/ VR 4/30 04/30/03 10:45 11:05 avg. of 1st 10 minutes: 9 37 14

avg. of 2nd10 minutes: 9 36 15

Average of all 9 36 15 4 16.25 25 3.8 6.5 2 mph from SE

ME3 - Refueling w/ VR 5/01 05/01/03 12:25 12:45 avg. of 1st 10 minutes: 14 24 16

avg. of 2nd10 minutes: 14 24 16

Average of all 14 24 16 3 16.42 5 7.6 11.9 2 - 4 mph from SE var

ME3 - Refueling w/ VR 5/02 05/02/03 10:36 10:56 avg. of 1st 10 minutes: 11 53 15

avg. of 2nd10 minutes: 10 54 14

Average of all 11 53 15 5 15.40 10 2.5 8.5 < 1 mph, some drizzle

ME3 - Refueling w/ VR 5/05 05/05/03 10:45 11:05 avg. of 1st 10 minutes: 12 35 17

avg. of 2nd10 minutes: 12 35 16

Average of all 12 35 17 6 17.50 12 3.9 9.0 <1 mph from SSE

ME4 - Refueling w/o VR 4/3004/30/03 9:21 9:41 avg. of 1st 10 minutes: 14 28 14

avg. of 2nd10 minutes: 14 28 14

Average of all 14 28 14 3 15.80 6 2.9 3.6 1 - 2 mph from NNW

ME4 - Refueling w/o VR 4/3004/30/03 12:01 12:21 avg. of 1st 10 minutes: 12 30 16

avg. of 2nd10 minutes: 13 28 16

Average of all 13 29 16 1 15.40 12 3.2 7.9 2 - 4 mph variable dir.

ME4 - Refueling w/o VR 5/0 05/01/03 11:06 11:26 avg. of 1st 10 minutes: 15 22 14

avg. of 2nd10 minutes: 14 22 14

Average of all 14 22 14 1 14.18 3 6.6 9.8 2 - 3 mph from SSE

ME4 - Refueling w/o VR 5/0205/02/03 9:18 9:38 avg. of 1st 10 minutes: 11 42 18

avg. of 2nd10 minutes: 10 44 17

Average of all 11 43 18 2 17.31 12 3.5 8.7 1 - 2 mph, overcast

ME4 - Refueling w/o VR 5/0505/05/03 9:23 9:43 avg. of 1st 10 minutes: 17 28 18

avg. of 2nd10 minutes: 17 30 18

Average of all 17 29 18 1 14.50 20 3.9 8.3 < 1 mph from W

Sampling Point Measures

Ambient Conditions

(DRI Weather Station)

3-39
3.4 Reconstructed Data 

One of the objectives of this study was to de termine if the original objective of using 

surrogate measures to determ ine the tim e seri es of com pounds of interest was valid. To 

answer this question, this section details the reconstruction of the time series for benzene and 

BTEX from the PID data and the comparison of this to the benzene and BTEX determined by 

the MS200 portable mass spectrometer. 

The procedure is first to average the 10 second data that is recorded by the PID 

instrument up to 1 minute data for com parison with the MS200 data set (1 m inute 

increments). This tim e series is then used along with the integrat ed canister value to 

reconstruct a tim e series of the canister concen trations. To accom plish this, a ratio is taken 

between th e PID value at each point and the average P ID value for th e tim e series. This 

number is multiplied b y the integr ated canister value to g ive a reconstructed value for that 

data point and is compared to the time-corresponding data point from the MS200. 

The first example presented is for the freeway driving (ME1) on 4/29/03. Figure 3.4-1 

shows the tim e series f or benzene in this ME. A few data points are m issing from the MS 

data where some electrical noise ren dered those data points invalid. Th e general trend of the 

peaks is reproduced by both the MS200 and the PID reconstructed data, however, the peak 

values are much higher in the MS200. This is confirmed by the comparison of the integrated 

values, where the MS200 showed 14.7 ppb and th e canister 9.1. ppb. This ratio (1.6) nearly 

accounts for the differences and may be due to offset (zero point) or calibration differences in 

the MS200. Comparing the time series for the su m of the BTEX species, we obtain the plot 

in Figure 3.4-2. In this figure, the structure of the time series and the magnitude of the peaks 

are both much more precisely reproduced than is the case with just ben zene. Due to both the 

higher concentrations of toluene and the C8 benzenes, and the better perform ance of the 

MS200 with these species. S ection 3.1.9 details the performance of th e MS200 versus the 

canisters an d shows that benzene is consis tently the m ost difficult s pecies to measure, 

especially at the lower levels. The integra ted canister measurement for this sam ple was 97 

ppb for the sum of the BTEX species while the MS200 reported 123 ppb. Looking at the two 

highest peaks in this tim e series (8:01 and 8:03 am ) it appears that the tim ing is slightly off 

with the MS200 lagging the PID reconstructed data. 

To further investigate the tim ing between these two instrum ents, we looked at a higher 

concentration sam ple with a si gnificant spike in the concentration (ME4 refueling w ithout 

vapor recovery from 5/2/03). Figure 3.4-3 shows the reconstructed tim e series for benzene 

along with the MS200 values for benzene. Figure 3.4-4 presents the same data for B TEX. In 

both figures, the series is well reproduced how ever the peak values reco rded by th e MS200 

are much lower than the reconstructed. Duri ng the “non-peak” part of the ME, the MS200 

appears to be reading consistently higher than the reconstructed values. Overall, however, the 

values match quite well with the ratio of MS200/canister of 1.05 for the BTEX species and 

1.18 for benzene. As with the previous exampl e, it appears that th e tim ing of the peak 

concentration is out of phase by one m inute. To look more closely at the peak concentration, 

we used the original 10 second data from the PID to reconstruct a 10 second tim e series for 

the BTEX species and plotted th at along with the 1 m inute data in Figure 3.4-5. This figure 

3-40
does not show the entire time series; rather it focuses on the period of the peak exposure from 

9:27 to 9:33 a m. In this figure, the 10-second reconstructed data shows two peaks where the 

1-minute reconstructed and the MS200 data show one peak. The 1-minute time averaged data 

may better represent what the MS200 is m easuring, since the MS200 does not integrate 

samples over the 1-m inute period. Rather, the nature of the flow-through system smears the 

peaks out over a longer tim e due to the tim e it takes analytes to di ffuse through the inlet 

system and into the mass analyzer. The flow-through system also means that some very short 

duration high peaks may not be seen at all. 

Overall the com parison of the reconstructed BTEX and MS200 BTEX values substantially 

agree and this provides added confidence that we can represen t the peak exposures well by 

using the PID values to reconstruct time series for the BTEX species. While we do not have a 

direct m easure for 1,3-butadie ne, we would suggest that it could also be adequately 

represented by the PID values, especially for exhaust-dominated MEs. 

0

5

10

15

20

25

30

35

7:26 7:40 7:55 8:09 8:24

Time

ppbv

MS200 Benzene

Reonstructed Bz

Figure 3.4-1. ME1 (freeway driving) on 4/29/03: Time series of benzene from the MS200 

and reconstructed benzene concentrations from the PID and canister measurements. 

3-41
0

50

100

150

200

250

7:26 7:40 7:55 8:09 8:24

Time

ppbv

MS200 BTEX

Reonstructed BTEX

Figure 3.4-2. ME1 (freeway driving) on 4/29/03 : Time series of BTEX from the MS200 and 

reconstructed BTEX concentrations from the PID and canister measurements. 

3-42
0

50

100

150

200

250

9:14 9:21 9:28 9:36 9:43

Time

ppbv

MS200 Benzene

Reonstructed Bz

Figure 3.4-3. ME4 (refueling without vapor rec overy) on 5/2/03: Tim e series of benzene 

from the MS200 and reconstructed benzene c oncentrations from t he PID and canister 

measurements. 

3-43
0

200

400

600

800

1000

1200

1400

9:14 9:21 9:28 9:36 9:43

Time

ppbv

MS200 BTEX

Reonstructed BTEX

Figure 3.4-4. ME4 (refueling without vapor recove ry) on 5/2/03: Tim e series of BTEX from 

the MS200 and reconstructed BTEX concentrations from the PID and canister measurements. 

3-44
0

1000

2000

3000

4000

5000

6000

7000

9:27 9:30 9:33

Time

ppbv

MS200 BTEX

Reonstructed BTEX

10 Sec BTEX

Figure 3.4-5. ME4 (refueling without vapor recove ry) on 5/2/03: Tim e series of BTEX from 

the MS200 and reconstructed BTEX concentra tions at both 1 m inute and 10 second time 

resolution. 

3-45
3.5 Breath Data 

Two subjects, labeled “B” and “J”, perform ed breath sample collections. The CO2 level in 

their breath sam ples was m easured prior to the comm encement of the pilot study, and 

averaged 5.4% for B and 6% for J. As de scribed in Section 2.1, tw o breath sam ples were 

collected at refueling ME (prior to refueling and 10 sec after refueling), and three during each 

commuter traffic and garage test (before, after a peak exposure, and at the end of the ME 

sampling time). All breath sam ples were an alyzed for CO2, BTEX, 1,3-butadiene, ethanol 

and MTBE as described in Section 2.3. The whole data set is presented in Appendix C. 

Figure 3.5–1 shows the CO2 values in the breath samples of subjects B and J collected in all 

ME, organized by the subject and by the m icroenvironment. It is clear that one pre- test 

freeway sample collected by J is in valid, since CO2 value is below 1%. Excluding this one 

sample, the m ean CO2 value for subject B averages at 5.4%, and for subject J at 6.07% for 

all ME. 

Figure 3.5-2A shows the concentrations of 1,3-butadiene, benzene, ethylbenzene, m/p- and oxylenes in the breath samples for all freeway tests (organized in the chronological order) and 

Figure 3.5-2B shows the c oncentrations of toluene and etha nol for the sam e ME. Figures 

3.5-3 A and B and Figure 3.5-4 A and B shows the same compound concentrations for the 

garage and refueling ME, respectively. The range of concentrations for 1,3-butadiene, 

benzene, ethylbenzene, m/p- and o-xylenes agree reasonably well for bo th subjects, there is 

clearly a large difference in the toluene conc entrations. Subject B contains m uch higher 

toluene concentrations in the breath – it looks like the toluene is present in the b reath of this 

subject, regardless of the exposure. The reason of this phenom enon is unknown to us. 

Ethanol concentrations are rath er high and variable, not dependa nt on the exposure. MTBE 

concentrations are very low and are not shown on these figures. Neither MTBE nor ethanol 

are present in the Reno fuel at this time of the year. 

3-46
Carbon Dioxide

0123456789

%

----------------------------------------------------------- B --------------------------------------------------------------------------------------

---------------------------------------------------

Figure 3.5–1. CO2 values in the breath sam ples of subjects B a nd J collected in all ME, orga nized by microenvironment. 

3-47
Freeway

0

2

4

6

8

10

12

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre,J

Freeway, Peak,J

Freeway, Post,J

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre,J

Freeway, Peak,J

Freeway, Post,J

ppb

bud13

benze

etbz

mp_xyl

o_xyl

A

Freeway

0

20

40

60

80

100

120

140

160

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre,J

Freeway, Peak,J

Freeway, Post,J

Freeway, Pre

Freeway, Peak

Freeway, Post

Freeway, Pre,J

Freeway, Peak,J

Freeway, Post,J

ppb

tolue

ethoh

B

Figure 3.5-2. The concentrations of 1,3-butadie ne, benzene, ethylbenzene, m /p- and oxylenes (A) and toluene and ethanol (B) in the breath samples of subject B (not labeled) and 

J in the freeway driving ME. The runs are shown in chronological order 

3-48
Garage

0

1

2

3

4

5

6

7

8

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre,J

Garage, Peak,J

Garage, Post,J

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre,J

Garage, Peak,J

Garage, Post,J

ppb

bud13

benze

etbz

mp_xyl

o_xyl

A

Garage

0

20

40

60

80

100

120

140

160

180

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre,J

Garage, Peak,J

Garage, Post,J

Garage, Pre

Garage, Peak

Garage, Post

Garage, Pre,J

Garage, Peak,J

Garage, Post,J

ppb

tolue

ethoh

B

Figure 3.5-3. The concentrations of 1,3-butadie ne, benzene, ethylbenzene, m /p- and oxylenes (A) and toluene and ethanol (B) in the breath samples of subject B (not labeled) and 

J in the garage ME. The runs are shown in chronological order 

3-49
Refueling

0

5

10

15

20

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre,J

Ref. W/O V, Post,J

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre,J

Ref. W/O V, Post,J

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre,J

Ref. W/V, Post,J

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre,J

Ref. W/V, Post,J

ppb

bud13

benze

etbz

mp_xyl

o_xyl

80 ppb

A

Refueling

0

50

100

150

200

250

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre,J

Ref. W/O V, Post,J

Ref. W/O V, Pre

Ref. W/O V, Post

Ref. W/O V, Pre,J

Ref. W/O V, Post,J

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre,J

Ref. W/V, Post,J

Ref. W/V, Pre

Ref. W/V, Post

Ref. W/V, Pre,J

Ref. W/V, Post,J

ppb

tolue

ethoh

B

Figure 3.5-4. The concentrations of 1,3-butadie ne, benzene, ethylbenzene, m /p- and oxylenes (A) and toluene and ethanol (B) in the breath samples of subject B (not labeled) and 

J during refueling. The runs are shown in chronological order 

3-50
3.6 Consistency of Microenvironment Conditions 

Each of the four m icroenvironments included in this pilot study was repeated 5 tim es to 

assess the v ariability of the environ mental c onditions and precision of the characterization 

methods. During the testing periods there were no significant variatio ns in m eteorological 

conditions and the sam e protocols were obser ved, so it is reasonable to attribute any 

variations in the range or m agnitude of m easurements to di fferences in activity in the 

microenvironment, daily variations in background concentrations, or m easurement 

uncertainty. Statistical summaries of the continuous CO and BTEX by PID data are presented 

in this section to exam ine this var iability. The statistics represented are the m aximum and 

mean of the running 1 m inute averages of th e continuous concentration m easurements 

recorded every 10 seconds during each test. The 10th and 90th percentile values for each test 

are also represented to g ive a better repres entation of the range of conc entrations observed. 

Charts of the average for each m icroenvironment and standard dev iation of the average 

among the 5 replicates are also included in Figure 3.6-3. 

3.6.1 CO 

Figure 3.6-1 shows the API NDIR CO data except for the first two repetitions of ME1 and 

the first ME3 for which the NDIR d ata was invalid because of insufficient battery. For those 

three tests discrete 1 m inute av erages from the electrochem ical CO instru ment are 

summarized in the chart. 

The range of concentrations is large for all tests, with the exceptio n of several of the 

refueling tests (ME3 and ME4) where CO c oncentrations were ne ar background throughout 

the tes ts. Despite the large rang e, the differen ces between m icroenvironments are clearly 

evident. The parking garage tests, ME 2, had higher m aximum and 90th percentile 

concentrations than all but one of the freeway tests even th ough the average concentrations 

are similar. The two refueling MEs are cons istently lower than the freeway or garage in both 

the mean and maximum values. The third freeway (ME1) test appears to be an outlier due to 

a high initial level of CO (see Figure 3.2-4), po ssibly a result of capturing exhaust from the 

van in the cabin prior to the start of the driving cycle. 

3-51
0

5

10

15

20

25

ME1 ME2 ME3 ME4

1 m inute running avg CO (ppm )

10th to

90th %

MAX

MEAN

Figure 3.6-1. Range and variability of CO con centration during tests. S tatistics for each of 

the five replicate tests are shown for each microenvironment. 

Data summarized are running 1-minute averages (at 10 second interval s) of NDIR CO data, 

except for the first two ME1s and fi rst ME3 which are dis crete 1 m inute averages from the 

electrochemical CO instrum ent. The shaded ba rs indicate the range from the 10th to 90th 

percentile. Microenvironments are: freeway driv ing (ME1), parking garage (ME2), refueling 

with vapor recovery (ME3), and refu eling without vapor recovery (ME4).

3-52
3.6.2 PID 

The range and variability of BTEX concentrations estim ated by the prim ary ppbRAE VOC 

monitor (PID1) are summarized in Figure 3.6-2. As with CO, the range of the m ean and 

maximum values is larg e for all tests, but s till smaller than the overa ll difference between 

microenvironments. The largest range occurred for refueling without vapor recovery (ME4), 

which is to be expected since very high VOC levels occurred during the refueling process. In 

all cases, the 10th percentile values were near th e lower limit of detection (they appear to be 

zero in the chart due to scale) suggesting that background levels of BTEX were very low. 

3-53
0

2000

4000

6000

8000

10000

12000

14000

16000

18000

ME1 ME2 ME3 ME4

1 m inute running avg BTE X by PID (ppb)

10th to

90th %

MAX

MEAN

0

100

200

300

400

500

600

700

800

900

1000

ME1 M E2 ME3 ME4

1 m inute running avg BTE X by PID (ppb)

10th to

90th %

MAX

MEAN

Figure 3.6-2. Range and variability of BTEX by PID concentration during tests. 

Statistics for each of th e five rep licate te sts are shown for each m icroenvironment. Data 

summarized are running 1-minute averages (at 10 second intervals) The shaded bars indicate 

the range from the 10th to 90th percentile. The lower chart shows the sam e dat a on an 

expanded s cale. M icroenvironments are: free way driving (ME1), parking garage (ME2), 

refueling with vapor recovery (ME3), and refueling without vapor recovery (ME4). 

3-54
A verage of replicate test mean c onc entrations

0

1

2

3

4

5

6

7

8

9

ME1 ME2 ME3 ME4

CO (ppm)

0

200

400

600

800

1000

1200

1400

ME1 ME2 ME3 ME4

BT EX by PID (p pb)

Figure 3.6-3. Range a nd variability of mean CO and m ean BTEX by PID concen tration for 

four microenvironments. 

Data summarized are running 1-minute averages (at 10 second interval s) The error bars 

indicate the standard de viation of the average of five repl icate tests. Microenvironments are: 

freeway driving (ME1), parking garage (ME2), refueling with vapo r rec overy (ME3 ), and 

refueling without vapor recovery (ME4). 

3-55
4. CONCLUSIONS 

Overall, the 2nd Reno Pilot study was a success. Specifically, we completed the stated goal 

of the study: to dem onstrate the proper operation and reliability of analytical instrumentation 

and com parability of tim e-integrated, se mi-continuous and continuous m ethods for 

compounds of interest. In addition, we dem onstrated the validity of the method of 

reconstructing time series for compounds of interest by using surrogate measurements. In this 

case, we specifically demonstr ated the validity of using the PID signal and the canister data 

to reconstruct the time series for BTEX. 

The following conclusions are drawn from the 2nd Reno Pilot Study results: 

Modifications to the sampling van and addition of the data acquisition system were 

significant improvem ents that allow ed for more com plete d ata collectio n. The new 

power system does not produce artifacts; howev er, it is insufficient to power the API 

CO instrument. Possible alternatives include use of a different brand of NDIR CO or 

the addition of m ore battery banks to sup port the A PI NDIR CO. Severa l 

improvements ar e still planned to the sa mpling van inc luding the ad dition of a 

continuously logged barom etric pressure se nsor, direct logging of flow to the 

integrated samplers, and logging of canister pressure. 

Data capture was generally quite good with near 100% data capture for the reference 

samples, canisters, DNPH and solid adsorbent. The SPME also had excellent data 

capture, as did the continuous instrum ents for CO and PI D. The MS200 performed 

well in the beginning of the study however at the end it was not working. The 

supplemental continuous for maldehyde instru ment is not reliable during m obile 

measurements, and should only be used for statio nary m easurements. Our 

environmental m onitoring equipm ent for te mperatures, hum idity, etc., lost only 14 

minutes of data over the entire study. 

The MS200 generally perform ed well agai nst the canister when comparing the 

average value from the MS to the integrat ed canister measurement for the same ME. 

However, there are still concerns with th is supplemental measurement system. There 

appears to be a concentration bias, especially for benzene. The instrum ent appears to 

miss very rapid changes in concentration su ch as those that occur du ring refueling 

events. There are still so me electrical nois es that appear in the van when in m otion. 

We did not detect these in the stationary MEs, and they did not invalidate more than a 

few spectra in a run. The MS200 did not run during the last day of the study due to 

several f actors re lating to th e sens itivity of th e dete ctor a nd the f ilament voltage 

control. Some of this appears to be electronic related and may be fixed when we send 

the electron ics box back to be upgraded to the new interface. The MS200 is a 

developing instrument that should provide interesting supplemental data to the study. 

The continuous for maldehyde analyzer wo rked well for two of the five garage 

sampling microenvironm ents (ME2-4 and ME 2-5) but did not work well for the 

freeway (ME1) or ref ueling (ME3 a nd ME4) microenvironments. The se nsitivity of 

the instrument to environmental noise associated with d riving while co llecting data 

may limit its utility under any sort of mobile environment. With proper operation and 

4-1
better characterization of instrument perform ance, the supplem ental continuous 

formaldehyde analyzer may prove useful for monitoring a stationary environment. 

Both an EPA-certified gas-filter correlation NDIR CO an alyzer (API model 300) and 

a portable battery-operated pa ssive electrochem ical cell instrum ent (Langan T15v) 

agree rea sonably well to within ab out 1 ppm . During low-ventil ation (half of the 

freeway tests) the CO concentration s remain at or decrease toward the lowest level 

measured during the high-vent phase. This be havior suggests that no in-cabin sources 

or interferences are present. 

In general the continuous PID and CO in struments perform ed very well. The two 

PIDs were compared both in controlled te sts and collocated during the MEs. In both 

cases, they tracked each other qu ite well. Differences appear to be due to an offset in 

one unit, and a slightly different response speed between the two units. The NDIR CO 

and electrochemical CO instruments compared favorably, usually within 1 ppm . This 

was partially attributed to the adaptive filtering of the API NDIR CO as demonstrated 

when comparing it to another NDIR instru ment made by Monitor Labs, Inc. For the 

purposes of this study, we strongly reco mmend using an instrum ent without the 

adaptive f ilter sin ce th e f ilter caus es change s in concentration to app ear le ss sha rp 

than actua l and causes peaks to shif t to later tim es which interf eres with 

intercomparisons among methods and instruments. 

Comparison of CO from the continuous instruments to that measured by GC from the 

canisters sh owed that the canister CO wa s generally 8% higher with no consistent 

bias correlated to any particular ME nor with concentration. The correlation between 

the CO and PID data was strongest for the garage ME. 

SPME sa mples show overall higher concen trations than MS200 (10-min averaged) 

concentrations. Also, S PME data averaged o ver th e entire sam pling period s are 

generally higher than canister data, due possibly to inadequate tem perature 

corrections of the SPME data. SPME fibers are very sensitive to temperature changes 

(they absorb m ore analytes under cold condi tions, as in this pilot study) and they 

might not be fully equilibrated to am bient temperatures prior to sampling. In the 

future study , the clean f ibers will be stored a t am bient tem perature in a closed 

container with activated charcoal. 

The proced ure f or collecting and a nalyzing b reath samples worked well; ther e was 

only one invalid sam ple (based on CO 2 concentration) during this study. The data 

shows consistently higher BTEX c oncentrations after the peak exposure and are 

comparable between the two subjects collecting the samples. One exception is toluene 

where it ap pears that o ne of the su bjects ha s toluene p resent in the b reath samples, 

regardless of the exposure. 

The 5-m inute canister sam ples had lower da ta recov ery (80%). Th is was partia lly 

because the sampler that was used to fill this canister was not optimal for the task. A 

relatively high flow rate was needed to pressurize a canister in only 5 m in and the 

sampler used was not designed for this m uch flow. For the final study, we have 

designed and built a new sampler specifically for this task. 

4-2
The reconstruction of the be nzene and BTEX tim e series from the PID data showed 

overall good com parison with the MS200 data . However, som e concentration peaks 

were not reproduced in m agnitude and appeared to be tim e shifted, a consequence of 

the averagin g of the PID data from 10 seconds down to 1 m inute. In addition, the 

MS200 does not integrate sam ples over the 1- minute period; rather the nature of the 

flow-through system smears the peaks over a longer period due to the tim e it takes to 

diffuse through the inlet system and into the m ass analyzer. Because of the flowthrough system , very short duration high p eaks m ay not be see n. In summ ary, for 

most of the MEs the reconstructed data and the MS200 data agr eed reasonably well, 

suggesting that the reconstruction m ethod works and should provide a m ethod to 

calculate the peak exposures during sampling at the MEs. 

4-3
5. REFERENCES: 

Chai, M. and J. Pawliszyn, 1995. Analysis of Environm ental Air Sam ples by Solid-Phase 

Microextraction and Gas Chrom atography/Ion T rap Mass Spectrom etry, 

Environmental Science and Technology, Vol. 29, No. 3. Pag 693-701. 

Grote C.and J.Pawlinszyn, 1997. Solid Phase Mi croextraction for the analysis of Hum an 

Breath. Anal Chem.. Volume 69, 587-596 

Kelly, T.J. and C.R. Fortune (1994). C ontinuous Monitoring of Gaseous Formaldehyde 

Using an Improved Fluorescence Approach. Intern. J. E nviron. Anal. Che m., 54: 

249-263 

Koziel, Jaceb, et al., 1999 Field air analysis with SPME device. Analytical Chimica Acta 400 

153-162 

Koziel, Jacek A. and Novak, I. 2002. Sa mpling and Sample-preparation Strategies Based on 

Solid-phase Microextraction for Analysis of Indoor Air. Trends in Analytical 

Chemistry, Vol 21, No.12. 

Lodge, James P. Methods of air sam pling an d analysis. Third edition. Lewis publishers. 

Intersociety committee. Michigan, 1989. pp15-16. 

Martos, P. and J. Pawliszyn, 1997. Calibratio n of Solid Phase Microextraction for Air 

Analysis B ased on Physical Chem ical Pr operties of the Coating. . Analytical 

Chemistry. 69: 206-215. 1997 

Martos, P. and J. Pawliszyn, 1999. Ti me-Weighted Average Sa mpling with Solid-Phase 

Microextraction Device: Implications for Enhanced Personal Exposure Monitoring to 

Airborne Pollutants, Analytical Chemistry, Vol. 71, No. 8, April 15. 

