United States Office of Air Quality EPA-454/R-99-053

Environmental Protection Planning and Standards September 1999

Agency Research Triangle Park, NC 27711

Air

 1998 Nonmethane Organic 

 Compounds (NMOC)

 And

 Speciated Nonmethane 

 Organic Compounds (SNMOC) 

 Monitoring Program
.
1998 Nonmethane Organic Compound (NMOC)

and Speciated Nonmethane Organic

Compound (SNMOC) Monitoring Program

Final Report

EPA Contract No. 68-D3-0095

Delivery Order 16

Prepared for:

Kathy Weant and Mike Jones

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Prepared by:

Eastern Research Group, Inc.

110 Hartwell Avenue

Lexington, MA 02421

January 1999
ii

DISCLAIMER

Through its Office of Air Quality Planning and Standards, the U.S. Environmental Protection

Agency funded and managed the research described in this report under EPA Contract

No. 68-D3-0095 to Eastern Research Group, Inc. This report has been subjected to the Agency’s

administrative review and has been approved for publication as an EPA document. Mention of

trade names or commercial products in this report does not constitute endorsement or

recommendation for their use.
iii

TABLE OF CONTENTS

Page

List of Figures ....................................................... vi

List of Tables ...................................................... viii

List of Abbreviations .................................................... x

About This Report ...................................................... xi

1.0 Introduction ...................................................... 1-1

2.0 The 1998 NMOC/SNMOC Monitoring Program ........................... 2-1

2.1 Monitoring Locations ............................................ 2-1

2.2 Compounds Selected for Monitoring ................................ 2-2

2.3 Sampling and Analytical Methods .................................. 2-4

2.3.1 Total NMOC ........................................... 2-6

2.3.2 SNMOC .............................................. 2-7

2.3.3 VOC ................................................. 2-9

2.3.4 Carbonyls ............................................. 2-9

2.4 Sampling Schedules ............................................ 2-10

3.0 Data Analysis Methodology ............................................ 3-1

3.1 Data Summary Parameters ........................................ 3-1

3.2 Comparison to Selected Meteorological Parameters .................... 3-3

3.3 Analyses of Annual Variations ..................................... 3-5

3.4 Other Analyses ................................................. 3-7

4.0 General Results of the 1998 NMOC/SNMOC Program ..................... 4-1

4.1 Total NMOC Concentrations During the 1998 Program ................. 4-1

4.2 Total NMOC Concentrations During the 1995–1997 Programs ........... 4-2

5.0 Monitoring Results for Dallas and Fort Worth, Texas (CAMS5, CAMS13,

DLTX) ...................................................... 5-1

5.1 Total NMOC Monitoring Data ..................................... 5-2

5.1.1 Data Summary .......................................... 5-3

5.1.2 Comparison to Selected Meteorological Conditions ............ 5-4

5.1.3 Annual Variations ....................................... 5-7

5.2 SNMOC Monitoring Data ........................................ 5-9

5.2.1 Data Summary ......................................... 5-10

5.2.2 Composition of Air Samples .............................. 5-12
TABLE OF CONTENTS (Continued)

iv

5.2.3 Annual Variations ...................................... 5-18

5.2.4 Reactivity of the Air Mass ............................... 5-21

5.3 Carbonyl Monitoring Data ....................................... 5-22

5.4 Chapter Summary .............................................. 5-24

6.0 Monitoring Results for Juarez, Mexico (JUMX) ........................... 6-1

6.1 Total NMOC Monitoring Data ..................................... 6-2

6.1.1 Data Summary .......................................... 6-2

6.1.2 Comparison to Selected Meteorological Conditions ............ 6-4

6.1.3 Annual Variations ....................................... 6-6

6.2 SNMOC Monitoring Data ........................................ 6-8

6.2.1 Data Summary .......................................... 6-8

6.2.2 Composition of Air Samples .............................. 6-10

6.2.3 Annual Variations ...................................... 6-12

6.2.4 Reactivity of the Air Mass ............................... 6-13

6.3 Carbonyl Monitoring Data ....................................... 6-14

6.4 Chapter Summary .............................................. 6-16

7.0 Monitoring Results for Long Island, New York (LINY) ..................... 7-1

7.1 Data Summary ................................................. 7-1

7.2 Comparison to Selected Meteorological Conditions .................... 7-3

7.3 Annual Variations .............................................. 7-6

7.4 Chapter Summary ............................................... 7-7

8.0 Monitoring Results for Newark, New Jersey (NWNJ) ...................... 8-1

8.1 Total NMOC Monitoring Data ..................................... 8-2

8.1.1 Data Summary .......................................... 8-2

8.1.2 Comparison to Selected Meteorological Conditions ............ 8-4

8.1.3 Annual Variations ....................................... 8-7

8.2 SNMOC Monitoring Data ........................................ 8-8

8.2.1 Data Summary .......................................... 8-9

8.2.2 Composition of Air Samples .............................. 8-10

8.2.3 Comparison of Total NMOC Concentrations Measured by Two

Different Methods ...................................... 8-11

8.3 VOC Monitoring Data .......................................... 8-12

8.3.1 Data Summary ......................................... 8-12

8.3.2 Data Trends for MTBE .................................. 8-13

8.3.3 Comparison of VOC and SNMOC Analytical Methods ......... 8-15

8.4 Carbonyl Monitoring Data ....................................... 8-15
TABLE OF CONTENTS (Continued)

v

8.5 Chapter Summary .............................................. 8-17

9.0 Conclusions and Recommendations ..................................... 9-1

9.1 Conclusions ................................................... 9-1

9.2 Recommendations .............................................. 9-4

10.0 References ..................................................... 10-1
vi

LIST OF FIGURES

2-1 Locations of the 1998 NMOC/SNMOC Monitoring Stations .................. 2-12

4-1 Average Concentrations of Total NMOC for the 1998 NMOC/SNMOC Monitoring

Program ...................................................... 4-4

4-2 Average Concentrations of Total NMOC Observed During the 1995–1997

NMOC/SNMOC Monitoring Programs .................................... 4-5

5-1 Dallas, Texas (CAMS5), Monitoring Station ............................... 5-27

5-2 Fort Worth, Texas (CAMS13), Monitoring Station .......................... 5-28

5-3 Dallas, Texas (DLTX), Monitoring Station ................................ 5-29

5-4 Distributions of Total NMOC in Dallas and Fort Worth ...................... 5-30

5-5 Comparison of Total NMOC Concentrations at CAMS5, CAMS13, and DLTX to

Selected Meteorological Parameters ............................... 5-31

5-6 Comparison of Total NMOC Concentrations at CAMS5, CAMS13, and DLTX to

Wind Direction ................................................ 5-34

5-7 Annual Variations in Average Concentrations of Total NMOC in Dallas and Fort

Worth 5-35

5-8 Annual Variations in the Frequency of Peak Concentrations of Total NMOC in the

Dallas–Fort Worth Area ......................................... 5-36

5-9 Relative Amounts of Alkanes, Olefins, and Aromatic Compounds (on a ppbv basis)

at the Dallas–Fort Worth Monitoring Stations ........................ 5-37

5-10 Composition Data for the Most Abundant Olefins at CAMS5, CAMS13, and

DLTX ..................................................... 5-38

5-11 Composition Data for the Most Abundant Alkanes at CAMS5, CAMS13, and 

DLTX ..................................................... 5-39

5-12 BTEX Concentration Ratios Calculated from the SNMOC Monitoring Data ...... 5-40

5-13 Annual Variations for the Most Abundant SNMOC at CAMS5 ................ 5-41

5-14 Annual Variations for the Most Abundant SNMOC at CAMS13 ............... 5-45

5-15 Annual Variations for the Most Abundant SNMOC at DLTX .................. 5-49

5-16 Ozone Indices for the 20 SNMOC with the Highest Geometric Mean Concentrations

at CAMS5 .................................................... 5-53

5-17 Ozone Indices for the 20 SNMOC with the Highest Geometric Mean Concentrations

at CAMS13 ................................................... 5-54

5-18 Ozone Indices for the 20 SNMOC with the Highest Geometric Mean Concentrations

at DLTX 5-55

6-1 Juarez, Mexico (JUMX), Monitoring Station ............................... 6-18

6-2 Distribution of Total NMOC Concentrations Measured at JUMX ............... 6-19

6-3 Comparison of NMOC Concentrations at JUMX to Selected Meteorological

Parameters ................................................... 6-20

6-4 Comparison of Total NMOC Concentrations at JUMX to Wind Direction ........ 6-21

6-5 Annual Variations in Average Concentrations of Total NMOC at JUMX ......... 6-22
LIST OF FIGURES (Continued)

vii

6-6 Annual Variations in the Frequency of Peak Concentrations of Total NMOC 

at JUMX ..................................................... 6-23

6-7 Contribution of “Identified” and “Unknown” Compounds to Total NMOC 

Concentrations at JUMX ........................................ 6-24

6-8 Annual Variations in Concentrations of Selected SNMOC at JUMX ............ 6-25

6-9 Ozone Indices for the 20 SNMOC with Highest Geometric Mean Concentration

at JUMX ..................................................... 6-29

7-1 Long Island, New York (LINY), Monitoring Station .......................... 7-9

7-2 Distribution of Total NMOC Concentrations Measured at LINY ............... 7-10

7-3 Comparison of NMOC Concentrations at LINY to Selected Meteorological

Parameters ................................................... 7-11

7-4 Comparison of Total NMOC Concentrations at LINY to Wind Direction ......... 7-12

7-5 Annual Variations in Average Concentrations of Total NMOC at LINY .......... 7-13

7-6 Annual Variations in Peak Concentrations of Total NMOC at LINY ............ 7-14

8-1 Newark, New Jersey (NWNJ), Monitoring Station .......................... 8-19

8-2 Distribution of Total NMOC Concentrations Measured at NWNJ ............... 8-20

8-3 Comparison of NMOC Concentrations at NWNJ to Selected Meteorological

Parameters ................................................... 8-21

8-4 Comparison of Total NMOC Concentrations at NWNJ to Wind Direction ........ 8-22

8-5 Annual Variations in Average Concentrations of Total NMOC at NWNJ ......... 8-23

8-6 Annual Variations in Peak Concentrations of Total NMOC at NWNJ ........... 8-24

8-7 Data Correlations for Ambient Air Concentrations of Selected Compounds ....... 8-25
viii

LIST OF TABLES

1-1 Organization of the 1998 NMOC/SNMOC Summary Report ................... 1-4

2-1 Background Information for the 1998 NMOC/SNMOC Monitoring Stations ...... 2-13

2-2 Summary of Sampling and Analytical Methods ............................. 2-14

2-3 SNMOC Detection Limits .............................................. 2-15

2-4 Precision Estimates for SNMOC Measurements ............................ 2-16

2-5 VOC Detection Limits ................................................ 2-19

2-6 Carbonyl Detection Limits ............................................. 2-20

2-7 Precision Estimates for Carbonyl Measurements ............................ 2-21

2-8 Sampling Schedules Implemented During the 1998 NMOC/SNMOC Program .... 2-22

3-1 Maximum Incremental Reactivities (MIRs) for SNMOC ....................... 3-8

5-1 Summary Statistics for Concentrations of Total NMOC in Dallas and Fort Worth . . 5-56

5-2 Summary Statistics for SNMOC Concentrations Measured at Dallas, TX

(CAMS5) ..................................................... 5-57

5-3 Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX

(CAMS13) ..................................................... 5-62

5-4 Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX) . 5-67

5-5 SNMOC with the Highest Geometric Mean Concentrations ................... 5-72

5-6 Emissions Source Profiles for Selected SNMOC ............................ 5-73

5-7 Abbreviations Used in Figures 5-16, 5-17, and 5-18 ......................... 5-74

5-8 Summary Statistics for Carbonyl Concentrations Measured at Dallas, TX

(CAMS5) ..................................................... 5-75

5-9 Summary Statistics for Carbonyl Concentrations Measured at Fort Worth, TX

(CAMS13) ..................................................... 5-76

5-10 Summary Statistics for Carbonyl Concentrations Measured at Dallas, TX (DLTX) . 5-77

6-1 Summary Statistics for Concentrations of Total NMOC at JUMX .............. 6-30

6-2 Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico

(JUMX) ..................................................... 6-31

6-3 Abbreviations Used in Figure 6-9 ........................................ 6-36

6-4 Summary Statistics for Carbonyl Concentrations Measured at Juarez, Mexico

(JUMX) ..................................................... 6-37

7-1 Summary Statistics for Concentrations of Total NMOC at LINY ............... 7-15

8-1 Summary Statistics for Concentrations of Total NMOC at NWNJ .............. 8-26

8-2 Summary Statistics for SNMOC Concentrations Measured at Newark, NJ

(NWNJ) ..................................................... 8-27

8-3 Summary Statistics for VOC Concentrations Measured at Newark, NJ (NWNJ) ... 8-32

8-4 Comparison of Concentrations for Compounds Measured by Both the VOC and
LIST OF TABLES (Continued)

ix

SNMOC Analytical Methods ..................................... 8-35

8-5 Summary Statistics for Carbonyl Concentrations Measured at Newark, NJ

(NWNJ) ..................................................... 8-36
x

LIST OF ABBREVIATIONS

AIRS Aerometric Information Retrieval System

AQS Air Quality Subsystem (of the Aerometric Information and Retrieval System)

BTEX benzene, toluene, ethylbenzene, and xylenes (o-, m-, and p-xylene)

EPA U.S. Environmental Protection Agency

FID flame ionization detection

GC gas chromatography

HPLC high-performance liquid chromatography

MIR maximum incremental reactivity

mph miles per hour

MSD mass selective detection

MTBE methyl tert-butyl ether

NAAQS national ambient air quality standard

NCDC National Climatic Data Center

ND nondetect

NJDEP New Jersey Department of Environmental Protection

NYSDEC New York State Department of Environmental Conservation

PDFID preconcentration direct flame ionization detection

ppbC parts per billion (by volume, on a carbon basis)

ppbv parts per billion (by volume)

RPD relative percent difference

SNMOC speciated nonmethane organic compound

TNRCC Texas Natural Resource Conservation Commission

total NMOC total nonmethane organic compounds

TRI Toxics Release Inventory

UV ultraviolet

VOC volatile organic compounds

Monitoring Stations

CAMS5 Dallas, Texas (1)

CAMS13 Fort Worth, Texas

DLTX Dallas, Texas (2)

JUMX Juarez, Mexico

LINY Long Island, New York

NWNJ Newark, New Jersey
xi

ABOUT THIS REPORT

This report summarizes and interprets ambient air monitoring data collected during the

summer of 1998 as part of the National Nonmethane Organic Compound and Speciated

Nonmethane Organic Compound Monitoring Program, which is also called the NMOC/SNMOC

Monitoring Program. Designed to characterize levels of air pollution in regions with ground-level

ozone problems, the NMOC/SNMOC Monitoring Program measures air concentrations of several

groups of pollutants that participate in the photochemical reactions that form “smog.” The 1998

NMOC/SNMOC Monitoring Program spanned 4 months (June to September), during which

ambient air samples were collected daily between 6:00 a.m. and 9:00 a.m., local time, at six

monitoring locations. These samples were analyzed for NMOC, SNMOC, volatile organic

compounds (VOC), carbonyls, or some combination of these categories. Overall, nearly 30,000

ambient air concentrations were measured during the 1998 program. 

This report uses various graphical, numerical, and statistical analyses to identify and

illustrate meaningful trends and patterns in this large volume of ambient air monitoring data. Some

of the analyses in this report, such as the concise data summary tables, intentionally follow the

same data analysis framework used in earlier reports on past National Program elements. This

consistent use of certain analyses facilitates comparisons between the 1998 program and earlier

NMOC/SNMOC programs. To provide the reader with a new perspective on the NMOC/SNMOC

monitoring data, however, this report includes several analyses that have not been addressed

previously, such as a detailed review of annual variations in air quality. Though the analyses in

this report highlight many trends in the data collected during the 1998 program, researchers are

encouraged to further examine the NMOC/SNMOC ambient air monitoring data to better

understand the complex ozone formation processes. Accordingly, the 1998 NMOC/SNMOC

monitoring data have been made publicly available in electronic format on the U.S. Environmental

Protection Agency’s Aerometric Information Retrieval System (AIRS).

The structure of this report differs significantly from that of earlier NMOC/SNMOC reports

in one important regard: instead of commenting primarily on the compound-specific trends

observed during the air monitoring program, as was done previously, this report instead focuses on

site-specific air quality trends. This revised structure allows for a much more thorough review of

data trends that are unique to a given metropolitan area—a topic suspected to be of interest to the

agencies that sponsor the NMOC/SNMOC monitoring stations. Site-specific trends presented in

this report should not be assumed to apply to geographical areas not considered in the 1998

NMOC/SNMOC Monitoring Program.

Though readers are encouraged to read this report in its entirety, a quick overview of the

major site-specific findings can be found in the following sections: Section 5 addresses the

monitoring data collected in the Dallas–Fort Worth metropolitan area; Section 6, the data collected

in Juarez, Mexico; Section 7, the data collected on Long Island, New York; and Section 8, the data

collected in Newark, New Jersey.
.
1-1

1.0 Introduction

This report summarizes ambient air monitoring data collected in or near three

metropolitan areas as part of the National “1998 Nonmethane Organic Compounds (NMOC) and

Speciated Nonmethane Organic Compounds (SNMOC) Monitoring Program.” Every year since

1984, the U.S. Environmental Protection Agency (EPA) has sponsored the NMOC/SNMOC

Monitoring Program to provide state and local environmental agencies with important

information on the composition and magnitude of air pollution in or near areas that are not in

attainment with the Agency’s national ambient air quality standard (NAAQS) for ozone. In

recent years, this program has entailed intensive field sampling—up to 4 months of daily

measurements—of four groups of compounds that affect ozone formation: total NMOC,

SNMOC, volatile organic compounds (VOC), and carbonyls. This report summarizes and

interprets the nearly 30,000 air quality measurements that were made during the 1998

NMOC/SNMOC Monitoring Program.

To supplement findings from previous NMOC/SNMOC Monitoring Programs and other

local air monitoring efforts, this report includes detailed numerical and statistical analyses of

the ambient air monitoring data collected during the 1998 program. So that new and historical

data can easily be compared, the descriptive summary statistics presented in this report have a

format identical to previous NMOC/SNMOC reports. To offer greater insight into the current

data, however, much of this report focuses on topics that previous NMOC/SNMOC reports have

not addressed in detail. Overall, there are four basic goals for this report:

C To provide thorough, site-specific summaries of the data collected during the 1998

NMOC/SNMOC Monitoring Program.

C To identify and characterize associations between levels of air pollution and variations

in selected meteorological conditions.

C To illustrate how ambient air concentrations of the most prevalent components of air

pollution changed from one year to the next.
1-2

C To conduct additional data analyses, as appropriate, to explain noteworthy trends and

patterns in the large volume of air monitoring data.

Unlike previous NMOC/SNMOC reports, which focused on compound-specific air

quality trends, this report focuses on site-specific air quality trends. Thus, rather than

presenting separate analyses for NMOC, SNMOC, VOC, and carbonyls, as was done in prior

reports, this report instead presents separate analyses for monitoring data collected at

Dallas–Fort Worth, Juarez (Mexico), Long Island, and Newark. This site-specific approach

allows for much more detailed analyses of the local factors (e.g., unique meteorological

conditions, motor vehicle sources, industrial sources) that affect air quality differently from one

metropolitan area to the next.

As previous NMOC/SNMOC reports have explained, the series of photochemical

reactions that contribute to ozone formation are extremely complex. As a result, the analyses in

this report, though extensive, do not offer a comprehensive description of air quality at the

monitoring stations that participated in the 1998 program. For a more informed understanding of

air pollution in ozone non-attainment areas, state and local environmental agencies are

encouraged to evaluate emission inventories, photochemical dispersion modeling results, and

additional monitoring data on ozone precursors (e.g., nitrogen oxides), in addition to evaluating

the data presented in this report. To facilitate further analysis of the 1998 NMOC/SNMOC

sampling results, appendices to this report present the entire set of ambient air monitoring data. 

Moreover, these data have been made available in electronic format on the Air Quality

Subsystem (AQS) of the Aerometric Information Retrieval System (AIRS), an electronic

database that EPA maintains.

This report is organized into ten sections; Table 1-1 lists the contents of each section. 

Sections 2 and 3 present necessary background information on the monitoring program and the

methodology used to interpret the monitoring data, and Section 4 provides an overview of the

total NMOC measurements collected during the 1998 program. Sections 5 through 8 then

present detailed analyses of the data collected at the six monitoring stations that comprised the

1998 NMOC/SNMOC Monitoring Program. Finally, Section 9 reviews the major findings of
1-3

 the report and offers several recommendations for future programs. Section 10 lists the

references cited throughout the report. As with previous NMOC/SNMOC reports, all figures

and tables in this report appear at the ends of their respective sections (figures first, followed by

tables).
1-4

Table 1-1

Organization of the 1998 NMOC/SNMOC Summary Report

Report

Section Section Title Overview of Contents

2

The 1998 NMOC/SNMOC Monitoring Program was implemented. Topics of discussion include sampling

Monitoring Program locations, compounds selected for sampling, sampling and analytical methods,

This section provides background information on how the 1998 NMOC/SNMOC

measurement accuracy and precision, and sampling schedules.

3 Data Analysis Methodology This section outlines the data analysis methodology used in Sections 5 through 9 to

analyze and interpret the large volume of NMOC/SNMOC monitoring data.

4 NMOC/SNMOC Monitoring

General Results from the 1998

Program

This section presents a general overview of the sampling results from the 1998

program, by comparing average concentrations of total NMOC that were observed at

the six monitoring stations that participated in the program. The section compares

this general trend to relevant data from previous NMOC/SNMOC reports.

5

Monitoring Results for Dallas and

Fort Worth These sections provide site-specific summaries of sampling results collected during

the 1998 NMOC/SNMOC Monitoring Program. Each section summarizes the data

collected during the 1998 program, compares trends in the monitoring data to trends

in local meteorological conditions, and examines how concentrations of certain

compounds have changed over the past couple of years.

6 Monitoring Results for Juarez

7 Monitoring Results for Long Island

8 Monitoring Results for Newark

9 Conclusions and Recommendations This section summarizes the most significant findings of the 1998 NMOC/SNMOC

Monitoring Program and makes several recommendations for future programs.

10 References This section lists the references cited throughout this report.
2-1

2.0 The 1998 NMOC/SNMOC Monitoring Program

This section describes four fundamental features—the monitoring locations, compounds

selected for monitoring, sampling and analytical methods, and sampling schedules—of the 1998

NMOC/SNMOC Monitoring Program. These four features are important to consider when

interpreting the results of any ambient air monitoring program. In general, the 1998 program

included six monitoring stations, all of which have participated in previous NMOC/SNMOC

programs. Monitoring devices at these stations collected 3-hour integrated samples according to

site-specific schedules, from June 1998 to September 1998. During this time frame, more than

600 air samples were collected and nearly 30,000 ambient air concentrations were measured,

including concentrations of total NMOC, SNMOC, VOC, and carbonyls. The remainder of this

section describes in greater detail these relevant features of the 1998 NMOC/SNMOC

Monitoring Program.

2.1 Monitoring Locations

The NMOC/SNMOC Monitoring Program is an EPA-sponsored program, in which state

and local environmental agencies can voluntarily participate. EPA works with participating

agencies to select appropriate monitoring locations. Figure 2-1 shows the locations of the six

monitoring stations that participated in the 1998 NMOC/SNMOC Monitoring Program. 

Table 2-1 presents additional information on these monitoring stations, including (1) each

station’s NMOC/SNMOC site code, which was used to track samples from the field to the

laboratory, (2) each station’s unique nine-digit AIRS site code, which was used to index

monitoring results in the AIRS database, and (3) each station’s starting and ending sampling

dates for the 1998 program, which Section 2.4 describes further. 

At each of the monitoring stations, air sampling equipment was installed in a small

enclosure (e.g., a trailer or a shed) with air sampling probes protruding through the roof; every

air monitor in this program sampled air at heights of approximately 5 to 20 feet above local

ground level. Sections 5 through 8 of this report include detailed maps and descriptions of the
2-2

surroundings of the six monitoring stations. These descriptions identify local emissions sources

that might have affected each station’s monitoring results.

The locations of the monitoring stations shown in Figure 2-1 present two important

limitations on the data analyses documented throughout this report:

C The monitoring stations that participated in the 1998 program are located in or near only

three metropolitan areas in the United States and Mexico: the Dallas–Fort Worth

metropolitan area, the El Paso–Juarez metropolitan area, and the New York–Newark

metropolitan area. As a result, the monitoring data characterize air quality in a very

small subset of ozone nonattainment areas, and trends in the data presented in this report

should not be viewed as being representative of air quality trends in other ozone

nonattainment areas in the United States or Mexico.

C The monitoring stations shown in Figure 2-1 characterize air quality at only discrete

locations within the three metropolitan areas. Because the number of emissions sources,

such as freeways and industrial facilities, varies with location in any given metropolitan

area, ambient air concentrations of certain compounds also vary within metropolitan

areas, sometimes by many orders of magnitude and over very short distances. Therefore,

the air quality data presented in this report should be viewed as a depiction of air quality

in the immediate vicinity of the monitoring stations and not necessarily as a depiction of

air quality for an entire metropolitan area.

To ensure that the NMOC/SNMOC monitoring data are interpreted in proper context, the

implications of the aforementioned data limitations are revisited throughout this report.

2.2 Compounds Selected for Monitoring

The agencies that sponsor NMOC/SNMOC monitoring stations decide what compounds

are to be measured. Agencies that participated in the 1998 program selected their monitoring

options from the following four groups of compounds:

C Total NMOC. In this option, air samples are analyzed to obtain a single value (total

NMOC) that characterizes the overall levels of hydrocarbons in the air. Some computer

models use total NMOC concentrations as a critical input for forecasting ozone
The SNMOC analytical method actually reports concentration values for only 78 different compounds 1

for each sample. Since the chromatographic analysis cannot differentiate isobutene from 1-butene or m-xylene

from p-xylene, a single concentration is reported for these pairs. Therefore, the 78 values measured by this

method characterize ambient levels of 80 compounds.

The VOC analytical method actually reports concentration values for only 46 different compounds for 2

each sample. Since the chromatographic analysis cannot differentiate m-xylene from p-xylene, a single

concentration is reported for this pair. Therefore, the 46 values measured by this method characterize ambient

levels of 47 compounds.

The carbonyl analytical method actually reports concentration values for only 13 different compounds 3

for each sample. Since the chromatographic analysis cannot differentiate butyraldehyde from isobutyraldehyde, a

single concentration is reported for this pair; and, since the method cannot distinguish the three tolualdehyde

isomers, a single concentration is reported for this trio. Therefore, the 13 values measured by this method

characterize ambient levels of 16 compounds.

2-3

concentrations. Section 2.3.1 describes the NMOC sampling and analytical method in

greater detail.

C SNMOC. Stations implementing this option collect air samples that are analyzed for

ambient air concentrations of 80 hydrocarbons, as well as for the concentration of total

NMOC. SNMOC concentrations also are used as inputs to certain ozone forecasting

simulations. Table 2-3 lists the 80 compounds identified by this monitoring option, and

Section 2.3.2 describes the SNMOC sampling and analytical method in greater detail.1

C VOC. With this monitoring option, ambient air samples are analyzed for concentrations

of 47 compounds, which include hydrocarbons, halogenated hydrocarbons, oxygenated

compounds, and nitriles. Most of these 47 compounds are not measured by the SNMOC 2

analytical method. Table 2-5 lists the compounds identified by this monitoring option,

and Section 2.3.3 describes salient features of the VOC sampling and analytical method,

including a noteworthy improvement made to this method prior to the start of the 1998

program.

C Carbonyls. Stations also could opt to have samples analyzed for concentrations of

16 carbonyls, all of which are not currently identified by either the SNMOC or VOC

monitoring options. Table 2-6 lists the 16 compounds identified by this option, and 3

Section 2.3.4 presents relevant background information on the carbonyl sampling and

analytical method.

Table 2-1 indicates the compound groups that were selected for monitoring at the six

stations participating in the 1998 NMOC/SNMOC Monitoring Program. Since nearly 90 percent

of the air samples collected during the 1998 program were analyzed for either NMOC or

SNMOC, the data analyses throughout this report focus on interpreting trends and patterns in the
2-4

large volume of NMOC and SNMOC monitoring results. Consistent with previous

NMOC/SNMOC reports, this report places a lesser emphasis on evaluating the VOC and

carbonyl monitoring results.

The compounds selected for monitoring present one important limitation on the

conclusions that can be drawn from the NMOC/SNMOC Monitoring Program: Though this

program measures ambient air concentrations of numerous compounds that contribute to ozone

formation, the program does not characterize ambient levels of all compounds that participate in

the photochemical reactions that form ozone. Thus, the data presented in this report provide an

extensive, but not a comprehensive, account of air quality in ozone nonattainment areas. 

Sponsoring agencies are encouraged to evaluate data trends for other compounds (e.g., nitrogen

oxides) that participate in photochemical reactions that form “smog.”

2.3 Sampling and Analytical Methods

The sampling and analytical methods used in a monitoring program ultimately determine

what compounds can be identified in air samples, and at what ranges of concentrations. As

noted previously, four different sampling and analytical methods were used during the 1998

NMOC/SNMOC Monitoring Program to measure ambient air concentrations of total NMOC,

SNMOC, VOC, and carbonyls. Since the final reports for the 1996 and 1997 NMOC/SNMOC

Monitoring Programs describe these sampling and analytical methods in detail (ERG 1997b,

1999), the following subsections only briefly highlight how air samples were collected and

analyzed. For quick reference, Table 2-2 summarizes general attributes (detection limits, units

of measurement, etc.) of the four sampling and analytical methods.

The following subsections also estimate how precisely the sampling and analytical

methods measured ambient air concentrations during the 1998 program. As is typical for air

monitoring programs, precision was determined by reviewing results of duplicate samples that

were analyzed in replicate. As previous NMOC/SNMOC reports have explained, comparison

of concentrations measured in replicate analyses characterizes analytical precision (how


2-7

During the 1998 program, results from 22 duplicate NMOC samples, all of which were

analyzed in replicate, indicated that the total NMOC sampling and analytical method consistently

generated highly precise results. More specifically, the program-average RPD for total NMOC

measurements was lower than 10 percent, both for analytical precision and for sampling and

analytical precision. In other words, total NMOC concentrations measured in duplicate samples

and replicate analyses consistently differed by 10 percent or less. Moreover, total NMOC

concentrations in duplicate samples and replicate analyses had an average concentration

difference lower than ±25 ppbC. Since program-average NMOC concentrations were

approximately 10 times higher than this average concentration difference (see Figure 4-1), the

variability introduced by the sampling and analytical method has little bearing on the general

trends in the total NMOC monitoring data. Sections 7 and 8 revisit this issue.

2.3.2 SNMOC

The 1998 NMOC/SNMOC Monitoring Program used an EPA research protocol called

“Determination of C2 through C12 Ambient Air Hydrocarbons in 39 U.S. Cities from 1984

through 1986” (USEPA 1989) to measure ambient air concentrations of SNMOC. This protocol

requires air samples to be collected in passivated stainless steel canisters, which are later

analyzed using a capillary gas chromatography (GC) column coupled with the FID. With this

analytical approach, SNMOC air samples are analyzed for ambient air concentrations of

80 organic compounds and total NMOC. Table 2-3 lists these 80 compounds and their

corresponding detection limits. The sidebar on the following page, “Appreciating Detection

Limits,” provides important background information on the meaning and derivation of detection

limits. All SNMOC concentrations were reported in units of ppbC, following standard

convention for this analytical method. As explained later in this report, concentrations of some

compounds were also converted to units of parts per billion on a volume basis (ppbv) to

perform certain data analyses.

During the 1998 NMOC/SNMOC Monitoring Program, 39 SNMOC samples were

collected in duplicate and analyzed in replicate; results from these samples and analyses

indicate
2-8

Appreciating Detection Limits

The detection limit of an analytical method must be considered carefully when ambient air

monitoring data are interpreted. By definition, the detection limit is the lowest level at which

laboratory equipment can reliably quantify concentrations of selected compounds to a

specific confidence level. If a compound’s concentration in ambient air does not exceed the

method sensitivity (as gauged by the detection limit), the analytical method might not

differentiate the compound from other compounds in the sample or from the random “noise”

inherent in laboratory analyses. Therefore, when samples contain concentrations at levels

below their respective detection limits, multiple analyses of the same sample might lead to a

wide range of results, including highly variable concentrations or “nondetect” observations. 

Because analytical methods do not quantify concentrations at levels below the detection limits

accurately or precisely, data analysts must exercise caution when interpreting monitoring data

that have many concentrations at levels near or below the corresponding detection limits.

For reference, the detection limits for the NMOC, SNMOC, VOC, and carbonyl analytical

methods were all determined according to EPA guidance specified in “Definition and

Procedure for the Determination of the Method Detection Limit” (FR 1984).

 that the SNMOC sampling and analytical method generated highly precise results. According to

performance criteria established in the SNMOC method documentation, analytical precision for

compounds with concentrations greater than 2 ppbC should have an RPD less than 30 percent,

and analytical compounds with concentrations lower than 2 ppbC should have an RPD less than

95 percent (USEPA 1989). As Table 2-4 shows, the precision estimates for the SNMOC

measurements during the 1998 program met these performance criteria: The RPDs for 74 of the

80 SNMOC were lower than 30 percent; the six remaining compounds (n-dodecane, 1-

dodecene, 1-heptene, n-tridecane, 1-tridecene, and 1-undecene) had average concentrations

lower than 2 ppbC and had RPDs considerably lower than 95 percent.

Corroborating the findings of the RPDs, the average concentration differences observed

in duplicate SNMOC samples and replicate analyses were typically better than ±1 ppbC—a

level indicative of excellent measurement precision. Therefore, the SNMOC monitoring data

presented in this report are of a known and high quality.
2-9

2.3.3 VOC

Following EPA’s Compendium Method TO-14A (USEPA 1999a), ambient air

concentrations of 47 VOC were measured by collecting ambient air in passivated stainless steel

canisters and analyzing the sampled air using a capillary gas chromatography column with mass

selective detection and flame ionization detection (GC/MSD-FID). The analytical techniques

used during the 1998 program differed from those used in earlier programs in one important

regard: Nafion dryers were removed from the analytical apparatus, thus allowing for the ®

measurement of nine compounds that previous air toxics programs could not detect. Table 2-5

lists the 47 VOC identified during the 1998 program and their corresponding detection limits. 

Following standard convention for this method, all VOC concentrations were reported in units

of ppbv.

Because only one monitoring station (Newark) collected VOC samples during the 1998

program, too few duplicate sampling results and replicate analyses were available to assess

measurement precision of the VOC sampling and analytical method. Nonetheless, the VOC

results presented for the Newark monitoring station are believed to be highly precise, largely

because the central laboratory for the NMOC/SNMOC Monitoring Program has a long record of

analyzing VOC samples to a high level of precision (ERG 1997a; 1999).

2.3.4 Carbonyls

Following the specifications of EPA’s Compendium Method TO-11A (USEPA 1999b),

concentrations of 16 carbonyl compounds were measured by passing ambient air over silica gel

cartridges coated with 2,4-dinitrophenylhydrazine (DNPH), a compound known to react

reversibly with carbonyls (i.e., aldehydes and ketones). For chemical analysis, the sampling

cartridges are eluted with acetonitrile, which liberates the hydrazones (the DNPH-carbonyl

derivatives) from the sampling matrix. The acetonitrile solution is then analyzed for chemical

constituents using high-performance liquid chromatography (HPLC) with ultraviolet detection. 

The 16 carbonyl compounds identified by this method are listed in Table 2-6, with their

detection limits.
2-10

During the 1998 NMOC/SNMOC Monitoring Program, four carbonyl samples were

collected in duplicate and analyzed in replicate, thus providing a limited basis for estimating

measurement precision. Table 2-7 presents the RPDs calculated both for sampling precision

and for sampling and analytical precision. Both sets of RPDs indicate that the carbonyl

sampling and analytical method precisely measured air concentrations of most compounds: All

compounds had analytical precision lower than 20 percent and sampling and analytical

precision of roughly 50 percent and lower. Measurement precision was particularly good for

acetaldehyde, acetone, and formaldehyde—the three carbonyls consistently present at the highest

concentrations in air samples. In short, the carbonyl monitoring data presented in this report,

like the NMOC, SNMOC, and VOC monitoring data, are believed to be of high quality.

2.4 Sampling Schedules

Each year, stations participating in the NMOC/SNMOC Monitoring Program collect

ambient air samples according to site-specific schedules. The agencies that sponsor these

monitoring stations ultimately decide how frequently each type of samples is to be collected. 

Tables 2-1 and 2-8 summarize the sampling schedules implemented at the six monitoring stations

that comprised the 1998 program. As Table 2-8 indicates, every station collected daily samples

that were analyzed for either NMOC or SNMOC, and five of the six stations periodically

collected samples that were analyzed for carbonyls or VOC. As part of the sampling schedule,

site operators collected duplicate samples on roughly 10 percent of the sampling days. These

duplicate samples were analyzed in replicate to characterize the precision of the sampling and

analytical methods.

Overall, the site-specific sampling schedules have two features in common, both of

which introduce important limitations to the data analyses; these limitations are emphasized

throughout this report:

C On each sampling day, ambient air is continuously sampled for 3 hours, starting at

6:00 a.m., local time. This sampling duration has been used in the previous

NMOC/SNMOC Monitoring Programs, because many ozone transport models require
2-11

ambient air concentrations measured between 6:00 a.m. and 9:00 a.m. as an input. 

However, this sampling duration should be kept in mind when interpreting the air

monitoring data: All concentrations presented in this report characterize local air

quality during only three morning hours. Since concentrations of many compounds are

known to vary considerably between the day and night, comparisons between the

NMOC/SNMOC monitoring data and other data sets with different sampling durations

(e.g., 24-hour average samples) should be made with caution.

C Sampling during the NMOC/SNMOC Monitoring Program is typically limited to the

summer months (June through September), since ambient air concentrations of ozone

peak during this time of year. Though the NMOC/SNMOC monitoring data thoroughly

characterize levels of air pollution during these summer months, the monitoring data are

not useful for evaluating seasonal changes in air quality. Moreover, because this

program does not consider levels of air pollution during the fall, winter, and spring, the

average concentrations of certain pollutants presented in this report might differ

considerably from their corresponding annual-average levels.
Juarez, Mexico

 (JUMX)

Dalas, TX

 (CAMS5)

Newark, NJ

 (NWNJ)

Long Island, NY

 (LINY)

Fort Worth, TX

 (CAMS13)

2-12

Figure 2-1

Locations of the 1998 NMOC/SNMOC Monitoring Stations

Note: The alphanumeric codes shown were used primarily to track samples from the monitoring stations to the analytical laboratory.
2-13

Table 2-1

Background Information for the 1998 NMOC/SNMOC Monitoring Stations

1998

NMOC/

SNMOC

Site Code

AIRS Site Code Location

Sampling Schedule Monitoring Options Selected

Starting Ending

Date Date NMOC SNMOC VOC Carbonyl

CAMS5 48-113-0045 Dallas, TX (1) June 23, 1998 September 30, 1998 T T

CAMS13 48-439-1002 Fort Worth, TX June 22, 1998 September 30, 1998 T T

DLTX 48-113-0069 Dallas, TX (2) June 22, 1998 September 30, 1998 T T

JUMX 80-006-0001 Juarez, Mexico August 25, 1998 September 29, 1998 T T

LINY 36-059-0005 Long Island, NY June 4, 1998 September 30, 1998 T

NWNJ 34-013-0011 Newark, NJ June 12, 1998 September 29, 1998 T T T T

Note: Due to construction activities, sampling at Juarez, Mexico, could not start in June, as was originally planned.

As Section 2.3.2 describes, the SNMOC monitoring option measures NMOC as well as the 80 compounds listed in Table 2-3.
2-14

Table 2-2

Summary of Sampling and Analytical Methods

Parameter NMOC SNMOC VOC Carbonyl

Sampling Silica gel cartridge

apparatus coated with DNPH Stainless steel canisters Stainless steel canisters Stainless steel canisters

Analytical Cryogenic trap and flame

approach ionization detection

Cryogenic trap at the Capillary gas

inlet of a capillary gas chromatography with High-performance liquid

chromatography column mass selective detection chromatography with

with flame ionization and flame ionization ultraviolet detection

detection detection

Output of amount of nonmethane

analysis organic compounds in the

Concentration of the total

sample

Concentrations of Concentrations of Concentrations of

80 different organic 47 different volatile 16 different carbonyl

hydrocarbons organic compounds compounds b c d

Units of

measurement a ppbC ppbC ppbv ppbv

Detection limit 5 ppbC See Table 2-3 See Table 2-5 See Table 2-6 a

Refer to the sidebars in Section 2.3 for information on the significance of units of measurement and detection limits. a

The SNMOC analytical method actually reports only 78 different concentrations for each sample. The method cannot differentiate isobutene from b

1-butene or m-xylene from p-xylene. Therefore, a single concentration is reported for these pairs.

The VOC analytical method actually reports only 46 different concentrations for each sample. The method cannot differentiate m-xylene from p-xylene c

and therefore reports a single concentration for this pair.

The carbonyl analytical method actually reports only 13 different concentrations for each sample. The method cannot differentiate butyraldehyde from d

isobutyraldehyde and therefore reports a single concentration for this pair. The method also cannot distinguish the three tolualdehyde isomers and

therefore reports a single concentration for this trio.
2-15

Table 2-3

SNMOC Detection Limits

Compound Compound Detection Limit Detection Limit

(ppbC) (ppbC)

Acetylene 0.33 3-Methyl-1-Butene 0.16

Benzene 0.23 Methylcyclohexane 0.51

1,3-Butadiene 0.16 Methylcyclopentane 0.23

n-Butane 0.16 2-Methylheptane 0.36

cis-2-Butene 0.16 3-Methylheptane 0.36

trans-2-Butene 0.16 2-Methylhexane 0.51

Cyclohexane 0.23 3-Methylhexane 0.51

Cyclopentane 0.16 2-Methylpentane 0.23

Cyclopentene 0.16 3-Methylpentane 0.23

n-Decane 0.28 2-Methyl-1-Pentene 0.23

1-Decene 0.28 4-Methyl-1-Pentene 0.23

m-Diethylbenzene 0.28 n-Nonane 0.28

p-Diethylbenzene 0.28 1-Nonene 0.28

2,2-Dimethylbutane 0.23 n-Octane 0.36

2,3-Dimethylbutane 0.23 1-Octene 0.36

2,3-Dimethylpentane 0.51 n-Pentane 0.16

2,4-Dimethylpentane 0.51 1-Pentene 0.16

n-Dodecane 0.28 cis-2-Pentene 0.16

1-Dodecene 0.28 trans-2-Pentene 0.16

Ethane 0.33 "-Pinene 0.28

2-Ethyl-1-Butene 0.23 $-Pinene 0.28

Ethylbenzene 0.28 Propane 0.33

Ethylene 0.33 n-Propylbenzene 0.28

m-Ethyltoluene 0.28 Propylene 0.33

o-Ethyltoluene 0.28 Propyne 0.33

p-Ethyltoluene 0.28 Styrene 0.28

n-Heptane 0.51 Toluene 0.51

1-Heptene 0.51 n-Tridecane 0.28

n-Hexane 0.23 1-Tridecene 0.28

1-Hexene 0.23 1,2,3-Trimethylbenzene 0.28

cis-2-Hexene 0.23 1,2,4-Trimethylbenzene 0.28

trans-2-Hexene 0.23 1,3,5-Trimethylbenzene 0.28

Isobutane 0.16 2,2,3-Trimethylpentane 0.36

Isobutene/1-Butene 0.16 2,2,4-Trimethylpentane 0.36

Isopentane 0.16 2,3,4-Trimethylpentane 0.36

Isoprene 0.16 n-Undecane 0.28

Isopropylbenzene 0.28 1-Undecene 0.28

2-Methyl-1-Butene 0.16 m,p-Xylene 0.28

2-Methyl-2-Butene 0.16 o-Xylene 0.28

Reference: FR, 1984.
Note: The number of observations for analytical precision indicates the number of replicates in which the

compound was detected in both analyses; the number of observations for sampling and analytical

precision indicates the number of duplicates in which the compound was detected in the four analyses of

the duplicate samples. By definition, both types of precision cannot be evaluated for compounds with

zero observations, hence compounds with no observations show an RPD of “NA.”

2-16

Table 2-4

Precision Estimates for SNMOC Measurements

Compound

Analytical Precision Sampling and Analytical Precision

Number of RPD Number of RPD

Observations (%) Observations (%)

Acetylene 77 9% 39 5%

Benzene 77 9% 39 6%

1,3-Butadiene 77 13% 39 9%

n-Butane 77 7% 39 5%

cis-2-Butene 77 8% 39 6%

trans-2-Butene 77 11% 39 9%

Cyclohexane 77 8% 39 22%

Cyclopentane 77 9% 39 7%

Cyclopentene 77 15% 39 13%

n-Decane 77 12% 39 13%

1-Decene 0 NA 0 NA

m-Diethylbenzene 77 20% 39 13%

p-Diethylbenzene 77 23% 39 14%

2,2-Dimethylbutane 77 10% 39 7%

2,3-Dimethylbutane 77 9% 39 6%

2,3-Dimethylpentane 77 11% 39 8%

2,4-Dimethylpentane 77 10% 39 6%

n-Dodecane 72 21% 36 42%

1-Dodecene 59 60% 28 49%

Ethane 76 9% 38 4%

2-Ethyl-1-Butene 77 9% 39 7%

Ethylbenzene 0 NA 0 NA

Ethylene 77 14% 39 7%

m-Ethyltoluene 77 10% 39 7%

o-Ethyltoluene 77 14% 39 10%

p-Ethyltoluene 77 13% 39 7%

n-Heptane 77 9% 39 5%

1-Heptene 4 44% 2 64%

n-Hexane 77 8% 39 6%

1-Hexene 77 13% 39 13%
Table 2-4 (Continued)

Precision Estimates for SNMOC Measurements

Compound

Analytical Precision Sampling and Analytical Precision

Number of RPD Number of RPD

Observations (%) Observations (%)

Note: The number of observations for analytical precision indicates the number of replicates in which the

compound was detected in both analyses; the number of observations for sampling and analytical

precision indicates the number of duplicates in which the compound was detected in the four analyses of

the duplicate samples. By definition, both types of precision cannot be evaluated for compounds with

zero observations, hence compounds with no observations show an RPD of “NA.”