McLaren and Zhou, 2000. Measurem ent of Oxygenated Hydrocarbons in Outdoor Air using 

Sold-Phase Microextraction Gas Chromatography. AAA Conference 2000. 

Namiesnik, Jacek. Generation of standard gaseous m ixtures. Journal of Chrom atography. 

300. 1984. pp. 79-108. 

Nelson, Gary O. Gas Mixtures: P reparation and Control. Lewis Pl ublishers. 1992. CRC 

Press. 

Parreira, F et al. Evaluation of Indoor Exposit ion to BTEX and Styren by passive sampling 

with SPME. Journal of Chromatography, Vol. 40, March 2002. 122-126. 

Pawliszyn, J., 1997. Solid Phase Microextraction: Theory and Practice, Wiley-VCH. 

Pawliszyn, J., 1999. Applications of Solid phase Microextra ction. Royal Society of 

Chemistry. 

Pawliszyn, 2002. Sam pling and Sa mple Pr eparation for Field and Laboratory. 

Comprehensive Analytical Chemistry, Vol 37. Elsevier. 

5-4
Pleil J.D. and A. B. Li ndstrom. (1995). Me asurement of volatile organic com pounds in 

exhaled breath as collected in evacuated electropolished canisters. J. Chromatogr. B, 

665: 271-279 

Tuduri, Ludovic et al. Potential of Sollid-Ph ase Microextraction fibers for the Analysis of 

VOC in air. Journal of Chrom atographic Science, Vol. 39, Decem ber 2001. pp 521-

529. 

Zielinska, B., E. M. Fujita and J. C. Sage biel (2003). Section 211(B) Tier 2 High End 

Exposure Screening Study of Bas eline a nd O xygenated Gasolin e - Summ er 2002 

Atlanta Field Study on Baseline Gasoline. Feb. 2003 

Zielinska, B., E. M. Fujita, J. C. Sagebiel, D. E. Campbell, J. D. McD onald, L. R. Smith, T. 

Johnson (2002). Exposure Protocol and St udy Plan for the Section 211(B) Tier 2 

High End Exposure Screening Study of Baseline and Oxygenated Gasoline. Revisied 

edition,Sept.30,2002

5-5
6.APPENDICIES 

6.1 Appendix A: SPME 

ppb 

me date strthhmm stophhmm an_date Storage Tavg RHavg benze tolue etbz mp_xyl o_xyl

ME3 4/29/03 1210 1220 4/29/03 2:40 10.69 28.03 6.66 47.13 10.18 29.32 7.99 

ME3 4/29/03 1200 1210 4/29/03 3:15 10.69 28.03 17.21 58.56 11.22 24.76 12.06

ME1 4/29/03 812 822 4/29/03 7:33 20.78 31.90 18.80 114.09 19.42 51.10 15.56

ME1 4/29/03 802 812 4/29/03 8:18 15.80 31.81 12.50 98.24 18.51 51.17 16.44

ME1 4/29/03 752 802 4/29/03 9:08 12.32 31.89 15.69 70.86 15.95 45.05 14.50

ME1 4/29/03 742 751 4/29/03 9:38 11.71 37.73 13.12 66.47 19.61 54.81 17.34

ME2 4/29/03 1652 1702 4/29/03 1:08 10.28 34.59 24.70 66.85 19.49 49.33 14.83

ME2 4/29/03 1702 1712 4/29/03 1:28 10.08 35.88 28.21 90.12 26.36 73.08 25.69

ME2 4/29/03 1642 1652 4/29/03 2:18 10.56 34.60 4.08 12.49 2.48 6.95 1.59 

ME4 4/30/03 1211 1221 4/30/03 1:04 27.68 12.82 11.74 65.18 15.12 34.53 7.41 

ME4 4/30/03 1201 1211 4/30/03 1:34 29.14 12.21 10.29 38.17 13.10 28.02 7.16 

ME3 4/30/03 1045 1055 4/30/03 3:15 8.93 36.59 6.61 24.51 6.31 20.73 5.50 

ME3 4/30/03 1055 1105 4/30/03 3:35 8.99 36.32 2.71 16.40 7.55 18.23 4.50 

ME1 4/30/03 809 819 4/30/03 6:36 25.54 25.88 20.41 155.78 22.19 66.59 19.90

ME1 4/30/03 759 809 4/30/03 7:11 20.69 28.02 21.92 139.74 30.27 80.99 27.37

ME1 4/30/03 739 749 4/30/03 7:56 9.72 42.59 27.17 113.76 33.86 84.96 27.28

ME1 4/30/03 749 759 4/30/03 8:26 12.98 34.35 26.52 101.84 14.13 59.19 18.05

ME4 4/30/03 921 931 4/30/03 7:39 14.10 27.98 17.04 85.61 15.34 57.68 17.01

ME4 4/30/03 931 941 4/30/03 7:49 14.03 28.33 41.04 140.14 20.70 75.84 22.48

ME2 4/30/03 1645 1655 4/30/03 3:35 32.77 11.59 28.60 89.19 13.52 49.40 16.85

ME2 4/30/03 1655 1705 4/30/03 3:45 32.71 10.84 19.14 69.59 16.89 58.29 19.66

ME2 4/30/03 1705 1715 4/30/03 3:55 33.04 11.07 64.00 173.74 48.88 154.57 58.11

ME1 5/1/03 720 730 5/1/03 2:30 11.32 43.40 49.70 152.00 36.87 104.52 34.61

ME1 5/1/03 750 800 5/1/03 2:30 21.41 33.72 29.58 195.04 24.92 81.88 26.47

ME1 5/1/03 730 740 5/1/03 3:10 15.96 30.60 29.78 130.20 26.21 87.38 28.80

ME1 5/1/03 740 750 5/1/03 3:30 19.82 30.06 21.32 110.07 19.09 63.33 23.26

ME4 5/1/03 1116 1126 5/1/03 2:44 13.72 21.79 8.05 54.91 14.50 44.03 12.10

ME4 5/1/03 1106 1116 5/1/03 3:24 14.50 22.27 5.55 43.57 14.64 35.20 8.71 

ME3 5/1/03 1225 1235 5/1/03 2:20 13.54 24.52 5.61 17.02 4.60 13.58 3.23 

ME2 5/1/03 1647 1656 5/1/03 1:13 14.92 24.64 6.53 38.15 8.80 23.63 6.48 

ME2 5/1/03 1707 1717 5/1/03 1:13 16.18 35.42 24.17 83.75 16.99 56.15 20.52

ME2 5/1/03 1657 1707 5/1/03 2:03 14.31 25.74 30.28 91.61 15.95 58.19 19.01

ME3 5/2/03 1036 1046 5/2/03 2:39 10.76 52.57 33.56 94.44 16.85 61.89 19.50

ME3 5/2/03 1046 1056 5/2/03 2:59 10.34 53.49 7.32 39.96 7.48 23.74 5.97 

ME3 5/2/03 918 928 5/2/03 4:52 10.77 42.35 4.85 27.41 6.35 18.09 4.01 

ME3 5/2/03 928 938 5/2/03 5:12 10.48 43.85 84.69 281.09 56.15 167.71 54.37

ME1 5/2/03 735 745 5/2/03 7:40 16.18 35.42 16.85 83.28 20.74 56.96 17.37

ME1 5/2/03 745 755 5/2/03 8:15 19.57 29.39 22.92 121.35 30.46 86.71 27.35

ME1 5/2/03 745 805 5/2/03 8:20 22.74 29.85 28.56 104.73 18.11 55.28 16.95

ME1 5/2/03 805 815 5/2/03 8:35 22.95 33.30 22.15 149.75 29.73 69.31 22.45

6-1
ME2 5/2/03 1645 1655 5/2/03 1:30 14.18 47.03 4.21 19.10 5.85 18.00 5.11 

ME2 5/2/03 1655 1705 5/2/03 1:40 13.67 47.85 7.92 26.49 5.24 13.67 4.05 

ME1 5/5/03 750 800 5/5/03 5:00 14.99 39.76 15.94 75.70 17.13 53.58 16.78

ME1 5/5/03 800 810 5/5/03 5:10 17.22 33.13 15.05 66.46 0.00 0.00 0.00 

ME1 5/5/03 820 830 5/5/03 6:20 21.77 38.99 21.32 151.16 12.04 46.64 13.37

ME1 5/5/03 810 820 5/5/03 6:50 19.78 35.90 24.70 138.72 25.47 90.35 30.36

ME4 5/5/03 923 933 5/5/03 5:57 17.46 28.63 1.76 10.36 1.61 5.98 1.23 

ME4 5/5/03 933 943 5/5/03 6:07 16.70 29.65 103.75 386.16 34.98 121.64 31.29

ME 3 5/5/03 1045 1055 5/5/03 5:15 12.42 35.10 4.94 14.62 2.06 8.31 1.89 

ME 3 5/5/03 1055 1105 5/5/03 5:25 12.31 35.33 6.55 21.64 2.92 11.16 2.29 

ME2 5/6/03 1645 1655 5/6/03 1:10 13.70 33.79 4.95 17.18 2.82 9.78 2.06 

ME2 5/6/03 1655 1705 5/6/03 1:20 13.49 34.22 1.39 1.26 0.32 1.07 0.23 

ME2 5/6/03 1705 1715 5/6/03 1:30 13.59 34.62 12.52 48.73 14.31 51.91 18.25

avg 4:29 16.54 32.25

max 9:38 33.04 53.49

min 1:04 8.93 10.84

6-2
C2-C12 Hydrocarbons Target List 

Mnemonics Names Formula MW Group 

1 ETHENE ethene C2H4 28.05 O 

2 ACETYL acetylene C2H2 26.04

3 ETHANE ethane C2H6 30.07 P 

4 PROPE Propene C3H6 O 

5 N_PROP n-propane C3H8 44.10 P 

6 I_BUTA isobutane 58.12 P 

7 LIBUTE isobutene C4H8 56.11 O 

8 LBUT1E C4H8 56.11 O 

9 BUDI1,3 1,3-butadiene C4H6 54.1 O 

10 n-butane C4H10 58.12 P 

11 T2BUTE t-2-Butene C4H8 56.11 O 

C2BUTE c-2-butene C4H8 56.11 O 

13 IPENTA isopentane C5H12 72.15 P 

14 PENTE1 1-pentene C5H10 70.13 O 

15 N_PENT n-pentane C5H12 72.15

16 I_PREN isoprene C5H8 68.11 O 

17 T2PENE t-2-Pentene C5H10 O 

18 C2PENE c-2-pentene C5H10 70.13 O 

19 BU22DM 2,2-dimethylbutane 86.17 P 

20 CPENTA cyclopentane C5H10 70.13 P 

21 BU23DM C6H14 86.17 P 

22 PENA2M 2-methylpentane C6H14 86.17 P 

23 

6.2 Appendix B: Canisters and Tenax 

Y 

42.08

C4H10 

1-butene 

N_BUTA 

12 

P 

70.13

C6H14 

2,3-dimethylbutane 

PENA3M 3-methylpentane C6H14 86.17 P 

24 P1E2ME 2-methyl-1-pentene C6H12 84.16 O 

25 N_HEX n-hexane C6H14 86.17

26 MCYPNA Methylcyclopentane C6H12 84.16 P 

27 PEN24M 2,4-dimethylpentane C7H16 100.20

28 BENZE benzene C6H6 78.11 A 

29 CYHEXA cyclohexane C6H12 84.16

30 HEXA2M 2-methylhexane C7H16 98.19 P 

31 PEN23M 

P 

P 

P 

2,3-dimethylpentane C7H16 100.20 P 

32 HEXA3M 3-methylhexane C7H16 100.20 P 

33 PA224M 2,2,4-trimethylpentane C8H18 114.23 P 

34 N_HEPT n-heptane C7H16 100.20 P 

35 MECYHX methylcyclohexane C7H14 98.19 P 

36 PA234M 2,3,4-trimethylpentane C8H18 114.23 P 

37 TOLUE toluene C7H8 92.14 A 

38 HEP2ME 2-methylheptane C8H18 114.23 P 

39 HEP3ME 3-methylheptane C8H18 114.23 P 

40 N_OCT n-octane C8H18 114.22 P 

41 ETBZ ethylbenzene C8H10 106.16 A 

42 MP_XYL mp-xylene C8H10 106.16 A 

43 STYR styrene C8H8 104.14 A 

44 O_XYL o-xylene C8H10 106.17 A 

45 N_NON n-nonane C9H20 128.26 P 

6-3
46 IPRBZ isopropylbenzene C9H12 120.20 A 

47 N_PRBZ n-propylbenzene C9H12 120.20 A 

48 M_ETOL m-ethyltoluene C9H12 120.20 A 

49 P_ETOL p-ethyltoluene C9H12 120.20 A 

50 BZ135M 1,3,5-trimethylbenzene C9H12 120.20 A 

51 O_ETOL o-ethyltoluene C9H12 120.20 A 

52 BZ124M 1,2,4-trimethylbenzene C9H12 120.20 A 

53 N_DEC n-decane C10H22 142.29 P 

54 BZ123M 1,2,3-trimethylbenzene C9H12 120.20 A 

55 DETBZ1 m-diethylbenzene C10H14 134.22 A 

56 DETBZ2 p-diethylbenzene C10H14 134.22 A 

57 N_UNDE n-undecane C11H24 156.30 P 

58 MTBE methyl t-butyl ether C5H12O 88.14 E 

TNMHC 

A = aromatic, AL = Aldehyde, O = alkene (olefin), P = parafin, Y = alkyne, K = ketone, 

E = ether, X = haogenated, OH = alcohol 

6-4
Concentrations in ppbC, Tenax 

site date starthhmm stophhmm duration

(min) 

ethoh mtbe tolue etbz mp

Freeway 4/29/03 0742 0822 40 0.00 0.00 215.22 43.24 

Freeway 4/29/03 0742 0822 40 0.00 0.00 229.54 44.83 

Refueling W/Vapor Re 4/29/03 1200 1220 20 0.00 0.00 82.06 11.65 

Garage 4/29/03 1642 1712 30 4.24 0.00 105.02 23.08 

Freeway 4/30/03 0739 0819 41.1 0.00 0.00 342.38 64.43 

Refueling W/O Vapor 4/30/03 0921 0941 19.92 0.00 0.00 240.68 38.40 

Refueling W/Vapor Re 4/30/03 1045 1105 20 0.00 0.00 19.61 4.20 

Refueling W/O Vapor 4/30/03 1205 1225 20 0.00 0.00 49.12 5.20 

Garage 4/30/03 1645 1715 30 0.00 0.00 187.19 47.86 

Refueling W/O Vapor 5/1/03 1106 1126 20.43 0.00 0.00 146.48 10.89 

Refueling W/Vapor Re 5/1/03 1225 1245 21.3 0.00 0.00 35.57 6.67 

Garage 5/1/03 1647 1717 30 0.00 0.00 222.61 54.49 

Freeway 5/2/03 0735 0815 40 0.00 0.00 238.47 39.24 

Refueling W/O Vapor 5/2/03 0918 0938 20 0.00 0.00 330.84 53.26 

Refueling W/Vapor Re 5/2/03 1036 1056 20 0.00 0.00 51.20 11.93 Garage 5/2/03 1645 1715 30 0.00 0.00 137.43 36.88 

Garage 5/2/03 1645 1715 30 0.00 0.00 159.00 40.65 

Garage-Blank 5/2/03 1710 1710 0 0.00 0.00 0.19 0.00 

Freeway 5/5/03 0750 0830 40 0.00 0.00 396.27 81.14 

Refueling W/O Vapor 5/5/03 0923 0943 20 0.00 0.00 270.81 24.47 

Refueling W/Vapor Re 5/5/03 1045 1105 20 0.00 0.00 10.47 2.37 

Garage 5/6/03 1645 1715 30 0.00 0.00 43.20 11.77 

6-5
Canister BTEX, ppbC 

site date time Time (min) an_type budi13 benze tolue etbz 

Freeway 4/29/03 742-822 20 p 10.78 54.57 317.43 59.84 Refueling W/Vapor Recovery 4/29/03 1200-1205 5 p 8.86 15.35 88.97 14.96 

Refueling W/Vapor Recovery 4/29/03 1200-1205 5 r 8.79 15.52 91.18 15.33 

Refueling W/Vapor Recovery 4/29/03 1200-1220 20 p 1.15 20.27 69.36 11.46 

Garage 4/29/03 1642-1712 20 p 6.78 33.88 102.67 24.81 

Refueling W/Vapor Recovery 4/30/03 1045-1105 20 p 0.99 7.74 31.64 7.79 

Refueling W/Vapor Recovery 4/30/03 1045-1105 20 r 0.99 7.84 31.81 7.8 

Refueling W/Vapor Recovery 4/30/03 1055-1100 5 p 0.83 16.7 88.09 17.5 

Refueling W/O Vapor Recovery 4/30/03 1205-1245 20 p 0.53 12.8 54.95 9.17 

Refueling W/O Vapor Recovery 4/30/03 1212-1217 5 p 0.14 6.97 23.5 3.01 

Garage 4/30/03 1645-1715 20 p 11.52 59.62 223.45 55.82 Freeway 4/30/03 739-819 20 p 12.67 60.04 376.27 69.5 

Refueling W/O Vapor Recovery 4/30/03 921-927 20 p 1.41 247.58 708.8 71.8 

Refueling W/O Vapor Recovery 4/30/03 921-941 20 p 1.08 56.75 239.86 44.01 

Refueling W/O Vapor Recovery 5/1/03 1106-1126 20 p 0.66 14.02 70.68 14.6 

Refueling W/O Vapor Recovery 5/1/03 1117-1123 5 p 0.89 132.77 385.71 37.26 

Refueling W/Vapor Recovery 5/1/03 1225-1245 20 p 1.06 9.66 43.99 9.62 Garage 5/1/03 1642-1717 20 p 13.18 63.78 239.78 57.81 

Freeway 5/1/03 720-800 20 p 21.38 109.66 534.75 99 

Freeway 5/1/03 720-800 20 r 20.43 107.86 523.17 97.41 Refueling W/Vapor Recovery 5/2/03 1036-1056 20 p 0.6 13.78 64.99 16.76 

Refueling W/Vapor Recovery 5/2/03 1046-1051 5 p 0.19 4.97 35.09 16 

Garage 5/2/03 1645-1715 20 p 6.93 31.72 119.67 30.29 

Freeway 5/2/03 735-815 20 p 10.22 43.61 215.65 38.17 Refueling W/O Vapor Recovery 5/2/03 918-938 20 p 49.8 122.93 419.54 65.06 

Refueling W/O Vapor Recovery 5/2/03 929-934 5 p 2.94 458.68 1320.65 199.46 

Refueling W/Vapor Recovery 5/5/03 1045-1105 20 p 0.54 9.3 50.59 11.11 

Refueling W/Vapor Recovery 5/5/03 1055-1100 5 p 1.33 14.65 82.79 16.5 

Freeway 5/5/03 750-830 20 p 10.66 57.6 312.85 66.46 

Refueling W/O Vapor Recovery 5/5/03 923-943 20 p 1.38 419.62 1093.91 101.8 

Garage 5/6/03 1645-1715 20 p 6.35 29.18 99.13 26 

6-6
Canisters - Full C2-C12 Speciation (ppbC) 

site Refueling

W/Vapor Recovery 

Refueling

W/Vapor Recovery 

Refueling W/O Vapor Recovery 

Refueling W/Vapor Recovery 

Refueling W/O Vapor Recovery 

Refueling W/O Vapor Recovery 

Refueling W/Vapor Recovery 

Refueling W/O Vapor Recovery 

Refueling W/O Vapor Recovery 

RefueliW/VapRecove

date 4/30/03 4/30/03 4/30/03 5/5/03 5/5/03 4/30/03 4/29/03 5/2/03 5/1/03 5/

time 1045-1105 1045-1105 921-941 1045-1105 923-943 1205-1245 1200-1220 918-938 1106-1126 1225-1

an_type p r p p p p p p p p 

canister C073 C073 C095 C136 C186 C085 C046 C153 C227 C076 

ethane 5.20 5.26 8.83 4.58 34.04 5.38 5.91 14.87 4.60 ethene 10.82 10.93 6.98 5.70 5.32 5.48 10.96 11.46 4.09 

acetyl 35.90 37.30 13.60 12.67 4.10 14.69 28.90 20.41 5.22 2

prope 4.42 4.41 20.39 3.04 555.07 6.25 9.43 84.86 3.66 

n_prop 3.03 3.04 44.31 3.37 654.88 22.07 11.72 138.73 9.06 i_buta 8.39 8.37 292.11 8.36 3119.11 49.79 76.51 781.1 85.79 3

lbut1e 1.02 1.02 14.77 0.64 68.50 2.32 4.04 25.06 10.58 

libute 1.69 1.67 53.12 0.60 335.61 7.86 0.00 127.69 5.55 

budi13 0.99 0.99 1.08 0.54 1.38 0.53 1.15 49.8 0.66 

n_buta 42.97 42.25 1350.13 52.08 15644.09 217.4 398.79 3806.37 354.28 1

t2bute 1.44 1.5 49.99 1.13 404.02 9.16 12.28 114.96 17.44 

c2bute 0.79 0.83 31.44 1.58 179.85 4.11 7.23 53.98 11.38 ipenta 99.66 99.21 3079.3 99.96 25116.14 557.31 812.57 8387.13 474.96 23

pente1 1.31 1.41 77.4 4.41 428.6 7.33 14.96 150.06 10.49 n_pent 16.7 16.89 496.47 17.43 4118.19 83.55 137.59 1229.93 83.29 4

i_pren 0.47 0.47 1.43 0.41 3.58 0.85 1 1.35 0.69 

t2pene 8.53 8.59 253.28 9.08 1998.16 42.71 72.47 596.83 45.39 2c2pene 3.42 4.02 100.55 3.73 795.77 16.87 29.41 235.57 18.81 1

bu22dm 2.04 1.99 41.61 2.52 370 8.72 11.7 116.55 6.16 

cpenta 1.91 1.85 42.07 2.44 386.01 8.45 11.17 112.46 8.76 

bu23dm 3.12 3.16 73.75 4.58 623.65 12.01 23.03 170.65 14.37 pena2m 12.57 12.62 265.51 19.01 2433.1 48.16 81.18 653.25 50.35 2

pena3m 7.56 8.25 149.77 11.81 1379.42 27.49 46.61 366.92 28.7 1

p1e2me 0.9 0.9 12.44 1.52 156.27 2.4 3.8 28.52 3.37 

n_hex 5.32 5.37 89.44 8.95 840.12 17.84 28.87 219.96 16.87 mcypna 8.73 8.85 142.4 15.07 1332.12 27.19 45.25 352.73 28.59 1

pen24m 0.97 1 14.4 1.79 112.79 2.89 4.52 32.78 4.3 

benze 7.77 7.79 57 9.26 419.62 12.8 20.36 123.05 14.03 

6-7
cyhexa 2.38 2.42 35.48 4.22 291.39 7.98 10.31 90.55 7.39 

hexa2m 5.57 5.48 62 10.02 467.73 14.18 19.39 145.54 14.93 pen23m 2.03 1.99 25.29 3.57 171.67 5.37 7.46 54.36 7.46 

hexa3m 0.3 0.28 3.32 0.43 21.31 0.56 0.84 6.21 0.74 

pa224m 2.19 2.1 23.45 3.75 173.5 5.21 7.13 55.49 4.76 

n_hept 4.25 4.49 45.47 8.45 278.39 10.66 13.79 103.51 11.51 

mecyhx 4.67 4.72 47.99 8.5 308.14 10.56 14.49 105.3 12.11 

pa234m 0.64 0.67 5.23 0.9 20.08 1.01 1.9 6.69 2.65 tolue 31.64 31.81 239.97 50.59 1093.91 54.95 69.39 419.54 70.68 4hep2me 2.29 2.34 17.19 3.64 67.26 3.62 4.91 29.51 4.61 

hep3me 2.6 2.58 17.28 3.86 65.21 3.8 5.51 29.53 5.03 

n_oct 1.96 1.96 11.36 2.57 33.32 2.52 3.77 17.78 2.52 

etbz 7.91 7.86 45.24 11.05 101.8 9.22 11.5 66.14 14.88 

mp_xyl 28.39 28.07 152.26 39.78 328.81 31.72 38.56 229.84 52.43 3styr 1.41 1.27 4.37 1.37 4.23 0.9 1.43 3.81 1.04 

o_xyl 11.72 11.75 58.83 15.37 109.53 12.11 15.65 85.91 20.23 1n_non 1.09 1.03 5.51 1.44 7.09 1.11 1.65 7.48 0.72 iprbz 0.69 0.66 3.48 0.81 4.19 0.76 0.82 4.34 1.09 n_prbz 2.7 2.62 11.77 3.06 12.85 2.38 3.05 14.76 4.03 

m_etol 9.17 8.76 34.14 10.41 36.04 3.62 4.45 42.76 13.27 

p_etol 4.38 4.12 16.91 4.68 15.85 7.53 9.41 20.54 6.11 

bz135m 4.32 4 14.92 4.61 13.89 3.53 4.4 18.18 5.98 o_etol 4.11 3.95 12.9 4.5 14.29 3.51 5.09 16.69 5.57 

bz124m 13.95 12.89 47.24 15.43 40.54 11.14 14.38 52.49 20.08 1

n_dec 1.97 2.27 1.72 0.39 1.73 1.18 1.36 3.26 0.46 bz123m 3.48 3.39 1.09 0.38 7.52 2.55 3.43 0.98 0.65 detbz1 0.99 1.04 2.25 0.78 1.92 0.74 1.54 2.98 1.09 

detbz2 3.24 3.14 6.54 2.78 5.08 2.01 2.93 7.31 3.28 n_unde 1.47 1.51 3.53 1.4 2.1 1.05 1.83 3.3 1.11 tnmhc 656.76 646.78 8908.06 702 72023.3 1690.04 2706.57 21748.67 1976.27 106

6-8
6.3 Appendix C: Breath Samples 

Site Date Time CO2, bud13

% 

ethoh mtbe benze tolue etbz 

Refueling W/Vapor Recovery , PreFuel 4/29 1200 5.09 0.27 133.86 0.74 0.87 99.31 0.53 Refueling W/Vapor Reco very, PostFuel 4/29 1215 4.38 0.10 87.75 0.46 0.89 78.42 0.49 