2-17

cis-2-Hexene 71 17% 36 15%

trans-2-Hexene 75 18% 38 14%

Isobutane 77 6% 39 4%

Isobutene/1-Butene 77 7% 39 5%

Isopentane 75 6% 38 8%

Isoprene 77 10% 39 8%

Isopropylbenzene 77 14% 39 8%

2-Methyl-1-Butene 77 11% 39 8%

2-Methyl-2-Butene 77 12% 39 11%

3-Methyl-1-Butene 71 24% 36 23%

Methylcyclohexane 77 10% 39 5%

Methylcyclopentane 77 10% 39 6%

2-Methylheptane 77 10% 39 6%

3-Methylheptane 77 12% 39 7%

2-Methylhexane 77 11% 39 8%

3-Methylhexane 77 8% 39 5%

2-Methylpentane 77 8% 39 6%

3-Methylpentane 77 8% 39 5%

2-Methyl-1-Pentene 77 14% 39 11%

4-Methyl-1-Pentene 53 22% 26 15%

n-Nonane 77 9% 39 7%

1-Nonene 75 26% 38 24%

n-Octane 77 9% 39 5%

1-Octene 73 26% 36 27%

n-Pentane 77 7% 39 4%

1-Pentene 77 12% 39 7%

cis-2-Pentene 77 9% 39 6%

trans-2-Pentene 77 9% 39 6%

"-Pinene 74 21% 37 23%

$-Pinene 77 19% 39 26%
Table 2-4 (Continued)

Precision Estimates for SNMOC Measurements

Compound

Analytical Precision Sampling and Analytical Precision

Number of RPD Number of RPD

Observations (%) Observations (%)

2-18

Propane 77 7% 39 3%

n-Propylbenzene 77 12% 39 7%

Propylene 77 7% 39 4%

Propyne 70 27% 34 21%

Styrene 77 14% 39 21%

Toluene 77 8% 39 5%

n-Tridecane 75 40% 37 37%

1-Tridecene 16 48% 5 27%

1,2,3-Trimethylbenzene 77 19% 39 13%

1,2,4-Trimethylbenzene 77 10% 39 8%

1,3,5-Trimethylbenzene 77 13% 39 8%

2,2,3-Trimethylpentane 77 12% 39 8%

2,2,4-Trimethylpentane 77 9% 39 5%

2,3,4-Trimethylpentane 77 9% 39 5%

n-Undecane 77 12% 39 23%

1-Undecene 60 31% 27 37%

m,p-Xylene 77 9% 39 7%

o-Xylene 77 9% 39 7%

Note: The number of observations for analytical precision indicates the number of replicates in which

the compound was detected in both analyses; the number of observations for sampling and

analytical precision indicates the number of duplicates in which the compound was detected in

the four analyses of the duplicate samples. By definition, both types of precision cannot be

evaluated for compounds with zero observations, hence compounds with no observations show

an RPD of “NA.”
2-19

Table 2-5

VOC Detection Limits

Compound Compound Detection Limit Detection Limit

(ppbv) (ppbv)

Acetonitrile 0.21 cis-1,3-Dichloropropene 0.03

Acetylene 0.07 trans-1,3-Dichloropropene 0.03

Acrylonitrile 0.06 Ethyl Acrylate 0.04

Benzene 0.06 Ethylbenzene 0.10

Bromochloromethane 0.04 Ethyl tert-Butyl Ether 0.05

Bromodichloromethane 0.05 Methylene Chloride 0.10

Bromoform 0.12 Methyl Ethyl Ketone 0.03

Bromomethane 0.04 Methyl Isobutyl Ketone 0.07

1,3-Butadiene 0.05 Methyl Methacrylate 0.06

Carbon Tetrachloride 0.09 Methyl tert-Butyl Ether 0.03

Chlorobenzene 0.04 n-Octane 0.09

Chloroethane 0.06 Propylene 0.03

Chloroform 0.04 Styrene 0.11

Chloromethane 0.06 tert-Amyl Methyl Ether 0.06

Chloroprene 0.03 1,1,2,2-Tetrachloroethane 0.05

Dibromochloromethane 0.04 Tetrachloroethylene 0.10

m-Dichlorobenzene 0.09 Toluene 0.10

o-Dichlorobenzene 0.09 1,1,1-Trichloroethane 0.06

p-Dichlorobenzene 0.10 1,1,2-Trichloroethane 0.03

1,1-Dichloroethane 0.03 Trichloroethylene 0.06

1,2-Dichloroethane 0.08 Vinyl Chloride 0.07

trans-1,2-Dichloroethylene 0.05 m,p-Xylene 0.08

1,2-Dichloropropane 0.09 o-Xylene 0.03

Reference: FR, 1984.
2-20

Table 2-6

Carbonyl Detection Limits

Compound Detection Limit (ppbv)

Acetaldehyde 0.009

Acetone 0.002

Acrolein 0.008

Benzaldehyde 0.008

Butyr/Isobutyraldehyde 0.009

Crotonaldehyde 0.009

2,5-Dimethylbenzaldehyde 0.007

Formaldehyde 0.004

Hexanaldehyde 0.011

Isovaleraldehyde 0.009

Propionaldehyde 0.008

Tolualdehydes 0.023

Valeraldehyde 0.011

Note: The carbonyl detection limit varies with the volume of ambient air drawn through the sampling

apparatus. The detection limits in this table are based on a sample volume of 1,000 liters of ambient

air.

Reference: FR, 1984.
2-21

Table 2-7

Precision Estimates for Carbonyl Measurements

Compound

Analytical Precision Sampling and Analytical Precision

Number of RPD Number of RPD

Observations (%) Observations (%)

Acetaldehyde 7 4% 3 21%

Acetone 7 15% 3 23%

Acrolein 7 18% 3 31%

Benzaldehyde 7 12% 3 10%

Butyr/Isobutyraldehyde 7 19% 3 51%

Crotonaldehyde 0 NA 0 NA

2,5-Dimethylbenzaldehyde 5 19% 2 42%

Formaldehyde 7 5% 3 24%

Hexanaldehyde 4 19% 2 40%

Isovaleraldehyde 5 16% 2 21%

Propionaldehyde 7 19% 3 23%

Tolualdehydes 0 NA 0 NA

Valeraldehyde 2 12% 1 11%

Notes: The number of observations for analytical precision indicates the number of replicate analyses in which

the compound was detected; the number of observations for sampling and analytical precision indicates

the number of duplicate samples in which the compound was detected. By definition, analytical

precision and sampling and analytical precision cannot be evaluated for compounds with zero

observations; these compounds have an RPD of “NA.”
2-22

Table 2-8

Sampling Schedules Implemented During the 1998 NMOC/SNMOC Program

Monitoring Monitoring

Option Location Sampling Schedules

NMOC Long Island, NY Both sites sampled NMOC every weekday of the monitoring

Newark, NJ program, except holidays.

SNMOC

Dallas (1), TX

Dallas (2), TX

Fort Worth, TX

Juarez, Mexico

These sites sampled SNMOC every weekday of the

monitoring program, except holidays. All samples were

analyzed for both NMOC and the 80 target SNMOC.

Newark, NJ monitoring program. All samples were analyzed for both

This site sampled SNMOC on 10 days throughout the

NMOC and the 80 target SNMOC.

Carbonyl Fort Worth, TX

Dallas (1), TX

Dallas (2), TX

Juarez, Mexico

Newark, NJ

These sites sampled carbonyls periodically over the course

of the program, according to site-specific schedules. The

number of sampling events for each station ranged from 4 to

11.

VOC Newark, NJ This site sampled VOC on 10 days throughout the

monitoring program.
3-1

3.0 Data Analysis Methodology

This section describes the methodology used in this report to summarize and interpret the

1998 NMOC/SNMOC ambient air monitoring data. This methodology includes various

graphical, numerical, and statistical techniques that help identify the most meaningful trends in the

large volume of NMOC/SNMOC monitoring data. So that readers can easily compare the 1998

monitoring results to monitoring results from previous years, some elements of the data analysis

methodology are identical to those used in earlier NMOC/SNMOC reports (e.g., data summary

parameters). To provide a different perspective on the monitoring data, however, some elements

of the methodology are included that have not been used previously (e.g., detailed analyses of

annual variations). In general, four categories of data analysis are used in this report:

• Data summary parameters use basic descriptive statistical parameters to provide a

succinct overview of the monitoring data (see Section 3.1)

• Comparison to selected meteorological parameters in order to identify and characterize

relationships between levels of air pollution and certain meteorological conditions (see

Section 3.2)

• Analyses of annual variations comment on long-term trends in air quality (see

Section 3.3)

• Other analyses are used, as necessary, to interpret notable data trends that do not fall

under the previous three categories (see Section 3.4)

The remainder of this section describes these four types of data analyses. Sections 5

through 8 then use these analyses to interpret the site-specific air quality trends identified during

the 1998 NMOC/SNMOC Monitoring Program.

3.1 Data Summary Parameters

Since previous NMOC/SNMOC reports define the four parameters that have been used to

summarize monitoring data generated in this program, as well as the limitations of using these

parameters, the following discussion only briefly reviews how these parameters efficiently

characterize the results of extensive ambient air monitoring studies. More information on these
3-2

parameters, and their limitations, can be found in earlier NMOC/SNMOC reports (ERG 1996;

1997b; 1999).

In general, the four data summary parameters—prevalence, concentration range, central

tendency, and variability—are used to provide a complete but succinct overview of the nearly

30,000 ambient air concentrations that were measured during the 1998 NMOC/SNMOC

Monitoring Program. Sections 5 through 8 present these summary parameters in a series of

tables, one for each category of compounds measured at each monitoring station. Brief

definitions and descriptions of the four data summary parameters follow:

• Prevalence of air monitoring data refers to the frequency with which compounds, or

groups of compounds, are detected; it is typically expressed as a percentage (e.g., a

compound detected in 15 of 20 samples has a prevalence of 75 percent). Compounds that

are never detected have a prevalence of 0 percent, and those that are always detected

have a prevalence of 100 percent. Because sampling and analytical methods cannot

reliably quantify concentrations of compounds at levels near their detection limits,

summary statistics for compounds with low prevalence values should be interpreted with

caution. It should be noted that compounds with a prevalence of zero might still be

present in ambient air, but at levels below the sensitivity of the corresponding sampling

and analytical methods.

• The concentration range of ambient air monitoring data refers to the span of measured

concentrations, from lowest to highest. Because the NMOC/SNMOC program only

measures 3-hour average concentrations during the summer months, the lowest and

highest concentrations presented in this report should not be viewed as the minimum and

maximum concentrations observed during an entire year. Since ambient levels of total

NMOC, SNMOC, VOC, and carbonyls might rise to higher levels during times of day or

times of year not considered in this program, the concentration range data presented in

this report might not be comparable to those from monitoring programs with different

sampling durations and schedules.

• The central tendency of air monitoring data gives a sense of the long-term average

ambient air concentrations. This report uses medians, arithmetic means, and geometric

means to characterize the central tendencies of concentration distributions. Previous

NMOC/SNMOC reports have explained the differences between these measures of

central tendency. Readers should note that the central tendencies in this report are based

only on ambient air concentrations sampled during the morning hours of the summer of

1998. Because ambient air concentrations of certain compounds might be consistently
3-3

higher or lower during the colder winter months, the central tendencies presented in this

report might not be comparable to those calculated from annual air monitoring efforts. 

As noted above, the central tendency data for compounds with low prevalence should be

interpreted with caution, due to the bias introduced by many nondetect observations.

• Variability in ambient air monitoring data indicates the extent to which concentrations of

certain compounds fluctuate with respect to the central tendency. This report

characterizes data variability using standard deviations and coefficients of variation. The

standard deviation is a commonly used statistical parameter that provides an absolute

indicator of variability, and the coefficient of variation (calculated by dividing the

standard deviation by the arithmetic mean) offers a relative indicator of variability. The

coefficient of variation is better suited for comparing variability across data distributions

for different sites and compounds.

All data summary parameters presented in this report were calculated from a database of

processed 1998 NMOC/SNMOC ambient air monitoring data. This database was generated by

manipulating the raw monitoring data in two steps. First, all nondetect observations were

assigned a concentration equal to one-half the corresponding detection limit; second, the results

of all duplicate sampling events and replicate laboratory analyses were averaged so that only one

concentration was considered for each compound for each sampling date. These data processing

steps are identical to those used to process the 1995, 1996, and 1997 NMOC/SNMOC

monitoring data.

3.2 Comparison to Selected Meteorological Parameters

The 1997 NMOC/SNMOC report examined how local meteorological conditions related

to ambient air concentrations of total NMOC. Though several potential data trends were

identified, the trends were not confirmed by tests for statistical significance, nor were they

validated against other data sets. To build on the analyses presented in the 1997 report, this

report also examines relationships between air quality and local meteorological conditions, with

an emphasis placed on determining whether trends are statistically significant and whether these

trends are consistent with those documented in the 1997 report.
 Previous NMOC/SNMOC reports, and most basic texts on statistics, define Pearson correlation coefficients, and 1

how they characterize pairwise data correlations. Information on the two-sample t-test has not been presented in previous

NMOC/SNMOC reports, but is well documented in many statistics texts (e.g., Harnett 1982).

3-4

Though many meteorological parameters are suspected of influencing air quality, Sections

5 through 8 examine how a subset of these parameters—wind speed, wind direction, temperature,

relative humidity, and precipitation—seems to affect the total NMOC concentrations. Several

different techniques are used to characterize correlations between the meteorological parameters

and the air concentrations: Pearson correlation coefficients are calculated to characterize the

magnitude and direction of data correlations, graphs are presented to illustrate the influences of

meteorological parameters on the ambient air monitoring data, and results of two-sample t-tests

are documented to identify which trends are statistically significant. Finally, the trends are 1

compared to those listed in the 1997 NMOC/SNMOC report. As with the previous report,

meteorological data for each monitoring station were obtained from the nearest meteorological

station that submits daily summary reports to the National Climatic Data Center (NCDC). Data

from the following meteorological stations were considered in this report:

C Meteorological data from the Dallas–Fort Worth International Airport was considered to

be representative of conditions at the CAMS5, CAMS13, and DLTX monitoring stations.

C Meteorological data from the El Paso International Airport was considered to be

representative of conditions at the JUMX monitoring station.

C Meteorological data from the John F. Kennedy International Airport was considered to be

representative of conditions at the LINY monitoring station.

C Meteorological data from the Newark International Airport was considered to be

representative of conditions at the NWNJ monitoring station.

It is important to note that the sources for meteorological data considered in this report

are identical to those considered in the 1997 NMOC/SNMOC report.
3-5

Though extensive, the analyses of meteorological parameters in this report should not be

viewed as comprehensive. For example, sophisticated computer simulations, such as detailed

atmospheric dispersion modeling analyses, might provide greater insight into how local

meteorological conditions affect air quality. Conducting such simulations, however, is beyond

the scope of the current work. As another example, this report does not address all

meteorological parameters that are known to affect ozone formation and transport. Detailed

analyses of parameters such as mixing heights, solar radiation, and upper atmosphere wind

patterns are needed for a more complete understanding of the impact of meteorological

conditions on levels of air pollution. As a result, agencies that sponsor NMOC/SNMOC

monitoring stations are encouraged to conduct further research on the influence of local

meteorological conditions on both the ambient air monitoring data and ozone formation

processes.

3.3 Analyses of Annual Variations

When assessing trends in air pollution over the long term, data analysts typically try to

answer one basic question: Are levels of air pollution generally increasing or decreasing? To

help agencies answer this question, Sections 5 through 8 assess how annual average

concentrations of total NMOC and selected SNMOC have changed from one NMOC/SNMOC

Monitoring Program to the next. Annual variations in ambient air concentrations of VOC and

carbonyls are not considered, due to the limited number of samples available for these compound

groups.

Analyses of annual variations in SNMOC concentrations are based only on monitoring

data collected during the current procurement, which spanned the 1995 to 1998 programs. 

Though some stations might have collected SNMOC samples as part of other programs prior to

1995, data from these earlier programs are not considered in this report because important

features of the current monitoring program (e.g., detection limits, laboratory analytical

equipment, field sampling equipment) might differ from similar features of the previous

monitoring programs. Since the Long Island and Newark stations have participated in the
3-6

NMOC/SNMOC Monitoring Program for roughly 10 years, annual variations in total NMOC

concentrations are presented for the entire history of these stations.

To characterize annual variations in air quality, Sections 5 through 8 present figures that

illustrate how average concentrations of total NMOC and selected SNMOC have changed from

one summer to the next. The graphs depict 95-percent confidence intervals of the average

concentrations as an indicator of the uncertainty associated with each value. For greater insight

into the annual variations, statistical tests (two-sample t-tests) were performed to distinguish

statistically significant annual variations from anomalous ones. Combined, these analyses of

annual variations not only characterize the extent to which levels of air pollution have changed

from year to year, but they also indicate whether these changes are statistically significant.

Though the annual variations presented in Sections 5 through 8 might suggest notable

trends in air quality, these trends should be interpreted in proper context. For instance, many

different factors could cause statistically significant changes in air quality from one year to the

next: Environmental regulations might have caused decreased emissions from certain industrial

sources, traffic patterns and the composition of motor vehicle fuels might change in a given year,

and certain meteorological conditions that affect photochemical reactivity and atmospheric

transport might fluctuate considerably. One factor considered in this report is the impact of

EPA’s recent requirement that, starting in 1995, all motor vehicles in certain parts of the country

(including the Dallas–Fort Worth and New York City metropolitan areas) use oxygenated fuels

or “reformulated fuels,” which have a notably different chemical composition from “conventional

fuels.” Though this report attempts to explain likely causes of annual variations in air quality,

participating agencies are encouraged to research the apparent causes of such variations in

greater detail.
3-7

3.4 Other Analyses

To highlight other notable site-specific air quality trends, Sections 5 through 8 present

additional data analyses, as appropriate, that do not fall under the data analyses categories

discussed above. The following additional analyses are considered in this report:

C Reactivity of air masses. The SNMOC monitoring data provide a wealth of information

on the composition of hydrocarbons found in ambient air. With studies showing that some

hydrocarbons are much more reactive in air than others (Carter 1994), the SNMOC data

can be used to characterize the relative ozone formation potential of air masses. Using

compound-specific “maximum incremental reactivities” reported in the literature (see

Table 3-1), the analyses in Sections 5 and 6 present reactivity-weighted concentrations. 

These analyses indicate an important finding that is not readily apparent from the

SNMOC monitoring data: The compounds with the highest concentrations (on a ppbC

basis) are often different from the compounds that are most reactive in air. The

reactivity-weighted concentrations, therefore, provide additional insight into the ozone

formation potential of the complex mixture of hydrocarbons in ambient air. (Note: This

analysis of air mass reactivity is also described and summarized in the 1996

NMOC/SNMOC report; Sections 7 and 8 do not present analyses of chemical reactivity

because the Long Island and Newark monitoring stations did not collect SNMOC samples

daily.)

C Fate of airborne aromatic hydrocarbons. The presence of three ambient air monitoring

stations in the Dallas–Fort Worth metropolitan area allowed for detailed analyses of how

the composition of an air mass varies within an air-shed. As Section 5 describes, the

breakdown of SNMOC concentrations at the CAMS13 station was found to be notably

different from that at the CAMS5 and DLTX stations. To explain this spatial variation,

Section 5 uses results of studies reported in the scientific literature, particularly those on

the fate of aromatic hydrocarbons in ambient air, to postulate mechanisms that might

account for the unique air quality trend observed among the Dallas–Fort Worth stations.

C Concentrations of methyl tert-butyl ether. Ever since motor vehicles in many parts of

the country started using reformulated fuels, which contain as much as 15 percent methyl

tert-butyl ether (MTBE), many environmental agencies have assessed the impact of this

fuel usage on the environment. One aspect of the many environmental impacts of use of

reformulated fuels is the increased ambient air concentrations of MTBE in regions where

such fuel use is required. Analyses in Section 8 identify several subtle, yet meaningful,

trends in the air monitoring data for MTBE at the Newark monitoring station—the only

monitoring station in the 1998 NMOC/SNMOC Monitoring Program that analyzed air

samples for this compound.
Notes: MIRs were copied from Sonoma 1996.

Compounds with an MIR of “NA” do not have a maximum incremental reactivity listed in the reference.

3-8

Table 3-1

Maximum Incremental Reactivities (MIRs) for SNMOC

Compound Compound (mole O /mole MIR

(mole O /mole compound) 3

MIR

3

compound)

Acetylene 0.14 Isobutane 0.37

Benzene 0.11 Isobutene/1-Butene 2.60

1,3-Butadiene NA Isopentane 0.41

n-Butane 0.31 Isoprene 2.58

cis-2-Butene 2.92 Isopropylbenzene 0.60

trans-2-Butene 2.92 2-Methyl-1-Butene NA

Cyclohexane 0.37 2-Methyl-2-Butene 1.87

Cyclopentane 0.70 3-Methyl-1-Butene NA

Cyclopentene 2.19 Methylcyclohexane 0.53

n-Decane 0.17 Methylcyclopentane 0.82

1-Decene NA 2-Methylheptane 0.29

m-Diethylbenzene NA 3-Methylheptane 0.29

p-Diethylbenzene NA 2-Methylhexane 0.32

2,2-Dimethylbutane 0.25 3-Methylhexane 0.42

2,3-Dimethylbutane 0.32 2-Methylpentane 0.45

2,3-Dimethylpentane 0.39 3-Methylpentane NA

2,4-Dimethylpentane 0.45 2-Methyl-1-Pentene NA

n-Dodecane NA 4-Methyl-1-Pentene 1.29

1-Dodecene NA n-Nonane NA

Ethane 0.08 1-Nonene NA

2-Ethyl-1-Butene NA n-Octane 0.18

Ethylbenzene 0.75 1-Octene NA

Ethylene 2.16 n-Pentane 0.31

m-Ethyltoluene NA 1-Pentene 1.81

o-Ethyltoluene NA cis-2-Pentene 2.57

p-Ethyltoluene NA trans-2-Pentene 2.57

n-Heptane 0.24 "-Pinene NA

1-Heptene NA $-Pinene NA

n-Hexane 0.29 Propane 0.15

1-Hexene NA n-Propylbenzene 0.58

cis-2-Hexene 1.96 Propylene 2.75

trans-2-Hexene 1.96 Propyne NA
Table 3-1 (Continued)

Maximum Incremental Reactivities (MIRs) for SNMOC

Compound Compound (mole O /mole MIR

(mole O /mole compound) 3

MIR

3

compound)

3-9

Styrene NA 2,2,3-Trimethylpentane NA

Toluene 0.74 2,2,4-Trimethylpentane 0.28

n-Tridecane NA 2,3,4-Trimethylpentane 0.48

1-Tridecene NA n-Undecane 0.12

1,2,3-Trimethylbenzene 2.60 1-Undecene NA

1,2,4-Trimethylbenzene 2.45 m,p-Xylene 2.05

1,3,5-Trimethylbenzene 2.81 o-Xylene NA

Notes: MIRs were copied from Sonoma 1996.

Compounds with an MIR of “NA” do not have a maximum incremental reactivity listed in the reference.
.
4-1

4.0 General Results of the 1998 NMOC/SNMOC Program

This section briefly summarizes how the total NMOC concentrations, on average, varied

from station to station between the 1995 and 1998 NMOC/SNMOC Monitoring Programs. This

brief overview of spatial variations gives a sense of the relative levels of air pollution at the six

monitoring stations—a topic not considered in the site-specific analyses presented in Sections 5

through 8. The spatial variations preview several key findings that are discussed in much greater

detail later in the report. Overall, the data presented in this section allow agencies that sponsor

monitoring stations to compare air quality within their jurisdictions to air quality in other parts of

the country. As discussed below, however, it is very important that these comparisons be made

in proper context.

4.1 Total NMOC Concentrations During the 1998 Program

Figure 4-1 illustrates how total NMOC concentrations, on average, varied among the six

monitoring stations that participated in the 1998 program. The following notable spatial

variations are readily apparent from inspection of the figure:

C Relatively higher concentrations of NMOC at JUMX. During the 1998 program, the

average concentration of total NMOC at JUMX (2.06 ppmC) was more than four times

higher than the average concentration at the other monitoring stations—a concentration

difference that was found to be statistically significant. As Section 6 describes, the

average concentration at JUMX is largely influenced by the detection of several “outlier”

concentrations. Nonetheless, even when these outliers are excluded from the computation

of average concentrations, the average total NMOC levels at JUMX are still higher than

those at the other five stations, though only marginally so. Though Figure 4-1 clearly

illustrates a statistically significant spatial variation, readers should remember that this

monitoring program measures levels of air pollution at only discrete locations within

large metropolitan areas. As a result, even though the total NMOC concentrations at the

JUMX monitoring station were considerably higher than those at the other monitoring

stations, it does not necessarily follow that the air throughout the El Paso–Juarez area is

more polluted than the air throughout the Dallas–Fort Worth and Newark–New York City

metropolitan areas. Ambient air monitoring at many other locations in these metropolitan

areas and for many other pollutants must be conducted and reviewed to support such a

conclusion.
4-2

C Moderate levels of total NMOC at CAMS13 and NWNJ. On average, concentrations of

total NMOC at CAMS13 and NWNJ during the 1998 program were roughly twice as high

as the levels observed at CAMS5, DLTX, and LINY. The difference in concentration

between CAMS13 and the three other stations (CAMS5, DLTX, and LINY) was found to

be statistically significant, but the difference in concentration between NWNJ and the

average concentrations at two of the other three stations was not. As Section 8 describes,

total NMOC concentrations at Newark were highly variable during the 1998 program. 