Garage, Pre 4/29 1642 5.91 0.21 78.10 0.46 0.81 72.49 0.46 

Garage, Peak 4/29 1654 6.06 0.04 12.11 0.18 0.23 2.12 0.16 

Garage, Post 4/29 1715 6.16 0.04 3.26 0.07 0.06 0.45 0.04 

Freeway, Pre 4/29 731 5.35 0.20 51.26 0.27 0.70 137.39 0.72 

Freeway, Peak 4/29 800 5.00 2.77 26.90 1.13 4.73 150.46 2.83 

Freeway, Post 4/29 826 5.44 0.85 26.60 0.36 1.88 125.08 0.99 

Refueling W/Vapor Recovery , PreFuel 4/30 1047 6.24 0.12 138.93 0.69 1.16 68.79 0.44 Refueling W/Vapor Reco very, PostFuel 4/30 1059 5.79 0.65 153.24 0.64 2.28 77.75 0.78 

Refueling W/O Vapor Recover y, PreFuel 4/30 1203 4.93 0.18 54.35 0.40 1.01 50.46 0.44 

Refueling W/O Vapor Recovery, PostFuel 4/30 1216 5.80 0.00 201.01 1.80 5.47 75.04 0.65 Garage, Pre 4/30 1643 6.11 1.35 137.30 0.32 1.87 60.47 0.62 

Garage, Peak 4/30 1707 6.01 3.65 107.43 0.33 5.35 61.73 1.73 Garage, Post 4/30 1721 5.83 5.24 123.88 0.57 7.17 63.39 1.68 

Freeway, Pre 4/30 727 5.64 0.15 86.91 0.48 0.64 87.07 0.57 

Freeway, Peak 4/30 757 4.71 4.48 51.23 0.75 7.92 102.67 3.49 

Freeway, Post 4/30 822 4.50 0.69 54.62 0.36 1.81 82.25 0.86 

Refueling W/O Vapor Recover y, PreFuel 4/30 923 4.92 0.18 65.02 0.46 1.22 75.46 0.69 

Refueling W/O Vapor Recovery, PostFuel 4/30 935 4.74 0.00 64.67 5.04 16.80 99.08 2.14 

Refueling W/O Vapor Recover y, PreFuel 5/1 1107 6.71 0.05 103.18 0.35 0.97 2.72 0.15 

6-9
Refueling W/O Vapor Recovery, PostFuel 5/1 1119 7.74 0.15 176.98 1.22 2.76 4.98 0.27 

Refueling W/Vapor Recovery , PreFuel 5/1 1227 6.02 0.11 118.30 0.69 1.27 2.63 0.15 

Refueling W/Vapor Reco very, PostFuel 5/1 1238 5.21 0.21 81.07 0.55 1.14 2.61 0.18 

Garage, Pre 5/1 1648 7.24 0.65 45.68 0.34 1.41 2.90 0.29 

Garage, Peak 5/1 1703 5.82 3.36 99.74 0.37 3.97 5.92 0.64 

Garage, Post 5/1 1719 6.30 0.75 60.61 0.33 1.79 3.43 0.28 

Freeway, Pre 5/1 712 6.33 0.07 36.68 0.24 0.29 0.64 0.04 

Freeway, Peak 5/1 735 5.05 3.79 36.45 0.67 7.03 19.53 1.93 

Freeway, Post 5/1 802 5.35 3.58 23.50 0.46 6.14 23.47 1.57 Refueling W/Vapor Recovery , PreFuel 5/2 1037 4.82 0.12 42.47 0.45 0.99 30.16 0.25 

Refueling W/Vapor Reco very, PostFuel 5/2 1050 5.70 0.13 28.59 0.47 1.25 35.16 0.52 

Garage, Pre 5/2 1645 5.25 0.93 72.42 0.00 1.32 29.85 0.34 

Garage, Peak 5/2 1706 5.25 0.56 69.43 0.18 1.01 27.71 0.26 

Garage, Post 5/2 1716 6.00 1.45 63.47 0.18 2.72 31.49 0.60 Freeway, Pre 5/2 729 5.31 0.19 113.50 0.20 0.49 41.32 0.26 

Freeway, Peak 5/2 749 4.93 1.96 66.01 0.35 3.65 46.59 1.14 

Freeway, Post 5/2 816 4.57 2.14 36.27 0.33 3.36 50.42 0.91 Refueling W/O Vapor Recover y, PreFuel 5/2 920 5.52 0.42 70.74 0.20 0.72 32.43 0.29 

Refueling W/O Vapor Recovery, PostFuel 5/2 932 6.09 0.00 64.88 5.15 16.07 62.34 1.30 

Refueling W/Vapor Recovery , PreFuel 5/5 1045 5.99 0.10 92.42 1.09 2.85 5.58 0.29 

Refueling W/Vapor Reco very, PostFuel 5/5 1058 5.59 0.05 33.13 0.86 3.52 7.34 0.36 

Freeway, Pre 5/5 744 0.98 0.06 17.62 0.27 0.31 0.53 0.05 

Freeway, Peak 5/5 755 5.89 2.03 17.71 0.48 2.93 4.80 0.50 

Freeway, Post 5/5 832 5.25 2.17 10.05 0.35 4.29 15.67 1.22 

Refueling W/O Vapor Recover y, PreFuel 5/5 923 6.30 0.18 88.50 0.23 0.67 1.77 0.13 

Refueling W/O Vapor Recovery, Post- 5/5 936 6.42 0.00 84.87 16.36 80.68 79.30 2.73 

6-10
Fuel 

Garage, Pre 5/6 1644 6.16 0.49 175.18 0.30 1.42 2.65 0.32 

Garage, Peak 5/6 1706 5.59 1.37 102.34 0.22 1.97 3.93 0.55 

Garage, Post 5/6 1718 6.48 0.65 58.69 0.27 1.57 3.05 0.34 

6-11
6.4 Appendix D: DNPH 

Site Date Start 

time 

Stop 

time 

Duration V (L) Vu 

(L) 

formal formalu acetal acetalu aceto acetou

Freeway 4/29/03 0742 0822 40 47.1 2.36 17.38 0.95 5.27 0.80 32.18 1.85

Freeway 4/30/03 0739 0819 41 45.2 2.26 19.02 1.04 4.67 0.80 28.35 1.64

Freeway 5/1/03 0720 0800 41.1 45.3 2.27 19.80 1.07 8.22 0.95 57.34 3.24

Freeway 5/2/03 0735 0815 40 44.1 2.21 19.13 1.05 4.84 0.82 20.67 1.23

Freeway 5/5/03 0750 0830 40 44.1 2.21 17.56 0.97 5.24 0.83 61.17 3.45

Garage 4/29/03 1642 1712 30 33.0 1.65 5.59 0.43 2.83 0.99 34.36 2.01

Garage 4/30/03 1645 1715 30 33.0 1.65 7.58 0.52 3.50 1.01 27.38 1.63

Garage 5/1/03 1642 1717 30 33.0 1.65 9.12 0.58 3.76 1.01 20.23 1.27

Garage 5/2/03 1645 1715 30 33.1 1.66 7.35 0.49 2.76 0.99 21.77 1.35

Garage 5/6/03 1645 1715 30 33.1 1.66 5.44 0.42 2.50 0.98 44.91 2.58

Garage-Blank 5/2/03 1706 1706 0 30.6 1.53 0.00 0.23 1.85 0.27 1.68 0.19

Garage-Blank 5/6/03 1612 1612 0 30.6 1.53 0.00 0.23 0.43 0.21 0.87 0.17

Refueling W/O Vapor 4/30/03 0921 0941 19.9 21.9 1.10 3.62 0.52 3.37 1.47 13.31 1.12

Refueling W/O Vapor 4/30/03 1205 1225 20 22.0 1.10 2.12 0.46 2.57 1.46 10.66 1.03

Refueling W/O Vapor 5/5/03 1106 1126 20.4 22.4 1.12 5.52 0.55 2.72 1.43 31.06 1.92

Refueling W/O Vapor 5/2/03 0918 0938 20 22.0 1.10 4.03 0.53 3.26 1.46 5.98 0.89

Refueling W/O Vapor 5/5/03 0923 0943 20 22.0 1.10 5.52 0.56 3.17 1.46 20.10 1.40

Refueling W /Vapor 

Re 

4/29/03 1200 1220 20 22.0 1.10 4.35 0.54 2.97 1.46 20.00 1.39

Refueling W /Vapor 

Re 

5/1/03 1225 1245 21.3 23.4 1.17 3.29 0.49 1.77 1.36 10.01 0.96

Refueling W /Vapor 

Re 

4/30/03 1045 1105 20 22.0 1.10 2.87 0.47 1.38 1.44 12.90 1.11

Refueling W /Vapor 

Re 

5/2/03 1036 1056 20 22.0 1.10 4.67 0.54 2.47 1.46 9.07 0.97

Refueling W /Vapor 

Re 

5/5/03 1045 1105 20 22.0 1.10 3.29 0.52 1.78 1.44 7.94 0.95

formal =Formaldehyde acetal = Acetaldehyde 

formalu =Formaldehyde uncertainty acetalu =Acetaldehyde uncertainty 

aceto=Acetone 

acetou=Acetone uncertainty 

6-12
Appendix F 

Evaporative and Tailpipe Emissions Support for S211b Tier 2 Exposure Study 

SwRI® Project 03.05383 – Final Report 

 
SOUTHWEST RESEARCH INSTITUTE ®

6220 CULEBRA ROAD i POST OFFICE DRAWER 28510 i SAN ANTONIO, TEXAS, USA 78228-0510 i (210) 684-5111 i WWW.SWRI.ORG 

HTTP://ENGINEANDVEHICLE .SWRI.ORG

ENGINE, EMISSIONS, AND VEHICLE RESEARCH DIVISION ISO 9001 CERTIFIED

FAX: (210) 522-3950 ISO 14001 Certified 

SAN ANTONIO, TEXAS 

HOUSTON, TEXAS i WASHINGTON, DC i ANN ARBOR, MI 

July 29, 2005 

TO: Desert Research Institute 

 2215 Raggio Parkway 

 Reno, NV 89512-1095 

ATTN: Dr. Barbara Zielinska 

SUBJECT: Final repo rt for SwRI ® Project 03.05383, “Evaporativ e and Tailpipe Em issions 

Support for S211b Tier 2 Exposure Study” 

1.0 INTRODUCTION 

 This report describes the work performed during the summe r of 2002 and the winter of 

2004/2005 by the Department of Engine and Emissions Research (DEER) at Southwest Research 

Institute® (SwRI) in support of Desert Research Inst itute’s (DRI) project entitled “S 211b Tier 2 

Exposure Study.” 

2.0 STATEMENT OF WORK 

 The objective of this project was to provide DR I with a variety of s upport activities, test 

vehicles, a support vehicle, and to perform laborat ory testing, all in support of DRI’s S211b Tier 

2 Exposure Study perform ed for the Am erican Petroleum Institute. The portion of DRI’s study 

performed in the San Antonio, Texas area consis ted of on-road em issions measurements using a 

trailing vehicle, garage testing of exhaust and evaporative emissions, and laboratory exhaust and 

evaporative emissions measurements. SwRI provided logistics support to DRI personnel for the 

on-road and garage testing, but perform ed no emissions measurements for these tasks. Two test 

vehicles were procured f or the program (a 1993 Toyota Camry V6 and a 1995 Ford F-150 V8), 

as well as a Dodge Caravan as a trailing vehicle for the on-road work in San Antonio. These 

vehicles were used for the on-road testing and garage testing, and then were utilized for hot soak 

evaporative and FTP exhaust emissions testing in the SwRI laboratory. All tests were performed 

with the vehicles in norm al and in a m alfunction condition. Tests were perform ed while 

operating on summ er and winder grade fuels, fr om Houston, Atlanta, and Chicago. Summ er 

grade fuels were used in 2002 and winter grade fuels were used in 2005. Selected properties of 

these fuels are presented in Table 1. 

 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 2 of 9 

Report 03-05383 

TABLE 1. TEST FUEL PROPERTIES 

Summer 2002 Winter 2005 

Parameter, method Houston Atlanta Chicago Houston Atlanta Chicago 

GA-4614 GA-4637 GA-4640 GA-5427 GA-5437 GA-5440

ASTM D5845 Petrospec®

MeOH, wt% N/A N/A N/A 0 0 0 

EtOH, wt% (D5599) N/A (0) (10.75) 0 0 10 

MTBE, wt% (D5599) (9.86) N/A N/A 10.7 0.4 0.6 

ETBE, wt% N/A N/A N/A 0 0 0 

TAME, wt% N/A N/A N/A 1.4 0 0 

DIPE, wt% N/A N/A N/A 0 0.2 0.5 

TBA, wt% N/A N/A N/A 0.3 0 0 

O2 Total wt% (D5599) (1.81) (0.01) (3.73) 2.23 0.1 3.66 

Benzene, vol% (D5580) (0.62) (1.24) (0.84) 0.5 1.06 1.03 

Aromatic, vol% (D1319) (19.9) (38.4) (17.1) 17.5 21.4 16.3 

Olefins, vol% (17.3) (10.5) (9.1) 9.4 6.0 15.2 

Saturate, vol% (52.8) (51.1) (70.9) 60.8 72.0 58.0 

RON N/A N/A N/A 92.2 90.5 92.3 

MON (D2700) N/A (81.9) (83.0) 83.5 82.9 82.8 

R+M/2 N/A N/A N/A 87.8 86.7 87.5 

T50, degF (D86) (190) N/A N/A 184 208 164 

T90, deg F (D86) (327) N/A N/A 330 336 319 

E200, % N/A N/A N/A 52 40 59 

E300, % N/A N/A N/A 82 83 83 

RVP, ASTM D5191 7.01 6.29 6.93 10.20 10.87 14.16 

API Gravity, ASTM D4052 61.1 55.5 63.7 62.1 60.3 62.8 

Specific Gravity, 

ASTM D4052 0.7347 0.7568 0.7390 0.7308 0.7379 0.7282 

Carbon content, wt%, 

ASTM D5291 84.77 86.76 82.30 83.99 86.28 80.85 

Hydrogen content, wt%, 

ASTM D5291 14.04 13.14 13.71 13.95 13.25 13.64 

In some instances, two different methods were utilized to determine fuel properties. In these instances, 

the second method and corresponding results are presented in parentheses. 

 

 SwRI utilized malfunction conditions determined in the 2002 portion of the study to give 

exhaust hydrocarbon emissions on the order of two grams per mile. These induced malfunctions 

included re moval of th e ca talysts on both vehicles plus a calibra ted m anifold air leak on th e 

Toyota Camry. The m alfunction for the hot soak por tion of the SHED test consisted sim ply of 

disconnecting the evaporative canisters from the vehicles. 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 3 of 9 

Report 03-05383 

 For the dynam ometer FTP exhaust em issions testing, regulated exhaust em issions (total 

hydrocarbons, THC; non-m ethane hydrocarbons, NMHC; carbon m onoxide, CO; and oxides of 

nitrogen, NOx), carbon dioxide, CO2; and speciated volatile organic compound (VOC) emissions 

(to include MTBE, ethanol, benzene, toluen e, ethy lbenzene, xylene, 1, 3-butadiene, 

formaldehyde, and acetaldehyde) were determ ined for each test. During hot soak tests, tota l 

hydrocarbon and VOC emissions (as above except without aldehyde/ketone measurements) were 

determined. A sealed housing for evaporative determinations (SHED) was utilized f or the hot 

soak tests. The test plan followed for the laboratory testing is presented in Table 2. 

TABLE 2. TEST PLAN 

STEP DESCRIPTION 

1 Verify proper mechanical operation of the test vehicle.

2 Remove canister from test vehicle.

3 Purge canister with 300°F “zero” nitrogen at 20L/min for five hours, reattach canister.

4 Drain fuel tank and fill to 40 percent capacity with test fuel.

5 Perform a 2-hour diurnal heat build from 70 to 120°F at a ramp rate of 0.4°F/min.

6 Operate vehicle on chassis dynamometer over one UDDS cycle.

7 Turn engine off for five minutes.

8 Start engine and idle for one minute.

9 Turn engine off for one minute.

10 Start engine and idle for one minute.

11 Remove canister from vehicle and purge canister with “zero” air for 60 minutes.

12 Reattach canister, drain fuel from tank, and fill to 40 percent capacity with chilled test fuel.

13 Conduct one hour DHB (no emission measurements).

14 Operate vehicle on chassis dynamometer over one UDDS.

15 Soak vehicle overnight.

16 Next day prior to the cold-start exhaust portion of the FTP, conduct one-hour Diurnal Heat Build. (DHB). 

17 Conduct 3-bag FTP exhaust emission test. Measure regulated gaseous emissions and VOC. emissions.

18 Conduct th e Hot Soak segmen t o f th e SHED test imme diately fo llowing t he ex haust em issions testing. 

19 Switch vehicle to malfunction condition, and disconnect evaporative canister.

20 Repeat Steps 6 through 10 and Steps 14 through 18.

21 Repeat Steps 1 through 20 for each of the remaining two test fuels. 

22 Switch to next test vehicle, and repeat Steps 1 through 21. 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 4 of 9 

Report 03-05383 

3.0 TEST PROCEDURES 

 The exhaust em ission portion of the FTP utilizes the Urban Dyna mometer Driving 

Schedule (UDDS), which is 1372 seconds in duration. The UDDS is divided into two segm ents; 

the first consisting of 505 seconds, and the second consisting of 867 seconds. A FTP i s 

composed of a 505-second cold-transient (bag 1) portion and an 867-second cold stabilized (bag 

2) portion, followed by a ten-minute soak and then a 505-second hot-transient (bag 3) portion. A 

summary of the cycle duration, driving distance, and average speed is given in Table 3. The FTP 

driving schedule with the cold- and hot-transient test segments identified is given in Figure 1. 

 The evaporative em ission portion of the FTP as conducted in this study consisted of a 

one-hour Diurnal Heat Build (DHB) (40 CFR 86.133-90) and a one-hour Hot Soak Loss Test 

(HSL) (40 CFR 86.138-90). Total hydrocarbons and VOC em issions were recorded only during 

the HSL se gment of th e te st. Prior to the c old-start ex haust po rtion of the FT P, the DHB 

evaporative segment of the FTP was conducted by fu eling the test vehicle to 40 percent of tank 

capacity with test fuel at a te mperature below 55°F. A heating blan ket was a ttached to th e 

outside of the fuel tank, and a thermocouple placed in the fuel inside the fuel tank was connected 

to the computer controller. The fuel inside the tank was raised to a nominal temperature of 60°F, 

at which point the DHB segm ent of t he test began. The fuel tem perature was raised at a linea r 

rate of 0.4°F per minute for the 60 minute test. The final nominal temperature was 84°F. 

 The HSL segment of the evaporative emission test was conducted immediately following 

FTP exhaust emission testing. The vehicle was allo wed to “soak” in the enclosure for one hour. 

Total hydrocarbon and VOC e missions were measured at the beginning a nd end of the one hour 

segment to perm it calculation of hot soak evapo rative emissions. Alcoh ol measurements were 

included only for the Chicago fuel. 

FIGURE 1. FTP DRIVING SCHEDULE 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 5 of 9 

Report 03-05383 

TABLE 3. SUMMARY OF FTP DRIVING SCHEDULE 

Segment Duration, 

Seconds

Distance, 

Miles

Average Speed, 

Miles/Hr.

Transient Phase 505 3.60 25.7 

Stabilized Phase 867 3.90 16.2 

UDDS 1372 7.50 19.7

 The following sections describe the sampling and analytical procedures that were utilized 

for this study. 

3.1 Exhaust Emissions

 Emissions of THC, NMHC, CO, NO x, and CO 2 were quantif ied in a m anner consistent 

with EPA protocols for light-duty emissions testing as given in the Code of Federal Regulations, 

Title 40, Part 86, Subpart B. Em issions of THC, CO, NO x, and CO 2 were s ampled using 

proportional exhaust gas sam ples collected in Te dlar bags. Total hydrocarbon em issions were 

measured using a flame ionization detector, while CO and CO 2 were determ ined using nondispersive infra-red instru ments. Em issions of NO x were m easured using a chem iluminescent 

instrument. W et absorption techniques were employed to collect alco hol and aldehyde VOC. 

Alcohol analysis was perform ed with gas chro matography – fla me ionization detection and 

aldehydes were m easured by high performance liquid chrom atography with ultra-violet 

absorbance detection. Values for NMHC were determined by subtracting methane (corrected for 

FID response factor) from THC.

3.2 Evaporative Emissions 

At the beginning and end of each Hot So ak Loss (HSL) segm ent, total hydrocarbon 

evaporative emissions were measured according to methods described in 40 CFR 86.138-90. In 

addition to total hydrocarbon em issions, bag samp les were taken at the beginning and end of 

each of the evaporative em ission test segm ents to permit hydrocarbon speciation an alyses to b e 

performed, and to collect sufficient sample for alcohol analyses (when an alcohol fuel blend was 

used during testing). Because approximately two minutes were required to adequately fill a bag 

for analys is, sam pling was initia ted one m inute before the start poin t and continu ed until one 

minute after the stop point. 

3.3 Hydrocarbon Speciation Procedures for VOC Determinations 

 The analytical procedures used for conducting hydroc arbon speciation (C 2 to C 12

hydrocarbons, aldehydes and ketones, and alcohols ) are similar to the CRC Auto/Oil Phase II 

methods. W ith these m ethods, exhaust and evapor ative emissions samples are analyzed for the 

presence of m ore than 200 different exhaust species. Four GC pro cedures and one HPCL 

procedure are used to identify and quantify compounds. In general, all emission “sample” bags 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 6 of 9 

Report 03-05383 

were analyzed before the “background” bags so that reactive exha ust com pounds can be 

analyzed as quickly as possible. A brief description of these procedures is given below. 

3.3.1 C2-C4 Species 

The first GC procedure uses a 15 m x 0.53 mm I.D. DB-WAX (1Fm film ) pre-column 

and a 50 m x 0.53 mm I.D. (10 Fm film) Alumina PLOT/KCI (Carbopack ®) column to pe rmit 

the separation and determ ination of exhaust concentrations of C 1-C4 individual hydrocarbon 

species, including ethan e; ethylene; acetylene; propane; propylene; propadiene; butane; trans-2 -

butene; 1-butyne; and cis-2-buten e. Bag sam ples were analyzed using a gas chrom atograph 

equipped with a F ID. The gas chrom atograph sy stem utilizes two an alytical colu mns. The 

carrier gas is helium. An external multiple component standard in zero air is used to quantify the 

results. Detection lim its for th e procedure are on the order of 5 ppbC in d ilute exhaust for all 

compounds.

3.3.2. C5-C12 Species 

 The second GC procedure uses a 60 m x 0.32 mm I.D. (10 Fm fil m) DB-1 column to 

provide separation and exhaust concentrations for m ore than 100 C 5-C12 individual HC 

compounds. Bag sam ples are analyzed using a ga s chromatograph equipped with a FID. The 

GC system utilizes a FI D, a pneumatic ally ope rated and electrically co ntrolled valve, and an 

analytical column. The carrier gas is helium . An external multiple co mponent standard in zero 

air is used to quantify the results. Detection limits for the procedure are on the order of 10 ppbC 

in dilute exhaust for all compounds. 

3.3.3 Benzene and Toluene 

The third GC procedure uses a separate syst em configured sim ilarly to the second GC 

method to determ ine individual concentration s of benzene and tolu ene accord ing to CRC 

Auto/Oil Phase II Protocols. The third GC utilizes a 30 m x 0.25 mm I.D. (0.25 Fm film) DB-5 

column instead of a DB-1 column. 

3.3.4 Aldehydes and Ketones 

A HPL C wi th a Zorbax ® ODS column was utilized for the analysis of aldehydes and 

ketones. Samples are collected by bubbling dilute exhaust at a nom inal flow rate of 4 L/ min 

through chilled glass im pingers containing an ac etonitrile solution of 2,4-DNPH and perchloric 

acid. For analysis, a p ortion of the acetonitrile so lution is injected in to a liquid chrom atograph 

equipped with a UV detector. External standard s of the aldehyde and ketone DNPH derivatives 

are used to quantify the resu lts. The aldeh ydes and ketones that were m easured include: 

formaldehyde, acetaldehyde, ac rolein, acetone, propionaldehyde, crotonaldehyde, nbutyraldehyde, benzaldehyde, is ovaleraldehyde, valeraldehyde, o-tolualdehyde, m+ptolualdehyde (not resolved from each other dur ing normal operating conditions, and so reported 

together), dimethylbenzaldehyde, and hexanaldehyde. Detection limits for this procedure are on 

the order of 0.005 ppm aldehyde or ketone in dilute exhaust. 
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 7 of 9 

Report 03-05383 

3.3.5 Alcohols 

 The fourth GC is utilized to analyze alcohol s. The collection of ethanol in exhaus t and 

from the SHED was a ccomplished by bubbling the sam ple through glass im pingers. Each 

impinger contains 25 mL of dei onized wa ter m aintained at ice -bath tem perature. Exhaus t 

samples were collected continuously during test cycles at a nominal flow rate of 4 L/min through 

a Teflon sample line held at 102°C (215°F). Ev aporative emissions were sampled from Tedlar 

bags using a system configured similarly to that used for exha ust emissions (except an unheated 

sample line is used to transfer the sample to impingers). 

 For analysis, a portion of the liquid sample is injected into a GC equipped with a FID and 

an analytical column. The analytical column is a 3 m x 0.53 mm I.D. capillary column with a 1-

μm film of DB-WAX as the stationary phase. The GC carrier gas is helium with a column head 

pressure of approxim ately 4 psi. External stan dards prepared in deion ized water are used to 

quantify the results. Detection lim its for this procedure are on the order of 0.06 ppm in dilute 

exhaust. 

4.0 RESULTS 

 Regulated emissions results for the Ford F-150 and the Toyota Cam ry are presented in 

Tables 4 through 7. Results are presented for the normal and m alfunction modes by fuel type. 

During the W inter 2005 season, fo r the Ford operating in norm al mode on the Chicago fuel, a 

second exhaust emissions test was performed because the CO result appeared unexpectedly high. 