This variability likely explains why statistically significant differences were not

observed between the total NMOC concentration at Newark and those at the other

stations. As emphasized above, readers should interpret the findings for CAMS13 and

NWNJ with caution: The spatial variations shown in Figure 4-1 compare levels of air

pollution observed in only three metropolitan areas, and only for discrete locations

within these metropolitan areas.

C Relatively low levels of total NMOC at CAMS5, DLTX, and LINY. Average levels of

total NMOC at the three remaining monitoring stations—CAMS5, DLTX, and

LINY—were comparable in magnitude and considerably lower than the average levels at

the three stations discussed previously. More specifically, the average concentrations of

total NMOC at CAMS5, DLTX, and LINY were no more than 15 percent different from

each other; none of these differences were found to be statistically significant.

The analyses in Sections 5 through 8 thoroughly examine notable site-specific data trends

that are not readily apparent from examining spatial variations. For additional perspective on the

spatial variations, however, the following discussion compares the spatial variations observed

during the 1998 NMOC/SNMOC Monitoring Program to those observed in the three previous

programs.

4.2 Total NMOC Concentrations During the 1995–1997 Programs

Figure 4-2 indicates how the spatial variations in total NMOC concentrations changed

from the 1995 to the 1997 NMOC/SNMOC Monitoring Programs. The figure is included to

comment on how spatial variations observed during the current program (see Figure 4-1)

compare to those observed previously. An overview of the past spatial variations follows:

C Trends that have remained unchanged over the years. The graphs in Figure 4-2

highlight certain data trends that, to a certain extent, did not change over the previous

three NMOC/SNMOC Monitoring Programs. For instance, in the 1995, 1996, and 1997
4-3

programs, total NMOC concentrations at JUMX and NWNJ were relatively high,

particularly when compared to levels observed at DLTX and LINY. Further, total

NMOC concentrations at DLTX and LINY, on average, have been comparable during the

summers of 1995, 1996, and 1997. Both of these trends are consistent with those

observed during the 1998 program, which Section 4.1 described.

C Trends that have notably changed from one year to the next. Though the relative levels

of total NMOC at DLTX, JUMX, LINY, and NWNJ have been somewhat consistent over

the past 4 years, the relative levels observed at CAMS5 and CAMS13 have exhibited

unique trends. More specifically, the average ambient air concentration of total NMOC

at CAMS5 ranked among the highest during the 1996 program, but average levels at this

station have ranked among the lowest in the years since. On the other hand, the relative

amounts of total NMOC at CAMS13 have exhibited the opposite trend, changing from

ranking among the lowest to ranking among the highest. Section 5.1.3 examines why

average levels of total NMOC observed at the three monitoring stations in the

Dallas–Fort Worth metropolitan area have exhibited notably different annual variations.

Overall, this historical perspective on spatial variations indicates that no universal trend

can explain how levels of total NMOC have changed at the six monitoring stations since the 1995

program. This observation is not surprising, however, because local influences on air quality

(e.g., industrial emissions sources, motor vehicle traffic, fluctuating weather conditions)

ultimately determine how levels of air pollution change at a given location from one year to the

next. Sections 5 through 8 examine these local influences by presenting detailed site-specific

analyses of annual variations.
0.25

0.51

0.27

2.06

0.23

0.41

0.00

0.50

1.00

1.50

2.00

2.50

CAMS5 CAMS13 DLTX JUMX LINY NWNJ

Monitoring Station

Average Total NMOC Concentration (ppmC)

4-4

Figure 4-1

Average Concentrations of Total NMOC for the 1998 NMOC/SNMOC Monitoring Program

Note: As Section 6 describes, the average concentration of total NMOC at JUMX is biased high, largely due to two outlier concentrations.

Refer to Section 4.1 for interpretations of this figure, including several important caveats regarding the displayed data trends.
1995 NMOC/SNMOC Monitoring Program

0.32 0.31

0.43

0.28

0.38

0.00

0.10

0.20

0.30

0.40

0.50

CAM S5 CAM S13 DLTX JUM X LINY NWNJ

Monitoring Station

Average Total NMOC 

Concentration (ppmC)

1996 NMOC/SNMOC Monitoring Program

0.44

0.34 0.34

0.50

0.36

0.45

0.00

0.10

0.20

0.30

0.40

0.50

0.60

CAM S5 CAM S13 DLTX JUM X LINY NWNJ

Monitoring Sta tion

Average Total NMOC 

Concentration (ppmC)

1997 NMOC/SNMOC Monitoring Program

0.15

0.64

0.23

0.56

0.26

0.43

0.00

0.20

0.40

0.60

0.80

CAM S5 CAM S13 DLTX JUM X LINY NWNJ

Monitoring Sta tion

Average Total NMOC 

Concentration (ppmC)

4-5

Figure 4-2

Average Concentrations of Total NMOC Observed During

the 1995–1997 NMOC/SNMOC Monitoring Programs

Notes: The CAMS5 station did not participate in the 1995 NMOC/SNMOC Monitoring Program.

The three graphs in this figure are shown on different scales.
.
5-1

5.0 Monitoring Results for Dallas and Fort Worth, Texas (CAMS5, CAMS13, DLTX)

This section summarizes and interprets the total NMOC, SNMOC, and carbonyl

monitoring data collected at two locations in Dallas, Texas (CAMS5 and DLTX), and at one

location in Fort Worth, Texas (CAMS13), during the 1998 NMOC/SNMOC Monitoring Program. 

The ambient air monitoring data from these three locations offer an extensive profile of the air

quality in the Dallas–Fort Worth metropolitan area.

Figures 5-1, 5-2, and 5-3 show the locations of the CAMS5, CAMS13, and DLTX

monitoring stations, respectively. The different numbers and types of emissions sources near

these locations account, in part, for the different levels of air pollution measured at these stations. 

The CAMS5 monitoring station is located at a school in a suburban area, approximately 8 miles

north of downtown Dallas. The Dallas North Tollway and Interstate 635 both pass within 1 mile

of the CAMS5 station. The DLTX monitoring station, on the other hand, is located much closer

to downtown Dallas, just 3 miles northwest of the city center. The station is in an area of mixed

industrial and commercial uses, and several heavily traveled roadways, including Interstate 35-E

and State Highway 183, pass within 1 mile of the DLTX station. Located in the city of Fort

Worth, the CAMS13 station is roughly 25 miles west of the CAMS5 and DLTX stations. Land

use surrounding CAMS13 is primarily residential, though open fields, an airport, and several

busy surface streets are located in the station’s immediate proximity. At all three stations,

emissions from a great variety of sources likely influence the local air quality.

During the 1998 NMOC/SNMOC Monitoring Program, SNMOC samples were collected

at CAMS5 on 74 days, and valid sampling results were obtained on 68 of those days; SNMOC

samples were collected at CAMS13 on 70 days, and valid results were obtained on 69 of them;

and SNMOC samples were collected at DLTX on 63 days, and valid results were obtained on 62

of them. Overall, the completeness of the SNMOC sampling, defined as the percentage of

attempted sampling events that were valid, was 92 percent at CAMS5, 99 percent at CAMS13,

and 98 percent at DLTX. Between the three monitoring stations, 30 carbonyl sampling events

were scheduled during the 1998 program, and 29 of these events generated valid results. Thus,
5-2

the completeness of the carbonyl sampling (at all three stations combined) was 97 percent. The

high completeness figures for all three monitoring stations suggest that samples were collected

and handled efficiently at the CAMS5, CAMS13, and DLTX stations throughout the program.

The remainder of this section puts the large volume of ambient air monitoring data

collected in the Dallas–Fort Worth area into perspective. Section 5.1 summarizes the total

NMOC data collected at the three stations, compares these data to selected meteorological

conditions, and discusses annual variations in total NMOC levels. Section 5.2 then reviews the

SNMOC data, comments on the composition of SNMOC in ambient air, and assesses the

reactivity of the air masses at the three stations. Finally, Section 5.3 briefly discusses trends and

patterns among the limited carbonyl monitoring data collected during the 1998 program. For

quick reference, Section 5.4 provides an overview of the key air quality trends identified for the

Dallas–Fort Worth area during the 1998 NMOC/SNMOC Monitoring Program.

5.1 Total NMOC Monitoring Data

As Section 2.3.2 explained, the SNMOC sampling and analytical method measures both

total NMOC concentrations and concentrations of 80 individual hydrocarbons. The following

discussion focuses on the total NMOC measurements made by this method in the Dallas–Fort

Worth area. More specifically, the discussion provides a concise summary of the total NMOC

data (Section 5.1.1), characterizes associations between total NMOC levels and meteorological

conditions (Section 5.1.2), and describes how total NMOC concentrations have changed in

Dallas and Fort Worth from year to year (Section 5.1.3).

When reading these sections, readers should note that total NMOC concentrations include

concentrations of a wide range of organic compounds, including, but not limited to, alkanes,

olefins, aromatics, oxygenates, and halogenated hydrocarbons. Although total NMOC levels

characterize ambient air concentrations of various compounds that affect ozone formation

processes, total NMOC does not include many air pollutants common to urban environments,

such as inorganic acids and particulate matter. In other words, the total NMOC concentrations
5-3

presented below provide a measure of many different air pollutants typically found in ambient

air, but do not provide a measure of every air pollutant found in ambient air.

5.1.1 Data Summary

Using the four data summary parameters defined in Section 3.1, Table 5-1 provides a

thorough overview of the total NMOC concentrations measured at CAMS5, CAMS13, and DLTX

during the 1998 program. An overview of the data summary follows:

• Prevalence. Total NMOC was detected in every sample collected at CAMS5, CAMS13,

and DLTX, and every total NMOC concentration was at least an order of magnitude

greater than the estimated method detection limit of 0.005 ppmC (or 5 ppbC). Therefore,

the prevalence of total NMOC at these stations was 100 percent. The summary statistics

presented below are believed to be highly representative of total NMOC levels in the

Dallas–Fort Worth area, since none of the statistics are biased by nondetect observations.

• Concentration range. According to Table 5-1, the concentration ranges of total NMOC

at CAMS13 and DLTX were much broader than that at CAMS5. In fact, the highest total

NMOC concentration measured at CAMS5 (0.645 ppmC) is roughly half the highest

levels measured at CAMS13 (1.165 ppmC) and DLTX (1.267 ppmC). The reason for

this spatial variation in concentration ranges is not known. However, examining the

quartiles of the concentration distributions offers a different perspective on the spatial

variations. More specifically, the 25 , 50 , and 75 percentile concentrations at th th th

CAMS13 are all considerably higher than those at both CAMS5 and DLTX. This trend

suggests that the entire concentration distribution at CAMS13 is centered on higher total

NMOC levels than the distributions at the other two stations.

To illustrate this trend, Figure 5-4 presents histograms of the total NMOC concentrations

measured at the three stations in the Dallas–Fort Worth area. The figure clearly shows

that the concentration distribution at CAMS13 is indeed centered on higher total NMOC

levels than the other two distributions. Further, the figure indicates that concentrations of

total NMOC at CAMS5 and DLTX predominantly fell into very narrow ranges of

concentrations, with relatively few outliers. The distribution at CAMS13, on the other

hand, was far more dispersed. The central tendency and variability summary parameters,

discussed below, reflect these differences in the concentration distributions.

When reviewing the concentration ranges, readers should remember that this monitoring

program measures ambient air concentrations only during the summertime morning hours. 

Levels of total NMOC during other times of the day, and during other times of year, might

have risen to higher or lower levels than the summary statistics indicate.
5-4

• Central tendency. As Table 5-1 shows, the three different measures of central tendency

concentration of total NMOC at CAMS13 (i.e., the median, arithmetic mean, and

geometric mean) were all roughly twice as high as those for CAMS5 and DLTX; these

concentration differences were statistically significant. The marginal difference in total

NMOC levels at CAMS5 and DLTX, however, was not statistically significant. The

analyses of annual variations (Section 5.1.3) and SNMOC monitoring data (Section 5.2)

put the concentration differences in the Dallas–Fort Worth area into perspective.

At all three stations, concentrations of total NMOC during August and September were,

on average, higher than those in June and July. These monthly variations in central

tendency levels were most pronounced at CAMS13, where the average concentrations of

total NMOC during August and September were nearly 70 percent greater than those

during June and July, but this concentration difference was not statistically significant. 

Therefore, although concentrations of total NMOC during the morning hours changed from

one month to the next at selected locations in Dallas and Fort Worth, the trend is possibly

anomalous and should be confirmed by additional monitoring.

• Variability. The standard deviations of the total NMOC concentrations measured in the

Dallas–Fort Worth area reflect the shapes of the concentration distributions shown in

Figure 5-4: The variability was least for CAMS5 (the station with the narrowest spread

in its concentration distribution) and highest for CAMS13 (the station with the widest

spread in its concentration distribution). The greater variability at CAMS13 suggests that

the factors that contribute to total NMOC levels at this station change considerably from

day to day. The lower variability at CAMS5 and DLTX, however, suggests that the

factors that affect total NMOC levels most do not vary greatly from one morning to the

next. A possible explanation for this trend is that morning rush-hour traffic, which likely

does not change dramatically from one weekday to the next, has a strong impact on air

quality at CAMS5 and DLTX, and that other factors—possibly long-range transport of

emissions or emissions from a local source—have a strong impact on air quality at

CAMS13. These hypotheses are revisited throughout this section.

5.1.2 Comparison to Selected Meteorological Conditions

To identify noteworthy air quality trends for the Dallas–Fort Worth metropolitan area, the

following discussion characterizes associations between total NMOC concentrations at CAMS5,

CAMS13, and DLTX and selected meteorological conditions. More specifically, the discussion

considers 3-hour average observations of humidity, precipitation, temperature, wind direction,

and wind speed, all of which were measured between 6:00 a.m. and 9:00 a.m. at the Dallas–Fort

Worth International Airport. Since the CAMS5, DLTX, and CAMS13 monitoring stations are all
5-5

located within approximately 20 miles of this airport, the meteorological data are believed to be

reasonably representative of conditions at the three monitoring stations. In the following

analysis, data trends that are statistically significant are clearly distinguished from those that are

not.

To enable readers to compare data trends identified during the current program to those

from earlier programs, this section follows a framework almost identical to that presented in

Section 5.2.3.1 of the 1997 NMOC/SNMOC report.

A review of the comparisons of total NMOC levels in Dallas and Fort Worth to local

meteorological conditions follows:

• Humidity. As Figure 5-5 illustrates, no trend is readily apparent between total NMOC

concentrations at CAMS5, CAMS13, and DLTX and concurrent observations of relative

humidity at the Dallas–Fort Worth International Airport. Moreover, most of the

concentration differences depicted in the figure are not statistically significant. As further

support of the absence of data trends, the Pearson correlation coefficient between the

total NMOC concentrations and relative humidity was -0.09 at CAMS5, 0.03 at

CAMS13, and 0.00 at DLTX. These low correlation coefficients indicate that relative

humidity was essentially uncorrelated with the air quality measurements in the

Dallas–Fort Worth area during the 1998 program.

It is interesting to note that the data collected during the 1997 program suggested that total

NMOC levels at the three monitoring stations in Dallas and Fort Worth tended to

decrease with increasing humidity (ERG 1999). The contradictory findings from the

1997 and 1998 programs suggests that humidity might only be weakly associated, if not

completely unassociated, with total NMOC levels in the Dallas–Fort Worth area. The

inconsistent trends also underscore an inherent difficulty with assessing impacts of local

meteorological conditions on air quality: Since so many different factors influence levels

of air pollution, the effect of a single factor (e.g., humidity) might be masked in years

when other factors (e.g., temperature) have unusually high or low levels. Conducting

multivariate statistical analyses on the data set might help researchers understand how

different combinations of meteorological conditions affect ambient air quality. Such

analyses, however, are not included in the scope of this project.

• Precipitation. Measurable rain was recorded at the Dallas–Fort Worth International

Airport during only two mornings when valid SNMOC samples were collected at the
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CAMS5, CAMS13, and DLTX monitoring stations. As a result of the limited sample

size, no statistically significant trends were observed between total NMOC concentration

on rainy days and total NMOC concentrations on days with no measurable precipitation. 

Though the science of atmospheric dispersion generally predicts that levels of most kinds

of air pollution are lower on or after rainy days (USEPA 1995), this trend could not be

verified by the SNMOC monitoring data collected in the summer of 1998 in Dallas and

Fort Worth.

• Temperature. One of the most pronounced features of the meteorological conditions in

the Dallas–Fort Worth metropolitan area during the 1998 NMOC/SNMOC Monitoring

Program was the record heat. Temperatures during approximately two-thirds of the

sampling events were greater than 84 degrees, and temperatures exceeded 100 degrees at

the Dallas–Fort Worth International Airport on 29 consecutive days during the program. 

According to the Dallas Morning News (September 9, 1998), the summer of 1998 was

the second warmest summer on record for the cities of Dallas and Fort Worth. As a

result, the monitoring data for the 1998 program offer insight into the extent to which

elevated temperatures affect ambient air concentrations of total NMOC.

As one indication of how temperature relates to air quality, Figure 5-5 indicates how

total NMOC concentrations, on average, varied with temperature. Clearly, for the

categories of temperature ranges selected, the temperature during a sampling event

seemed to have little bearing on the magnitude of the total NMOC concentration. 

Corroborating this finding is the fact that Pearson correlation coefficients between total

NMOC levels at CAMS5, CAMS13, and DLTX and temperature were all less than 0.1. 

In other words, the total NMOC levels and temperature were essentially uncorrelated,

which is the same conclusion that was reached for these sampling locations in both the

1996 and 1997 reports.

As Section 5.1.3 notes, ambient air concentrations of total NMOC during the record heat

of the 1998 program were not unusually higher or lower than those observed during

previous years—an observation that further supports the finding that temperature is

weakly associated with, if not completely unassociated with, ambient air concentrations

of total NMOC during the morning hours in Dallas and Fort Worth.

• Wind Speed. As Figure 5-5 illustrates, ambient air concentrations of total NMOC at

CAMS5, CAMS13, and DLTX on windy days tended to be lower than those on days with

calm or light winds. Moreover, the concentration differences for most wind speed

categories shown in the figure were statistically significant. The Pearson correlation

coefficients between wind speed and total NMOC concentration are generally consistent

with the data trends indicated in Figure 5-5: The correlation coefficients for CAMS5,

CAMS13, and DLTX were -0.52, -0.46, and -0.47, respectively. These negative

correlation coefficients indicate that total NMOC levels at the three monitoring stations

tended to be lower when wind speeds were higher, and vice versa. This same data trend
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was observed at the three monitoring stations in Dallas and Fort Worth during the 1997

NMOC/SNMOC Monitoring Program and is generally consistent with air dispersion

modeling algorithms, which predict that higher wind speeds enhance dispersion of

pollutants in the atmosphere (USEPA 1995).

• Wind Direction. The scatter plots in Figure 5-6 show how total NMOC concentrations at

CAMS5, CAMS13, and DLTX varied with wind direction. The plots do not include

results from the six valid samples that were collected when winds were either variable

or calm. Though Figure 5-6 clearly indicates that southerly winds occurred most

frequently during the morning hours at the Dallas–Fort Worth International Airport, the

scatter plots suggest that total NMOC concentrations during the 1998 program were not

considerably elevated when winds blew from any particular direction. More simply, the

magnitude of total NMOC concentrations at the three monitoring stations during the

morning hours appeared to be largely independent of the wind direction. The 1997 report

reached the same conclusion.

In review, ambient air concentrations of total NMOC that were measured during the

morning hours at three locations in Dallas and Fort Worth were very weakly correlated, if not

completely uncorrelated, with several meteorological parameters (humidity, temperature, wind

direction), but were negatively correlated with wind speed. This finding suggests that wind

speed has a much greater influence on levels of total NMOC during the morning hours in the

Dallas–Fort Worth area than other meteorological parameters. However, the absence of

correlations for certain meteorological parameters suggests either that the parameters have no

influence on levels of air pollution in Dallas and Fort Worth or that the parameters’ influence on

levels of air pollution is masked by the influences of other parameters (such as wind speed). To

better understand the combined influences of different parameters, researchers are encouraged to

conduct multivariate statistical analyses on the NMOC/SNMOC monitoring data. Such analyses,

however, are not included in the scope of this report.

5.1.3 Annual Variations

The CAMS13 and DLTX monitoring stations have participated in the NMOC/SNMOC

Monitoring Program since 1995, and the CAMS5 station has participated in the program since

1996, thus providing several years of data for evaluating annual variations in total NMOC levels

in the Dallas–Fort Worth metropolitan area. However, since these stations did not participate in
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this program in years prior to when reformulated fuels were introduced to the Dallas–Fort Worth

area (i.e., prior to 1995), the monitoring data from 1995 to 1998 are not sufficient for assessing

the air quality impacts of this environmental initiative.

To put long-term air quality trends for this area into perspective, the following discussion

reviews how average levels of total NMOC and peak levels of total NMOC have changed at

CAMS5, CAMS13, and DLTX from year to year. It is important to remember that the annual

variations presented in this section only characterize changes in total NMOC concentrations

during the summertime morning hours. Annual variations based on concentrations measured

during other times of day and other times of year might differ considerably from the annual

variations discussed below.

An overview of the long-term trends in total NMOC concentrations in Dallas and Fort

Worth follows:

C Changes in average concentrations of total NMOC. Figure 5-7 shows how the average

concentrations of total NMOC have changed at CAMS5, CAMS13, and DLTX since the

summer of 1995. Several important observations can be made from the data presented in

the figure. For example, the annual variations depicted in Figure 5-7 clearly differ among

the three monitoring stations in the Dallas–Fort Worth metropolitan area. As a result, one

cannot determine, based on the data collected in this monitoring program, whether total

NMOC levels throughout this urban area have generally increased, decreased, or

stayed the same. Further, though temperatures during the 1998 program were consistently

higher than those during earlier programs, average concentrations of total NMOC at all

three monitoring stations during the 1998 program were not unusually higher or lower

than those from prior programs. The absence of considerable changes in total NMOC

levels during the record heat of 1998 confirms a finding presented in the previous

section: Concentrations of total NMOC during the morning hours at CAMS5, CAMS13,

and DLTX appeared to be largely independent of temperature.

The data shown in Figure 5-7 allow for the interpretation of site-specific trends. For

instance, according to the figure, the average concentration of total NMOC at CAMS5

decreased by more than a factor of two from the summer of 1996 to the summer of 1997

(a statistically significant decrease) and then increased slightly between the summers of

1997 and 1998. Average levels of total NMOC at DLTX also decreased from 1996 to

1997, but only by 23 percent (a statistically significant decrease). The annual variations
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at CAMS13, on the other hand, increased by nearly a factor of two from 1996 to 1997 (a

statistically significant increase). The reasons for these conflicting trends are not readily

apparent, and researchers are encouraged to examine local emissions inventories, if they

are available, to understand why annual variations in total NMOC levels vary across the

three monitoring stations.

C Changes in peak concentrations of total NMOC. As another indicator of annual

variations in air quality, Figure 5-8 illustrates how the frequency of peak levels of total

NMOC (defined here as concentrations greater than 1.0 ppmC) changed at CAMS5,

CAMS13, and DLTX since the 1995 NMOC/SNMOC Monitoring Program. As the figure

shows, concentrations of total NMOC at the two stations in Dallas (CAMS5 and DLTX)

exceeded 1.0 ppmC in fewer than 2 percent of the samples collected in the 1995, 1996,

1997, and 1998 programs; the opposite trend, however, was observed at CAMS13. Not

only were elevated concentrations at CAMS13 more frequent than those at the other

stations, but the frequency of elevated concentrations during the summers of 1997 and

1998 were more than twice as high as those during 1995 and 1996. In short, total NMOC

concentrations greater than 1.0 ppmC appear to be more common at CAMS13 than at

CAMS5 and DLTX, and the frequency of elevated concentrations at CAMS13 has

increased in recent years.

Overall, the analyses of annual variations do not indicate consistent trends for the entire

Dallas–Fort Worth area: In some parts of these cities (e.g., CAMS13), average concentrations of

total NMOC during the morning hours increased in recent years; in other parts of these cities

(e.g., CAMS5 and DLTX), concentrations have decreased. Though some of the changes in total

NMOC levels from year to year were considerable, ambient air monitoring data from several

more years are needed to determine whether distinct long-term trends in air quality are apparent

for this region. Moreover, detailed information on site-specific emissions is also needed to put

the annual variations into perspective.