The CO result remained relatively high, however. 

TABLE 4. REGULATED AND HOT SOAK EMISSIONS 

FOR FORD F-150, SUMMER 2002 

Houston Fuel Atlanta Fuel Chicago Fuel 

Parameter Units 

Normal Malfunction Normal Malfunction Normal Malfunction 

HC g/mi 0.397 2.19 0.469 2.45 0.430 2.27

NMHC g/mi 0.296 2.09 0.366 2.35 0.281 2.17

CO g/mi 2.19 15.6 1.88 16.89 1.66 15.2

NOx g/mi 0.989 2.11 1.05 2.13 1.40 2.07

Fuel Economy mi/gal 14.9 15.0 15.3 15.1 14.5 14.8

Hot Soak HC g 0.00 2.60 0.07 2.18 0.00 1.95
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 8 of 9 

Report 03-05383 

TABLE 5. REGULATED AND HOT SOAK EMISSIONS 

FOR FORD F-150, WINTER 2005 

Houston Fuel Atlanta Fuel Chicago Fuel 

Parameter Units 

Normal Malfunction Normal Malfunction Normal Normal Malfunction

HC g/mi 0.570 2.39 0.588 2.63 0.795 0.794 2.41

NMHC g/mi 0.464 2.23 0.487 2.54 0.637 0.637 2.31

CO g/mi 2.95 16.3 2.90 17.2 9.32 8.19 16.4

NOx g/mi 1.04 2.02 1.08 2.20 1.12 1.26 2.27

Fuel Economy mi/gal 13.6 14.1 14.2 14.0 13.4 13.5 13.8

Hot Soak HC g 0.21 6.83 0.28 13.9 0.42 N/C* 21.0

*N/C = not conducted 

TABLE 6. REGULATED AND HOT SOAK EMISSIONS 

FOR TOYOTA CAMRY, SUMMER 2002 

Houston Fuel Atlanta Fuel Chicago Fuel 

Parameter Units 

Normal Malfunction Normal Malfunction Normal Malfunction 

HC g/mi 0.227 4.05 0.288 3.89 0.244 4.21

NMHC g/mi 0.186 3.55 0.249 3.49 0.208 3.71

CO g/mi 3.18 64.4 2.64 59.5 2.61 60.4

NOx g/mi 0.525 2.56 0.581 2.64 0.516 2.44

Fuel Economy mi/gal 26.8 19.5 22.2 19.9 22.8 19.7

Hot Soak HC g 0.09 0.77 0.01 0.62 0.05 2.16

TABLE 7. REGULATED AND HOT SOAK EMISSIONS FOR TOYOTA CAMRY 

FOR TOYOTA CAMRY, WINTER 2005 

Houston Fuel Atlanta Fuel Chicago Fuel 

Parameter Units 

Normal Malfunction Normal Malfunction Normal Malfunction 

HC g/mi 0.268 3.99 0.384 4.03 0.388 3.75

NMHC g/mi 0.199 3.47 0.346 3.58 0.276 3.29

CO g/mi 2.72 64.5 3.78 63.0 3.89 55.0

NOx g/mi 1.15 1.98 0.877 2.46 0.873 2.76

Fuel Economy mi/gal 24.3 19.8 23.2 20.1 21.9 19.3

Hot Soak HC g 0.02 8.02 0.00 4.84 0.11 8.66
Dr. Barbara Zielinska 

Desert Research Institute 

July 29, 2005 

Page 9 of 9 

Report 03-05383 

 The speciated hydrocarbon results are presented in Appendix A for the Ford F-150 and in 

Appendix B for the Toyota Camry. 

5.0 SUMMARY 

 This report describes a project in w hich SwRI provided logistic support to DRI for onroad and garage exposure studies, and for laborator y exhaust and evaporative em issions testing. 

Hot Soak evaporative and FTP tailpip e vehicle emissions were m easured for two vehicles 

operating on six fuels, to include operation in normal and in malfunction conditions. 

6.0 CLOSURE 

 It has been a pleasure to perform this project for DRI. If you have any questions of a 

technical nature, please contact Patrick Merr itt by telephone at (210) 522 -5422, by fax at (210) 

522-3950, or by e-mail at pmerritt@swri.org. 

Prepared by: Reviewed by: 

 

Patrick M. Merritt Lawrence R. Smith 

Senior Research Scientist Manage r, Light-Duty and Unregulated Emissions 

Department of Engine and Emissions Research Department of Engine and Emissions Research 

Approved by: 

Jeff J. White 

Director of Development 

Department of Engine and Emissions Research 

c: Sherry Twilligear, SwRI Contracts 
APPENDIX A 

HYDROCARBON SPECIATION DATA 

FOR FORD F-150

TABLE OF CONTENTS FOR APPENDIX A 

FTP Composite Results, Winter 2005, pp. A1-A5 

SHED Test Results, Winter 2005, pp. A6-A10 

FTP Composite Results, Summer 2002, pp. A11-A15 

SHED Test Results, Summer 2002, pp. A16-A20 

A blank space in the tables indicates that the compound was not detected during analysis. A 

“Trace” value indicates that th e compound was dete cted, but computations of mass or mass rate 

resulted in a value of less than 0.05. An “*” in the table indicates a malfunction of the analytical 

equipment during sample analysis and that no data are available. 
HYDROCARBON SPECIATION DATA: 

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

METHANE 101.9 91.2 100.3 95.3 147.5 92.8

ETHANE 29.9 31.9 29.8 34.2 34.8 34.4

ETHYLENE 40.9 261.7 37.4 269.6 78.7 276.7

PROPANE 3.3 2.5 2.5 2.5 3.1 3.3

PROPYLENE 9.3 143.2 11.2 158.2 13.6 145.0

ACETYLENE 6.9 139.3 3.7 147.6 8.0 139.5

PROPADIENE 0.2 9.6 0.3 8.6 0.2 7.7

BUTANE 35.6 39.9 61.0 61.7 96.9 81.1

TRANS-2-BUTENE 1.4 10.9 1.6 11.7 3.6 11.7

1-BUTENE 2.0 25.5 2.0 25.6 3.9 24.7

2-METHYLPROPENE (ISOBUTYLENE) 11.6 104.1 3.8 57.4 5.3 44.6

2,2-DIMETHYLPROPANE (NEOPENTANE) 57.6 87.0 60.6 88.6 78.2 104.7

PROPYNE 0.3 11.6 0.3 10.6 0.2 1.1

1,3-BUTADIENE 0.7 32.9 1.0 33.7 1.1 39.1

2-METHYLPROPANE (ISOBUTANE) 5.0 5.8 5.4 5.5 6.1 5.4

1-BUTYNE

METHANOL

CIS-2-BUTENE 0.3 8.3 0.6 8.8 3.3 8.6

3-METHYL-1-BUTENE

ETHANOL 21.1 120.3

2-METHYLBUTANE (ISOPENTANE) 1.0 10.8

2-BUTYNE

1-PENTENE 0.9 8.9 0.5 3.2 1.3 2.0

2-METHYL-1-BUTENE 1.0 18.5 1.2 12.2 2.2 16.2

PENTANE 24.4 43.5 32.5 54.8 32.2 47.0

UNIDENTIFIED C5 OLEFINS Trace 1.7 Trace 0.5 0.3

2-METHYL-1,3-BUTADIENE 0.1 10.8 0.3 10.0 0.3 12.3

TRANS-2-PENTENE 1.4 11.5 1.3 8.1 3.2 14.4

3,3-DIMETHYL-1-BUTENE 0.4 0.1 0.5 Trace 0.5

CIS-2-PENTENE 0.7 6.4 0.6 4.7 1.8 8.5

2-METHYL-2-BUTENE 0.7 13.5 1.2 11.1 3.1 21.7

TERT-BUTANOL

CYCLOPENTADIENE 2.4 2.4 2.2

2,2-DIMETHYLBUTANE 6.3 10.6 4.9 8.0 2.8 5.4

CYCLOPENTENE 0.4 4.3 0.4 3.2 1.6 6.0

4-METHYL-1-PENTENE 0.3 3.5 1.0 2.3 0.5 3.7

3-METHYL-1-PENTENE

CYCLOPENTANE 1.4 5.8 1.3 4.4 2.1 4.5

2,3-DIMETHYLBUTANE 4.8 13.3 6.2 12.7 6.0 11.5

MTBE 7.5 83.7 0.1 1.7 0.2 2.4

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 30.0 64.8 18.5 41.6 19.8 40.8

4-METHYL-TRANS-2-PENTENE 3.4 0.2 1.7 0.5 3.4

3-METHYLPENTANE 20.6 44.2 12.5 27.0 12.8 26.6

2-METHYL-1-PENTENE 0.3 3.4 0.4 2.8 0.5 4.0

1-HEXENE 0.3 3.4 0.4 2.8 0.5 4.0

HEXANE 18.3 43.6 11.5 26.4 9.6 21.9

UNIDENTIFIED C6 0.2 12.0 0.7 7.1 0.2 10.7

TRANS-3-HEXENE

CIS-3-HEXENE 0.4 2.6 0.3 1.4 0.6 3.3

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 0.5 3.7 0.4 2.7 0.8 5.1

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE A-1
HYDROCARBON SPECIATION DATA: 

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 0.7 5.7 0.6 3.8 1.6 9.1

2-METHYL-2-PENTENE 0.4 3.4 0.4 2.7 0.9 5.5

3-METHYLCYCLOPENTENE Trace

CIS-2-HEXENE 0.2 2.0 0.2 1.0 0.5 2.7

ETBE

3-METHYL-CIS-2-PENTENE 0.4 3.2 0.4 2.1 1.1 5.8

2,2-DIMETHYLPENTANE, NOTE A 4.6 13.1 3.2 8.9 4.4 12.0

METHYLCYCLOPENTANE, NOTE A 4.5 12.8 3.1 8.7 4.3 11.8

2,4-DIMETHYLPENTANE 2.5 7.4 3.5 9.4 1.9 6.2

2,2,3-TRIMETHYLBUTANE 0.3 1.3 0.4 0.9 0.1 0.8

3,4-DIMETHYL-1-PENTENE 0.4 0.3 0.7

1-METHYLCYCLOPENTENE 1.0 5.6 1.0 4.7 1.2 7.6

BENZENE 6.5 46.5 10.6 81.3 14.8 80.5

3-METHYL-1-HEXENE 1.4 0.3 1.2

3,3-DIMETHYLPENTANE 2.1 3.9 1.4 2.3 0.9 0.5

CYCLOHEXANE 0.4 2.0 1.0 2.7 1.1 5.5

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 14.4 43.5 12.4 38.7 7.8 23.4

1,1-DIMETHYLCYCLOPENTANE 0.1 Trace 0.5 0.3 1.2

TERT-AMYL METHYL ETHER

CYCLOHEXENE 0.8 11.1 0.1 1.3 0.2 2.7

3-METHYLHEXANE 12.1 35.6 8.4 26.5 4.9 14.3

CIS-1,3-DIMETHYLCYCLOPENTANE 0.3 4.0 1.0 2.7 2.3 6.4

3-ETHYLPENTANE 1.2 3.3 1.4 5.6 1.5 7.9

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.9 1.7 1.1 3.4 0.6 5.7

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 3.8 15.4 21.7 57.4 6.7 17.9

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 1.0 0.2 1.6 0.5 3.9

HEPTANE 7.5 27.0 6.8 23.1 4.3 14.0

CIS-3-HEPTENE

UNIDENTIFIED C7 1.0 6.5 0.3 2.9 1.3 6.7

2-METHYL-2-HEXENE 0.5 1.3 0.5 2.9

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 0.2 1.4 0.1 1.2 0.3 2.1

3-ETHYL-CIS-2-PENTENE Trace

2,4,4-TRIMETHYL-1-PENTENE 0.2 1.7 0.3 1.5 0.4 2.5

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 0.1 1.1 1.0 0.2 1.5

METHYLCYCLOHEXANE 1.8 8.0 2.4 9.4 4.5 16.8

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.5 2.4 0.5 2.0 0.4 2.1

2,4,4-TRIMETHYL-2-PENTENE 0.1 Trace 0.2 0.1 Trace 0.3

2,2,3-TRIMETHYLPENTANE 0.5 2.6 2.2 9.4 1.1 6.8

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 1.4 9.1 2.8 11.9 1.0 6.2

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.5 2.3 0.3 2.3 0.5 2.1

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.1 0.8 0.2 0.7 0.3 2.0

PAGE A-2
HYDROCARBON SPECIATION DATA: 

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 1.0 4.1 4.8 16.9 2.5 10.0

2,3,3-TRIMETHYLPENTANE 0.9 2.0 2.6 11.4 2.9 9.0

TOLUENE 8.4 85.5 20.7 189.2 14.7 114.8

2,3-DIMETHYLHEXANE 1.2 3.6 1.7 11.9 1.1 7.9

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 0.2 0.1 1.7

3,4-DIMETHYLHEXANE, NOTE B 1.9 1.6 0.8

4-METHYLHEPTANE 3.2 13.2 3.1 9.9 1.8 7.6

3-METHYLHEPTANE 3.3 12.9 3.1 11.3 1.8 6.6

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE 0.4 2.7 0.2 2.6 0.7 3.6

2,2,5-TRIMETHYLHEXANE 0.3 1.4 0.8 3.6 1.5 5.6

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.3 2.2 0.2 2.0 0.5 2.1

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.1 1.0 0.1 0.7 0.1 1.3

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 0.1 1.6 0.2 1.0 0.2 2.0

1-OCTENE

TRANS-4-OCTENE 0.3 0.1 1.9 0.9

OCTANE 1.6 7.7 1.7 7.9 1.2 4.5

UNIDENTIFIED C8 1.2 3.4 0.3 4.2 0.9 4.4

TRANS-2-OCTENE

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE Trace 0.7 0.1 0.5 0.1 0.6

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE Trace

2,3,5-TRIMETHYLHEXANE Trace 0.4 0.1 0.8 0.3 1.0

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.1 1.0 0.1 0.9 0.1 1.0

2,4-DIMETHYLHEPTANE 0.2 1.0 0.1 1.0 0.2 0.7

4,4-DIMETHYLHEPTANE 0.1 0.5 0.1 0.3 0.1 0.5

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.3 1.7 0.3 2.1 0.7 1.7

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.2 1.2 0.2 1.2 0.2 1.0

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E 0.2 1.2 0.2 1.2 0.2 1.0

ETHYLBENZENE 3.1 33.3 4.4 43.7 3.3 22.1

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 9.6 110.1 12.8 122.9 9.6 65.2

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 1.0 6.5 0.8 5.0 0.6 3.8

3-METHYLOCTANE 0.7 4.2 0.6 3.4 0.4 2.3

STYRENE 0.3 15.5 0.8 19.4 0.3 11.2

PAGE A-3
HYDROCARBON SPECIATION DATA: 

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 3.5 42.6 5.0 48.1 3.3 23.5

1-NONENE 0.1 1.1 0.2 1.4 0.1 1.9

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.3 3.0 0.4 2.9 0.4 2.6

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.5 0.1 0.6 Trace 0.5

2,2-DIMETHYLOCTANE Trace 0.6 0.1 0.5 0.1 0.9

2,4-DIMETHYLOCTANE 0.1 0.7 0.1 0.3 0.1 1.0

n-PROPYLBENZENE 0.5 9.8 0.8 12.0 0.6 6.7

1-METHYL-3-ETHYLBENZENE 2.3 52.6 3.3 47.0 2.6 31.8

1-METHYL-4-ETHYLBENZENE 0.9 7.9 1.5 21.5 0.8 10.6

1,3,5-TRIMETHYLBENZENE 1.1 19.4 1.7 19.6 0.8 13.2

1-METHYL-2-ETHYLBENZENE 0.8 15.7 1.5 19.8 0.7 10.4

1,2,4-TRIMETHYLBENZENE 1.6 70.5 5.4 77.5 2.5 47.8

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 0.1 1.3 0.3 1.4 Trace 2.4

ISOBUTYLBENZENE, NOTE F 0.1 1.2 0.3 1.3 Trace 2.3

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene) 0.8 0.1 1.4 0.2 0.9

1-METHYL-3-ISOPROPYLBENZENE Trace

1,2,3-TRIMETHYLBENZENE 0.4 14.2 1.2 18.4 0.4 11.3

1-METHYL-4-ISOPROPYLBENZENE 0.9 0.1 1.0 0.2 0.9

INDAN

1-METHYL-2-ISOPROPYLBENZENE 6.6 0.4 5.4 0.1 7.6

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE 0.1 0.5 Trace 0.7

1-METHYL-3-N-PROPYLBENZENE 0.1 5.7 0.2 10.3 0.2 6.8

1-METHYL-4-N-PROPYLBENZENE, NOTE G 0.4 14.4 0.8 16.8 0.5 13.4

1,2 DIETHYLBENZENE 0.2 1.0 1.0

1-METHYL-2-N-PROPYLBENZENE 2.3 0.1 4.0 2.4

1,4-DIMETHYL-2-ETHYLBENZENE 5.8 0.7 8.5 6.5

1,3-DIMETHYL-4-ETHYLBENZENE 4.4 0.7 8.8 0.4 5.6

1,2-DIMETHYL-4-ETHYLBENZENE 0.8 1.9 1.7 0.9 1.8

1,3-DIMETHYL-2-ETHYLBENZENE 1.9 1.4 0.9

UNDECANE Trace 3.7 0.2 4.5 0.1 2.8

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE 2.7 4.5 5.6

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE 0.3 7.6 0.7 10.4 0.5 2.2

TERT-1-BUT-2-METHYLBENZENE 2.4 Trace 3.6 Trace 4.9

1,2,3,4-TETRAMETHYLBENZENE 4.3 4.8 Trace 4.1

N-PENT-BENZENE 2.0 2.2 2.0

TERT-1-BUT-3,5-DIMETHYLBENZENE

TERT-1-BUTYL-4-ETHYLBENZENE 5.0 3.3 6.2

NAPHTHALENE

DODECANE Trace 2.4 Trace 4.1 0.1 1.0

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE A-4
HYDROCARBON SPECIATION DATA: 

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 3.7 76.1 3.6 92.4 5.2 94.8

FORMALDEHYDE 9.3 56.5 5.4 38.7 6.6 34.1

ACETALDEHYDE 2.2 17.3 2.1 16.9 4.9 32.0

ACROLEIN 0.1 4.6 0.2 6.6 0.2 8.2

ACETONE 0.8 7.5 0.3 5.9 0.8 4.4

PROPIONALDEHYDE Trace 8.2 0.3 5.1 0.3 4.3

CROTONALDEHYDE 0.3 5.4 0.2 4.9 0.2 5.3

ISOBUTYRALDEHYDE, NOTE H 0.1 1.2 Trace 1.0 0.2 1.2

METHYL ETHYL KETONE, NOTE H 0.1 1.2 Trace 1.0 0.2 1.2

BENZALDEHYDE 0.5 10.2 0.6 13.8 0.1 7.8

ISOVALERALDEHYDE 0.2 1.2 0.9 Trace 1.5

VALERALDEHYDE 1.1 0.8 0.8

O-TOLUALDEHYDE 4.0 0.1 4.0 Trace 2.3

M/P-TOLUALDEHYDE 0.2 13.0 0.4 13.6 0.1 8.2

HEXANALDEHYDE 0.2 Trace 0.5 Trace 1.3

DIMETHYLBENZALDEHYDE 0.1 4.1 Trace 5.2 0.1 3.7

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

H - Isobutyraldehyde and methyl ethyl ketone co-elute. LC peak area split equally between the two compounds.

PAGE A-5
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

METHANE -- -- -- -- -- --

ETHANE 1.5 3.3 0.9 4.6 5.6 6.7

ETHYLENE 0.3 0.4 0.3 0.6 0.2

PROPANE 1.1 40.5 1.5 82.6 57.1 145.8

PROPYLENE 0.2 5.7 0.6 15.6 7.4 22.5

ACETYLENE

PROPADIENE

BUTANE 53.8 2311.0 106.2 3837.5 494.4 4161.4

TRANS-2-BUTENE 2.1 50.2 2.8 117.8 7.7 211.3

1-BUTENE 0.7 27.8 0.9 61.2 6.1 115.1

2-METHYLPROPENE (ISOBUTYLENE) 1.2 33.2 1.3 70.8 7.3 134.3

2,2-DIMETHYLPROPANE (NEOPENTANE) 43.9 1183.5 61.9 2925.1 151.9 4437.8

PROPYNE

1,3-BUTADIENE 1.2 2.4 7.9

2-METHYLPROPANE (ISOBUTANE) 5.7 199.7 10.4 481.5 68.0 792.8

1-BUTYNE

METHANOL

CIS-2-BUTENE 38.9 96.4 5.7 162.6

3-METHYL-1-BUTENE

ETHANOL 227.0 3370.0

2-METHYLBUTANE (ISOPENTANE)

2-BUTYNE

1-PENTENE 56.0 1.0 104.5 6.4 234.0

2-METHYL-1-BUTENE 125.1 2.7 238.4 14.1 500.5

PENTANE 21.0 506.3 25.7 1109.7 65.4 1711.8

UNIDENTIFIED C5 OLEFINS

2-METHYL-1,3-BUTADIENE 1.6 4.9 7.9 35.9

TRANS-2-PENTENE 5.2 129.2 2.4 245.5 5.4 530.8

3,3-DIMETHYL-1-BUTENE 2.6 14.2

CIS-2-PENTENE 2.9 73.9 1.1 134.6 2.1 291.7

2-METHYL-2-BUTENE 9.8 220.7 6.4 414.3 30.7 883.9

TERT-BUTANOL

CYCLOPENTADIENE 1.5 4.3 4.7 15.3

2,2-DIMETHYLBUTANE 2.6 27.8 1.8 59.8 2.8 96.4

CYCLOPENTENE 24.6 44.7 4.0 96.2

4-METHYL-1-PENTENE 0.4 12.6 2.4 23.4 1.2 49.6

3-METHYL-1-PENTENE

CYCLOPENTANE 28.1 55.3 4.2 96.2

2,3-DIMETHYLBUTANE 5.5 58.6 3.3 118.7 6.9 200.6

MTBE 170.1 46.9 1.1 78.2

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 30.1 219.1 15.5 389.8 25.9 673.2

4-METHYL-TRANS-2-PENTENE 20.0 2.0 44.3

3-METHYLPENTANE 9.1 118.0 7.2 222.2 15.1 384.3

2-METHYL-1-PENTENE 1.1 12.1 0.6 22.7 2.0 50.0

1-HEXENE 1.1 12.1 0.6 22.7 2.0 50.0

HEXANE 8.7 90.4 7.5 167.0 13.6 279.1

UNIDENTIFIED C6 0.7 6.7 1.0 5.8 13.7 28.3

TRANS-3-HEXENE

CIS-3-HEXENE 1.7 10.7 0.8 20.9 46.9

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 14.3 1.4 30.0 3.5 66.6

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE A-6
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 4.2 29.1 1.7 51.9 4.8 116.1

2-METHYL-2-PENTENE 1.5 17.8 1.8 30.7 3.6 66.8

3-METHYLCYCLOPENTENE

CIS-2-HEXENE 1.0 9.1 16.0 1.7 36.3

ETBE

3-METHYL-CIS-2-PENTENE 2.0 18.7 1.0 34.2 2.1 77.1

2,2-DIMETHYLPENTANE, NOTE A 3.5 38.5 2.5 68.2 6.7 132.1

METHYLCYCLOPENTANE, NOTE A 3.4 37.6 2.5 66.8 6.5 129.4

2,4-DIMETHYLPENTANE 1.9 17.3 1.6 35.5 2.7 59.2

2,2,3-TRIMETHYLBUTANE 2.4 1.7 7.0

3,4-DIMETHYL-1-PENTENE 0.8 1.4 3.7

1-METHYLCYCLOPENTENE 1.8 17.5 1.9 34.0 83.1

BENZENE 6.7 27.2 7.3 65.6 0.2 133.8

3-METHYL-1-HEXENE 2.1 5.0

3,3-DIMETHYLPENTANE 4.0 1.6 3.8 5.2 3.0

CYCLOHEXANE 1.3 11.6 20.0 44.8

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 7.0 44.4 5.3 84.0 8.4 120.0

1,1-DIMETHYLCYCLOPENTANE 1.6 2.8 6.3

TERT-AMYL METHYL ETHER

CYCLOHEXENE 2.2 3.3 0.5 7.7

3-METHYLHEXANE 5.8 33.1 3.9 52.8 5.1 73.2

CIS-1,3-DIMETHYLCYCLOPENTANE 1.3 9.5 0.8 17.3 2.1 35.0

3-ETHYLPENTANE 1.2 10.4 0.9 24.4 2.0 43.4

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 1.3 7.8 0.6 15.0 1.6 28.8

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 2.7 21.4 4.0 59.6 4.0 65.7

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 0.5 4.0 0.4 7.3 0.9 15.8

HEPTANE 5.5 21.4 4.1 39.7 5.0 60.2

CIS-3-HEPTENE

UNIDENTIFIED C7 0.4 3.4 17.1 0.5 42.4

2-METHYL-2-HEXENE 18.4

3-METHYL-TRANS-3-HEXENE 1.6

TRANS-2-HEPTENE 0.2 2.3 0.2 3.0 0.5 5.5

3-ETHYL-CIS-2-PENTENE 3.1

2,4,4-TRIMETHYL-1-PENTENE 0.6 3.6 0.4 6.3 1.0 14.1

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 1.5 0.2 2.8 0.4 6.0

METHYLCYCLOHEXANE 2.7 18.1 2.2 32.8 4.8 66.4

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 1.3 0.2 2.5 0.3 5.1

2,4,4-TRIMETHYL-2-PENTENE 0.9 0.2

2,2,3-TRIMETHYLPENTANE 1.6 3.7 0.9 8.1 1.7 23.6

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 1.8 11.0 0.5 8.9 2.0 13.5

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.2 3.4 0.4 6.3

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 1.7 0.2 5.2

PAGE A-7
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 2.4 11.2 1.6 17.7 2.4 29.2

2,3,3-TRIMETHYLPENTANE 1.0 7.8 1.3 12.9 22.4

TOLUENE 12.8 37.6 15.1 82.5 125.9

2,3-DIMETHYLHEXANE 4.1 7.8 15.9

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 1.1 0.2 3.8

3,4-DIMETHYLHEXANE, NOTE B

4-METHYLHEPTANE 1.6 6.9 1.3 10.2 1.6 15.8

3-METHYLHEPTANE 1.7 7.0 1.3 11.4 1.9 11.6

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE 0.3 0.8 7.1

2,2,5-TRIMETHYLHEXANE 0.6 3.3 0.5 4.2 0.8 7.8

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.6 1.5 0.1 1.2 0.2 1.8

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.2

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 0.4 0.6 0.2 0.1 3.0

1-OCTENE

TRANS-4-OCTENE 0.6 1.7

OCTANE 1.2 2.8 0.9 3.4 1.2 7.0

UNIDENTIFIED C8 6.0 18.1 0.3 9.8

TRANS-2-OCTENE 0.4 0.7 0.8 2.6

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.9

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.3 0.3 0.9

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.3 0.3 0.9

2,4-DIMETHYLHEPTANE 0.2 0.5 0.1 0.1 0.3

4,4-DIMETHYLHEPTANE 0.1 0.6

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.4 1.0 0.2 1.5 0.3 3.3

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.1 0.3 0.4 0.1 0.9

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E 0.1 0.3 0.4 0.1 0.9

ETHYLBENZENE 3.0 5.2 2.8 9.4 3.3 10.8

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 7.4 12.6 6.0 25.7 7.6 31.8

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 1.4 0.1 2.5

3-METHYLOCTANE 1.1 1.6

STYRENE

PAGE A-8
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 1.5 2.6 0.9 8.6 1.3 10.0

1-NONENE 0.3 0.4 0.1 0.4

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.1 0.5

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.1 0.2

2,2-DIMETHYLOCTANE 0.2

2,4-DIMETHYLOCTANE 0.1

n-PROPYLBENZENE 0.1 0.2

1-METHYL-3-ETHYLBENZENE

1-METHYL-4-ETHYLBENZENE

1,3,5-TRIMETHYLBENZENE

1-METHYL-2-ETHYLBENZENE 0.3

1,2,4-TRIMETHYLBENZENE 2.0

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F

ISOBUTYLBENZENE, NOTE F

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene)

1-METHYL-3-ISOPROPYLBENZENE 0.5

1,2,3-TRIMETHYLBENZENE 0.3 0.3

1-METHYL-4-ISOPROPYLBENZENE

INDAN

1-METHYL-2-ISOPROPYLBENZENE

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE

1-METHYL-3-N-PROPYLBENZENE

1-METHYL-4-N-PROPYLBENZENE, NOTE G

1,2 DIETHYLBENZENE

1-METHYL-2-N-PROPYLBENZENE

1,4-DIMETHYL-2-ETHYLBENZENE

1,3-DIMETHYL-4-ETHYLBENZENE

1,2-DIMETHYL-4-ETHYLBENZENE

1,3-DIMETHYL-2-ETHYLBENZENE

UNDECANE

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE

TERT-1-BUT-2-METHYLBENZENE

1,2,3,4-TETRAMETHYLBENZENE

N-PENT-BENZENE

TERT-1-BUT-3,5-DIMETHYLBENZENE

TERT-1-BUTYL-4-ETHYLBENZENE

NAPHTHALENE

DODECANE 0.1

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE A-9
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

F-HOU-N F-HOU-MF F-ATL-N F-ATL-MF F-CHI-N F-CHI-MF

COMPOUND 3/16/2005 3/17/2005 3/23/2005 3/24/2005 3/28/2005 3/29/2005

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 0.2 1.6 2.2 1.1 8.4

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

PAGE A-10
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

METHANE 97.4 100.8 101.5 104.5 94.3 95.0

ETHANE 32.7 37.0 27.0 35.9 35.3 34.9

ETHYLENE 27.7 245.4 30.1 255.5 25.0 232.7

PROPANE 3.8 3.6 4.1 3.8 2.9 6.4

PROPYLENE 7.2 108.8 12.2 132.7 7.4 124.7

ACETYLENE 3.4 121.1 5.3 102.1 1.9 70.1

PROPADIENE

BUTANE 3.8 9.1 7.5 12.6 3.2 4.3

TRANS-2-BUTENE 1.0 7.3 2.0 6.6 5.2 17.6

1-BUTENE 2.3 19.2 1.6 18.6 1.2

2-METHYLPROPENE (ISOBUTYLENE) 8.8 100.9 4.2 60.4 3.4 64.4

2,2-DIMETHYLPROPANE (NEOPENTANE) 0.4 2.0 0.6 2.0 0.2 1.0

PROPYNE

1,3-BUTADIENE 1.5 37.6 1.2 48.9 0.3 32.9

2-METHYLPROPANE (ISOBUTANE) 0.2 8.6 3.8 9.3 0.2 6.9

1-BUTYNE

METHANOL

CIS-2-BUTENE 1.3 6.0 9.1 0.4 6.3

3-METHYL-1-BUTENE

ETHANOL 12.1 182.6

2-METHYLBUTANE (ISOPENTANE) 23.1 49.3 13.7 59.4 29.6 46.9

2-BUTYNE

1-PENTENE 0.4 7.8 0.8 1.2 0.4 6.8

2-METHYL-1-BUTENE 0.7 13.6 0.6 11.2 0.5 12.5

PENTANE 10.9 27.6 12.6 33.5 4.3 10.9

UNIDENTIFIED C5 OLEFINS 0.1 0.5 2.0 0.7 12.3

2-METHYL-1,3-BUTADIENE 0.2 6.6 10.3 0.2 11.9

TRANS-2-PENTENE 0.8 10.9 0.4 8.2 0.7 7.6

3,3-DIMETHYL-1-BUTENE 0.4 0.7 0.4 Trace 1.0

CIS-2-PENTENE 0.4 6.2 Trace 4.6 2.4 4.5

2-METHYL-2-BUTENE 1.1 14.9 1.1 12.1 1.3 16.8

TERT-BUTANOL

CYCLOPENTADIENE 0.1 2.8 8.4 0.1 7.4

2,2-DIMETHYLBUTANE 1.8 4.6 2.1 6.2 2.6 7.0

CYCLOPENTENE 0.3 4.0 0.3 2.9 0.2 3.4

4-METHYL-1-PENTENE 0.1 2.0 0.2 2.0 0.1 2.8

3-METHYL-1-PENTENE

CYCLOPENTANE 0.9 3.2 0.6 3.4 0.7 2.7

2,3-DIMETHYLBUTANE 3.6 11.1 2.3 9.2 5.6 17.0

MTBE 0.9 41.9

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 11.7 39.4 7.9 31.2 7.8 26.5

4-METHYL-TRANS-2-PENTENE

3-METHYLPENTANE 8.9 32.2 5.3 20.9 5.7 20.6

2-METHYL-1-PENTENE 0.1 2.5 0.1 2.5 0.1 2.0

1-HEXENE 0.2 2.8 0.1 2.5 0.1 2.0

HEXANE 8.7 31.2 5.2 19.3 4.6 14.4

UNIDENTIFIED C6 0.1 6.2 2.0 7.3 0.5 9.5

TRANS-3-HEXENE

CIS-3-HEXENE 0.1 1.6 0.1 1.0 0.1 0.9

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 0.2 2.4 0.1 1.9 0.1 1.8

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE A-11
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 0.3 4.1 0.3 3.2 0.2 3.5

2-METHYL-2-PENTENE 0.2 2.9 0.1 2.1 0.1 2.5

3-METHYLCYCLOPENTENE

CIS-2-HEXENE 0.1 1.5 0.1 0.9 0.1 0.8

ETBE

3-METHYL-CIS-2-PENTENE 0.3 2.7 0.2 1.9 0.5 1.7

2,2-DIMETHYLPENTANE, NOTE A 1.6 7.3 1.4 7.2 2.1 9.5

METHYLCYCLOPENTANE, NOTE A 1.6 7.1 1.4 7.0 2.0 9.3

2,4-DIMETHYLPENTANE 1.7 5.5 1.6 5.6 3.5 11.7

2,2,3-TRIMETHYLBUTANE 0.3 3.0 Trace 0.4 0.2 0.4

3,4-DIMETHYL-1-PENTENE 0.3

1-METHYLCYCLOPENTENE 0.7 2.9 2.6 3.1

BENZENE 6.1 60.5 14.2 103.6 6.0 62.0

3-METHYL-1-HEXENE

3,3-DIMETHYLPENTANE 0.6 1.4 0.5 1.2 0.2 0.8

CYCLOHEXANE 0.4 2.8 0.8 5.3 1.9 10.7

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 6.4 20.9 6.0 22.9 10.2 32.8

1,1-DIMETHYLCYCLOPENTANE 1.3

TERT-AMYL METHYL ETHER

CYCLOHEXENE Trace 1.0 1.2 Trace 1.8

3-METHYLHEXANE 4.6 15.4 4.4 15.8 5.0 16.7

CIS-1,3-DIMETHYLCYCLOPENTANE 0.3 2.1 0.3 2.0 0.6 3.3

3-ETHYLPENTANE 0.3 2.6 0.4 1.2

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.4 2.1 0.4 2.0 0.8 3.2

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 10.4 26.2 13.9 41.0 15.5 43.2

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 0.1 1.7 1.1 0.2

HEPTANE 2.9 10.1 4.6 16.2 5.3 14.9

CIS-3-HEPTENE

UNIDENTIFIED C7 0.2 1.3 0.2 2.9 0.1 1.9

2-METHYL-2-HEXENE 1.3

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 0.1 1.1 Trace 0.7 Trace 0.7

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.2 1.4 0.1 0.6 0.1 0.8

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 0.1 1.1 0.1 0.8 0.1 1.0

METHYLCYCLOHEXANE 0.9 4.5 1.4 7.6 2.1 11.1

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.2 0.8 0.3 1.1 0.4 1.4

2,4,4-TRIMETHYL-2-PENTENE

2,2,3-TRIMETHYLPENTANE 2.0 6.0 1.3 6.1 2.6 9.9

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 1.2 6.4 1.5 8.3 1.7 8.3

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.2 1.4 0.5 1.1 0.3 1.9

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.1 0.3 0.1 0.4 0.1 0.7

PAGE A-12
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 3.8 12.2 3.8 11.3 5.7 18.5

2,3,3-TRIMETHYLPENTANE 3.6 21.6 3.0 13.4 6.6 31.8

TOLUENE 6.5 87.5 27.1 232.4 8.0 102.1

2,3-DIMETHYLHEXANE 1.8 16.0 3.2 20.1 3.0 20.0

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 6.7 1.8 7.3

3,4-DIMETHYLHEXANE, NOTE B 0.1 0.1 1.6 1.1

4-METHYLHEPTANE 2.2 1.1 0.2 1.5 2.8 9.8

3-METHYLHEPTANE 2.2 7.7 1.8 7.8 2.3 8.8

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE 0.1

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE Trace 1.8 0.2 1.7 0.4 2.0

2,2,5-TRIMETHYLHEXANE 1.0 3.8 1.2 5.4 2.7 10.6

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.2 1.9 0.1 2.5 0.2 2.0

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.1 0.8 Trace 0.8 Trace 0.6

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE Trace 1.0 0.1 0.8 0.1 0.7

1-OCTENE

TRANS-4-OCTENE

OCTANE 1.1 4.4 1.6 6.5 1.7 6.7

UNIDENTIFIED C8 0.2 3.6 0.3 1.2 4.9 1.1

TRANS-2-OCTENE 0.1 1.2 0.1 0.7 Trace 0.5

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.1 0.7 Trace 0.3 0.3

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.1 0.7 0.1 1.0 0.3 1.9

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.1 0.7 0.1 0.6 Trace 0.7

2,4-DIMETHYLHEPTANE 0.1 0.3 0.2 0.9 2.6 1.0

4,4-DIMETHYLHEPTANE Trace 1.2 0.2 0.1 0.2

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.4 0.6 0.2 1.6 0.5 2.2

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.4 1.6 0.6 2.1 0.6 2.7

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E

ETHYLBENZENE 2.6 22.1 5.2 37.8 1.9 17.8

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 6.9 61.5 18.0 120.0 5.7 57.6

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.8 5.4 1.2 6.8 0.8 6.4

3-METHYLOCTANE 0.6 3.0 0.7 3.3 0.6 4.9

STYRENE 0.4 11.8 1.4 20.6 0.3 12.6

PAGE A-13
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 2.9 27.8 7.6 48.6 2.4 27.1

1-NONENE 0.1 2.3 0.2 3.1 0.3 3.8

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.5 3.1 1.2 3.6 0.8 4.7

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.9 1.4 0.2 3.4 0.1 1.8

2,2-DIMETHYLOCTANE 0.1 0.4 0.1 Trace 0.2

2,4-DIMETHYLOCTANE Trace 0.3 0.1 0.3 Trace 0.3

n-PROPYLBENZENE 0.5 6.4 1.5 13.4 0.4 6.1

1-METHYL-3-ETHYLBENZENE 2.7 32.2 6.8 12.6 1.9 26.0

1-METHYL-4-ETHYLBENZENE 1.0 13.6 3.1 50.5 0.6 10.3

1,3,5-TRIMETHYLBENZENE 1.0 11.3 3.1 24.6 0.7 10.9

1-METHYL-2-ETHYLBENZENE 1.0 12.2 2.9 22.0 0.7 7.4

1,2,4-TRIMETHYLBENZENE 3.0 46.6 11.2 96.2 2.4 44.3

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 0.1 1.1 0.3 2.3 0.1 1.1

ISOBUTYLBENZENE, NOTE F 0.1 1.0 0.3 2.1 0.1 1.0

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene)

1-METHYL-3-ISOPROPYLBENZENE 1.9

1,2,3-TRIMETHYLBENZENE 0.6 10.8 2.7 23.2 0.5 9.1

1-METHYL-4-ISOPROPYLBENZENE 0.4

INDAN

1-METHYL-2-ISOPROPYLBENZENE 1.8

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE Trace

1-METHYL-3-N-PROPYLBENZENE 0.1 5.5 1.0 7.7 0.3 7.4

1-METHYL-4-N-PROPYLBENZENE, NOTE G 0.5 13.0 1.9 21.8 0.3 11.7

1,2 DIETHYLBENZENE 0.1 0.2

1-METHYL-2-N-PROPYLBENZENE 0.2 2.0 0.1 2.9 0.2 2.1

1,4-DIMETHYL-2-ETHYLBENZENE 6.1

1,3-DIMETHYL-4-ETHYLBENZENE 0.4 16.3 1.1 18.9 0.3 5.3

1,2-DIMETHYL-4-ETHYLBENZENE 0.1 10.9 1.4 9.5 0.4 1.8

1,3-DIMETHYL-2-ETHYLBENZENE 3.9

UNDECANE Trace 2.3 0.5 6.3 0.1 2.3

1,2-DIMETHYL-3-ETHYLBENZENE 0.7

1,2,4,5-TETRAMETHYLBENZENE Trace 3.7 0.6 9.9 0.1 4.0

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE

TERT-1-BUT-2-METHYLBENZENE 5.7

1,2,3,4-TETRAMETHYLBENZENE

N-PENT-BENZENE 1.9

TERT-1-BUT-3,5-DIMETHYLBENZENE 0.1 0.8 0.2 2.6 17.1

TERT-1-BUTYL-4-ETHYLBENZENE

NAPHTHALENE 0.3

DODECANE 0.1 0.3 0.8 5.8 1.6

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE A-14
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

FORD F-150

FTP Composite, mg/mi

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 3.0 81.0 18.8 238.9 4.6 105.3

FORMALDEHYDE 9.4 94.0 14.6 75.5 12.7 85.2

ACETALDEHYDE 4.6 22.6 4.3 21.1 5.7 36.2

ACROLEIN 1.2 11.0 0.9 13.4 0.3 11.6

ACETONE 5.6 12.5 4.3 7.4 4.1 7.3

PROPIONALDEHYDE 0.5 8.9 0.5 4.7 0.5 6.5

CROTONALDEHYDE 2.0 9.9 0.8 6.4 1.1 7.6

ISOBUTYRALDEHYDE, NOTE H 0.8 3.0 0.6 2.2 0.4 2.1

METHYL ETHYL KETONE, NOTE H 0.8 3.0 0.6 2.2 0.4 2.1

BENZALDEHYDE 0.1 10.5 0.7 19.5 0.3 10.9

ISOVALERALDEHYDE 0.3 2.1 0.1 1.7 0.1 1.4

VALERALDEHYDE 0.2 1.1 0.3 1.6 0.2 0.3

O-TOLUALDEHYDE 0.3 4.0 5.6 3.2

M/P-TOLUALDEHYDE 0.3 11.8 0.8 18.9 0.3 11.0

HEXANALDEHYDE 0.3

DIMETHYLBENZALDEHYDE 0.4 4.0 0.2 6.9 0.4 3.9

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

H - Isobutyraldehyde and methyl ethyl ketone co-elute. LC peak area split equally between the two compounds.

PAGE A-15
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

METHANE

ETHANE 7.2 Trace 0.6

ETHYLENE 7.3 2.8

PROPANE 0.4 6.0 4.3

PROPYLENE 1.2 0.6

ACETYLENE

PROPADIENE

BUTANE 2.0 123.7 3.1 94.8 2.3 70.5

TRANS-2-BUTENE 3.8

1-BUTENE 2.8

2-METHYLPROPENE (ISOBUTYLENE) 3.4 2.1 6.0

2,2-DIMETHYLPROPANE (NEOPENTANE) 2.8 3.0 0.7

PROPYNE

1,3-BUTADIENE

2-METHYLPROPANE (ISOBUTANE) 0.6 22.7 25.6 1.1 16.2

1-BUTYNE

METHANOL

CIS-2-BUTENE

3-METHYL-1-BUTENE

ETHANOL 10.6 193.4

2-METHYLBUTANE (ISOPENTANE) 647.3 687.0 5.7 532.7

2-BUTYNE

1-PENTENE 1.8 27.2 25.3 23.4

2-METHYL-1-BUTENE 1.0 38.4 8.6 38.4 36.9

PENTANE 3.2 105.9 0.7 118.6 0.8 87.0

UNIDENTIFIED C5 OLEFINS

2-METHYL-1,3-BUTADIENE 1.4 2.7 1.1 2.5 1.1

TRANS-2-PENTENE 1.2 43.6 0.9 39.5 37.6

3,3-DIMETHYL-1-BUTENE 0.4 0.3 1.1 0.4

CIS-2-PENTENE 0.5 24.0 0.5 21.9 0.5 21.1

2-METHYL-2-BUTENE 2.4 59.0 2.4 56.4 2.2 54.2

TERT-BUTANOL

CYCLOPENTADIENE 0.8 0.5 0.5

2,2-DIMETHYLBUTANE 0.5 21.3 0.4 23.3 0.5 23.1

CYCLOPENTENE 7.6 0.3 7.5 0.4 6.7

4-METHYL-1-PENTENE 3.5 2.6 3.1

3-METHYL-1-PENTENE

CYCLOPENTANE 0.6 12.2 0.6 13.7 0.5 12.1

2,3-DIMETHYLBUTANE 1.7 47.4 1.3 48.3 1.6 51.3

MTBE 97.0

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 6.7 77.1 6.6 86.6 6.9 81.1

4-METHYL-TRANS-2-PENTENE

3-METHYLPENTANE 3.4 57.7 2.8 52.5 2.9 50.4

2-METHYL-1-PENTENE 0.2 2.9 0.3 2.8 0.4 2.5

1-HEXENE 0.2 2.9 0.3 2.8 0.4 2.5

HEXANE 3.6 40.1 2.9 35.7 3.4 33.1

UNIDENTIFIED C6 1.9 4.6 12.4 11.3

TRANS-3-HEXENE

Houston Fuel Atlanta Fuel Chicago Fuel

 PAGE A-16
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

CIS-3-HEXENE 2.5 2.1 2.1

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 0.4 4.0 3.2 3.3

3-METHYL-TRANS-2-PENTENE 5.9 0.3 6.1 5.5

2-METHYL-2-PENTENE 0.3 3.7 0.4 3.4 0.4 3.1

3-METHYLCYCLOPENTENE

CIS-2-HEXENE 2.5 0.3 5.6 0.3 2.5

ETBE

3-METHYL-CIS-2-PENTENE 4.6 0.6 4.2 0.5 4.0

2,2-DIMETHYLPENTANE, NOTE A 1.9 16.8 1.1 17.5 1.3 18.7

METHYLCYCLOPENTANE, NOTE A 1.9 16.4 1.1 17.1 1.2 18.4

2,4-DIMETHYLPENTANE 1.5 13.5 1.2 15.2 1.5 17.1

2,2,3-TRIMETHYLBUTANE 1.1 0.9 1.0

3,4-DIMETHYL-1-PENTENE

1-METHYLCYCLOPENTENE 0.9 13.9 2.1 9.1 0.9 8.5

BENZENE 3.8 23.1 5.6 25.2 5.6 21.4

3-METHYL-1-HEXENE

3,3-DIMETHYLPENTANE 0.4 0.8 1.9 1.1

CYCLOHEXANE 16.9 16.3 21.3

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 5.1 32.2 4.1 34.7 4.5 38.0

1,1-DIMETHYLCYCLOPENTANE

TERT-AMYL METHYL ETHER

CYCLOHEXENE 0.4 0.5 0.3

3-METHYLHEXANE 3.0 17.3 2.7 18.5 3.0 18.1

CIS-1,3-DIMETHYLCYCLOPENTANE 0.6 3.0 0.5 3.3 0.5 4.1

3-ETHYLPENTANE 0.6 0.5 0.6 6.6

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.4 2.4 0.3 3.1 0.4 3.2

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 4.2 34.8 3.6 38.2 4.2 31.8

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 1.2 1.1

HEPTANE 4.2 15.5 4.0 17.8 4.6 17.2

CIS-3-HEPTENE

UNIDENTIFIED C7 1.4 3.3 0.5

2-METHYL-2-HEXENE

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 1.4 0.7 0.7

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.3 1.9 0.3 1.0 1.2

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 1.1 0.5 0.6

METHYLCYCLOHEXANE 1.7 6.0 1.5 7.4 1.7 9.5

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 1.0 1.0 1.2

2,4,4-TRIMETHYL-2-PENTENE 0.3

2,2,3-TRIMETHYLPENTANE 1.3 6.9 0.4 6.3 9.0

 PAGE A-17
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 0.8 5.9 0.3 1.4 0.6 3.5

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.3 1.5 0.3 1.3 1.6

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.6 0.5 0.6

2,3,4-TRIMETHYLPENTANE 2.7 13.8 2.6 10.8 2.9 13.9

2,3,3-TRIMETHYLPENTANE 2.1 17.5 1.9 10.6 2.4 19.3

TOLUENE 10.2 31.4 14.8 44.4 15.7 32.3

2,3-DIMETHYLHEXANE 10.2 8.3 9.5

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 1.7

3,4-DIMETHYLHEXANE, NOTE B

4-METHYLHEPTANE 1.5 7.9 6.6 1.9 8.0

3-METHYLHEPTANE 1.7 8.4 1.4 4.7 1.9 8.0

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE

2,2,5-TRIMETHYLHEXANE 0.8 3.7 0.6 3.8 1.1 5.3

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.7 0.5 0.6

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.4

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 0.3 0.4

1-OCTENE

TRANS-4-OCTENE

OCTANE 1.3 4.1 1.5 4.0 1.5 4.8

UNIDENTIFIED C8 0.3 1.1 1.7

TRANS-2-OCTENE 0.4

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.3 0.3 0.3 0.7

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.3

2,4-DIMETHYLHEPTANE 0.6 0.7

4,4-DIMETHYLHEPTANE

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.3 1.1 0.5 1.0 0.5 1.5

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.3 0.9 0.4 1.0 0.5 1.5

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E

ETHYLBENZENE 2.9 6.0 4.4 7.3 3.8 6.4

 PAGE A-18
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 7.7 14.3 13.8 23.1 10.9 18.4

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.4 1.4 0.7 2.3 0.6 1.6

3-METHYLOCTANE 0.3 1.0 1.1 1.3

STYRENE

o-XYLENE 0.5 5.1 1.6 8.0 10.2 8.7

1-NONENE 7.0 1.3

TRANS-3-NONENE

CIS-3-NONENE

NONANE 2.5 0.6 0.9 0.6 1.1

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.5 1.8 0.5

2,2-DIMETHYLOCTANE 0.9

2,4-DIMETHYLOCTANE

n-PROPYLBENZENE 1.3 1.3 0.5 0.4

1-METHYL-3-ETHYLBENZENE 3.5 3.4 0.9

1-METHYL-4-ETHYLBENZENE 0.5 0.9 0.3

1,3,5-TRIMETHYLBENZENE 2.5 1.8 0.3

1-METHYL-2-ETHYLBENZENE 1.8 0.4 0.6

1,2,4-TRIMETHYLBENZENE

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 1.4 2.3

ISOBUTYLBENZENE, NOTE F 1.3 2.1

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene)

1-METHYL-3-ISOPROPYLBENZENE

1,2,3-TRIMETHYLBENZENE 2.2 0.7

1-METHYL-4-ISOPROPYLBENZENE 1.0 1.1

INDAN

1-METHYL-2-ISOPROPYLBENZENE 0.3

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE

1-METHYL-3-N-PROPYLBENZENE 0.3 0.3

1-METHYL-4-N-PROPYLBENZENE, NOTE G 1.8

1,2 DIETHYLBENZENE 1.8

1-METHYL-2-N-PROPYLBENZENE 0.5

1,4-DIMETHYL-2-ETHYLBENZENE 0.7

1,3-DIMETHYL-4-ETHYLBENZENE 0.4 1.1 1.5 0.6

1,2-DIMETHYL-4-ETHYLBENZENE

1,3-DIMETHYL-2-ETHYLBENZENE

UNDECANE 0.4

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

 PAGE A-19
HYDROCARBON SPECIATION DATA

SHED TEST

FORD F-150

SHED results, mg

FT-4614-S FT-4614-M FT-4637-S FT-4637-M FT-4640-S FT-4640-M

COMPOUND 7/17/2002 7/19/2002 7/24/2002 7/23/2002 7/26/2002 7/29/2002

Houston Fuel Atlanta Fuel Chicago Fuel

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE

TERT-1-BUT-2-METHYLBENZENE

1,2,3,4-TETRAMETHYLBENZENE

N-PENT-BENZENE 0.3

TERT-1-BUT-3,5-DIMETHYLBENZENE 0.1

TERT-1-BUTYL-4-ETHYLBENZENE 1.3

NAPHTHALENE

DODECANE 0.8

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

UNIDENTIFIED C9-C12+ 7.5 3.3 15.8 16.7 4.5 8.6

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

 PAGE A-20
APPENDIX B 

HYDROCARBON SPECIATION DATA 

FOR TOYOTA CAMRY 

TABLE OF CONTENTS FOR APPENDIX B 

FTP Composite Results, Winter 2005, pp. B1-B5 

SHED Test Results, Winter 2005, pp. B6-B10 

FTP Composite Results, Summer 2002, pp. B11-B15 

SHED Test Results, Summer 2002, pp. B16-20 

A blank space in the tables indicates that the compound was not detected during analysis. A 