5.2 SNMOC Monitoring Data

During the 1998 NMOC/SNMOC Monitoring Program, SNMOC samples were collected

on weekday mornings at the three monitoring stations in the Dallas–Fort Worth area. These

samples were analyzed for concentrations of 80 organic compounds (all hydrocarbons) as well

as for the concentration of total NMOC. Following the data analysis methodology presented in

Section 3, the following discussion reviews the large volume of SNMOC monitoring data
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collected at CAMS5, CAMS13, and DLTX. More specifically, the discussion presents a brief

overview of the SNMOC monitoring data (Section 5.2.1), comments on the composition of air

pollutants in the SNMOC samples (Section 5.2.2), analyzes annual variations in ambient air

concentrations of selected SNMOC (Section 5.2.3), and assesses the reactivity of the air mass in

Dallas and Fort Worth (Section 5.2.4).

5.2.1 Data Summary

Using the data summary parameters defined in Section 3.1, Tables 5-2, 5-3, and 5-4

summarize the SNMOC monitoring data collected at CAMS5, CAMS13, and DLTX,

respectively. An overview of the data summary parameters follows:

• Prevalence. As the data summary tables show, 76 of the 80 hydrocarbons identified by

the SNMOC sampling and analytical method were detected in more than 50 percent of the

samples collected at CAMS5, CAMS13, and DLTX during the 1998 program. The

summary statistics for these compounds, many of which had a prevalence of 100 percent,

are believed to be highly representative of air quality during the summertime morning

hours, since few nondetect observations were recorded. The fact that 76 compounds

were detected in most samples indicates that ambient air in Dallas and Fort Worth

contains a wide range of pollutants.

Four compounds (1-decene, 2-ethyl-1-butene, 1-heptene, and 1-tridecene), on the other

hand, were detected in fewer than 50 percent of the sampling events at the three

monitoring stations. Summary statistics for these compounds should be interpreted with

caution, since they are likely to be biased by the frequent nondetect observations. As

explained in Section 2, nondetects were replaced in the SNMOC air monitoring database

with an estimated concentration of one-half the detection limit.

• Concentration range. Not surprisingly, ambient air concentrations of the 80 SNMOC

varied greatly among the samples collected at the three monitoring stations in Dallas and

Fort Worth. As Tables 5-2, 5-3, and 5-4 indicate, the majority of the compounds were

never measured at concentrations exceeding 25 ppbC in the Dallas–Fort Worth area. At

the CAMS5 monitoring station, ten compounds had at least one ambient air concentration

greater than 25 ppbC, and the highest concentrations were observed for isopentane

(69.60 ppbC), n-tridecane (61.56 ppbC), and toluene (44.78 ppbC). At CAMS13, 13

compounds had at least one concentration greater than 25 ppbC, with the highest

concentrations observed for isopentane (160.84 ppbC), 2,3-dimethylbutane (97.60

ppbC), and n-butane (85.89 ppbC). Finally, at DLTX, nine compounds had at least one

concentration greater than 25 ppbC and the highest levels were observed for toluene
5-11

 (940.16 ppbC), cyclohexane (84.57 ppbC), and isopentane (82.67 ppbC). Since the

highest concentrations might occur following, or during, a one-time release of certain

compounds from a nearby emissions source, the compounds with the highest

concentrations often differ from those with consistently elevated concentrations. The

following bullet item emphasizes this distinction.

As noted throughout this report, the concentration range data in the summary tables should

be interpreted in proper context: The data characterize concentration ranges for only

weekday mornings during the summer. Ambient air concentrations for many SNMOC

may have risen to higher levels or fallen to lower levels during other times of day and

other times of the year.

• Central tendency. Tables 5-2, 5-3, and 5-4 present three different measures of central

tendency concentrations (the median, arithmetic mean, and geometric mean) for the

80 hydrocarbons identified by the SNMOC sampling and analytical method. Due to the

high prevalence for most SNMOC, the three measures of central tendency are expected to

accurately represent actual central tendency levels for most compounds. The following

observations are apparent from the central tendency data listed in the data summary

tables:

(1) Most of the 80 compounds identified by the SNMOC sampling and analytical

method had geometric mean concentrations lower than 5 ppbC. More

specifically, 70 of the 80 compounds at CAMS5, 60 of the 80 compounds at

CAMS13, and 71 of the 80 compounds at DLTX had geometric mean

concentrations lower than 5 ppbC.

(2) For insight into trends among the central tendency levels, Table 5-5 lists the

compounds with the ten highest geometric mean concentrations at CAMS5,

CAMS13, and DLTX. As the table shows, the following compounds have

geometric mean concentrations that rank among the ten highest at all three

monitoring stations in the Dallas–Fort Worth area: n-butane, 2,3-dimethylbutane,

isopentane, 2-methylpentane, n-pentane, propane, toluene, and m,p-xylene. Thus,

a small subset of the 80 SNMOC was consistently measured at elevated levels at

the three monitoring stations in Dallas and Fort Worth. Moreover, for each of the

three stations, the sum of the concentrations of the compounds listed in Table 5-5

accounts for roughly half of the total concentration of compounds identified by the

SNMOC sampling and analytical method. In other words, even though the

ambient air in Dallas and Fort Worth contains a wide range of hydrocarbons, a

small number of these compounds comprise a large portion of the airborne

SNMOC.

(3) Despite the similarities between the compounds with the highest concentrations at

the three stations, Table 5-5 clearly demonstrates a distinct difference in the
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magnitude of ambient air concentrations in the Dallas–Fort Worth area: The

highest geometric mean concentrations observed at CAMS13 for most compounds

listed in Table 5-5 are roughly two or three times higher than those observed at

CAMS5 and DLTX. The analyses in Section 5.2.2 examine these concentration

differences in greater detail.

(4) Comparison of the central tendency data in Table 5-5 to the concentration range

data in Tables 5-2, 5-3, and 5-4 shows that, in some cases, the compounds with

the highest geometric mean concentrations differ from those with the highest

concentrations. For example, though the peak concentration of cyclohexane at

DLTX and of n-tridecane at CAMS5 ranked among the highest concentrations

observed at these stations, neither compound’s geometric mean concentration

ranked among the top ten central tendency concentrations shown in Table 5-5. 

For these compounds, therefore, the highest concentrations appear to be outliers,

as supported by the variability data in the following bullet item.

Overall, the central tendency data provide useful insight into the relative quantities of

individual SNMOC. Section 5.2.2 comments further on this topic by characterizing how

the composition of SNMOC air samples differed among the three monitoring stations in

Dallas and Fort Worth.

• Variability. According to Tables 5-2, 5-3, and 5-4, most SNMOC at CAMS5, CAMS13,

and DLTX have coefficients of variation lower than 1.0, suggesting that most compounds’

ambient air concentrations have comparable variability in the Dallas–Fort Worth area

during the morning hours. The compounds with the most variable ambient air monitoring

data (i.e., the compounds with coefficients of variation greater than 1.0) generally fall

into two categories. First, highly variable air monitoring data were observed for

compounds with extreme data outliers, such as n-tridecane at CAMS5 and cyclohexane at

all three stations. Second, because calculations of coefficients of variations from

concentrations measured in units of ppbC inherently give greater weight to compounds

with more carbon atoms, highly variable air monitoring data also were observed for

compounds with 10 or more carbons, such as n-dodecane at CAMS5 and DLTX, nundecane at DLTX and CAMS13, and 1-dodecene at CAMS13.

5.2.2 Composition of Air Samples

The relative quantities of pollutants in ambient air are useful for identifying the

predominant sources of air pollution in a given area and for evaluating the extent to which air

pollution varies from one year to the next. To reveal notable trends among the complex mixture

of air pollutants at the three monitoring stations in the Dallas–Fort Worth metropolitan area, the

following discussion considers three different measures of composition: the relative quantities
 Two alkynes, acetylene and propyne, were identified by the SNMOC analytical method. These compounds were 1

considered in the olefin category for the composition calculations. Some compounds (e.g., styrene) include both olefinic and

aromatic functional groups. Such compounds were considered to be aromatics for the analyses of chemical composition.

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of “unknown” and “identified” compounds; the relative quantities of alkanes, olefins, and

aromatic compounds; and the relative quantities of benzene, toluene, ethylbenzene, and xylene 1

isomers (collectively known as the BTEX compounds).

5.2.2.1 “Identified” vs. “Unknown” Compounds

As Section 2.3.2 explained, the SNMOC sampling and analytical method measures

ambient air concentrations of total NMOC as well as concentrations of 80 hydrocarbons (i.e., the

“identified” compounds). In any given sample, the sum of the concentrations of the identified

compounds is lower than the corresponding concentration of total NMOC. The concentrations of

the various compounds that the SNMOC sampling and analytical method cannot identify (i.e., the

“unknown” compounds) account for the difference between the identified compounds and total

NMOC. The unknown compounds include, but are not limited to, oxygenated hydrocarbons,

halogenated hydrocarbons, and other substituted hydrocarbons.

According to the data in Tables 5-2, 5-3, and 5-4, the identified compounds, on average,

accounted for 80 percent of the total NMOC at CAMS5, 84 percent of the total NMOC at

CAMS13, and 79 percent of the total NMOC at DLTX. These composition figures are nearly

identical to those documented in the 1997 NMOC/SNMOC report. Several observations can be

made based on the breakdown of identified and unknown compounds in Dallas and Fort Worth:

C At the CAMS5, CAMS13, and DLTX monitoring stations, the 80 hydrocarbons identified

by the SNMOC sampling and analytical method account for more than three-fourths of the

airborne organic compounds. As a result, pollution control initiatives focused on

reducing emissions of the 80 identified compounds are expected to have a greater impact

on reducing ambient air concentrations of total NMOC than initiatives focused on

reducing emissions of other compounds.
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C The relative amounts of identified and unknown compounds do not differ dramatically

across the three monitoring stations in the Dallas and Fort Worth area. The consistent

proportions of these two classes of compounds suggest that widespread reductions in

emissions of the 80 identified compounds would be likely to lead to a considerable

reduction in levels of total NMOC throughout the Dallas–Fort Worth area, and not just in

any particular location.

C Since the relative quantities of identified and unknown compounds at the three monitoring

stations changed little in previous summers, the relative magnitude of emissions of

identified and unknown compounds also likely did not change considerably during this

time.

Though the previous observations offer insight into air quality trends for the cities of

Dallas and Fort Worth, the relative amounts of “identified” and “unknown” compounds provide a

very limited basis for characterizing the composition of air pollution. A more detailed review of

the composition of the SNMOC samples follows.

5.2.2.2 Alkanes, Olefins, and Aromatic Compounds

The relative amounts of alkanes, olefins, and aromatic compounds in ambient air are

useful for identifying the types of emissions sources suspected of having the greatest impacts on

air quality. As an example of such analyses, the following discussion presents relevant

composition trends for CAMS5, CAMS13, and DLTX, and interprets the significance of these

trends.

Figure 5-9 depicts the relative amounts of alkanes, olefins, and aromatic compounds that

were measured at CAMS5, CAMS13, and DLTX during the morning hours of the 1998 program. 

To avoid biasing the composition calculations by the number of carbon atoms in each compound,

the data in Figure 5-9 are based on ambient air concentrations of SNMOC in units of ppbv. The

composition data in Figure 5-9 highlight two subtle trends among the air monitoring data for the

Dallas–Fort Worth area: The relative quantities of alkanes were highest at CAMS13, followed

next by those at CAMS5, and last by those at DLTX; and the relative quantities of olefins were

highest at DLTX, followed next by those at CAMS5, and last by those at CAMS13. The same
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trends in chemical composition were documented in the 1997 NMOC/SNMOC report. Closer

examination of the SNMOC monitoring data for the three stations offers insight into the factors

that possibly account for the composition trends depicted in Figure 5-9, as documented below:

C Compounds that account for the spatial variations in chemical composition. To

understand why the composition of air masses differed at the three monitoring stations in

Dallas and Fort Worth, the relative quantities of every alkane and olefin were calculated

for the SNMOC monitoring data. Figures 5-10 and 5-11 depict the results of these

calculations, by illustrating how the composition of the most abundant olefins and

alkanes, respectively, varied across the CAMS5, CAMS13, and DLTX monitoring

stations. Two consistent trends are apparent from the figures.

First, as Figure 5-10 shows, ambient air at DLTX contained the greatest proportion of

each of the most abundant olefins (acetylene, ethylene, isobutene, 1-butene, and

propylene), followed by the ambient air at CAMS5, and followed last by the ambient air

at CAMS13. Conversely, as Figure 5-11 shows, with two exceptions, ambient air at

CAMS13 contained the greatest proportion of each of the most abundant alkanes

(n-butane, 2,3-dimethylbutane, n-hexane, isopentane, 2-methylpentane, 3-methylpentane,

and n-pentane), followed by the ambient air at CAMS5, and followed last by the ambient

air at DLTX. For two alkanes (ethane and propane), however, the relative amounts were

greatest at DLTX, followed by CAMS5, and followed last by CAMS13. These figures

indicate that no single compound appears to account for the general trends depicted in

Figure 5-9. Rather, the relative amounts of the most abundant olefins were consistently

highest at DLTX and lowest at CAMS13, and the relative amounts of the most abundant

alkanes were consistently highest at CAMS13 and lowest at DLTX. The significance of

this finding is highlighted in the next bullet item.

C Comparison of the chemical composition to emissions source profiles. When

interpreting air quality trends, researchers often compare the composition of ambient air

at a given location to emissions source profiles. Since many different types of emissions

sources are commonly found in urban areas, the composition of ambient air is not

expected to match the emissions profile of any single source. However, similarities

between the composition of air samples and the composition of emissions can indicate the

types of sources that appear to have the greatest influence on air quality at a given

location.

To interpret the composition of air samples indicated by Figures 5-10 and 5-11, the

composition data were compared to emissions source profiles that were recently

documented in the scientific literature (Scheff and Wadden 1993). Table 5-6 summarizes

these profiles, by indicating the relative amounts of selected alkanes and olefins reported

as being emitted by motor vehicles, gasoline vapor, and petroleum refineries. Three key
5-16

features of these source profiles help explain the composition trends in the Dallas–Fort

Worth area.

First, according to the source profile data in Table 5-6, mobile source emissions contain

a greater proportion of the most abundant olefins than the emissions from either gasoline

vapor or petroleum refineries. This source profile offers a possible explanation for the

data trends depicted in Figure 5-10: The relatively greater proportion of olefins in the air

at DLTX (when compared to the air at CAMS13) suggests, though certainly does not

prove, that mobile source emissions might have a greater impact on the air quality at

DLTX than on the air quality at CAMS13. 

Second, according to the source profiles, emissions from gasoline vapor as well as

emissions from petroleum refineries contain a greater proportion of several alkanes,

namely n-butane, n-hexane, isopentane, 2-methylpentane, 3-methylpentane, and n-pentane,

when compared to emissions from mobile sources. These source profile data help

explain the composition trends depicted in Figure 5-11: The relatively greater proportion

of the aforementioned alkanes in the air at CAMS13 (when compared to the air at DLTX)

suggests, though again does not prove, that emissions from gasoline vapor or from

petroleum refineries might have a greater impact on the air quality at CAMS13 than on the

air quality at DLTX. Data trends outlined in the next paragraph, however, rule out the

possibility that emissions from petroleum refineries account for the composition trends

observed at CAMS13.

Third, according to the source profiles, emissions from motor vehicles generally contain

a greater proportion of ethane and propane than emissions from gasoline vapor, and

emissions from petroleum refineries generally contain a far greater proportion of propane

than emissions from motor vehicles. The source profile data for ethane and propane

support some of the hypotheses raised in the previous paragraphs. More specifically,

Figure 5-11 clearly shows that the air at DLTX contained a greater proportion of ethane

and propane than the air at CAMS13, thus further supporting the hypothesis that mobile

source emissions have a greater influence on the air at DLTX than on the air at CAMS13. 

Moreover, since the relative amounts of propane at most stations are comparable to those

for other alkanes, the composition data for all stations are not consistent with the source

profile for petroleum refineries. Therefore, the relatively greater quantities of alkanes

measured at CAMS13 appear to be associated with a greater influence from gasoline

vapor emissions than from petroleum refinery emissions.

Overall, comparisons between the composition data and emissions source profile data

offer insight into why the relative quantities of alkanes, olefins, and aromatic compounds vary

with location in Dallas and Fort Worth. In short, the data considered in this section provide

compelling evidence that mobile source emissions have a greater influence on air quality at
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DLTX than at CAMS13 and that gasoline vapor emissions have a greater influence on air quality

at CAMS13 than at DLTX. A detailed review of emissions inventory, including the number and

locations of gasoline stations, is needed to confirm this hypothesis.

Despite the many consistencies between the composition data and the emissions source

profiles, readers should note two limitations in the above analyses. First, this report considers

the findings of just one emissions source study, which characterized the composition of emissions

from only a subset of the types of emissions sources commonly found in urban environments. A

more detailed review of emissions source profiles might provide other explanations for the

composition trends depicted in Figures 5-10 and 5-11. Second, this section offered only

qualitative comparisons between the composition data and source profiles. For a more rigorous

comparison of the data, researchers are encouraged to perform “factor analyses” or use other

statistical tools to quantify the extent to which certain source profiles are reflected in the ambient

air monitoring data. Such statistical analyses, however, are not included in the scope of this

report.

5.2.2.3 BTEX Concentration Profiles

To identify the emissions sources that have the strongest effect on local air quality, many

researchers have compared the relative quantities of benzene, toluene, ethylbenzene, and the

xylene isomers (BTEX) compounds in ambient air to the relative quantities of these compounds

emitted by different sources. In fact, the previous NMOC/SNMOC reports have shown a striking

similarity between the relative quantities of BTEX compounds in ambient air at most monitoring

locations and mobile source emissions profiles of BTEX compounds. Consistent with this

finding from previous reports, Figure 5-12 shows that the BTEX concentration profiles at the

three monitoring stations in the Dallas–Fort Worth area were again quite similar. Not shown in

Figure 5-12 is the fact that the concentration profiles observed during the 1998 NMOC/SNMOC

Monitoring Program were nearly identical to a mobile source emissions profile recently reported

in the scientific literature (Conner et al. 1995).
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The similarity in the BTEX concentration profiles at CAMS5, CAMS13, and DLTX

strongly suggests that the aromatic compounds originate, to a great extent, from an emissions

source common to the three distinct locations, rather than from site-specific emissions sources. 

Moreover, the similarity between the concentration profiles and the mobile source emissions

profiles provides compelling evidence that mobile source emissions account for a considerable

portion of the airborne aromatic compounds at CAMS5, CAMS13, and DLTX. This same

finding was presented in the 1996 and 1997 NMOC/SNMOC reports.

5.2.3 Annual Variations

Since the CAMS5, CAMS13, and DLTX monitoring stations have sampled SNMOC for

at least 3 years, a large volume of monitoring data is available for evaluating long-term trends in

air quality in the Dallas–Fort Worth area. This section presents and interprets trends for the most

abundant SNMOC at each of the three stations. Researchers interested in characterizing annual

variations for other SNMOC should refer to the raw ambient air monitoring that have been

submitted to AIRS.

Figures 5-13, 5-14, and 5-15 illustrate the annual variations for the most abundant

SNMOC (on a ppbC basis) at CAMS5, CAMS13, and DLTX, respectively. An overview of

these annual variations follows:

C Annual Variations at CAMS5. The annual variations for most of the compounds

considered in Figure 5-13 exhibit similar trends as the annual variations in total NMOC

at CAMS5 (see Figure 5-7). More specifically, with some exceptions, concentrations of

the most abundant SNMOC exhibited a statistically significant decrease between the 1996

and 1997 programs, and a marginal increase occurred between the 1997 and 1998

programs. For many compounds, the increase between the 1997 and 1998 programs was

not statistically significant. The similar annual variations for the many different SNMOC

suggests that changes in a particular source—possibly mobile source emissions—might

account for most of the annual variations depicted in Figure 5-13.

As exceptions to the general trend mentioned above, ambient air concentrations for

acetylene, ethane, ethylene, and propane remained virtually unchanged during the

summers of 1996, 1997, and 1998. The reason for the relatively constant ambient levels
5-19

for these compounds is not known. As another exception, the average concentration of

2,3-dimethylbutane increased by more than 700 percent between the 1997 and 1998

programs (a statistically significant increase), while the concentrations of most other

compounds exhibited only marginal increases over this time frame. Although the

considerably higher concentrations of 2,3-dimethylbutane during the 1998 program

parallel the considerably higher temperatures observed in the Dallas–Fort Worth area

during the summer of 1998, additional monitoring data must be reviewed and collected to

determine whether temperature exhibits a particularly strong influence on ambient air

concentrations of this one compound.

C Annual Variations at CAMS13. As Figure 5-14 shows, the annual variations in average

levels of the most abundant SNMOC at CAMS13 were generally similar to the annual

variations for this station’s total NMOC data. These annual variations, in general terms,

exhibit the following features: Average concentrations for the 1995 and 1996 programs

were similar and considerably lower than the average levels during the 1997 and 1998

programs. To a certain extent, the annual variations for n-butane, benzene, n-hexane,

isopentane, 2-methylpentane, 3-methylpentane, n-pentane, toluene, and m,p-xylene all

exhibit these general features of the total NMOC trends. The consistent data trends for

these compounds suggest that their ambient air concentrations are collectively influenced

by the same group of sources. This hypothesis can be confirmed by comparing the air

quality trends depicted in Figure 5-14 to annual variations in emissions inventories for

the area surrounding CAMS13.

Despite the consistent annual variations for most compounds shown in Figure 5-14, some

compounds exhibited unique annual variations at CAMS13. For example, concentrations

of acetylene, ethane, and propane changed little at this station during the summers of

1995, 1996, 1997, and 1998. The reason for the relatively constant levels of these

compounds, during times when concentrations of other hydrocarbons changed

considerably, is not known; however, it is interesting to note that this same trend was

observed at the CAMS5 station (see previous bullet item). As another example of a

unique trend, of the compounds shown in Figure 5-14, only 2,3-dimethylbutane exhibited

a statistically significant increase in average concentrations between the 1997 and 1998

programs. In fact, concentrations of the compound increased by roughly 200 percent

between these summers. Though the increase for 2,3-dimethylbutane might be linked to

the record heat observed during the 1998 program, analysis of additional monitoring data

is needed to verify this theory.

C Annual Variations at DLTX. According to Figure 5-7, the annual variations in total

NMOC concentrations at DLTX were much weaker than those observed at CAMS5 and

CAMS13. Consistent with the trend observed for total NMOC levels, Figure 5-15

indicates that concentrations of the most abundant SNMOC at DLTX generally changed

little between the summers of 1995 and 1998, and many of the concentration differences

shown in Figure 5-15 were not statistically significant.
5-20

As exceptions to the trend described above, the average concentrations of two

compounds (2,3-dimethylbutane and toluene) at DLTX during the summer of 1998 were

considerably higher than those observed during the three previous summers. First, the

average concentration of 2,3-dimethylbutane during the 1998 program was roughly 400

percent higher than that observed during the 1995, 1996, and 1997 programs. Not only

was this concentration difference statistically significant, but it parallels data trends

observed at the two other monitoring stations in the Dallas–Fort Worth area. Further

research is needed to confirm whether the notably elevated concentrations of 2,3-

dimethylbutane at CAMS5, CAMS13, and DLTX during the summer of 1998 were linked

to the record heat. 

As the second unique data trend at DLTX, the average concentration of toluene during the

1998 program (29.63 ppbC) was considerably higher than the average concentrations

during the earlier programs. However, this concentration difference is not statistically

significant and appears to be largely influenced by a single outlier concentration of

toluene during the 1998 program (i.e., a concentration of 940.16 ppbC on

September 30, 1998). Excluding this outlier from the data analysis, the average

concentration of toluene at DLTX during the 1998 program is only 14.70 ppbC—a level

that is comparable to the average concentrations during the 1995, 1996, and

1997 programs.

Although the annual variations in SNMOC differ among the three monitoring stations in

the Dallas–Fort Worth area, some consistent trends were observed. First, the long-term trends in

concentrations of the most abundant SNMOC typically mirror the long-term trends in total

NMOC concentrations. Second, the concentrations of acetylene, ethane, and propane exhibited

relatively weak annual variations at all stations over the last 4 years. Third, concentrations of

2,3-dimethylbutane at CAMS5, CAMS13, and DLTX during the 1998 program were

considerably higher than levels observed during the 1995, 1996, and 1997 programs. Though the

elevated levels of 2,3-dimethylbutane occurred during the summer with the warmest

temperatures, additional research is needed to determine whether or not this correspondence is

coincidental.

When reviewing the annual variations depicted in Figures 5-13 to 5-15, readers should

note a key limitation posed by reviewing only 4 years of monitoring data: Though the data are
5-21

sufficient for characterizing how levels of air pollution vary from year to year, it is impossible to

determine whether these variations are merely naturally occurring fluctuations in air quality or

part of continuing trends over the long term. Review of a longer record of ambient air monitoring

data is needed to make this distinction.

5.2.4 Reactivity of the Air Mass

Though identifying the compounds with the highest ambient air concentrations is useful

for characterizing the composition of air pollution, such evaluations do not always identify the

compounds having the greatest potential to form ozone. In some cases, highly reactive

compounds with relatively low concentrations exhibit a greater ozone formation potential than

less reactive compounds with relatively high concentrations. To put the reactivity of the air mass

into perspective, this section presents an “ozone index” for the most abundant SNMOC. As

Section 3.4 defined, the ozone indices in this report are the product of a compound’s maximum

incremental reactivity (MIR) (see Section 3.4) and its geometric mean ambient air concentration. 

In other words, the ozone index represents a reactivity-weighted concentration.

To illustrate the ozone formation potential of selected compounds, Figures 5-16, 5-17,

and 5-18 show ozone indices for the 20 SNMOC with the highest geometric mean concentrations

at CAMS5, CAMS13, and DLTX, respectively. According to these three figures, the compounds

with the greatest potential for forming ozone (i.e., the compounds with the highest ozone index)

are not always the same as the compounds with the highest ambient air concentration. More

specifically, ethylbenzene, isopentane, toluene, 1,2,4-trimethylbenzene, and m,p-xylene had the

highest ozone indices at the three monitoring locations in Dallas and Fort Worth, even though

some of these compounds did not rank among the ten with the highest ambient air concentrations. 

Since this analysis highlights the importance of interpreting the SNMOC monitoring data by

different metrics, researchers are encouraged to perform more detailed analyses on the reactivity

of the air in the Dallas–Fort Worth area, possibly through use of photochemical modeling.
5-22

5.3 Carbonyl Monitoring Data

During the 1998 NMOC/SNMOC Monitoring Program, the monitoring stations in Dallas

and Fort Worth collected carbonyl samples roughly once a week, and only during the months of

July, August, and September. This weekly sampling provides insight into ambient air

concentrations of 16 carbonyls, all of which the SNMOC sampling and analytical method does

not identify. The ambient air concentrations of carbonyls are of particular interest because this

group of compounds participates in the complex series of photochemical reactions that produce

ozone.

Because the CAMS5, CAMS13, and DLTX collected a limited number of carbonyl

samples (i.e., 11 or fewer), not enough data are available for identifying statistically significant

trends and patterns among the data. As a result, this section only presents descriptive summary

statistics for the carbonyl monitoring. Using the data summary parameters that were defined in

Section 3.1, Tables 5-8, 5-9, and 5-10 summarize the carbonyl monitoring data collected at

CAMS5, CAMS13, and DLTX, respectively, during the summer of 1998. An overview of these

summary parameters follows:

• Prevalence. According to the data summary tables, eight carbonyls were detected in

more than half of the samples collected at all three stations. In other words, these

compounds (acetaldehyde, acetone, benzaldehyde, butyraldehyde, formaldehyde,

hexanaldehyde, isobutyraldehyde, and propionaldehdye) were consistently found in the

ambient air at all three stations during the morning hours of weekdays. These

compounds’ summary statistics are believed to be highly representative of carbonyl

concentrations during the morning hours in Dallas and Fort Worth, since few of the

samples were nondetects. In addition to the eight carbonyls mentioned above, acrolein

also had high prevalence figures, but only at the monitoring stations in Dallas.

For the remaining carbonyls, summary statistics should be interpreted with caution, since

they might be biased by the many nondetect observations. As explained earlier in this

report, nondetects were replaced in the air monitoring database with a concentration of

one-half the detection limit.

• Concentration range. At all three monitoring stations in Dallas and Fort Worth, the three

carbonyls with the highest concentrations were acetaldehyde, acetone, and formaldehyde;

ambient air concentrations of the other carbonyls rarely exceeded 1.0 ppbv. Though this
5-23

same data trend was observed during the 1996 and 1997 programs, readers should note

two limitations when interpreting the concentration range data in Tables 5-8, 5-9, and

5-10. First, because ambient air concentrations of many carbonyl compounds reach their

highest levels during the early afternoon hours (Brimblecombe, 1995), and not during the

scheduled sampling times for the NMOC/SNMOC program (i.e., between 6:00 a.m. and

9:00 a.m.), concentrations of the 16 carbonyls during the 1998 program might have

actually reached higher levels than the concentration range data indicate. Second, the

concentration range data in Tables 5-8 to 5-10 should be compared to annual air

monitoring efforts with caution, since the NMOC/SNMOC Monitoring Program does not

consider air quality during the spring, fall, or winter.

• Central tendency. Consistent with data trends from the 1996 and 1997 programs, the

central tendency parameters in Tables 5-8 to 5-10 indicate a clear break in the carbonyl

monitoring data: At all three stations, the compound with the highest geometric mean

concentration was formaldehyde, followed by acetone, then by acetaldehyde; and all

three compounds had geometric mean concentrations greater than 1.0 ppbv. The

remaining carbonyls, on the other hand, had geometric mean concentrations less than 0.5

ppbv. In fact, at all three stations, acetaldehyde, acetone, and formaldehyde accounted

for more than 90 percent of the total concentration of carbonyls detected in the air

samples.

To put the geometric mean concentrations of carbonyls into perspective, the carbonyl

monitoring data were converted to units of ppbC and compared to the concentrations of

total NMOC at the three monitoring stations in Dallas and Fort Worth. According to this

analysis, the 16 carbonyls identified by the sampling and analytical method accounted for,

on average, 11 percent of total NMOC at CAMS5 and 8 percent of total NMOC at DLTX,

but for only 3 percent of total NMOC at CAMS13. Thus, ambient air at CAMS5 and

DLTX contains a considerably greater proportion of carbonyls than the ambient at

CAMS13. Since mobile sources emit many of the carbonyls considered in this program

(Grosjean 1991), the relatively greater proportion of carbonyls in the air at CAMS5 and

DLTX suggests that mobile source emissions have a greater influence on air quality at

these stations when compared to CAMS13—a hypothesis that was raised in

Section 5.2.2.2.

Not only did the relative quantities of the 16 carbonyls combined vary across the three

monitoring stations, but the relative quantities of individual carbonyls also differed at

CAMS5, CAMS13, and DLTX. For instance, of the 80 SNMOC and 16 carbonyls

monitored during the 1998 program at CAMS5, formaldehyde had the highest geometric

mean concentration (on a ppbv basis), and acetone had the fourth highest. A similar trend

was observed at DLTX: Formaldehyde had the fourth highest geometric mean

concentration, and acetone had the fifth highest. At CAMS13, however, ambient levels of

the most abundant carbonyls ranked much lower than at the other stations in the area: 

Formaldehyde had the ninth highest geometric mean concentration, and acetone had the

twelfth highest. These rankings of individual compounds are generally consistent with the
5-24

trends highlighted in the previous paragraph; namely, ambient air concentrations of

carbonyls accounted for a greater portion of air pollution at CAMS5 and DLTX than at

CAMS13.

• Variability. According to the data summary tables, no consistent trends on data

variability are readily apparent. Some carbonyl compounds had highly variable

monitoring data at one of the stations in Dallas and Fort Worth, but moderately variable

data at the other two stations. In many cases, the compounds with the most variable data

(e.g., crotonaldehyde at CAMS5, acrolein at CAMS13, and valeraldehyde at DLTX) had

a prevalence less than 50 percent. The variability data for these compounds should be

interpreted with caution, since they are likely to be biased by the many nondetect

observations of these compounds.

Though the carbonyl monitoring data collected at CAMS5, CAMS13, and DLTX are

limited, they highlight several important air quality trends. First, at all three stations, only three

compounds (acetaldehdye, acetone, and formaldehyde) account for most of the airborne

carbonyls considered in this program. Second, the concentrations of these three carbonyls were

consistently higher than the concentrations of most of the 80 SNMOC. Third, carbonyls

comprised a larger portion of total NMOC levels at CAMS5 and DLTX than at CAMS13—a

trend that is consistent with the hypothesis that mobile source emissions have a greater effect on

the ambient air at CAMS5 and DLTX than on the ambient at CAMS13.

5.4 Chapter Summary

The 1998 NMOC/SNMOC Monitoring Program extensively characterized air quality

during summertime morning hours at three locations in the Dallas–Fort Worth area, and revealed

several notable spatial and temporal variations in levels of air pollution. As a measure of the

overall levels of airborne organics, total NMOC concentrations at CAMS13 (in Fort Worth)

were, on average, roughly twice as high as the levels at CAMS5 and DLTX (both in Dallas). At

all three stations, ambient air concentrations of total NMOC were very weakly correlated with, if

not completely uncorrelated with, humidity, precipitation, temperature, and wind direction. On

the other hand, total NMOC concentrations on windier days were consistently lower than those

on days with calm or light winds; this trend was statistically significant. Since the summer of
5-25

1995, average concentrations of total NMOC increased in some areas (CAMS13), but decreased

in others (CAMS5 and DLTX). No regional trends were apparent in the annual variations in air

quality, suggesting that local factors might account for the changes in total NMOC levels from

year to year.

The SNMOC measurements clearly indicated that air pollution in both Dallas and Fort

Worth generally contains more than 70 different hydrocarbons, though a small subset of these

compounds accounts for a large portion of the total airborne organic compounds. Close

examination of the SNMOC data revealed that the relative quantities of alkanes were greatest at

CAMS13 and least at DLTX, while the relative quantities of olefins exhibited the opposite trend. 

The composition of the air samples collected at these stations suggested that mobile source

emissions have a greater influence on air quality at DLTX than at CAMS13 and that gasoline

vapor emissions have a greater influence on air quality at CAMS13 than at DLTX, though both

types of sources undoubtedly contribute to air pollution at both locations. The analyses of BTEX

concentration profiles confirmed that mobile source emissions account for a considerable portion

of air pollution at CAMS5, CAMS13, and DLTX. Nonetheless, researchers are encouraged to

compare the SNMOC monitoring data for these stations to site-specific emissions inventories to

test the hypotheses raised in this report.

Annual variations in most SNMOC at the three monitoring stations paralleled the annual

variations in total NMOC concentrations, with two notable exceptions. First, average levels of

acetylene, ethane, and propane exhibited relatively weak annual variations at all three stations,

but the reason for the relatively unchanging concentrations of these compounds is not known. 

Second, at all three monitoring stations in Dallas and Fort Worth, the average concentration of

2,3-dimethylbutane during the 1998 program was considerably higher than the average levels

during the 1995, 1996, and 1997 programs. Though this statistically significant concentration

difference might be linked to the record heat observed during the 1998 program, further research

is encouraged to identify the factors that accounted for this unique annual variation.
5-26

The carbonyl monitoring data collected at CAMS5, CAMS13, and DLTX offer a more

complete account of air quality in Dallas and Fort Worth. At all three stations, acetaldehyde,

acetone, and formaldehyde accounted for more than 90 percent of the airborne carbonyls

identified by the sampling and analytical method—a trend that has been observed at these stations

over the three previous summers. Further, carbonyls accounted for a greater portion of total

NMOC at CAMS5 and DLTX than at CAMS13. Since mobile source emissions are known to

contain elevated levels of several carbonyls, the trend in composition of carbonyls further

supports the hypothesis that mobile source emissions have a greater impact on air quality at

CAMS5 and DLTX than on air quality at CAMS13. Once again, review of site-specific

emissions inventories is needed to test this hypothesis.

As emphasized throughout this section, this report provides an extensive and meaningful

review of the ambient air monitoring data collected in 1998 at Dallas and Forth Worth, but the

analyses in this section are not comprehensive. As a result, researchers are encouraged to further

study the total NMOC, SNMOC, and carbonyl monitoring data from CAMS5, CAMS13, and

DLTX to identify and characterize subtle trends not considered in this report. Examples of such

additional studies include performing multivariate statistical analyses, modeling photochemical

reactivity of the air mass, and comparing the data from this report to concurrent observations of

nitrogen oxides and ozone.
5-27

Figure 5-1

Dallas, Texas (CAMS5), Monitoring Station

Source: USGS 7.5 Minute Series. Map scale: 1:24,000.
5-28

Figure 5-2

Fort Worth, Texas (CAMS13), Monitoring Station

Source: USGS 7.5 Minute Series. Map scale: 1:24,000.
5-29

Figure 5-3

Dallas, Texas (DLTX), Monitoring Station

Source: USGS 7.5 Minute Series. Map scale: 1:24,000.
Distribution for CAMS5

0

19

5

7

2 1 0 0 0 0

34

0

10

20

30

40

<=0.1 >0.1

and

<=0.2

>0.2

and

<=0.3

>0.3

and

<=0.4

>0.4

and

<=0.5

>0.5

and

<=0.6

>0.6

and

<=0.7

>0.7

and

<=0.8

>0.8

and

<=0.9

>0.9

and

<=1.0

>1.0

Concentration Range (ppmC)

Ob

s

erv

ations in

Li

sted Range

Distribution for CAM S13

0

7 7

13

10 11

7

2

6

2

4

0

5

10

15

20

<=0.1 >0.1

and

<=0.2

>0.2

and

<=0.3

>0.3

and

<=0.4

>0.4

and

<=0.5

>0.5

and

<=0.6

>0.6

and

<=0.7

>0.7

and

<=0.8

>0.8

and

<=0.9

>0.9

and

<=1.0

>1.0

Conce ntra tion Range (ppmC)

Ob

s

erv

ations in 

Li

sted Range

Distribution for DLT X

1

24

22

7

4

0

1

2

0 0

1

0

10

20

30

<=0.1 >0.1

and

<=0.2

>0.2

and

<=0.3

>0.3

and

<=0.4

>0.4

and

<=0.5

>0.5

and

<=0.6

>0.6

and

<=0.7

>0.7

and

<=0.8

>0.8

and

<=0.9

>0.9

and

<=1.0

>1.0

Conce ntra tion Range (ppmC)

Ob

s

erv

ations in

Li

sted Range

5-30

Figure 5-4

Distributions of Total NMOC in Dallas and Fort Worth

Note: The scale for the “Observations in Listed Range” is different in each graph, but the scale for the “Concentration Range”

is the same for the three graphs.
CAM S5: NMOC Concentration vs. Humidity

0

50

100

150

200

250

300

<60 >=60 and <70 >=70

Relative Hum idity (%)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

CAM S13: NMOC Concentration vs. Humidity

0

100

200

300

400

500

600

700

<60 >=60 and <70 >=70

Relative Hum idity (%)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

DLTX: NMOC Concentration vs. Humidity

0

50

100

150

200

250

300

350

<60 >=60 and <70 >=70

Relative Hum idity (%)

Av

erage 

Concentr

ation of

Total NMOC (ppbC)

5-31

Figure 5-5 (Page 1 of 3)

Comparison of Total NMOC Concentrations at CAMS5, CAMS13, and 

DLTX to Selected Meteorological Parameters

Note: Every graph has a different scale for average concentrations of total NMOC.
CAMS5: NMOC Concentration vs. Temperature

0

50

100

150

200

250

300

<85 >=85 and <90 >=90

T empe rature Range (degrees Fahrenheit)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

CAMS13: NMOC Concentration vs. Temperature

0

100

200

300

400

500

600

<85 >=85 and <90 >=90

T empe rature Range (degrees Fahrenheit)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

DLTX: NMOC Concentration vs. Temperature

0

50

100

150

200

250

300

<85 >=85 and <90 >=90

T empe rature Range (degrees Fahrenheit)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

5-32

Figure 5-5 (Page 2 of 3)

Comparison of Total NMOC Concentrations at CAMS5, CAMS13, and 

DLTX to Selected Meteorological Parameters

Note: Some of the graphs have a different scale for average concentrations of total NMOC.
CAMS5: NMOC Concentration vs. Wind Speed

0

100

200

300

400

500

<=5 >5 and <=10 >10

W ind Speed (mph)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

CAMS13: NMOC Concentration vs. Wind Speed

0

200

400

600

800

<=5 >5 and <=10 >10

W ind Speed (mph)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

DLTX: NMOC Concentration vs. Wind Speed

0

100

200

300

400

500

<=5 >5 and <=10 >10

W ind Speed (mph)

Av

erage 

Concentr

ation of 

Total NMOC (ppbC)

5-33

Figure 5-5 (Page 3 of 3)

Comparison of Total NMOC Concentrations at CAMS5, CAMS13, and 

DLTX to Selected Meteorological Parameters

Note: Some of the graphs have a different scale for average concentrations of total NMOC.
CAMS5: NMOC Concentration vs. Wind Direction

0

100

200

300

400

500

600

0 60 120 180 240 300 360

W ind Direction (degrees)

Total NMOC 

Concentr

ation 

(ppbC)

CAMS13: NMOC Concentration vs. Wind Direction

0

300

600

900

1,200

1,500

0 60 120 180 240 300 360

Wind Direction (de g rees)

Total NMOC 

Concentr

ation 

(ppbC)

DLTX: NMOC Concentration vs. Wind Direction

0

300

600

900

1,200

1,500

0 60 120 180 240 300 360

Wind Direction (de g rees)

Total NMOC 

Concentr

ation 

(ppbC)

5-34

Figure 5-6

Comparison of Total NMOC Concentrations at CAMS5,

CAMS13, and DLTX to Wind Direction

Notes: Every plot has a different scale for average concentrations of total NMOC.

Wind direction in the graphs is the direction from which wind blows.

Total NMOC data are not shown for the six mornings when winds were calm or variable.
Annual Variations for CAMS5

0.00

0.10

0.20

0.30

0.40

0.50

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

Annual Variations for CAM S13

0.00

0.20

0.40

0.60

0.80

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

Annual Variations for DLT X

0.00

0.10

0.20

0.30

0.40

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

5-35

Figure 5-7

Annual Variations in Average Concentrations of Total NMOC in Dallas and Fort Worth

Note: Every plot has a different scale for average concentrations of total NMOC.

The “error bars” in the graph indicate the 95-percent confidence intervals of the average concentrations.

The CAMS5 station did not participate in the 1995 NMOC/SNMOC Monitoring Program.
Annual Variations for CAMS5

1.3% 0.0% 0.0%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

1995 1996 1997 1998

Year

Percent of 

Sampling Days 

when Total NMOC 

Levels Exceeded 

1.0 ppmC

Annual Variations for CAM S13

2.5% 2.5%

25.3%

5.8%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

1995 1996 1997 1998

Year

Percent of 

Sampling Days 

when Total NMOC 

Levels Exceeded 

1.0 ppmC

Annual Variations for DLT X

1.2% 0.0% 0.0% 1.6%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

1995 1996 1997 1998

Year

Percent of 

Sampling Days 

when Total NMOC 

Levels Exceeded 

1.0 ppmC

5-36

Figure 5-8

Annual Variations in the Frequency of Peak Concentrations of 

Total NMOC in the Dallas–Fort Worth Area

Notes: The three figures are shown on the same scale.

The CAMS5 station did not participate in the 1995 NMOC/SNMOC Monitoring Program.
0%

10%

20%

30%

40%

50%

60%

70%

80%

CAMS5 CAMS13 DLTX

Monitoring Station

Relative Quantity of Identified Compounds

(on a ppbv basis)

Alkanes

Olefins

Aromatics

5-37

Figure 5-9

Relative Amounts of Alkanes, Olefins, and Aromatic Compounds (on a ppbv basis)

at the Dallas–Fort Worth Monitoring Stations
0%

1%

2%

3%

4%

5%

6%

7%

Acetylene Ethylene Isobutene and 1-butene Propylene

Compound

Relative Amount of Compound in SNMOC 

Samples (on a ppbv basis)

CAMS5

CAMS13

DLTX

5-38

Figure 5-10

Composition Data for the Most Abundant Olefins at CAMS5, CAMS13, and DLTX

Note: As Section 5.2.2.2 explains, acetylene is an alkyne, but is included among the olefins for the composition calculations.
0%

2%

4%

6%

8%

10%

12%

14%

16%

n-Butane 2,3-Dimethyl

butane

Ethane n-Hexane Isopentane 2-Methyl

pentane

3-Methyl

pentane

n-Pentane Propane

Compound

Relative Amount of Compound in SNMOC

Samples (on a ppbv basis)

CAMS5

CAMS13

DLTX

5-39

Figure 5-11

Composition Data for the Most Abundant Alkanes at CAMS5, CAMS13, and DLTX
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

CAMS5 CAMS13 DLTX

Monitoring Station

Ratio of Concentrations of BTEX Compounds

Benzene/Ethylbenzene

Toluene/Ethylbenzene

m,p-Xylene/Ethylbenzene

o-Xylene/Ethylbenzene

5-40

Figure 5-12

BTEX Concentration Ratios Calculated from the SNMOC Monitoring Data
Acetylene and Ethane

0.00

5.00

10.00

15.00

20.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Benzene

0.00

2.50

5.00

7.50

10.00

1996 1997 1998

Year

Av

erage 

Concentr

ation

(ppbC)

n-Butane

0.00

3.00

6.00

9.00

12.00

15.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-41

Figure 5-13 (Page 1 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS5

Notes: Acetylene and ethane are presented in the same graph because the sampling and analytical method used during the 1996

program could not differentiate these compounds.

Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
2,3-Dime thylbutane

0.00

3.00

6.00

9.00

12.00

15.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Ethylene

0.00

2.00

4.00

6.00

8.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Hexane

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-42

Figure 5-13 (Page 2 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS5

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Isopentane

0.00

10.00

20.00

30.00

40.00

50.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

2-M e thylpentane

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n-Pentane

0.00

5.00

10.00

15.00

20.00

25.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-43

Figure 5-13 (Page 3 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS5

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Propane

0.00

3.00

6.00

9.00

12.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Toluene

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

m ,p -Xylene

0.00

3.00

6.00

9.00

12.00

15.00

1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-44

Figure 5-13 (Page 4 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS5

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Acetylene and Ethane

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Butane

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Benzene

0.00

3.00

6.00

9.00

12.00

15.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-45

Figure 5-14 (Page 1 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS13

Notes: Acetylene and ethane are presented in the same graph because the sampling and analytical method used during the 1996

program could not differentiate these compounds.

Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
2,3-Dimethylbutane

0.00

10.00

20.00

30.00

40.00

50.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Hexane

0.00

10.00

20.00

30.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Isopentane

0.00

20.00

40.00

60.00

80.00

100.00

120.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-46

Figure 5-14 (Page 2 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS13

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
2-M e thylpentane

0.00

10.00

20.00

30.00

40.00

50.00

60.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

3-M e thylpentane

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Pentane

0.00

10.00

20.00

30.00

40.00

50.00

60.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-47

Figure 5-14 (Page 3 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS13

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Propane

0.00

5.00

10.00

15.00

20.00

25.00

30.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Toluene

0.00

10.00

20.00

30.00

40.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

m ,p -Xylene

0.00

5.00

10.00

15.00

20.00

25.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-48

Figure 5-14 (Page 4 of 4)

Annual Variations for the Most Abundant SNMOC at CAMS13

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Acetylene and Ethane

0.00

10.00

20.00

30.00

40.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Benzene

0.00

1.00

2.00

3.00

4.00

5.00

6.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Butane

0.00

2.00

4.00

6.00

8.00

10.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-49

Figure 5-15 (Page 1 of 4)

Annual Variations for the Most Abundant SNMOC at DLTX

Notes: Acetylene and ethane are presented in the same graph because the sampling and analytical method used during the 1996

program could not differentiate these compounds.

Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
2,3-Dimethylbutane

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Ethylene

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Hexane

0.00

1.00

2.00

3.00

4.00

5.00

6.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-50

Figure 5-15 (Page 2 of 4)

Annual Variations for the Most Abundant SNMOC at DLTX

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Isopentane

0.00

10.00

20.00

30.00

40.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

2-M e thylpentane

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

n -Pentane

0.00

2.00

4.00

6.00

8.00

10.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-51

Figure 5-15 (Page 3 of 4)

Annual Variations for the Most Abundant SNMOC at DLTX

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Propane

0.00

5.00

10.00

15.00

20.00

25.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

Toluene

0.00

10.00

20.00

30.00

40.00

50.00

60.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

m ,p -Xylene

0.00

5.00

10.00

15.00

20.00

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation 

(ppbC)

5-52

Figure 5-15 (Page 4 of 4)

Annual Variations for the Most Abundant SNMOC at DLTX

Notes: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
0.0

5.0

10.0

15.0

20.0

25.0

ispna

tolu

23dmb

etha

m/pxy

propa

nbutanpnta

2mpna

nhexa

benzethyl

124tmb224tmp

isbta

1bute

acetyl

ebenz

2mhxa3mhxa

Compound

Geometric Mean Concentration (ppbC)

0

2

4

6

8

10

12

14

16

18

"Ozone Index" (see Section 5.2.4)

Geometric Mean Concentration

Ozone Index

5-53

Figure 5-16

Ozone Indices for the 20 SNMOC with the Highest Geometric Mean Concentrations at CAMS5

Notes: Only those compounds with MIR values listed in Table 3-1 were considered.

Table 5-7 lists the abbreviations used for the compounds.
0.0

10.0

20.0

30.0

40.0

50.0

60.0

ispna

23dmb

tolu

npntanbuta

2mpna

m/pxynhexa

propa

etha

benz

224tmp

mcpna

124tmb

2m2be

3mhxa2mhxa

t2pne

isbtaethyl

Compound

Geometric Mean Concentration (ppbC)

0

5

10

15

20

25

30

35

"Ozone Index" (see Section 5.2.4)

Geometric Mean Concentration

Ozone Index

5-54

Figure 5-17

Ozone Indices for the 20 SNMOC with the Highest Geometric Mean Concentrations at CAMS13

Notes: Only those compounds with MIR values listed in Table 3-1 were considered.

Table 5-7 lists the abbreviations used for the compounds.
0.0

5.0

10.0

15.0

20.0

25.0

ispna

tolu

propa

etha

m/pxy

23dmb

nbutanpnta

2mpna

ethyl

acetyl

benz

nhexa

124tmb

isbta

224tmp

1bute

ebenz

prpyl

3mhxa

Compound

Geometric Mean Concentration (ppbC)

0

2

4

6

8

10

12

14

16

18

"Ozone Index" (see Section 5.2.4)

Geometric Mean Concentration

Ozone Index

5-55

Figure 5-18

Ozone Indices for the 20 SNMOC with Highest Geometric Mean Concentration at DLTX

Notes: Only those compounds with MIR values listed in Table 3-1 were considered.

Table 5-7 lists the abbreviations used for the compounds.
5-56

Table 5-1

Summary Statistics for Concentrations of Total NMOC in Dallas and Fort Worth

Category Parameter

Monitoring Station

CAMS5 CAMS13 DLTX

Prevalence Number of nondetects 0 0 0

Number of valid sampling days 68 69 62

Frequency of detection 100% 100% 100%

Concentration

Range

Lowest concentration (ppmC) 0.115 0.114 0.089

25th percentile concentration (ppmC) 0.159 0.312 0.144

50th percentile concentration (ppmC) 0.200 0.455 0.222

75th percentile concentration (ppmC) 0.286 0.637 0.293

Highest concentration (ppmC) 0.645 1.165 1.267

Central 0.247 0.509 0.266

Tendency

Median concentration (ppmC) 0.200 0.455 0.222

Arithmetic mean concentration

(ppmC)

Geometric mean concentration

(ppmC) 0.222 0.446 0.227

Variability

Standard deviation (ppmC) 0.125 0.255 0.191

Coefficient of variation 0.51 0.50 0.72
ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-57

Table 5-2

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (CAMS5)

(Based on 68 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

Acetylene 0 100% 0.80 18.45 2.30 3.05 2.48 2.57 0.84

Benzene 0 100% 1.77 11.66 4.14 4.76 4.19 2.54 0.53

1,3-Butadiene 1 99% ND 1.32 0.27 0.33 0.28 0.23 0.68

n-Butane 0 100% 2.71 30.74 6.19 8.01 6.64 5.85 0.73

cis-2-Butene 0 100% 0.09 2.17 0.58 0.68 0.54 0.46 0.67

trans-2-Butene 0 100% 0.06 2.23 0.45 0.61 0.46 0.47 0.77

Cyclohexane 0 100% 0.33 25.20 1.32 2.91 1.64 4.66 1.60

Cyclopentane 0 100% 0.20 3.57 0.76 1.05 0.83 0.79 0.76

Cyclopentene 0 100% 0.32 3.71 0.89 1.08 0.93 0.65 0.60

n-Decane 0 100% 0.26 3.65 0.82 0.98 0.86 0.57 0.58

1-Decene 68 0% ND ND 0.14 0.14 0.14 0.00 0.00

m-Diethylbenzene 0 100% 0.07 1.98 0.50 0.51 0.43 0.29 0.56

p-Diethylbenzene 0 100% 0.11 1.80 0.44 0.47 0.40 0.27 0.58

2,2-Dimethylbutane 0 100% 0.23 3.08 0.94 1.09 0.92 0.65 0.59

2,3-Dimethylbutane 0 100% 3.03 44.66 6.60 11.29 8.45 10.18 0.90

2,3-Dimethylpentane 0 100% 0.31 3.02 1.12 1.26 1.14 0.57 0.45

2,4-Dimethylpentane 0 100% 0.34 2.67 0.93 1.12 0.97 0.61 0.55

n-Dodecane 5 93% ND 7.17 0.37 0.61 0.41 0.93 1.53
Table 5-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (CAMS5)

(Based on 68 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-58

1-Dodecene 23 66% ND 1.38 0.14 0.24 0.19 0.23 0.95

Ethane 0 100% 2.63 33.98 8.82 9.90 8.29 6.18 0.62

Ethylbenzene 0 100% 1.08 8.77 2.22 2.85 2.47 1.68 0.59

2-Ethyl-1-Butene 68 0% ND ND 0.12 0.12 0.12 0.00 0.00

Ethylene 0 100% 1.23 13.06 3.40 4.04 3.49 2.32 0.58

m-Ethyltoluene 0 100% 1.09 8.45 1.98 2.61 2.28 1.52 0.58

o-Ethyltoluene 0 100% 0.42 3.42 0.94 1.16 1.03 0.60 0.52

p-Ethyltoluene 0 100% 0.53 5.32 1.22 1.55 1.36 0.86 0.56

n-Heptane 0 100% 1.01 7.79 1.85 2.42 2.05 1.60 0.66

1-Heptene 41 40% ND 0.94 0.26 0.25 0.23 0.12 0.46

n-Hexane 0 100% 1.86 18.78 4.06 5.85 4.69 4.60 0.79

1-Hexene 0 100% 0.12 1.03 0.24 0.32 0.27 0.21 0.66

cis-2-Hexene 4 94% ND 0.97 0.14 0.23 0.17 0.21 0.94

trans-2-Hexene 0 100% 0.07 1.59 0.22 0.38 0.28 0.36 0.94

Isobutane 0 100% 0.83 9.53 2.94 3.12 2.65 1.87 0.60

Isobutene/1-Butene 0 100% 1.39 6.77 2.39 2.69 2.54 1.00 0.37

Isopentane 0 100% 9.84 69.60 21.25 25.28 22.67 13.14 0.52

Isoprene 0 100% 0.58 7.15 1.60 1.67 1.46 0.99 0.59
Table 5-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (CAMS5)

(Based on 68 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-59

Isopropylbenzene 0 100% 0.05 1.55 0.47 0.45 0.36 0.24 0.53

2-Methyl-1-Butene 0 100% 0.13 4.84 0.68 1.15 0.84 1.10 0.95

2-Methyl-2-Butene 0 100% 0.20 8.31 0.95 1.88 1.25 2.03 1.08

3-Methyl-1-Butene 6 91% ND 1.70 0.27 0.47 0.30 0.44 0.93

Methylcyclohexane 0 100% 0.57 4.03 1.19 1.38 1.26 0.69 0.50

Methylcyclopentane 0 100% 0.97 7.20 1.91 2.63 2.21 1.76 0.67

2-Methylheptane 0 100% 0.34 2.90 0.78 0.97 0.85 0.56 0.57

3-Methylheptane 0 100% 0.28 2.59 0.76 0.92 0.80 0.51 0.56

2-Methylhexane 0 100% 0.76 7.24 2.09 2.64 2.35 1.42 0.54

3-Methylhexane 0 100% 1.02 7.34 2.04 2.67 2.31 1.62 0.61

2-Methylpentane 0 100% 2.93 23.16 5.21 7.11 5.84 5.24 0.74

3-Methylpentane 0 100% 1.35 14.95 3.05 4.37 3.48 3.44 0.79

2-Methyl-1-Pentene 0 100% 0.07 1.45 0.26 0.40 0.30 0.35 0.89

4-Methyl-1-Pentene 27 60% ND 0.40 0.12 0.12 0.10 0.08 0.68

n-Nonane 0 100% 0.30 3.57 0.83 0.95 0.85 0.52 0.55

1-Nonene 8 88% ND 0.43 0.14 0.16 0.15 0.08 0.46

n-Octane 0 100% 0.50 4.34 1.09 1.33 1.17 0.74 0.55

1-Octene 6 91% ND 0.86 0.10 0.12 0.10 0.10 0.85
Table 5-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (CAMS5)

(Based on 68 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-60

n-Pentane 0 100% 2.18 24.01 5.63 7.75 6.30 5.60 0.72

1-Pentene 0 100% 0.07 3.68 0.70 0.98 0.74 0.79 0.81

cis-2-Pentene 0 100% 0.12 3.47 0.70 0.99 0.74 0.80 0.81

trans-2-Pentene 0 100% 0.27 6.46 1.03 1.69 1.25 1.53 0.91

"-Pinene 2 97% ND 2.29 0.32 0.42 0.32 0.38 0.91

$-Pinene 0 100% 0.29 2.54 0.82 0.96 0.84 0.52 0.54

Propane 0 100% 2.46 38.32 8.25 9.18 7.76 5.86 0.64

n-Propylbenzene 0 100% 0.29 3.11 0.79 0.92 0.82 0.48 0.52

Propylene 0 100% 0.89 6.12 1.53 1.90 1.70 1.02 0.54

Propyne 8 88% ND 0.64 0.14 0.16 0.13 0.10 0.63

Styrene 0 100% 0.65 3.19 1.21 1.39 1.30 0.55 0.40

Toluene 0 100% 5.51 44.78 11.76 15.06 12.86 9.20 0.61

n-Tridecane 3 96% ND 61.56 0.13 1.09 0.14 7.45 6.85

1-Tridecene 46 32% ND 0.17 0.14 0.12 0.11 0.04 0.35

1,2,3-Trimethylbenzene 0 100% 0.25 3.02 0.70 0.89 0.75 0.56 0.63

1,2,4-Trimethylbenzene 0 100% 1.39 12.67 2.75 3.76 3.26 2.27 0.60

1,3,5-Trimethylbenzene 0 100% 0.36 4.76 1.06 1.40 1.20 0.85 0.61

2,2,3-Trimethylpentane 0 100% 0.13 2.80 0.68 0.91 0.76 0.58 0.64
Table 5-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (CAMS5)

(Based on 68 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

5-61

2,2,4-Trimethylpentane 0 100% 1.41 10.66 2.62 3.55 3.04 2.18 0.62

2,3,4-Trimethylpentane 0 100% 0.58 4.22 1.08 1.40 1.22 0.82 0.59

n-Undecane 0 100% 0.19 3.46 0.85 0.97 0.83 0.58 0.60

1-Undecene 21 69% ND 0.25 0.10 0.11 0.10 0.05 0.43

m,p-Xylene 0 100% 3.38 30.43 6.91 9.38 7.96 6.00 0.64

o-Xylene 0 100% 1.38 10.42 2.53 3.32 2.86 2.00 0.60

TNMOC (w/ unknowns) 0 100% 115.25 645.14 200.37 246.52 222.04 124.86 0.51

TNMOC (speciated) 0 100% 74.38 539.96 161.84 201.40 177.86 110.23 0.55

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-62

Table 5-3

Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 69 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

Acetylene 0 100% 0.89 15.24 3.63 4.52 3.57 3.21 0.71

Benzene 0 100% 2.01 23.43 7.97 8.84 7.61 4.69 0.53

1,3-Butadiene 1 99% ND 2.32 0.36 0.53 0.39 0.46 0.86

n-Butane 0 100% 2.59 85.89 19.29 22.13 17.66 14.93 0.67

cis-2-Butene 0 100% 0.16 5.42 1.43 1.81 1.49 1.11 0.61

trans-2-Butene 1 99% ND 5.42 1.29 1.67 1.31 1.12 0.67

Cyclohexane 0 100% 0.37 52.49 2.47 4.60 2.57 7.93 1.73

Cyclopentane 0 100% 0.29 7.40 2.98 3.26 2.68 1.77 0.54

Cyclopentene 0 100% 0.33 4.97 1.62 1.78 1.54 0.97 0.54

n-Decane 0 100% 0.21 4.69 1.06 1.39 1.15 0.93 0.67

1-Decene 69 0% ND ND 0.14 0.14 0.14 0.00 0.00

m-Diethylbenzene 0 100% 0.07 1.59 0.59 0.65 0.56 0.30 0.46

p-Diethylbenzene 0 100% 0.06 1.62 0.57 0.61 0.54 0.30 0.48

2,2-Dimethylbutane 0 100% 0.29 10.00 2.49 2.83 2.36 1.71 0.61

2,3-Dimethylbutane 0 100% 3.23 97.60 32.64 36.18 29.07 21.64 0.60

2,3-Dimethylpentane 0 100% 0.10 5.59 2.31 2.39 2.06 1.17 0.49

2,4-Dimethylpentane 0 100% 0.31 5.93 2.28 2.41 2.07 1.22 0.51

n-Dodecane 4 94% ND 5.00 0.49 0.78 0.52 0.93 1.19
Table 5-3 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 69 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-63

1-Dodecene 19 72% ND 4.34 0.16 0.26 0.18 0.51 1.96

Ethane 0 100% 2.47 76.21 11.30 13.93 10.23 12.63 0.91

Ethylbenzene 0 100% 1.02 12.33 4.09 4.87 4.16 2.72 0.56

2-Ethyl-1-Butene 69 0% ND ND 0.12 0.12 0.12 0.00 0.00

Ethylene 0 100% 1.50 19.51 4.20 5.44 4.32 4.12 0.76

m-Ethyltoluene 0 100% 1.05 11.14 3.90 4.47 3.86 2.47 0.55

o-Ethyltoluene 0 100% 0.39 4.38 1.70 1.86 1.62 0.96 0.51

p-Ethyltoluene 0 100% 0.49 5.73 2.06 2.51 2.20 1.27 0.51

n-Heptane 0 100% 0.93 12.99 4.60 5.00 4.22 2.73 0.55

1-Heptene 60 13% ND 1.13 0.26 0.29 0.28 0.15 0.51

n-Hexane 0 100% 1.98 41.99 13.84 15.27 12.62 8.59 0.56

1-Hexene 0 100% 0.13 2.01 0.64 0.73 0.61 0.41 0.57

cis-2-Hexene 1 99% ND 1.87 0.69 0.72 0.56 0.42 0.58

trans-2-Hexene 0 100% 0.07 3.45 1.19 1.28 0.99 0.76 0.60

Isobutane 0 100% 1.04 20.71 4.55 5.71 4.51 4.21 0.74

Isobutene/1-Butene 0 100% 1.27 20.42 2.76 3.83 3.13 3.08 0.80

Isopentane 0 100% 11.53 160.84 52.10 61.12 52.06 33.94 0.56

Isoprene 0 100% 0.38 2.99 0.96 1.08 1.00 0.46 0.43
Table 5-3 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 69 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-64

Isopropylbenzene 0 100% 0.04 1.37 0.56 0.60 0.51 0.27 0.45

2-Methyl-1-Butene 0 100% 0.28 10.28 3.17 3.81 2.99 2.48 0.65

2-Methyl-2-Butene 0 100% 0.34 17.48 6.08 6.93 5.36 4.25 0.61

3-Methyl-1-Butene 3 96% ND 4.05 0.84 1.15 0.83 0.91 0.79

Methylcyclohexane 0 100% 0.54 7.38 2.37 2.41 2.10 1.26 0.52

Methylcyclopentane 0 100% 1.01 17.09 6.66 6.99 5.84 3.77 0.54

2-Methylheptane 0 100% 0.28 4.21 1.49 1.69 1.47 0.88 0.52

3-Methylheptane 0 100% 0.24 3.91 1.47 1.65 1.41 0.87 0.53

2-Methylhexane 0 100% 1.42 13.99 5.01 5.59 4.84 2.91 0.52

3-Methylhexane 0 100% 1.09 15.51 5.50 5.99 5.07 3.29 0.55

2-Methylpentane 0 100% 2.90 52.49 19.40 20.94 17.48 11.49 0.55

3-Methylpentane 0 100% 1.42 34.60 12.32 13.04 10.75 7.27 0.56

2-Methyl-1-Pentene 0 100% 0.09 3.27 1.17 1.29 1.03 0.73 0.57

4-Methyl-1-Pentene 4 94% ND 0.86 0.32 0.35 0.28 0.20 0.58

n-Nonane 0 100% 0.29 3.56 1.28 1.49 1.30 0.77 0.52

1-Nonene 4 94% ND 0.71 0.20 0.24 0.21 0.14 0.59

n-Octane 0 100% 0.44 5.29 1.92 2.13 1.87 1.06 0.50

1-Octene 4 94% ND 0.36 0.13 0.14 0.13 0.06 0.45
Table 5-3 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 69 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-65

n-Pentane 0 100% 2.89 72.32 20.94 25.23 20.12 15.90 0.63

1-Pentene 0 100% 0.24 8.35 2.20 2.73 2.22 1.73 0.64

cis-2-Pentene 0 100% 0.19 7.13 2.64 3.03 2.46 1.69 0.56

trans-2-Pentene 0 100% 0.42 13.89 5.06 5.76 4.63 3.31 0.57

"-Pinene 2 97% ND 2.34 0.40 0.58 0.43 0.50 0.86

$-Pinene 0 100% 0.29 2.76 0.87 0.96 0.85 0.49 0.51

Propane 0 100% 2.27 74.41 11.74 14.83 11.06 12.47 0.84

n-Propylbenzene 0 100% 0.28 3.39 1.23 1.46 1.29 0.72 0.49

Propylene 0 100% 0.74 10.33 2.27 2.94 2.36 2.19 0.74

Propyne 8 88% ND 0.95 0.19 0.27 0.21 0.20 0.77

Styrene 0 100% 0.62 4.50 1.30 1.50 1.39 0.67 0.45

Toluene 0 100% 6.12 75.99 25.90 28.23 23.94 15.66 0.55

n-Tridecane 6 91% ND 4.86 0.14 0.26 0.15 0.59 2.30

1-Tridecene 44 36% ND 5.30 0.14 0.21 0.12 0.63 3.03

1,2,3-Trimethylbenzene 0 100% 0.27 3.86 1.27 1.49 1.27 0.83 0.56

1,2,4-Trimethylbenzene 0 100% 1.41 16.14 5.33 6.28 5.41 3.45 0.55

1,3,5-Trimethylbenzene 0 100% 0.44 5.79 1.88 2.31 1.98 1.28 0.55

2,2,3-Trimethylpentane 0 100% 0.24 5.02 1.66 1.86 1.55 1.08 0.58
Table 5-3 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 69 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

5-66

2,2,4-Trimethylpentane 0 100% 1.40 18.47 6.53 7.66 6.53 4.23 0.55

2,3,4-Trimethylpentane 0 100% 0.50 7.33 2.37 2.75 2.33 1.57 0.57

n-Undecane 0 100% 0.15 24.37 0.87 1.47 0.97 2.90 1.97

1-Undecene 17 75% ND 1.74 0.13 0.18 0.13 0.25 1.44

m,p-Xylene 0 100% 3.29 41.63 14.79 16.53 14.00 9.37 0.57

o-Xylene 0 100% 1.27 13.85 4.81 5.69 4.87 3.15 0.55

TNMOC (w/ unknowns) 0 100% 113.97 1,164.63 454.51 509.22 446.05 255.09 0.50

TNMOC (speciated) 0 100% 89.77 1,010.04 390.07 434.69 375.62 225.29 0.52

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-67

Table 5-4

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX)

(Based on 62 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

Acetylene 0 100% 0.96 21.87 3.92 5.50 4.06 4.71 0.86

Benzene 0 100% 1.44 14.75 3.96 4.46 3.94 2.57 0.58

1,3-Butadiene 0 100% 0.13 2.04 0.39 0.50 0.41 0.38 0.77

n-Butane 0 100% 1.92 29.48 5.75 7.26 5.93 5.38 0.74

cis-2-Butene 0 100% 0.12 2.05 0.56 0.62 0.54 0.37 0.59

trans-2-Butene 0 100% 0.09 1.76 0.44 0.54 0.46 0.34 0.63

Cyclohexane 0 100% 0.25 84.57 1.17 4.27 1.51 13.36 3.13

Cyclopentane 0 100% 0.16 2.39 0.68 0.83 0.71 0.53 0.64

Cyclopentene 0 100% 0.16 3.00 0.89 1.14 0.93 0.73 0.64

n-Decane 0 100% 0.21 5.33 1.06 1.45 1.13 1.09 0.75

1-Decene 62 0% ND ND 0.14 0.14 0.14 0.00 0.00

m-Diethylbenzene 0 100% 0.05 1.35 0.48 0.50 0.42 0.27 0.54

p-Diethylbenzene 0 100% 0.06 1.09 0.41 0.42 0.36 0.22 0.53

2,2-Dimethylbutane 0 100% 0.17 2.71 0.92 1.03 0.91 0.54 0.53

2,3-Dimethylbutane 0 100% 0.74 34.90 6.01 8.03 6.14 7.14 0.89

2,3-Dimethylpentane 0 100% 0.17 4.23 1.16 1.29 1.17 0.63 0.49

2,4-Dimethylpentane 0 100% 0.18 2.83 0.86 0.97 0.86 0.52 0.54

n-Dodecane 6 90% ND 9.49 0.42 0.84 0.46 1.53 1.84
Table 5-4 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX)

(Based on 62 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-68

1-Dodecene 22 65% ND 2.31 0.14 0.21 0.15 0.30 1.41

Ethane 0 100% 2.58 42.52 8.30 9.92 8.01 7.45 0.75

Ethylbenzene 0 100% 0.63 10.08 2.49 3.12 2.56 2.09 0.67

2-Ethyl-1-Butene 62 0% ND ND 0.12 0.12 0.12 0.00 0.00

Ethylene 0 100% 0.45 20.51 4.62 5.67 4.66 4.07 0.72

m-Ethyltoluene 0 100% 0.90 9.38 2.10 2.49 2.14 1.72 0.69

o-Ethyltoluene 0 100% 0.22 3.64 0.99 1.14 1.00 0.70 0.61

p-Ethyltoluene 0 100% 0.39 4.80 1.27 1.46 1.28 0.90 0.61

n-Heptane 0 100% 0.60 9.91 2.03 2.55 2.14 1.72 0.68

1-Heptene 53 15% ND 0.70 0.26 0.25 0.24 0.08 0.34

n-Hexane 0 100% 1.06 15.40 3.49 4.52 3.69 3.18 0.70

1-Hexene 1 98% ND 0.78 0.19 0.23 0.19 0.17 0.71

cis-2-Hexene 12 81% ND 0.60 0.12 0.15 0.12 0.14 0.89

trans-2-Hexene 4 94% ND 1.08 0.16 0.24 0.18 0.24 0.98

Isobutane 0 100% 0.95 10.52 2.90 3.46 2.88 2.22 0.64

Isobutene/1-Butene 0 100% 1.24 15.72 2.69 3.27 2.83 2.35 0.72

Isopentane 0 100% 7.51 82.67 22.25 24.65 21.67 14.45 0.59

Isoprene 0 100% 0.39 3.17 1.23 1.25 1.14 0.52 0.42
Table 5-4 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX)