“Trace” value indicates that th e compound was dete cted, but computations of mass or mass rate 

resulted in a value of less than 0.05. An “*” in the table indicates a malfunction of the analytical 

equipment during sample analysis and that no data are available. 
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

METHANE 67.0 497.2 37.8 441.0 104.6 422.3

ETHANE 6.0 29.1 7.6 31.1 8.5 29.8

ETHYLENE 19.7 317.6 27.6 323.9 29.0 309.1

PROPANE 0.4 2.4 1.0 2.6 1.2 2.6

PROPYLENE 11.0 127.8 16.5 148.6 15.8 123.1

ACETYLENE 8.5 772.5 10.7 736.3 9.9 621.4

PROPADIENE 0.6 11.5 0.8 10.7 8.8

BUTANE 5.5 58.8 10.3 82.0 16.5 95.5

TRANS-2-BUTENE 0.9 9.2 1.3 10.3 1.4 9.2

1-BUTENE 2.2 21.7 2.9 22.6 3.1 20.8

2-METHYLPROPENE (ISOBUTYLENE) 8.7 80.1 6.1 49.9 5.1 38.2

2,2-DIMETHYLPROPANE (NEOPENTANE) 9.4 131.9 11.6 115.4 17.9 128.1

PROPYNE 0.1 1.0 0.1 1.1

1,3-BUTADIENE 2.7 32.0 3.7 34.3 4.3 36.7

2-METHYLPROPANE (ISOBUTANE) 0.8 9.4 1.0 7.0 1.1 7.1

1-BUTYNE

METHANOL

CIS-2-BUTENE 0.7 7.4 0.9 8.1 1.0 6.9

3-METHYL-1-BUTENE

ETHANOL 15.0 165.2

2-METHYLBUTANE (ISOPENTANE) 0.6 14.5 0.7 1.2 0.9 11.9

2-BUTYNE

1-PENTENE 0.7 10.7 0.7 6.3 1.4 8.0

2-METHYL-1-BUTENE 1.3 18.5 0.8 11.3 1.6 15.6

PENTANE 4.0 65.4 6.6 70.1 7.4 51.7

UNIDENTIFIED C5 OLEFINS 0.8 2.5 Trace 0.7 0.6

2-METHYL-1,3-BUTADIENE 0.5 9.5 0.8 8.6 1.3 9.0

TRANS-2-PENTENE 0.8 14.7 0.7 8.7 1.7 14.8

3,3-DIMETHYL-1-BUTENE 0.1 0.5 Trace 0.4 Trace 0.4

CIS-2-PENTENE 0.4 7.9 0.4 5.0 0.9 6.9

2-METHYL-2-BUTENE 0.5 21.2 0.8 11.6 2.5 22.9

TERT-BUTANOL

CYCLOPENTADIENE 3.4 0.1 1.9 0.1 1.6

2,2-DIMETHYLBUTANE 1.0 13.8 1.0 9.5 0.8 5.1

CYCLOPENTENE 0.3 4.5 0.3 3.1 0.6 5.3

4-METHYL-1-PENTENE 0.3 3.2 0.3 2.0 0.5 3.0

3-METHYL-1-PENTENE

CYCLOPENTANE 0.4 8.1 0.4 5.4 0.6 4.5

2,3-DIMETHYLBUTANE 1.5 19.4 1.6 15.9 1.8 12.1

MTBE 3.8 149.5 1.9 0.2 2.5

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 7.2 98.2 5.5 53.7 6.5 44.5

4-METHYL-TRANS-2-PENTENE 1.4 1.7 0.1 1.6 0.2 3.1

3-METHYLPENTANE 4.8 66.8 3.7 34.7 4.4 28.8

2-METHYL-1-PENTENE 0.3 4.5 0.3 3.1 0.6 4.0

1-HEXENE 0.3 4.5 0.3 3.1 0.6 4.0

HEXANE 4.7 68.9 3.5 35.6 3.6 24.7

UNIDENTIFIED C6 0.9 9.5 0.6 5.5 0.7 5.4

TRANS-3-HEXENE

CIS-3-HEXENE 0.2 3.7 0.1 1.8 0.4 3.8

DI-ISOPROPYL ETHER 0.1

TRANS-2-HEXENE 0.3 5.9 0.2 3.0 0.7 5.7

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE B-1
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 0.3 7.1 0.3 4.4 1.0 9.3

2-METHYL-2-PENTENE 0.2 5.8 0.2 2.7 0.6 5.8

3-METHYLCYCLOPENTENE 0.1 Trace

CIS-2-HEXENE 0.1 1.7 Trace 1.6 0.3 3.1

ETBE

3-METHYL-CIS-2-PENTENE 0.6 5.0 0.7 2.9 0.7 6.7

2,2-DIMETHYLPENTANE, NOTE A 1.2 20.6 0.9 11.9 1.9 13.6

METHYLCYCLOPENTANE, NOTE A 1.2 20.2 0.9 11.7 1.9 13.4

2,4-DIMETHYLPENTANE 0.8 10.8 1.3 11.9 1.0 6.3

2,2,3-TRIMETHYLBUTANE 0.1 1.5 0.1 0.9 Trace 0.4

3,4-DIMETHYL-1-PENTENE Trace 0.4 Trace 0.4 0.1 0.5

1-METHYLCYCLOPENTENE 0.3 6.4 0.5 4.5 0.6 4.8

BENZENE 5.0 78.4 9.9 116.0 8.3 84.6

3-METHYL-1-HEXENE 0.1 0.6 1.3 1.2

3,3-DIMETHYLPENTANE 0.6 5.9 0.4 3.3 0.4 0.4

CYCLOHEXANE 0.2 2.8 0.3 3.7 0.6 6.3

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 5.0 69.0 5.5 51.6 3.8 26.2

1,1-DIMETHYLCYCLOPENTANE 0.1 0.1 0.8 0.1 1.1

TERT-AMYL METHYL ETHER

CYCLOHEXENE 0.6 20.4 0.1 1.2 0.3 2.2

3-METHYLHEXANE 4.4 57.2 3.8 36.1 2.4 16.2

CIS-1,3-DIMETHYLCYCLOPENTANE 0.5 7.0 0.5 4.9 1.0 7.7

3-ETHYLPENTANE 0.8 11.5 0.8 7.8 1.2 8.8

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.4 6.1 0.5 4.7 0.9 7.1

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 1.2 14.3 8.2 72.9 2.9 19.9

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 0.2 2.1 0.1 1.8 0.4 4.1

HEPTANE 3.1 41.0 3.5 34.0 2.6 17.4

CIS-3-HEPTENE

UNIDENTIFIED C7 0.3 6.6 0.1 2.3 0.6 5.0

2-METHYL-2-HEXENE 1.9 0.6 3.8

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 0.1 2.6 0.1 1.7 0.2 2.5

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.1 3.0 0.1 1.6 0.3 3.2

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 0.1 1.6 0.1 1.2 0.2 1.7

METHYLCYCLOHEXANE 1.0 13.4 1.5 14.1 2.9 20.7

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.1 2.4 0.3 2.6 0.3 1.9

2,4,4-TRIMETHYL-2-PENTENE 0.1 0.1 0.1 0.1 0.1

2,2,3-TRIMETHYLPENTANE 0.6 7.5 1.2 13.5 0.9 7.2

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 0.7 9.0 1.4 15.6 1.0 5.9

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.2 4.2 0.2 3.2 0.4 2.7

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.1 1.6 0.1 1.3 0.2 2.4

PAGE B-2
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 0.5 7.0 1.9 24.0 1.8 12.1

2,3,3-TRIMETHYLPENTANE 0.2 3.1 2.1 19.8 0.8 9.8

TOLUENE 8.4 121.2 21.8 242.4 9.9 107.2

2,3-DIMETHYLHEXANE 1.0 10.9 1.4 20.4 0.5 9.4

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 1.0 0.2 1.6

3,4-DIMETHYLHEXANE, NOTE B 0.4 4.7 0.7 3.0 0.1 0.3

4-METHYLHEPTANE 1.5 18.6 1.0 16.4 1.4 10.1

3-METHYLHEPTANE 1.8 22.5 0.1 18.6 1.2 8.1

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE 0.3 0.4

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE 4.9 1.6 3.6 0.7 6.0

2,2,5-TRIMETHYLHEXANE 0.2 2.3 0.6 5.2 1.0 6.8

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE Trace

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.2 3.2 0.2 2.1 0.6 3.6

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.1 2.0 0.1 1.1 0.1

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 0.1 2.5 0.1 1.6 0.2 2.6

1-OCTENE

TRANS-4-OCTENE 0.1 2.3 Trace 1.0 1.0

OCTANE 1.1 14.3 1.4 12.4 0.9 6.1

UNIDENTIFIED C8 0.9 10.9 0.3 3.7 0.4 4.2

TRANS-2-OCTENE 2.0 1.6

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.1 1.1 0.1 0.7 0.1 0.8

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.1 0.6 0.1 1.0 0.1 1.3

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 1.7 0.1 1.2 0.1 1.2

2,4-DIMETHYLHEPTANE 0.2 1.6 0.1 1.4 0.1 0.9

4,4-DIMETHYLHEPTANE 0.1 1.0 0.1 0.6 0.1 0.7

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE 0.2

2,6-DIMETHYLHEPTANE, NOTE D 0.3 3.2 0.3 2.7 0.4 2.8

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.2 2.4 0.2 2.0 0.2 1.2

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E 0.2 2.4 0.2 2.0 0.2 1.2

ETHYLBENZENE 3.7 45.8 6.2 54.5 3.5 23.3

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 13.2 165.9 19.2 170.4 10.9 75.3

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.9 12.2 0.9 8.6 0.6 5.0

3-METHYLOCTANE 0.6 8.1 0.7 5.7 0.4 3.2

STYRENE 1.1 16.1 1.8 19.7 9.2

PAGE B-3
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 5.3 64.1 7.7 66.7 3.9 27.3

1-NONENE 0.2 2.0 0.2 2.4 0.3 2.6

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.4 5.9 0.5 4.9 0.4 3.6

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) Trace 0.8 Trace 0.6 Trace 0.4

2,2-DIMETHYLOCTANE 0.1 1.4 0.1 0.9 0.1 1.3

2,4-DIMETHYLOCTANE 0.1 1.4 0.1 0.7 0.2 1.6

n-PROPYLBENZENE 1.0 16.1 1.6 17.5 0.9 8.3

1-METHYL-3-ETHYLBENZENE 4.5 66.5 7.1 69.6 3.7 34.2

1-METHYL-4-ETHYLBENZENE 1.9 27.3 2.7 27.7 1.5 12.5

1,3,5-TRIMETHYLBENZENE 2.3 32.6 2.8 30.4 2.3 17.9

1-METHYL-2-ETHYLBENZENE 1.9 23.6 2.6 26.9 1.8 12.2

1,2,4-TRIMETHYLBENZENE 7.2 105.3 10.8 114.8 6.6 58.7

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 0.2 2.5 Trace 1.8 0.8 3.3

ISOBUTYLBENZENE, NOTE F 0.2 2.4 Trace 1.7 0.7 3.1

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene) 0.1 1.3 0.3 2.0 0.1 1.2

1-METHYL-3-ISOPROPYLBENZENE

1,2,3-TRIMETHYLBENZENE 1.6 23.9 2.5 28.0 1.9 14.4

1-METHYL-4-ISOPROPYLBENZENE 0.1 1.3 0.1 1.4 0.1 1.2

INDAN

1-METHYL-2-ISOPROPYLBENZENE 0.8 11.3 1.3 9.0 1.1 10.0

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE Trace 0.3

1-METHYL-3-N-PROPYLBENZENE 0.5 11.0 2.4 19.4 0.9 9.0

1-METHYL-4-N-PROPYLBENZENE, NOTE G 1.2 17.7 1.9 24.7 1.8 15.5

1,2 DIETHYLBENZENE 1.8 0.1 1.4 0.2

1-METHYL-2-N-PROPYLBENZENE 0.2 2.3 0.5 6.9 0.3 1.3

1,4-DIMETHYL-2-ETHYLBENZENE 1.3 11.1 1.1 7.9

1,3-DIMETHYL-4-ETHYLBENZENE 1.3 13.3 1.3 7.4 1.9 9.5

1,2-DIMETHYL-4-ETHYLBENZENE 2.1

1,3-DIMETHYL-2-ETHYLBENZENE 1.6 0.1 2.9 0.2 1.3

UNDECANE 0.2 4.9 0.7 7.3 0.7 3.7

1,2-DIMETHYL-3-ETHYLBENZENE 0.4 5.3

1,2,4,5-TETRAMETHYLBENZENE 0.1 7.2 0.7 9.3 1.0 9.7

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE 0.1

1,2,3,5-TETRAMETHYLBENZENE 1.0 11.8 1.4 17.4 0.9

TERT-1-BUT-2-METHYLBENZENE 0.2 7.1 0.6 8.0 1.2 7.1

1,2,3,4-TETRAMETHYLBENZENE 0.1 10.7 0.8 8.6

N-PENT-BENZENE 0.3 7.0 0.5 7.8 0.1 3.0

TERT-1-BUT-3,5-DIMETHYLBENZENE

TERT-1-BUTYL-4-ETHYLBENZENE Trace 8.0 0.3 5.8 0.2 2.6

NAPHTHALENE 2.5 1.3

DODECANE 0.2 5.1 0.2 4.3 0.1 1.5

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE B-4
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 6.3 136.7 9.4 120.6 13.9 144.1

FORMALDEHYDE 4.8 36.2 4.0 48.7 3.6 49.6

ACETALDEHYDE 1.1 9.3 1.3 9.1 3.0 18.7

ACROLEIN 0.4 3.8 0.3 4.4 0.1 2.5

ACETONE 0.8 5.5 0.4 2.1 0.4 1.7

PROPIONALDEHYDE 0.2 4.2 0.2 2.9 0.5 4.7

CROTONALDEHYDE 0.3 4.0 0.3 2.8 0.5 2.9

ISOBUTYRALDEHYDE, NOTE H Trace 0.8 0.2 0.8 0.2 0.7

METHYL ETHYL KETONE, NOTE H Trace 0.8 0.2 0.8 0.2 0.7

BENZALDEHYDE 0.4 5.4 0.9 8.1 0.6 4.6

ISOVALERALDEHYDE Trace 0.6 0.1 0.7 0.1 0.8

VALERALDEHYDE 0.5 0.1 0.6 0.1 0.6

O-TOLUALDEHYDE 0.1 1.7 0.2 0.9 0.1 1.5

M/P-TOLUALDEHYDE 0.9 7.4 1.2 7.7 0.7 4.3

HEXANALDEHYDE 0.1 0.1 0.1 0.1 0.1 0.1

DIMETHYLBENZALDEHYDE 0.2 3.5 0.5 3.3 0.4 2.1

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

H - Isobutyraldehyde and methyl ethyl ketone co-elute. LC peak area split equally between the two compounds.

PAGE B-5
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

METHANE -- -- -- -- -- --

ETHANE 0.2 6.8 1.6 0.1 3.3

ETHYLENE 1.0 0.4 0.4

PROPANE 34.4 22.8 0.1 55.6

PROPYLENE 0.2 9.3 11.2 0.2 7.7

ACETYLENE

PROPADIENE

BUTANE 4.9 2046.6 8.8 1982.4 22.2 2917.3

TRANS-2-BUTENE 0.6 80.8 0.5 43.9 0.9 69.3

1-BUTENE 49.3 19.3 0.2 38.3

2-METHYLPROPENE (ISOBUTYLENE) 0.4 39.5 0.2 18.5 0.4 45.2

2,2-DIMETHYLPROPANE (NEOPENTANE) 7.5 1790.2 6.9 1065.8 14.3 1695.8

PROPYNE

1,3-BUTADIENE 3.7 0.5 1.6

2-METHYLPROPANE (ISOBUTANE) 356.6 0.4 225.1 1.0 266.1

1-BUTYNE

METHANOL

CIS-2-BUTENE 0.4 74.1 0.2 42.7 0.6 53.2

3-METHYL-1-BUTENE

ETHANOL 44.7 1301.8

2-METHYLBUTANE (ISOPENTANE)

2-BUTYNE

1-PENTENE 0.4 73.7 3.3 20.6 0.7 67.6

2-METHYL-1-BUTENE 0.9 95.6 1.1 42.6 1.6 163.0

PENTANE 2.8 675.1 5.8 480.1 8.9 611.6

UNIDENTIFIED C5 OLEFINS

2-METHYL-1,3-BUTADIENE 9.6 0.7 7.0

TRANS-2-PENTENE 1.2 128.2 0.9 41.9 2.9 169.2

3,3-DIMETHYL-1-BUTENE 4.0 2.6

CIS-2-PENTENE 0.7 67.2 0.4 21.5 1.3 93.2

2-METHYL-2-BUTENE 2.8 140.4 1.8 63.6 4.6 292.2

TERT-BUTANOL

CYCLOPENTADIENE 3.6 3.3

2,2-DIMETHYLBUTANE 0.3 76.3 0.3 33.7 0.4 27.9

CYCLOPENTENE 22.1 6.8 0.7 32.2

4-METHYL-1-PENTENE 0.8 12.8 0.5 3.7 16.0

3-METHYL-1-PENTENE

CYCLOPENTANE 48.4 20.7 0.9 32.2

2,3-DIMETHYLBUTANE 0.6 96.9 0.8 48.9 1.1 65.5

MTBE 1529.3 6.3 25.2

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 3.2 414.3 8.6 152.5 4.6 218.8

4-METHYL-TRANS-2-PENTENE 2.1 25.5 7.6 1.9 15.0

3-METHYLPENTANE 2.0 252.0 2.3 85.2 2.8 124.8

2-METHYL-1-PENTENE 0.4 0.2 3.5 0.4 16.0

1-HEXENE 0.4 0.2 3.5 0.4 16.0

HEXANE 3.4 208.1 3.3 67.5 3.5 90.1

UNIDENTIFIED C6 0.4 39.2 0.3 4.2

TRANS-3-HEXENE

CIS-3-HEXENE 12.2 4.0 0.6 14.6

DI-ISOPROPYL ETHER 21.4

TRANS-2-HEXENE 0.4 15.8 0.4 5.3 0.8 37.2

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE B-6
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 1.3 25.8 0.6 8.8 1.3 21.7

2-METHYL-2-PENTENE 0.5 16.8 0.3 5.4 0.5

3-METHYLCYCLOPENTENE 0.2

CIS-2-HEXENE 0.3 10.4 3.3 0.4 11.2

ETBE

3-METHYL-CIS-2-PENTENE 0.4 15.5 0.4 5.3 0.5 23.4

2,2-DIMETHYLPENTANE, NOTE A 1.2 54.8 0.9 19.9 1.4 42.8

METHYLCYCLOPENTANE, NOTE A 1.2 53.6 0.9 19.5 1.4 41.9

2,4-DIMETHYLPENTANE 24.1 0.3 15.8 0.1 18.1

2,2,3-TRIMETHYLBUTANE 0.2 3.5 1.2 0.5 2.2

3,4-DIMETHYL-1-PENTENE 1.2 1.0

1-METHYLCYCLOPENTENE 0.9 11.5 1.0 6.2 1.1 24.2

BENZENE 3.1 23.8 2.6 28.2 5.4 41.4

3-METHYL-1-HEXENE

3,3-DIMETHYLPENTANE 10.0 0.6 3.9 1.0 2.1

CYCLOHEXANE 6.9 14.3

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 1.8 91.1 2.0 42.5 2.7 40.9

1,1-DIMETHYLCYCLOPENTANE 1.6

TERT-AMYL METHYL ETHER 2.6

CYCLOHEXENE 21.9 0.5

3-METHYLHEXANE 1.3 79.2 1.8 27.2 1.8 23.1

CIS-1,3-DIMETHYLCYCLOPENTANE 0.4 11.5 0.2 4.4 0.4 11.1

3-ETHYLPENTANE 0.4 13.4 0.3 6.0 0.5 12.1

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.3 7.7 0.2 3.7 0.3 9.6

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 0.6 13.6 0.5 39.7 1.4 20.7

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 0.2 1.4 0.4 5.0

HEPTANE 1.6 36.4 1.9 20.2 2.4 19.8

CIS-3-HEPTENE

UNIDENTIFIED C7 0.8 6.6 0.6 0.3 6.0

2-METHYL-2-HEXENE 3.9 5.4

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 2.7 0.8 2.4

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.2 3.4 1.2 0.2 4.2

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 1.7 0.6 1.8

METHYLCYCLOHEXANE 1.1 12.2 0.7 7.7 1.3 21.7

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.7 1.9 1.0 1.3

2,4,4-TRIMETHYL-2-PENTENE 3.3 0.5 1.7 0.3

2,2,3-TRIMETHYLPENTANE 3.3 4.3 0.4 3.7

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 0.3 4.3 0.3 4.3 0.3 7.0

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 1.5 0.8 1.8

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.5 1.4

PAGE B-7
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 0.5 5.9 0.4 8.4 1.0 9.5

2,3,3-TRIMETHYLPENTANE 0.3 1.4 0.4 4.7 0.4 5.7

TOLUENE 4.8 31.3 8.2 48.9 11.8 43.5

2,3-DIMETHYLHEXANE 4.1 1.7 2.4

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 1.2

3,4-DIMETHYLHEXANE, NOTE B 0.6 0.4

4-METHYLHEPTANE 8.8 0.5 5.1 0.9 5.1

3-METHYLHEPTANE 0.6 9.2 0.5 4.8 0.9 5.9

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE

2,2,5-TRIMETHYLHEXANE 1.6 0.1 1.3 0.3 3.1

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 1.2 0.4 0.2 1.1

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.2

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 1.1

1-OCTENE

TRANS-4-OCTENE 0.2 0.6

OCTANE 0.4 4.2 0.5 2.2 0.5 2.8

UNIDENTIFIED C8 0.8 2.3 0.3 0.2

TRANS-2-OCTENE 0.8 0.2 0.5

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.2

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.5

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.3 0.2

2,4-DIMETHYLHEPTANE 0.1 0.2 0.4

4,4-DIMETHYLHEPTANE 0.4

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.7 0.4 0.9

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.3 0.1 0.2

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E 0.3 0.1 0.2

ETHYLBENZENE 1.6 5.2 2.0 4.4 2.2 5.2

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 3.3 11.4 4.3 10.0 3.0 11.9

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.6

3-METHYLOCTANE

STYRENE

PAGE B-8
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 1.8 0.7 2.2 0.2 2.2

1-NONENE 0.2

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.3

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE)

2,2-DIMETHYLOCTANE

2,4-DIMETHYLOCTANE

n-PROPYLBENZENE

1-METHYL-3-ETHYLBENZENE

1-METHYL-4-ETHYLBENZENE

1,3,5-TRIMETHYLBENZENE

1-METHYL-2-ETHYLBENZENE

1,2,4-TRIMETHYLBENZENE 0.2 0.3

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F

ISOBUTYLBENZENE, NOTE F

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene)

1-METHYL-3-ISOPROPYLBENZENE

1,2,3-TRIMETHYLBENZENE

1-METHYL-4-ISOPROPYLBENZENE

INDAN

1-METHYL-2-ISOPROPYLBENZENE

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE

1-METHYL-3-N-PROPYLBENZENE

1-METHYL-4-N-PROPYLBENZENE, NOTE G

1,2 DIETHYLBENZENE

1-METHYL-2-N-PROPYLBENZENE

1,4-DIMETHYL-2-ETHYLBENZENE

1,3-DIMETHYL-4-ETHYLBENZENE

1,2-DIMETHYL-4-ETHYLBENZENE

1,3-DIMETHYL-2-ETHYLBENZENE

UNDECANE

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE

TERT-1-BUT-2-METHYLBENZENE

1,2,3,4-TETRAMETHYLBENZENE

N-PENT-BENZENE 0.2

TERT-1-BUT-3,5-DIMETHYLBENZENE

TERT-1-BUTYL-4-ETHYLBENZENE

NAPHTHALENE

DODECANE

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE B-9
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

C-HOU-N C-HOU-MF C-ATL-N C-ATL-MF C-CHI-N C-CHI-MF

COMPOUND 3/31/2005 4/1/2005 4/5/2005 4/6/2005 4/12/2005 4/13/2005

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 1.3 0.4 0.3

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

PAGE B-10
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 7/18/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

METHANE 39.8 482.9 39.0 395.1 34.7 480.9

ETHANE 5.2 * 8.2 27.6 * 38.8

ETHYLENE 11.4 * 19.9 344.8 * 337.8

PROPANE * 0.3 3.0 * 6.4

PROPYLENE 0.2 * *

ACETYLENE 3.9 * 4.9 528.6 * 530.1

PROPADIENE * *

BUTANE 1.3 * 1.2 14.4 * 8.8

TRANS-2-BUTENE * 0.6 6.9 * 1.9

1-BUTENE 1.0 * 2.0 22.4 * 2.4

2-METHYLPROPENE (ISOBUTYLENE) 6.0 * 4.2 56.5 * 6.1

2,2-DIMETHYLPROPANE (NEOPENTANE) 0.3 * 0.7 *

PROPYNE * *

1,3-BUTADIENE * 0.3 7.7 *

2-METHYLPROPANE (ISOBUTANE) * 166.5 *

1-BUTYNE * *

METHANOL * *

CIS-2-BUTENE * 0.1 16.0 *

3-METHYL-1-BUTENE * *

ETHANOL * 7.2 256.2

2-METHYLBUTANE (ISOPENTANE) 3.5 * 0.6 11.0 * 71.7

2-BUTYNE

1-PENTENE 0.4 9.0 6.2 0.4 2.1

2-METHYL-1-BUTENE 0.6 14.5 0.4 10.7 0.5 13.5

PENTANE 2.4 40.6 1.1 42.8 1.0 17.5

UNIDENTIFIED C5 OLEFINS 0.2 6.3 0.3 2.9 9.0

2-METHYL-1,3-BUTADIENE 0.5 9.1 2.4 8.3 0.6 11.2

TRANS-2-PENTENE 0.7 14.2 0.7 9.1 0.6 11.4

3,3-DIMETHYL-1-BUTENE 0.3 0.4 0.3 4.8

CIS-2-PENTENE 0.4 8.3 0.3 5.0 0.3 6.0

2-METHYL-2-BUTENE 1.1 20.4 0.9 13.5 1.2 19.9

TERT-BUTANOL

CYCLOPENTADIENE 0.2 7.3 5.3 0.3 6.3

2,2-DIMETHYLBUTANE 0.5 6.4 0.5 7.2 0.6 9.7

CYCLOPENTENE 1.2 4.8 0.2 3.2 0.2 4.1

4-METHYL-1-PENTENE 0.2 2.8 0.2 2.6 0.1 1.8

3-METHYL-1-PENTENE 1.7

CYCLOPENTANE 0.3 4.9 0.2 4.4 0.3 2.4

2,3-DIMETHYLBUTANE 0.9 16.8 0.8 11.8 1.5 24.7

MTBE 1.3 54.8

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 2.6 62.7 2.5 40.0 2.6 44.5

4-METHYL-TRANS-2-PENTENE 0.2 2.2 Trace 0.9

3-METHYLPENTANE 2.5 47.5 1.8 26.9 1.6 32.1

2-METHYL-1-PENTENE 0.2 4.1 0.2 2.5 0.1 2.4

1-HEXENE 0.2 3.5 0.2 2.5 0.1 2.5

HEXANE 2.8 50.8 1.8 26.8 1.3 27.4

UNIDENTIFIED C6 0.4 61.2 0.5 7.9 0.3 6.6

TRANS-3-HEXENE

CIS-3-HEXENE 2.8 0.1 1.3 1.6

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 0.1 4.5 0.1 2.1 0.1 2.5

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE B-11
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 7/18/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 0.2 6.6 0.2 16.6 0.2 4.4

2-METHYL-2-PENTENE 0.3 4.3 0.1 2.4 0.1 3.1

3-METHYLCYCLOPENTENE 0.2

CIS-2-HEXENE 0.2 2.5 0.1 1.2 1.4

ETBE

3-METHYL-CIS-2-PENTENE 0.4 5.2 0.3 2.6 0.2 3.5

2,2-DIMETHYLPENTANE, NOTE A 0.6 11.5 0.5 9.6 0.8 16.5

METHYLCYCLOPENTANE, NOTE A 0.6 11.3 0.5 9.4 0.8 16.2

2,4-DIMETHYLPENTANE 0.7 9.2 0.7 8.0 1.3 20.3

2,2,3-TRIMETHYLBUTANE 0.9 0.5 1.1

3,4-DIMETHYL-1-PENTENE 0.1

1-METHYLCYCLOPENTENE 0.4 8.2 0.2 6.5 0.3 6.2

BENZENE 3.8 95.9 9.0 138.3 42.9 99.3

3-METHYL-1-HEXENE Trace

3,3-DIMETHYLPENTANE 0.3 2.1 0.1 1.4 1.6

CYCLOHEXANE 0.2 3.4 0.4 5.6 0.9 11.9

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 2.7 33.0 2.8 30.5 4.3 56.6

1,1-DIMETHYLCYCLOPENTANE 0.6 1.3

TERT-AMYL METHYL ETHER

CYCLOHEXENE 0.1 1.2 0.1 1.0 1.3

3-METHYLHEXANE 2.4 23.2 2.0 21.7 2.3 28.8

CIS-1,3-DIMETHYLCYCLOPENTANE 0.2 3.6 0.2 2.9 0.3 6.3

3-ETHYLPENTANE 0.1 3.9 3.3

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.1 3.4 0.2 2.6 0.4 6.3

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 3.4 38.1 5.4 51.8 5.9 66.5

2-METHYL-1-HEXENE

TRANS-3-HEPTENE 0.1 2.6 0.1 1.0 0.6

HEPTANE 0.8 15.7 0.5 21.9 2.8 32.7

CIS-3-HEPTENE

UNIDENTIFIED C7 0.2 2.4 1.1 1.7

2-METHYL-2-HEXENE 2.6

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 0.1 1.9 Trace 0.8 0.8

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.1 2.3 0.1 1.2 1.4

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 0.1 1.6 0.1 0.9 0.1 1.1

METHYLCYCLOHEXANE 0.6 7.6 0.8 11.2 1.4 20.6

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.1 1.2 0.1 1.5 0.1 2.3

2,4,4-TRIMETHYL-2-PENTENE

2,2,3-TRIMETHYLPENTANE 0.5 9.3 0.9 6.6 16.6

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 0.3 9.2 0.8 8.5 2.3 12.2

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.2 2.2 0.2 2.0 0.2 3.3

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE 0.0 0.9 Trace 0.5 1.4

PAGE B-12
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 7/18/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 1.8 19.3 1.6 15.0 2.8 30.7

2,3,3-TRIMETHYLPENTANE 2.3 34.8 1.5 18.2 2.9 52.4

TOLUENE 7.9 142.2 24.6 309.2 9.2 154.3

2,3-DIMETHYLHEXANE 1.3 18.0 1.7 2.5 29.1

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE 0.9

3,4-DIMETHYLHEXANE, NOTE B 1.1 0.1 0.8 0.1 1.7

4-METHYLHEPTANE 0.3 12.2 1.4 12.1 1.5 17.1

3-METHYLHEPTANE 1.0 12.4 0.9 10.3 1.3 14.1

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE 0.7

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE 0.1 3.0 0.3 2.0 0.4 4.3

2,2,5-TRIMETHYLHEXANE 0.4 5.8 0.6 7.0 1.7 17.3

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 1.0 3.1 0.3 2.0 0.3 3.3

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE 0.1 1.5 0.1 0.9 0.9

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE 0.1 2.0 0.1 1.0 0.1 1.2

1-OCTENE

TRANS-4-OCTENE

OCTANE 0.7 8.4 1.0 9.6 1.0 11.8

UNIDENTIFIED C8 0.2 3.8 0.7 0.1 1.7

TRANS-2-OCTENE 0.1 2.4 0.9 0.3

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.1 1.1 Trace 0.4 0.2 0.3

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.1 1.1 0.1 1.3 0.3 3.0

CIS-1-METHYL-2-ETHYLCYCLOPENTANE 0.1 1.1 0.1 0.9 1.0

2,4-DIMETHYLHEPTANE 0.1 1.0 0.1 1.3 0.2 1.5

4,4-DIMETHYLHEPTANE Trace 0.5 Trace 0.3 0.5

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE 0.3 0.1

2,6-DIMETHYLHEPTANE, NOTE D 0.1 1.8 0.2 1.7 0.5 3.7

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.2 2.4 0.4 3.4 0.5 4.9

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E

ETHYLBENZENE 2.4 28.5 4.3 42.5 2.3 23.4

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 7.7 82.8 15.1 147.7 8.3 78.8

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.7 8.1 1.1 7.1 0.9 9.0

3-METHYLOCTANE 0.5 4.6 0.5 4.6 0.6 6.1

STYRENE 0.7 12.0 1.2 16.1 0.7 9.7

PAGE B-13
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 7/18/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 3.6 35.3 6.1 57.3 3.7 33.0

1-NONENE 0.2 2.7 0.2 2.0 0.4 4.3

TRANS-3-NONENE

CIS-3-NONENE

NONANE 0.4 3.1 0.7 5.3 0.9 8.0

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.1 0.2 0.3 0.3 0.8

2,2-DIMETHYLOCTANE 0.1 0.4 0.1 0.8

2,4-DIMETHYLOCTANE 0.3 0.7 0.1 0.5 0.7

n-PROPYLBENZENE 0.8 8.6 1.7 15.6 0.7 8.5

1-METHYL-3-ETHYLBENZENE 2.9 42.6 7.1 53.4 4.6 39.3

1-METHYL-4-ETHYLBENZENE 0.8 19.5 3.4 19.4 12.2

1,3,5-TRIMETHYLBENZENE 1.5 19.5 3.8 29.7 1.5 14.4

1-METHYL-2-ETHYLBENZENE 1.3 16.2 3.1 24.4 0.9 12.5

1,2,4-TRIMETHYLBENZENE 7.0 76.8 14.8 79.5 6.1 70.2

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 0.3 0.5 1.0 3.6 0.3 2.0

ISOBUTYLBENZENE, NOTE F 0.3 0.4 0.9 3.4 0.2 1.9

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene) 0.3 2.2 0.7

1-METHYL-3-ISOPROPYLBENZENE 19.2

1,2,3-TRIMETHYLBENZENE 1.3 0.5 3.5 30.6 1.2 15.6

1-METHYL-4-ISOPROPYLBENZENE 0.2 1.7

INDAN

1-METHYL-2-ISOPROPYLBENZENE 14.7 0.2 1.6 0.2 3.9

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE 6.3 1.0 0.5 1.2

1-METHYL-3-N-PROPYLBENZENE 0.6 1.9 21.1 0.9 14.7

1-METHYL-4-N-PROPYLBENZENE, NOTE G 1.6 0.6 0.1 39.2 1.4 0.2

1,2 DIETHYLBENZENE 0.1 1.2

1-METHYL-2-N-PROPYLBENZENE 0.2 1.2 0.2 1.5 0.2 4.5

1,4-DIMETHYL-2-ETHYLBENZENE 29.2 2.0 13.8 1.8 12.3

1,3-DIMETHYL-4-ETHYLBENZENE 2.1 3.2 13.0 3.3

1,2-DIMETHYL-4-ETHYLBENZENE 1.1 20.9 3.2 28.6 17.6

1,3-DIMETHYL-2-ETHYLBENZENE 2.6 0.3 0.3

UNDECANE 0.3 2.5 0.3 2.6 0.3 1.6

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE 0.1 9.0 2.0 17.9 0.4 11.7

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE 2.0 0.2 0.1 0.8 0.4

TERT-1-BUT-2-METHYLBENZENE 10.8 Trace 0.7

1,2,3,4-TETRAMETHYLBENZENE 6.5 0.2 5.7 0.3 4.0

N-PENT-BENZENE 0.3

TERT-1-BUT-3,5-DIMETHYLBENZENE 0.1 11.2 1.1 23.2 29.0

TERT-1-BUTYL-4-ETHYLBENZENE

NAPHTHALENE 0.4 0.2 3.4 0.5 0.6

DODECANE 0.3 3.2 0.4 1.1 0.1 3.0

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE B-14
HYDROCARBON SPECIATION DATA

FTP COMPOSITE

TOYOTA CAMRY

FTP Composite, mg/mi

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 7/18/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 8.4 152.9 22.0 175.3 9.9 184.7

FORMALDEHYDE 2.2 59.2 2.6 53.0 2.3 63.6

ACETALDEHYDE 5.0 13.9 1.7 13.5 2.6 34.5

ACROLEIN 1.2 8.2 0.4 6.3 0.4 8.6

ACETONE 6.4 6.1 0.8 4.0 0.6 5.7

PROPIONALDEHYDE 0.8 2.7 0.4 6.4 0.2 3.0

CROTONALDEHYDE 2.9 4.0 0.8 4.8 0.3 3.9

ISOBUTYRALDEHYDE, NOTE H 1.1 2.1 0.2 1.4 0.2 1.5

METHYL ETHYL KETONE, NOTE H 1.1 2.1 0.2 1.4 0.2 1.5

BENZALDEHYDE 0.3 6.6 0.7 11.6 0.2 5.3

ISOVALERALDEHYDE 0.4 1.2 0.1 0.2 1.2

VALERALDEHYDE 0.6 0.8 0.1 1.0 0.1 1.1

O-TOLUALDEHYDE 0.4 2.1 0.3 3.3 0.1 2.1

M/P-TOLUALDEHYDE 0.4 7.0 0.6 11.2 0.2 6.6

HEXANALDEHYDE Trace Trace 0.1 Trace

DIMETHYLBENZALDEHYDE 0.2 4.0 Trace 2.4

*C1 - C4 DATA NOT AVAILABLE DUE TO INSTRUMENT MALFUNCTION

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

H - Isobutyraldehyde and methyl ethyl ketone co-elute. LC peak area split equally between the two compounds.

PAGE B-15
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 8/19/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

METHANE

ETHANE * * *

ETHYLENE * * *

PROPANE * * 6.0 * 9.2

PROPYLENE * * *

ACETYLENE * * *

PROPADIENE * * *

BUTANE * * 2.0 81.0 * 76.7

TRANS-2-BUTENE * * *

1-BUTENE * * 1.6 *

2-METHYLPROPENE (ISOBUTYLENE) * * 7.7 13.5 *

2,2-DIMETHYLPROPANE (NEOPENTANE) * * *

PROPYNE * * *

1,3-BUTADIENE * * * *

2-METHYLPROPANE (ISOBUTANE) * * 0.6 29.9 * 34.0

1-BUTYNE * * *

METHANOL * * *

CIS-2-BUTENE * * 3.5 *

3-METHYL-1-BUTENE * * *

ETHANOL * * 21.0 301.1

2-METHYLBUTANE (ISOPENTANE) * * * 495.8

2-BUTYNE

1-PENTENE 7.1 3.5

2-METHYL-1-BUTENE 1.3 10.6 6.9 18.7

PENTANE 4.1 48.4 0.5 46.1 1.1 38.2

UNIDENTIFIED C5 OLEFINS 11.1 2.2

2-METHYL-1,3-BUTADIENE 1.7 0.6 2.6 0.3 2.9 76.2

TRANS-2-PENTENE 13.0 7.2 0.6 0.7

3,3-DIMETHYL-1-BUTENE 0.9 1.0 35.5

CIS-2-PENTENE 3.2 7.5 0.4 3.7 0.6 19.2

2-METHYL-2-BUTENE 0.5 18.3 1.2 11.4 1.5 54.7

TERT-BUTANOL

CYCLOPENTADIENE 0.3

2,2-DIMETHYLBUTANE 3.0 4.1 1.7 23.4

CYCLOPENTENE 0.7 2.9 0.3 1.6 0.6 6.6

4-METHYL-1-PENTENE 0.7 1.3 0.8 2.7

3-METHYL-1-PENTENE

CYCLOPENTANE 4.2 0.4 3.4 0.9 11.9

2,3-DIMETHYLBUTANE 1.9 7.5 0.8 6.0 1.4 49.3

MTBE 59.8

4-METHYL-CIS-2-PENTENE

2-METHYLPENTANE 10.6 20.2 7.8 20.6 7.6 71.6

4-METHYL-TRANS-2-PENTENE 0.5 0.4

3-METHYLPENTANE 4.1 18.9 2.4 12.5 2.7 46.8

2-METHYL-1-PENTENE 1.7 0.2 0.7 2.6

1-HEXENE 1.7 0.2 0.7 2.6

HEXANE 4.8 19.4 3.4 10.2 3.5 31.9

UNIDENTIFIED C6 0.3 1.0

TRANS-3-HEXENE

CIS-3-HEXENE 1.0 0.4 1.8

DI-ISOPROPYL ETHER

TRANS-2-HEXENE 1.0 0.3 2.2

Houston Fuel Atlanta Fuel Chicago Fuel

PAGE B-16
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 8/19/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

3-METHYL-TRANS-2-PENTENE 0.7 2.3 0.7 1.1 4.6

2-METHYL-2-PENTENE 0.5 1.8 0.9 0.6 3.1

3-METHYLCYCLOPENTENE

CIS-2-HEXENE 0.5 1.4 0.6 1.9

ETBE

3-METHYL-CIS-2-PENTENE 0.8 2.4 0.4 0.9 0.5 3.2

2,2-DIMETHYLPENTANE, NOTE A 1.9 4.0 0.7 3.3 1.3 18.2

METHYLCYCLOPENTANE, NOTE A 1.8 3.9 0.7 3.3 1.3 17.8

2,4-DIMETHYLPENTANE 1.8 3.5 0.7 3.0 1.6 17.3

2,2,3-TRIMETHYLBUTANE 0.4 0.9

3,4-DIMETHYL-1-PENTENE 0.5

1-METHYLCYCLOPENTENE 2.5 0.8 2.4 1.1 9.7

BENZENE 7.0 8.2 4.2 12.7 6.6 29.8

3-METHYL-1-HEXENE

3,3-DIMETHYLPENTANE 0.5 0.3 0.3 1.0 0.7

CYCLOHEXANE 1.6 2.0 0.6 2.6 3.5 16.7

2-METHYLHEXANE

2,3-DIMETHYLPENTANE 6.8 10.8 2.8 8.8 5.1 34.6

1,1-DIMETHYLCYCLOPENTANE

TERT-AMYL METHYL ETHER

CYCLOHEXENE

3-METHYLHEXANE 3.9 7.2 1.9 5.8 3.4 18.3

CIS-1,3-DIMETHYLCYCLOPENTANE 0.7 1.1 0.7 4.0

3-ETHYLPENTANE 0.8 0.7 0.6 5.9

TRANS-1,2-DIMETHYLCYCLOPENTANE

TRANS-1,3-DIMETHYLCYCLOPENTANE 0.5 0.7 0.5 0.7 3.4

1-HEPTENE

2,2,4-TRIMETHYLPENTANE 4.4 8.5 2.2 8.9 3.7 28.2

2-METHYL-1-HEXENE 0.8

TRANS-3-HEPTENE

HEPTANE 4.3 5.4 2.7 6.7 4.2 16.6

CIS-3-HEPTENE

UNIDENTIFIED C7 1.5 0.9

2-METHYL-2-HEXENE

3-METHYL-TRANS-3-HEXENE

TRANS-2-HEPTENE 0.3 0.6 0.7

3-ETHYL-CIS-2-PENTENE

2,4,4-TRIMETHYL-1-PENTENE 0.5 0.8 0.4 0.7 1.2

2,3-DIMETHYL-2-PENTENE

CIS-2-HEPTENE 0.4 0.4

METHYLCYCLOHEXANE 2.3 2.2 0.9 2.5 1.9 9.6

CIS-1,2-DIMETHYLCYCLOPENTANE

2,2-DIMETHYLHEXANE

1,1,3-TRIMETHYLCYCLOPENTANE 0.3 0.3 1.4 0.8

2,4,4-TRIMETHYL-2-PENTENE

2,2,3-TRIMETHYLPENTANE 0.7 1.0 0.3 0.6 7.1

2,5-DIMETHYLHEXANE

ETHYLCYCLOPENTANE

2,4-DIMETHYLHEXANE 0.3 0.6 3.9

1-TRANS-2-CIS-4-TRIMETHYLCYCLOPENTANE 0.5 0.4 0.5

3,3-DIMETHYLHEXANE

1-TRANS-2-CIS-3-TRIMETHYLCYCLOPENTANE

PAGE B-17
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 8/19/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

2,3,4-TRIMETHYLPENTANE 3.9 4.9 1.4 3.3 2.2 10.8

2,3,3-TRIMETHYLPENTANE 1.7 0.7 2.4 12.4

TOLUENE 28.7 18.2 17.2 38.9 29.7 51.7

2,3-DIMETHYLHEXANE 5.4 6.3

1,1,2-TRIMETHYLCYCLOPENTANE

2-METHYLHEPTANE

3,4-DIMETHYLHEXANE, NOTE B

4-METHYLHEPTANE 2.1 2.7 1.0 2.5 1.0 6.7

3-METHYLHEPTANE 2.5 2.8 1.1 2.0 1.7 6.7

1-CIS,2-TRANS,3-TRIMETHYLCYCLOPENTANE

CIS-1,3-DIMETHYLCYCLOHEXANE

TRANS-1,4-DIMETHYLCYCLOHEXANE

3-ETHYLHEXANE

2,2,5-TRIMETHYLHEXANE 1.3 1.3 0.4 0.9 1.0 4.2

TRANS-1-METHYL-3-ETHYLCYCLOPENTANE

CIS-1-METHYL-3-ETHYLCYCLOPENTANE 0.3 0.3 0.4

1,1-DIMETHYLCYCLOHEXANE

TRANS-1-METHYL-2-ETHYLCYCLOPENTANE

1-METHYL-1-ETHYL-CYCLOPENTANE

2,4,4-TRIMETHYLHEXANE

2,2,4-TRIMETHYLHEXANE

TRANS-1,2-DIMETHYLCYCLOHEXANE

1-OCTENE

TRANS-4-OCTENE

OCTANE 1.8 1.7 0.8 1.9 2.1 4.2

UNIDENTIFIED C8 0.4 0.3 1.6

TRANS-2-OCTENE

TRANS-1,3-DIMETHYLCYCLOHEXANE, NOTE C

CIS-2-OCTENE 0.9

ISOPROPYLCYCLOPENTANE

2,2-DIMETHYLHEPTANE

2,3,5-TRIMETHYLHEXANE 0.4

CIS-1-METHYL-2-ETHYLCYCLOPENTANE

2,4-DIMETHYLHEPTANE 1.7 0.4

4,4-DIMETHYLHEPTANE

CIS-1,2-DIMETHYLCYCLOHEXANE

ETHYLCYCLOHEXANE

2,6-DIMETHYLHEPTANE, NOTE D 0.6 0.7 0.3 1.1 1.0

1,1,3-TRIMETHYLCYCLOHEXANE

2,5-DIMETHYLHEPTANE, NOTE E 0.4 0.4 0.6 0.9

3,3-DIMETHYLHEPTANE

3,5-DIMETHYLHEPTANE, NOTE E

ETHYLBENZENE 6.0 5.7 3.6 6.7 6.3 8.0

2,3,4-TRIMETHYLHEXANE

2,3-DIMETHYLHEPTANE

m-& p-XYLENE 17.4 14.6 9.6 21.4 18.1 23.7

4-METHYLOCTANE

3,4-DIMETHYLHEPTANE

4-ETHYLHEPTANE

2-METHYLOCTANE 0.7 0.6 0.8

3-METHYLOCTANE 0.7 0.6 0.7

STYRENE

PAGE B-18
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 8/19/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

o-XYLENE 7.0 5.7 3.1 8.3 6.2 8.5

1-NONENE

TRANS-3-NONENE 0.7

CIS-3-NONENE

NONANE 0.3 0.4

TRANS-2-NONENE

ISOPROPYLBENZENE (CUMENE) 0.4

2,2-DIMETHYLOCTANE

2,4-DIMETHYLOCTANE 0.5

n-PROPYLBENZENE 0.7 0.3

1-METHYL-3-ETHYLBENZENE 2.6

1-METHYL-4-ETHYLBENZENE

1,3,5-TRIMETHYLBENZENE 0.8

1-METHYL-2-ETHYLBENZENE 0.3 0.3 1.1 0.9

1,2,4-TRIMETHYLBENZENE

TERT-BUTYLBENZENE

1-DECENE

DECANE, NOTE F 0.3 1.6 1.0 0.8

ISOBUTYLBENZENE, NOTE F 0.3 1.5 0.9 0.7

1,3,-DIMETHYL-5-ETHYLBENZENE

METHYLPROPYLBENZENE (sec butylbenzene)

1-METHYL-3-ISOPROPYLBENZENE 2.6

1,2,3-TRIMETHYLBENZENE

1-METHYL-4-ISOPROPYLBENZENE

INDAN

1-METHYL-2-ISOPROPYLBENZENE 1.5

1,3-DIETHYLBENZENE

1,4-DIETHYLBENZENE

1-METHYL-3-N-PROPYLBENZENE

1-METHYL-4-N-PROPYLBENZENE, NOTE G

1,2 DIETHYLBENZENE

1-METHYL-2-N-PROPYLBENZENE 2.4 0.6

1,4-DIMETHYL-2-ETHYLBENZENE 0.3

1,3-DIMETHYL-4-ETHYLBENZENE

1,2-DIMETHYL-4-ETHYLBENZENE 0.6

1,3-DIMETHYL-2-ETHYLBENZENE

UNDECANE

1,2-DIMETHYL-3-ETHYLBENZENE

1,2,4,5-TETRAMETHYLBENZENE

2-METHYLBUTYLBENZENE (sec AMYLBENZENE)

3,4 DIMETHYLCUMENE

1,2,3,5-TETRAMETHYLBENZENE

TERT-1-BUT-2-METHYLBENZENE

1,2,3,4-TETRAMETHYLBENZENE

N-PENT-BENZENE 0.5

TERT-1-BUT-3,5-DIMETHYLBENZENE

TERT-1-BUTYL-4-ETHYLBENZENE 0.6

NAPHTHALENE

DODECANE

1,3,5-TRIETHYLBENZENE

1,2,4-TRIETHYLBENZENE

HEXYLBENZENE

PAGE B-19
HYDROCARBON SPECIATION DATA

SHED TEST

TOYOTA CAMRY

SHED results, mg

TC-4614-S TC-4614-M TC-4637-S TC-4637-M TC-4640-S TC-4640-M

COMPOUND 8/19/2002 8/20/2002 8/2/2002 8/9/2002 8/14/2002 8/15/2002

Houston Fuel Atlanta Fuel Chicago Fuel

UNIDENTIFIED C9-C12+ 0.4 4.7 4.8 0.5

*C1 - C4 DATA NOT AVAILABLE DUE TO INSTRUMENT MALFUNCTION

A - 2,2-Dimethylpentane and methylcyclopentane co-elute. GC peak area split equally between the two compounds.

B - 3-Methyl-3-ethyl-pentane co-elutes with reported compound. Not reported separately.

C - Cis-1,4-Dimethylcyclohexane co-elutes with reported compound. Not reported separately.

D - Propylcyclopentane co-elutes with reported compound. Not reported separately.

E - 2,5-Dimethylheptane and 3,5-dimethylheptane co-elute. GC peak area split equally between the two compounds.

F - Decane and isobutylbenzene co-elute. GC peak area split equally between the two compounds.

G - n-Butylbenzene co-elutes with reported compound. Not reported separately.

H - Isobutyraldehyde and methyl ethyl ketone co-elute. LC peak area split equally between the two compounds.

PAGE B-20
Appendix G 

API Section 211(B) Tier-2 Exposure Database – Naming Convention 

 
API Section 211(B) Tier-2 Exposure Database 

The data have been organized into four data files (API Data_Continuous.xls, API 

Data_SPME.xls, API Data_Time-integrated.xls and API Data_Reconstructed.xls) 

containing the continuous, SPME, time-integrated and reconstructed exposure data. All 

files include data fields describing the sample collection conditions (e.g.; 

microenvironment, fuel type, test mode) as well as data flags indicating problems with 

the analytical or sample collection methods. Tables explaining the meaning of each data 

field are also included with each file. The files are supplied in Excel workbook format for 

convenience, but have been formatted to be compatible with common database software 

(the value -99 is used for missing data points, and time is in hhmm text format) 

The time-integrated data contains speciation results from canister, DNPH 

cartridge, and TENAX adsorbent tubes, plus time-averaged values of pollutants and 

environmental parameters that were measured continuously during the batch sample 

collection periods. Within the time-integrated data file there are 4 sub-categories that are 

presented separately due to the differing number of experimental variables for each type: 

1) microenvironment exposure measurements from the three cities, 2) breath samples 

collected from subjects participating in 4 of the microenvironments, 3) residence with 

attached garage, and 4) trailing vehicle exposure tests. 

The SPME data set is assembled in essentially the same manner as the timeintegrated data, but contains only the BTEX hydrocarbon compounds and uses some 

different sample descriptors where necessary to identify which portion of each test the 

sample was collected. The same sample IDs are used to facilitate comparison of the two 

sampling methods. 

The third data file contains 1-minute averages of the pollutants and environmental 

parameters that were measured continuously during the microenvironment exposure tests 

in the 3 cities. Data were typically logged every 10 seconds during testing, but to reduce 

measurement noise, make the data set more manageable, and reduce the effect of minor 

timing discrepancies between instruments due to imperfect clock synchronization or 

differences in sample line residence time, the data was time averaged by minute. Each 

data record in this file has both a time/date stamp and an identification code that relates it 

to the corresponding time-integrated sample. Data flags are given to identify any missing 

or invalid data for each minute. Due to the large size of this file, the various sample 

descriptors have not been included but these can be derived from the identification code 

as described in the included key. 

The fourth file contains 1-min reconstructed data for benzene, 1,3-butadiane and 

formaldehyde based on PID and NDIR CO continuous data, as described in Chapter 1 of 

this report. Both full time canister and DNPH-carbonyl samples and 5-min canister 

samples collected over a peak exposure in selected MEs are included. 

Table G-1 contains the key to the name of the samples collected during this study.
Table G-1. Naming convention for the API data 

Experiment Position Type 1st Location 2nd Season 3rd + 4th 5th Mode 6th 7th 8thMEAtlanta A S-Summer W-winter ME number (01, etc) M-main P- 5 min 

B-breath 

Under score 

Replicate number 

BreathB-pea

MEChicago C S-Summer W-winter ME number M-main P- 5 min 

B-breath 

Under score 

Replicate number 

BreathB-pea

MEHouston H S-Summer W-winter ME number M-main P- 5 min 

B-breath 

Under score 

Replicate number 

BreathB-peapost; denud

trailing Vehicle 

V S-Summer 

W-winter 

Fuel (a,c,h) + vehicle (ttruck, s-sedan) 

MalFunction (F) Normal (N) 

Under score 

High (H), Low (L) vent, or coMbined (m) 

BackgA; Idle-C 

Residence w/attached garage 

R S-Summer 

W-winter 

Fuel (a,c,h) + vehicle (ttruck, s-sedan) 

MalFunction (F) Normal (N) 

Under score 

Kichen (K) or Garage(G) location 

BackgA; Ma

For example: AS02M_1 means Atlanta, summer, ME#2, first replicate. HW11B_3B means Houston, winter, Mpeak VWasN_HC means trailing vehicle, winter, Atlanta fuel, sedan, normal mode, high vent, idle. RSctF_KA m

Chicago fuel, truck, malfunction, kitchen, background 
Appendix H 

Measurement Data Quality Objectives 

 
Appendix H. Data Quality 

Table of Contents 

1.1 Measurement Data Quality Objectives..................................................................... 2 

1.2 Quality Control and Assurance................................................................................. 4 

1.2.1 External Performance Audit for the API Section 211(b) Study ....................... 4 

1.2.2 Laboratory Comparison and External Performance Audits.............................. 4 

1.2.3 Time-Integrated Methods.................................................................................. 5 

1.2.4 Semi-Continuous Methods................................................................................ 7 

1.2.5 Continuous Methods......................................................................................... 8 

1
2

1.1 Measurement Data Quality Objectives 

Data quality objectives, including measures of accuracy, precision, detection limit, time 

resolution, and known interferences, are summarized in Table H-1. For the two CO 

instruments and the PID, we use manufacturer’s specifications for most data quality 

parameters. 

There are also some limitations that are not covered by the tabular summary. For the T-15 

CO (electrochemical detector), we find that although the data system can collect data every 

10 sec, the response of this instrument responds to rapid changes in concentration on a longer

time frame. This may occur since CO must diffuse across a membrane to be measured. The 

finite diffusion time means that rapid spikes in concentration may not achieve steady-state 

values across the membrane and are thus not fully measured. Comparisons among CO 

methods are good over integration times greater than one minute. There were interferences 

from batteries (H2 emissions) that were used to power instruments inside the van that showed 

up as a rising signal from the T-15 CO unit when the vehicle windows were closed. Under 

high-ventilation conditions in the vehicle or outdoors, no such interferences were observed. 

At high humidity near saturation we did observe high T-15 CO readings that we suspect are 

due to the humidity. 

The PID does not have an accuracy measure since this instrument reports the total ion signal, 

which will differ with the distribution of compounds ionizable at 10.6 eV. However, since we 

find a good correlation of PID signal with BTEX as measured in the canisters, we feel this 

measurement provides a reasonable surrogate time series signal for these compounds. This 

instrument does respond to very high humidity where there is condensation of water on the 

lamp and other areas of the electrometer that are exposed to air. In addition, we observed 

some summer instances where the PID readings increased inside the vehicle cabin under low 

ventilation conditions with no change in any other measurement. This may be a response to 

off-gassing of plasticizers in cabin materials that are mostly phthalate esters. 
Instrument Accuracy Precision Det Lim Time Res. Artifacts Specifications 

CO-T15 +/- 1 ppm +/-0.05 ppm 0.1 ppm 10 sec H2, very high humidity Electrochemical Detector 

CO-NDIR 0.50% +/-0.02 ppm 0.04 ppm 1 sec None NDIR 

PID NA 10% 1 ppb 1 sec Plasticizers, very high 

humidity 

10.6 eV lamp PID 

HCHO (a) <15% <5% 1 ppb 1 min None Hantzch rxn/fluorescence 

MS-200 <8% <5% 1-3 ppbv 1 min None Mass spectrometer 

SPME 3-50% 2-15% 0.2 ppbv variable None GC/FID & PID 

Canister <5% <3% 0.05 ppbC variable None GC/FID 

DNPH <5% <3% 0.1 ppbv variable None HPLC/Photodiode array 

(a) HCHO performance parameters based on Battelle instrument performance in the Reno pilot study. Table H-1. Measurement data quality 
1.2 Quality Control and Assurance 

1.2.1 External Performance Audit for the API Section 211(b) Study 

A site visit to the mobile laboratory and all twelve microenvironment (ME) sampling 

sites in Atlanta, GA was conducted during February 23-27, 2004, by the independent 

auditor, Christine Sexsmith, Sexsmith Consulting Services, LLC. The auditor was on site 

at the mobile lab or in the sampling van and witnessed measurement in at least one of 

each of the 12 microenvironments sampled. A technical procedure inspection was 

conducted to verify that DRI personnel were following the approved exposure protocol 

and that no special circumstances occurred that could affect the outcome of the study. 

This audit was followed up by the DRI Organic Analytical Laboratory audit in April 

2005. The reports from these two audits are available from the API upon request. 

1.2.2 Laboratory Comparison and External Performance Audits 

The DRI Organic Analytical Laboratory (OAL) participated in the International 

Hydrocarbon Intercomparison Experiment, organized by National Center for 

Atmospheric Research (NCAR). The results of Tasks I, II, and III of this laboratory 

intercomparison have been published (Apel et al., 1994; 1999). Task I involved analysis 

of a two-component hydrocarbon mixture of known composition and unknown 

concentration prepared by NIST. The DRI results were within the acceptable range of ±

5% of the nominal values provided by NIST. In Task II the participating laboratories 

were asked to identify and quantify 16 components present, in the ppb range, in a mixture 

prepared by NIST. The agreement between the DRI values and the NCAR values, as 

well as with nominal values provided by NIST, were within acceptable ranges (± 15%). 

Task III was more complex, involving the analysis of 60 commonly observed 

hydrocarbons at low ppbv concentrations in a mixture prepared and analyzed by ScottMarrin, Inc., NCAR and U.S. EPA laboratory. The next tasks, IV and V, which were 

carried out in 1996 -1997, involved the analysis of ambient air samples in the ppbv and 

pptv concentration ranges, respectively. The DRI has successfully completed these tasks 

with agreement between the DRI values and the NCAR values for Tasks III – V within 

the acceptable range (± 10%). 

In the summers of 1995 and 1996 the DRI OAL participated in the NARSTO-Northeast 

hydrocarbon intercomparison study, involving the analysis of two ambient air samples by 

participating laboratories. Participants included Biospheric Research Corporation (BRC), 

State University of New York at Albany (SUNYA), EPA Region I, DRI, and eight of the 

PAMS network labs in the northeastern U.S. The DRI laboratory performed best in 

comparison with all other participants (Fujita et al., 1997). In the summer of 1997, the 

DRI OAL participated in the SCOS97-NARSTO performance audit and laboratory 

comparisons involving speciated non-methane hydrocarbons (NMHC), carbonyl 

compounds, halogenated compounds and biogenic hydrocarbons (Fujita et al., 2003). 

Again, the agreement between DRI values and nominal values were within the acceptable 

range (± 10%). 

4
During the last six years, the DRI laboratory participated in non-methane hydrocarbon 

laboratory performance audits, organized by the Quality Assurance Section, Monitoring 

and Laboratory Division, CARB. The last intercomparison studies, organized in 1999-

2002, involved the analysis of ambient air samples by California district laboratories and 

the DRI OAL laboratory. The results of these intercomparison studies were always very 

favorable for OAL. 

1.2.3 Time-Integrated Methods 

Sample Custody. For our quality assurance plan, a sample is considered in custody when 

it is received by the DRI Division of Atmospheric Sciences (DAS) receiving department 

from an official package courier. At this time it is logged into the general receiving 

department's logbook and the Organic Analytical Laboratory is notified of the package's 

arrival. A representative of the laboratory signs for the package and returns with it to the 

laboratory where he opens it. The samples are logged into the Organic Analytical 

Laboratory’s receiving logbook, the chain-of-custody form is updated, and the samples 

are stored appropriately for the sample type. At this time any unusual situations 

(damaged shipping container, evidence of damage and/or tampering, etc.) are brought to 

the attention of the laboratory manager. If necessary, a review will be initiated to 

determine if the damage compromised the integrity and/or quality of the sample. 

Samples are stored in the Organic Analytical Laboratory, inside the DRI Northern 

Nevada Science Center (2215 Raggio Parkway, Reno, NV). The room is locked when 

not in use and the building has limited access (i.e., it is locked from 1730 to 0730

weekdays and all weekends to ensure access only to authorized personnel). 

When a sample is analyzed, its identification number (sample number) is recorded both in 

the written log book for each instrument and in the Laboratory Information Management 

System (LIMS) file created for that analysis. The sample number serves as a tracking 

number, as does the LIMS file itself. Canisters will not be cleaned until each sample has 

passed initial validation. 

Sampling Systems. The sampling equipment is leak-tested and the electronic flow 

controllers are calibrated prior to the delivery to the field. The flow controllers are recalibrated after the program to determine if any significant change in the calibration has 

occurred. In addition, the flow controllers are checked at least weekly in the field with a 

Galibrator (an instrumented soap bubble flow meter). The average of the pre- and postsampling flow rates is used to determine the sample volume. 

Sampling systems that have internal surfaces upstream of the collection media (e.g., 

canister sampler), must be cleaned and certified for cleanliness prior to sampling. 

Sampling Media Preparation and Certification. Multibed adsorbent cartridges consisting 

of Tenax TA, Carbotrap (or Carboxen) and Carbosieve are used for ethanol sample 

collection. Prior to use, the Tenax-TA solid adsorbent is cleaned by Soxhlet extraction 

with hexane/acetone mixture (4/1 v/v) overnight, and dried in a vacuum oven at ~ 80 °C. 

The dry Tenax is packed into Pyrex glass tubes together with Carbotrap and Carbosieve 

and thermally conditioned for four hours in an oven at 300 °C under nitrogen purge. 

Approximately 10% of the precleaned cartridges are tested by GC/FID prior to sampling. 

5
After cleaning, the cartridges are sealed using clean Swagelok caps (brass) with 

graphite/Vespel ferrules, placed in metal containers with activated charcoal, and kept in a 

clean environment at room temperature until use. 

The DNPH impregnated SiO2 cartridges are purchased from Waters, Inc., in batches of 

25. One cartridge from each batch is tested for background contamination by the High 

Performance Liquid Chromatography (HPLC) method prior to sampling. 

The canisters are cleaned by repeated evacuation and pressurization with humidified zero 

air, as described in the EPA document "Technical Assistance Document for Sampling 

and Analysis of Ozone Precursors" (October 1991, EPA/600-8-91/215). Six sequential 

cycles of evacuation to ~ 0.5 torr absolute pressure and pressurization with ultra-highpurity (UHP) humid zero air to ~ 20 psig are used. The DRI procedure differs from the 

EPA method in that canisters are heated to 140 °C during the vacuum cycle in the DRI 

procedure and more vacuum-pressure cycles are used. According to our experience and 

that of others (Rasmussen, 1992), heating is essential to achieve the desired canister 

cleanliness. Also, the canisters are maintained longer under vacuum, about one hour in 

the DRI method, as opposed to half of an hour in the EPA method. 

At the end of the cleaning procedure, one canister out of twelve in a lot is filled with 

humidified UHP zero air and analyzed by the gas chromatograph/flame ionization 

detection (GC/FID) method. The canisters are considered clean if the total non-methane 

organic compound (NMOC) concentration is less than 10 ppbC, and the concentration of 

any individual targeted compound is less than 0.2 ppbv. Canister cleaning and 

certification are described in the DRI SOP1-701.4 . 

Analytical Systems. Prior to analysis, all analytical systems (i.e., GC/ECD/FID, HPLC, 

GC/MS, and GC/IRD/MSD) are checked for cleanliness and are certified clean (less than 

0.1 ppbv of targeted compound). Quality control in the laboratory includes instrument 

calibration for each batch of samples analyzed, replicates of standards, and reanalysis of 

approximately 10% of the samples for estimation of analytical precision, which 

historically has been better than 6%. In past programs, field blanks have come in at 0.5-1 

ppb levels, based on the air volume of the samples. Coefficients of variation (CV) 

calculated from observed differences between duplicate samples were less than 10%. 

The data quality in this program was within DRI’s historical range. 

Standards and Materials. Each primary reference standard is traceable to an NIST 

Standard Reference Material (SRM). For canister hydrocarbon speciation, we use NIST 

SRM 1805, which consists of 254 ppb of benzene in nitrogen. 

Gas cylinders of helium, nitrogen, hydrogen, and ultra zero air (all UHP grade) — from 

the best sources available — are used for the GC/FID and GC/MSD. The current 

inventory of reference samples at DRI's Organic Analytical Laboratory consists of over 

250 single- and multi-component reference samples, and includes compounds of interest 

in this project. 

Calibrations. The GC/FID, HPLC, and GC/MS systems are calibrated initially by 

multipoint calibration (i.e., three levels plus humid zero air), and regularly checked by a 

one-point calibration, using the appropriate NIST SRM or other standard. A day-to-day 

6
reproducibility of ±10% is acceptable for either standard. Control charts are used for 

assessing analytical system performance. 

Samples that fall outside the calibration range are diluted until bracketed by the 

calibration curve. Instrument responses to calibration standards for each parameter are 

analyzed using a least squares linear regression. The calibration must generate a 

correlation co-efficient (R2

) of 0.99 to be acceptable. 

During the course of analysis, calibration standards are routinely analyzed to ensure that 

the instrument response has not changed. The criterion of an instrument response within 

10% of the expected response is used by the analyst to determine whether the instrument 

must be recalibrated. 

Relative Accuracy and Precision of Sampling and Analysis. Accuracy involves the 

closeness of a measurement to a reference value and reflects elements of both bias and 

precision. Percent relative accuracy is calculated: 

 

 % Relative Accuracy = X - Y x 100 

 X 

where: 

Y = concentration of the targeted compound, as determined by the analytical instrument, 

and 

X = concentration of the targeted compound in the NIST (or traceable) standard. 

If the percent relative accuracy does not fall below 20%, the instrument is recalibrated. 

Precision is a measure of the repeatability of the results. The overall precision of 

sampling and analysis is determined by the analysis of collocated samples. These 

precision tests depend upon available resources. Historically, we have performed 

collocated sampling of all samplers, of each type, that were deployed in the measurement 

program to establish equivalency and overall measurement precision prior to actual field 

sampling. Overall precision was within 20%. 

Removal of Ozone and NOx Interferences. Since the carbonyl compound ambient 

measurement results are subject to various artifacts due to interaction with ozone, we use 

either a honeycomb O3 denuder coated with sodium carbonate/sodium nitrite/glycerol 

mixture (method developed by Dr. Koutrakis from the Harvard School of Public Health), 

or a copper tube O3 denuder coated with KI, as recommended by EPA Method TO-11a. 

Since ambient NO2 might react with 1,3 butadiene, we use a honeycomb NO2 denuder 

coated with triethanolamine (a method also developed by Dr. Koutrakis). 

1.2.4 Semi-Continuous Methods 

For SPME fibers, blanks and calibration checks were performed daily in order to 

determine the performance of the instrument and quality of the data. Fibers were kept in 

the injector port throughout the sample run in order to guarantee that the entire sample 

had been desorbed and to aid in conditioning of the fiber. In addition, fibers were 

cleaned in a fiber conditioner at 300 °C for at least one hour. The fiber conditioner 

7
consisted of a 304 SS container with 5 ports and a Watlow heater/temperature controller 

capable of maintaining temperatures in the 200-300 °C range. A helium flow was 

maintained during fiber conditioning. One fiber per batch of 5 was checked for 

cleanliness after conditioning. 

Multi-level calibrations were done initially and throughout the summer field study. 

Liquid calibration was done by injecting 1 μl of a liquid standard prepared in pentane 

with benzene, toluene, ethylbenzene, and xylenes (BETX) at different concentrations (1, 

5, 10, 20, 40, 50, and 100 ng/μl). Gas calibration was performed with certificated 

standards at different concentrations (20, 80, 100, 200, and 500 ppbv for each 

compound). Gas standards were stored in canisters and transferred to 1L Tedlar bags for 

static exposures of SPME fibers. Gas calibrations were performed for different fiber 

exposure times. 

SPME 75 μm Carboxen-PDMS fibers were used with portable or manual samplers. When 

manual samplers were used, the tip of the needle was closed with a septum or Teflon 

tape. Fibers were kept after sampling in sealed Mylar bags inside a cooler with dry ice. 

Storage stability tests showed that samples were preserved without any loss of analyte up 

to 5 hours (and reasonably preserved without substantial losses for as long as three days) 

when stored at dry ice temperature. In Atlanta, SPME samples were analyzed, on 

average, 10 hours after sampling, with a minimum of 1 hour and a maximum of 26 hours 

between sampling and analysis; 54% of the samples were analyzed before 10 hours of 

storage at dry ice temperature). 

Detection limits for the BTEX compounds were benzene 0.2 ppbv, toluene 0.3 ppbv, 

ethylbenzene 0.2 ppbv, m-p-xylene 0.2 ppbv, and o-xylene 0.2 ppbv. Precision was 

evaluated in the laboratory by comparing replicates and standards reproducibility. Two 

sets of replicates were placed side by side for 10 minutes inside solvent cabinets. Also, 

three replicates of 4 different standard concentrations were included in the analysis. 

Replicates ranged from 2 to 15% error for all species. Accuracy was determined by daily 

calibration checks that varied within a range of 3-30% for benzene. When the relative 

accuracy did not fall within the 0-30% range for benzene, the GC was recalibrated. 

The agreement between canister and SPME methods during the Atlanta field study was 

within 3-50%. For comparison, Li et al., 2001, shows an agreement between SPME and 

a charcoal sampling method within a factor of two (100%), with a fiber repeatability of 

20-30%, for 75 μm Carboxen/PDMS. 

1.2.5 Continuous Methods 

The CO instruments were calibrated by standards purchased from Scott Specialty and 

zero points were established by zero air purchased from Air Gas. Since both the T-15 and 

NDIR instruments have only zero and span controls, we used a span gas close to our 

expected concentrations, in this case 10 ppmv. For the T-15 CO instrument, a cap is used 

to flood the sensor with either zero or span gas. The cap is kept in place until a stable 

reading is obtained. For the NDIR, the gas was introduced through the sample inlet line. 

8
Instruments were checked weekly and recalibrated as needed. In general the CO 

instruments were very stable. The PID was calibrated with isobutene as a span gas as 

recommended by the manufacturer. 

The MS-200 is calibrated by a standard containing pentane, isopentane, benzene, toluene, 

and o-xylene. This standard is mixed at DRI and tested against NIST traceable standards 

before being used in the field. Although the MS-200 is very stable once calibrated and 

essentially needs only zero checks before each run with the zero air cylinder carried with 

the instrument, calibration checks are made every few days to confirm instrument 

calibration. DRI purchased an Alpha Omega continuous HCHO instrument, the only 

commercially available instrument of its type, for use in the Atlanta field study. The 

instrument is, in theory, identical to the Battelle instrument that performed well in our 

Reno pilot study in February 2002. It uses the same reagents, the same reaction, and the 

same fluorescence basis for detection. However, there are engineering differences in the 

air/fluid interface, the pumping system, the mixing of the reagents, the flow through the 

reactor, and the detectors. Although we have made a number changes to the instrument, it 

did not performed well in this study. 

Precision evaluation of portable PID instruments. A series of tests were performed to 

evaluate the precision of the estimated VOC concentrations measured by the ppbRAE 

portable PID instruments. Although it is known that the concentrations recorded by these 

instruments vary with changes in the composition of the ambient VOC, making the 

accuracy of the instruments hard to quantify, the precision can be evaluated by comparing 

the concentrations measured by two identical instruments sampling from the same source. 

This measure of precision is important if simultaneous measurements of VOC 

concentration in two locations are to be compared. 

In each test, both instruments were connected to the same inlet using a stainless steel ‘T’ 

and tubing. After synchronizing the internal clocks, data logging was started and a VOC 

source was introduced at varying concentrations up to 10 ppm for a period of 20 to 45 

minutes. The resulting 1-minute average concentrations from the two units were 

compared by linear regression to determine the level of correlation and bias. The test was 

repeated on 4 separate days over a 10-day period. Zero checks and calibrations with 10 

ppm isobutylene were made prior to the first test and between the second and third. 

In all tests, the correlation was high (R2 = 0.97 or better) with a zero intercept. Slopes 

ranged from 0.79 to 1.45, indicating no consistent comparative bias. Since the average 

concentration in most microenvironments is typically less than 100 ppb, we also 

evaluated the precision in this range. In two tests following the calibrations, the 

correlation was good (R2

 = 0.98)with the slope varying from 0.75 to 1.36. For two other 

tests, correlations were less (R2 = 0.45 and 0.66) with slopes of 0.73 and 0.55. As earlier, 

the intercepts were zero. Overall, the test results suggest that instrument sensitivity 

varies, even with frequent calibration. Averaged ambient data may have a precision of 

about ± 35% or higher when comparing small numbers of measurements or when at nearbackground concentrations. 

9
References: 

Apel, E.C., J.G. Calvert and F.C. Fehsenfeld (1994). “The Nonmethane Hydrocarbon 

Intercomparison Experiment (NOMHICE): Tasks 1 and 2.” J. Geophys. Res., 99: 

16,651-16,664. 

Apel, E.C., J.G. Calvert, T.M. Gilpin, F.C. Fehsenfeld, D.D. Parrish, W. A. Lonneman 

(1999). The Nonmethane Hydrocarbon Intercomparison Experiment 

(NOMHICE): Task 3. Journal of Geophysical Research, 104: 20,069-26,086 

Fujita, E., Z. Lu, G. Harshfield, and B. Zielinska (1997). NARSTO-Northeast: 

Hydrocarbon and Carbonyl Measurement Audits for the 1995 Field Study. Final 

Report prepared for the Electric Power Research Institute, Palo Alto, CA, July 

1997 

Fujita, E., G. Harshfield, L. Sheetz (2003). Performance Audits and Laboratory

Comparisons for SCOS97-NARSTO Measurements of Speciated Volatile 

Organic Compounds. Atmos. Environ. 37, Supplement No. 2, S135-S147. 

Li, K.; A. Santilli, M.; Goldthorp, S.; Whiticar, P.; and Lambert, M. F.; Solvent vapour

monitoring in work space by solid phase microextraction. J. Hazard. Mater. 2001, 

83, 83-91. 

10
Appendix I 

Houston Test House Floor Plan Schematic 
Two-Car Garage

Pantry

Kitchen

Breakfast Room

Family Room

Dining

Room

Living 

Room

Stairs

Foyer

Study

Powder

Master

Suite