(Based on 62 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-69

Isopropylbenzene 3 95% ND 1.07 0.47 0.47 0.40 0.22 0.47

2-Methyl-1-Butene 0 100% 0.22 4.16 0.62 0.87 0.68 0.81 0.92

2-Methyl-2-Butene 0 100% 0.28 6.57 0.85 1.32 0.96 1.43 1.08

3-Methyl-1-Butene 7 89% ND 2.67 0.18 0.43 0.25 0.55 1.27

Methylcyclohexane 0 100% 0.45 5.99 1.50 1.75 1.51 1.04 0.60

Methylcyclopentane 0 100% 0.55 7.53 1.94 2.22 1.88 1.46 0.66

2-Methylheptane 0 100% 0.17 3.20 0.89 1.01 0.89 0.57 0.57

3-Methylheptane 0 100% 0.15 3.19 0.77 0.94 0.81 0.57 0.61

2-Methylhexane 0 100% 0.87 10.65 2.17 2.61 2.29 1.60 0.61

3-Methylhexane 0 100% 0.71 11.17 2.29 2.70 2.31 1.78 0.66

2-Methylpentane 0 100% 1.52 17.44 4.66 5.82 4.85 3.98 0.68

3-Methylpentane 0 100% 0.77 11.69 2.80 3.57 2.95 2.57 0.72

2-Methyl-1-Pentene 1 98% ND 0.99 0.19 0.27 0.22 0.22 0.83

4-Methyl-1-Pentene 28 55% ND 0.31 0.12 0.11 0.09 0.06 0.57

n-Nonane 0 100% 0.23 3.23 0.88 1.09 0.94 0.65 0.60

1-Nonene 7 89% ND 0.69 0.15 0.19 0.16 0.12 0.64

n-Octane 0 100% 0.34 4.45 1.15 1.36 1.20 0.81 0.60

1-Octene 13 79% ND 0.28 0.11 0.12 0.11 0.05 0.45
Table 5-4 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX)

(Based on 62 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

5-70

n-Pentane 0 100% 1.90 23.60 5.60 6.92 5.71 4.90 0.71

1-Pentene 0 100% 0.14 2.51 0.58 0.74 0.63 0.53 0.71

cis-2-Pentene 0 100% 0.11 4.89 0.60 0.80 0.63 0.74 0.93

trans-2-Pentene 0 100% 0.30 5.64 0.87 1.26 1.01 1.10 0.87

"-Pinene 3 95% ND 3.37 0.41 0.58 0.41 0.62 1.08

$-Pinene 1 98% ND 2.94 0.72 0.84 0.71 0.50 0.59

Propane 0 100% 3.26 49.47 10.55 13.04 10.48 9.75 0.75

n-Propylbenzene 0 100% 0.20 2.73 0.77 0.87 0.77 0.50 0.57

Propylene 0 100% 0.82 9.43 2.29 2.77 2.37 1.81 0.65

Propyne 12 81% ND 0.83 0.17 0.25 0.21 0.17 0.67

Styrene 0 100% 0.30 4.94 1.23 1.60 1.36 1.02 0.64

Toluene 0 100% 3.49 940.16 12.28 29.63 13.04 117.99 3.98

n-Tridecane 11 82% ND 2.67 0.14 0.22 0.16 0.34 1.54

1-Tridecene 45 27% ND 0.14 0.14 0.12 0.11 0.03 0.28

1,2,3-Trimethylbenzene 0 100% 0.16 3.61 0.77 0.95 0.79 0.69 0.73

1,2,4-Trimethylbenzene 0 100% 0.89 13.68 3.14 3.66 3.11 2.64 0.72

1,3,5-Trimethylbenzene 0 100% 0.23 5.46 1.31 1.47 1.24 1.04 0.71

2,2,3-Trimethylpentane 0 100% 0.26 3.10 0.71 0.88 0.74 0.61 0.69
Table 5-4 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Dallas, TX (DLTX)

(Based on 62 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

5-71

2,2,4-Trimethylpentane 0 100% 1.01 11.72 2.82 3.38 2.86 2.32 0.69

2,3,4-Trimethylpentane 0 100% 0.44 4.58 1.12 1.31 1.14 0.85 0.65

n-Undecane 2 97% ND 17.14 0.91 1.53 0.95 2.33 1.53

1-Undecene 23 63% ND 0.69 0.14 0.13 0.11 0.11 0.83

m,p-Xylene 0 100% 1.95 33.71 7.71 10.09 7.97 7.38 0.73

o-Xylene 0 100% 0.77 11.84 2.79 3.46 2.85 2.36 0.68

TNMOC (w/ unknowns) 0 100% 89.20 1,267.42 221.66 266.14 226.71 191.18 0.72

TNMOC (speciated) 0 100% 71.82 1,394.53 181.21 218.09 179.43 191.20 0.88

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
5-72

Table 5-5

SNMOC with the Highest Geometric Mean Concentrations

CAMS5 CAMS13 DLTX

Compound Concentration Compound Concentration Compound Concentration

Geometric Mean Geometric Mean Geometric Mean

(ppbC) (ppbC) (ppbC)

Isopentane 22.67 Isopentane 52.06 Isopentane 21.67

Toluene 12.86 2,3-Dimethylbutane 29.07 Toluene 13.04

2,3-Dimethylbutane 8.45 Toluene 23.94 Propane 10.48

Ethane 8.29 n-Pentane 20.12 Ethane 8.01

m,p-Xylene 7.96 n-Butane 17.66 m,p-Xylene 7.97

Propane 7.76 2-Methylpentane 17.48 2,3-Dimethylbutane 6.14

n-Butane 6.64 m,p-Xylene 14.00 n-Butane 5.93

n-Pentane 6.30 n-Hexane 12.62 n-Pentane 5.71

2-Methylpentane 5.84 Propane 11.06 2-Methylpentane 4.85

n-Hexane 4.69 3-Methylpentane 10.75 Ethylene 4.66
5-73

Table 5-6

Emissions Source Profiles for Selected SNMOC

Compound

Relative Amount of Compound Emitted (%), by Source Type

Mobile Source Emissions from Emissions from

Emissions Gasoline Vapor Petroleum Refineries

Source profiles for the alkanes shown in Figure 5-11

n-Butane 9.0 30.2 17.6

2,3-Dimethylbutane NA NA NA

Ethane 3.1 0.0 4.8

n-Hexane 1.4 2.0 3.6

Isopentane 7.2 31.4 16.8

2-Methylpentane 2.9 4.9 7.2

3-Methylpentane 1.9 2.5 4.3

n-Pentane 3.2 13.2 7.3

Propane 6.7 0.39 21.3

Source profiles for the olefins shown in Figure 5-10

Acetylene 7.8 0.0 0.1

Ethylene 18.2 0.0 0.7

Isobutene/1-Butene NA NA NA

Propylene 3.2 0.0 0.80

Notes: Source profile data were copied from Scheff and Wadden 1993.

NA = Source profile data were not listed for this compound in Scheff and Wadden 1993.

As Section 5.2.2.2 explains, acetylene is an alkyne, but is included among the olefins for the composition calculations.

The source profiles reported in Scheff and Wadden 1993 were normalized to a list of 23 organic compounds. 

Therefore, the data in this table are useful for understanding the relative quantities of only selected compounds

in emissions from specific groups of sources. Since emissions sources emit many compounds in addition to

the 23 considered in Scheff and Wadden 1993, the percentages listed in this table do not characterize each

compound’s actual percent of emissions from these sources. As an example, according to this table, ethane

accounts for 3.1 percent of the emissions of 23 organic compounds from motor vehicles, but ethane accounts

for a much smaller proportion of the emissions of all organic compounds from motor vehicles. 
5-74

Table 5-7

Abbreviations Used in Figures 5-16, 5-17, and 5-18

Abbreviation Compound

124tmb 1,2,4-Trimethylbenzene

1bute Isobutene/1-Butene

224tmp 2,2,4-Trimethylpentane

23dmb 2,3-Dimethylbutane

2m2be 2-Methyl-2-Butene

2mhxa 2-Methylhexane

2mpna 2-Methylpentane

3mhxa 3-Methylhexane

acetyl Acetylene

benz Benzene

ebenz Ethylbenzene

etha Ethane

ethyl Ethylene

isbta Isobutane

ispna Isopentane

m/pxy m,p-Xylene

mcpna Methylcyclopentane

nbuta n-Butane

nhexa n-Hexane

npnta n-Pentane

propa Propane

prpyl Propylene

t2pne trans-2-Pentene

tolu Toluene
5-75

Table 5-8

Summary Statistics for Carbonyl Concentrations Measured at Dallas, TX (CAMS5)

(Based on 9 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetaldehyde 1 89% ND 13.94 1.76 3.07 1.18 4.17 1.36

Acetone 0 100% 1.24 13.93 4.13 5.11 4.03 3.88 0.76

Acrolein 1 89% ND 0.22 0.13 0.12 0.08 0.07 0.57

Benzaldehyde 4 56% ND 0.45 0.12 0.15 0.04 0.18 1.17

Butyr/Isobutyraldehyde 0 100% 0.07 2.73 0.55 0.75 0.47 0.81 1.08

Crotonaldehyde 7 22% ND 0.33 0.00 0.05 0.01 0.11 2.05

2,5-Dimethylbenzaldehyde 7 22% ND 0.33 0.00 0.06 0.01 0.12 2.01

Formaldehyde 0 100% 2.95 14.95 4.78 6.01 5.24 3.79 0.63

Hexanaldehyde 1 89% ND 0.46 0.12 0.16 0.10 0.13 0.84

Isovaleraldehyde 5 44% ND 0.24 0.00 0.06 0.02 0.09 1.37

Propionaldehyde 2 78% ND 3.13 0.25 0.51 0.13 0.99 1.92

Tolualdehydes 6 33% ND 0.39 0.01 0.10 0.03 0.14 1.40

Valeraldehyde 5 44% ND 0.43 0.01 0.07 0.02 0.14 1.84

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
5-76

Table 5-9

Summary Statistics for Carbonyl Concentrations Measured at Fort Worth, TX (CAMS13)

(Based on 11 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetaldehyde 0 100% 0.72 2.55 1.16 1.41 1.29 0.64 0.45

Acetone 0 100% 0.56 6.35 2.77 2.81 1.95 2.15 0.77

Acrolein 6 45% ND 0.34 0.00 0.07 0.02 0.11 1.51

Benzaldehyde 4 64% ND 0.28 0.10 0.11 0.04 0.10 0.94

Butyr/Isobutyraldehyde 1 91% ND 2.03 0.44 0.50 0.28 0.53 1.06

Crotonaldehyde 11 0% ND ND 0.00 0.00 0.00 0.00 0.00

2,5-Dimethylbenzaldehyde 6 45% ND 0.30 0.00 0.10 0.02 0.12 1.24

Formaldehyde 0 100% 1.46 4.73 2.68 3.02 2.79 1.22 0.40

Hexanaldehyde 4 64% ND 0.23 0.09 0.09 0.04 0.08 0.88

Isovaleraldehyde 7 36% ND 0.14 0.00 0.03 0.01 0.04 1.47

Propionaldehyde 1 91% ND 0.36 0.18 0.18 0.13 0.10 0.55

Tolualdehydes 11 0% ND ND 0.01 0.01 0.01 0.00 0.00

Valeraldehyde 7 36% ND 0.11 0.01 0.03 0.01 0.04 1.28

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
5-77

Table 5-10

Summary Statistics for Carbonyl Concentrations Measured at Dallas, TX (DLTX)

(Based on 9 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetaldehyde 0 100% 0.65 2.45 1.42 1.39 1.31 0.52 0.37

Acetone 0 100% 2.40 3.55 3.15 3.11 3.08 0.39 0.13

Acrolein 1 89% ND 0.29 0.12 0.14 0.09 0.09 0.67

Benzaldehyde 1 89% ND 0.20 0.11 0.11 0.08 0.05 0.47

Butyr/Isobutyraldehyde 1 89% ND 1.38 0.39 0.46 0.26 0.39 0.86

Crotonaldehyde 8 11% ND 0.08 0.00 0.01 0.01 0.02 1.92

2,5-Dimethylbenzaldehyde 6 33% ND 0.19 0.00 0.04 0.01 0.07 1.51

Formaldehyde 0 100% 1.95 5.93 3.29 3.55 3.37 1.24 0.35

Hexanaldehyde 0 100% 0.05 0.25 0.13 0.13 0.12 0.06 0.46

Isovaleraldehyde 4 56% ND 0.15 0.08 0.06 0.03 0.06 0.94

Propionaldehyde 1 89% ND 0.29 0.16 0.16 0.11 0.08 0.52

Tolualdehydes 7 22% ND 0.15 0.01 0.04 0.02 0.06 1.44

Valeraldehyde 8 11% ND 0.13 0.01 0.02 0.01 0.04 2.13

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
.
6-1

6.0 Monitoring Results for Juarez, Mexico (JUMX)

This section summarizes and interprets the total NMOC, SNMOC, and carbonyl

monitoring data collected at the Juarez, Mexico (JUMX), monitoring station during the 1998

NMOC/SNMOC Monitoring Program; total NMOC and SNMOC monitoring data from previous

years are also included for the purpose of investigating annual variations.

Figure 6-1 shows the location of the JUMX monitoring station and illustrates land use in

its vicinity. Since the monitoring station is approximately 1 mile from the Rio Grande (the river

that separates Juarez, Mexico, from El Paso, Texas), emissions from motor vehicles and

industrial facilities within both El Paso and Juarez are likely to impact levels of air pollution at

JUMX. Though the monitoring station is on the grounds of a university (Instituto Technologico

Monterrey), the surrounding land is used for a wide range of commercial, industrial, and

agricultural purposes. More specifically, several small industrial facilities are located to the

north, west, and southwest of the station; open space and farmland are located to the east and

southeast; and a nearby area that was previously open space is being developed into a

residential neighborhood.

During the 1998 NMOC/SNMOC Monitoring Program, the JUMX station collected

ambient air samples on weekday mornings in August and September, 1998. Overall, SNMOC

samples were collected on 21 days and carbonyl samples on 4 days; every attempted sampling

event was valid. Thus, the completeness for both the SNMOC and carbonyl sampling, defined

as the percentage of attempted samples that are valid, was 100 percent.

The remainder of this section comments on notable trends in the monitoring data

collected at JUMX. Section 6.1 provides detailed analyses of the total NMOC monitoring data,

including comparisons to selected meteorological conditions and evaluations of long-term

trends. Section 6.2 puts the SNMOC monitoring data into perspective by commenting on the

composition of air samples, annual variations in air quality, and ozone formation potential. 

Section 6.3 briefly summarizes the four carbonyl sampling events at JUMX, and Section 6.4
6-2

provides an overview of air quality trends observed at JUMX since the 1995 NMOC/SNMOC

Monitoring Program.

6.1 Total NMOC Monitoring Data

As Section 2.3.2 noted, the SNMOC sampling and analytical method measures

concentrations of total NMOC, in addition to measuring concentrations of 80 organic

compounds. This section summarizes the total NMOC measurements that were made at JUMX

using the SNMOC sampling and analytical method. More specifically, the following discussion

puts the total NMOC monitoring data from JUMX into context by presenting data summary

parameters (Section 6.1.1), associations between total NMOC levels and selected

meteorological parameters (Section 6.1.2), and a review of annual variations in total NMOC

levels (Section 6.1.3).

When reading these sections, it is important to remember that total NMOC consists of a

wide range of organic compounds (e.g., alkanes, olefins, aromatics, oxygenates, and halogenated

hydrocarbons), thus providing a measure of the total air concentration for many different “ozone

precursors.” However, total NMOC should not be considered a measure of total levels of air

pollution, since many common air pollutants (e.g., inorganic acids, particulate matter, and

heavier organic compounds) are not a subset of total NMOC.

6.1.1 Data Summary

Using the four data summary parameters that were defined in Section 3.1, Table 6-1

presents a thorough, yet concise, overview of the total NMOC measurements at JUMX during the

summer of 1998. Key findings from the data summary follow:

• Prevalence. Total NMOC was measured in every sample collected at JUMX during the

1998 program, and each measured concentration was at least an order of magnitude

greater than the estimated method detection limit of 0.005 ppmC (or 5 ppbC). Thus, the

prevalence of total NMOC at JUMX was 100 percent. With no nondetect observations

in the total NMOC data set, the summary statistics presented in Table 6-1 are believed to

be highly representative of air quality trends at JUMX.
6-3

• Concentration range. According to Table 6-1, total NMOC concentrations at JUMX

ranged from 0.173 ppmC to 20.317 ppmC during the 1998 program—a range that was

notably broader than the range observed at every other monitoring station. In fact, the

highest concentration observed at JUMX (20.317 ppmC) is the highest level of total

NMOC that has been measured at any station that participated in the 1995, 1996, 1997,

and 1998 NMOC/SNMOC Monitoring Programs. On the date the highest concentration

occurred (September 18, 1998), a duplicate sample was collected and was later

analyzed in replicate. The four concentrations measured from these analyses (19.2

ppmC, 23.2 ppmC, 19.0 ppmC, and 19.8 ppmC) were in excellent agreement, thus ruling

out the possibility that the highest concentration at JUMX might have resulted from a

sampling or analytical bias.

Not only was the magnitude of the highest concentration at JUMX considerably higher

than that observed at the other monitoring stations, but the frequency with which elevated

concentrations occurred at JUMX was also considerably higher than that observed at the

other stations. More specifically, total NMOC concentrations exceeded 1.0 ppmC at

JUMX during five sampling events, but they exceeded this level no more than twice at

any of the other stations. The significance of this trend is more apparent when expressed

as frequencies: Total NMOC concentrations exceeded 1.0 ppmC at JUMX in 24 percent

of the sampling events, but exceeded this level at the other stations in no more than

3 percent of the sampling events. Thus, elevated concentrations of total NMOC were

much more common at JUMX than at the other stations that participated in the 1998

NMOC/SNMOC Monitoring Program. Section 6.2.2 provides information on the

composition of air samples at JUMX on days when total NMOC concentrations

exceeded 1.0 ppmC.

For greater insight into the concentration range at JUMX, Figure 6-2 presents a histogram

of the total NMOC monitoring data for this station during the 1998 program. The figure

indicates that roughly one third of the samples had concentrations in the range

0.1–0.4 ppmC, roughly one third in the range 0.5–0.7 ppmC, and roughly one third

greater than 0.9 ppmC. This distribution suggests that ambient air concentrations of total

NMOC at JUMX during the morning hours on summer days tended to span a wide range

of concentrations, as opposed to being limited to a fairly narrow range, as was observed

at the other monitoring stations (see Sections 5.1.1, 7.1, and 8.1.1).

• Central tendency. During the 1998 program, the geometric mean concentration of total

NMOC at JUMX was 0.84 ppmC. Not only was this the highest geometric mean

concentration observed among the six stations that participated in the 1998 program, but

this was the highest geometric mean concentration observed at JUMX since the station

first participated in the NMOC/SNMOC Monitoring Program in 1995. 

Not surprisingly, the geometric mean concentration at JUMX was influenced by the

outlier measurement of 20.317 ppmC, as well as by the four other measurements where
6-4

total NMOC concentrations exceeded 1.0 ppmC. However, even when the five highest

measurements are excluded from the central tendency calculation, the geometric mean

concentration of total NMOC at JUMX still exceeds the geometric mean levels observed

during the 1995, 1996, and 1997 programs. Therefore, levels of total NMOC in Juarez

during the summer of 1998, on average, appear to have been higher than they were in

1995, 1996, and 1997. Section 6.1.3 revisits this issue.

• Variability. According to Table 6-1, the standard deviation of the total NMOC levels

measured at JUMX was 4.414 ppmC, and the coefficient of variation was 2.14. This

data variability is considerably greater than the variability that was observed at JUMX

in previous monitoring programs. For comparison, the coefficients of variation for total

NMOC measurements at JUMX during the 1995, 1996, and 1997 programs were all

lower than 1.0. The greater variability during the current program largely results from

the many elevated concentrations measured at JUMX during the summer of 1998.

6.1.2 Comparison to Selected Meteorological Conditions

To provide greater insight into the trends and patterns among the total NMOC

concentrations at Juarez, this section compares the measured levels of total NMOC to selected

meteorological conditions. The following analyses consider 3-hour average observations of

relative humidity, precipitation, temperature, wind direction, and wind speed, all of which were

measured between 5:00 and 8:00 a.m. at the El Paso International Airport. Since this airport is

located within 5 miles of the monitoring station, the meteorological data are believed to be

reasonably representative of conditions at the JUMX site. The outlier concentration of

20.317 ppmC was not included in the comparisons to meteorological conditions, because this

unusually high concentration, which was believed to represent an episodic event, tended to bias

the calculations. 

To enable readers to compare data trends from the 1998 program to those from earlier

programs, the following analyses of associations between local meteorological conditions and

total NMOC concentrations are presented in a format almost identical to that used for JUMX in

Section 5.2.3.2 of the 1997 NMOC/SNMOC report.
6-5

An overview of the comparisons of meteorological conditions to total NMOC levels at

JUMX follows:

• Humidity. According to Figure 6-3, concentrations of total NMOC at JUMX, on average,

tended to be higher on mornings with lower relative humidity; the 1997 NMOC/SNMOC

report indicated a similar observation for total NMOC measurements at JUMX. It

should be noted, however, that the difference in concentrations for the two categories

shown in Figure 6-3 is marginal (less than 25 percent) and not statistically significant. 

Moreover, no statistically significant trends were observed upon grouping the total

NMOC levels into different ranges of relative humidity observations. Therefore, the

data collected during the 1998 program are not sufficient for determining the association

between relative humidity and levels of total NMOC at JUMX. Analysis of future

monitoring data is needed to characterize data trends between these parameters.

• Precipitation. Since no measurable rain was recorded at the El Paso International

Airport on any of the 21 days that SNMOC samples were collected at JUMX, the

monitoring data collected during the 1998 program are not sufficient for evaluating

associations between total NMOC concentrations at JUMX and precipitation.

 

• Temperature. Consistent with findings presented in the 1996 and 1997 reports,

Figure 6-3 shows that total NMOC concentrations measured on relatively warm

mornings at JUMX were, on average, considerably higher than those measured on cooler

mornings. In fact, the average concentration of total NMOC on the 13 mornings when the

temperature exceeded 75 degrees Fahrenheit was more than twice the average

concentration measured on the remaining 7 mornings. However, this concentration

difference, as well as the concentration differences for other ranges of temperatures, was

not statistically significant. Therefore, although the monitoring data certainly imply that

levels of total NMOC at JUMX are higher on warmer mornings, not enough samples

were collected to be certain of this association. Further research is needed to determine

the nature and extent of correlations between temperature and total NMOC

concentrations at JUMX.

• Wind Speed. According to Figure 6-3, total NMOC concentrations at JUMX on windy

mornings were, on average, notably lower than those on mornings with light or calm

winds—a trend that was also observed at JUMX during the 1997 program. During the

1998 program, total NMOC concentrations on mornings with wind speeds less than or

equal to 5 miles per hour were more than four times higher than those on windier

mornings; this concentration difference was statistically significant. This general trend

of decreasing levels of air pollution on windier days was observed at all six monitoring

stations that participated in the 1997 NMOC/SNMOC Monitoring Program. A likely

explanation for this trend is the fact that air pollutants disperse more efficiently as wind

speeds increase (USEPA 1995).
6-6

• Wind Direction. The scatter plot in Figure 6-4 shows how concentrations of total

NMOC at JUMX varied with wind direction during the 1998 program. Readers should

note that results from two valid sample dates are not displayed in the figure because

winds were either calm or variable while these samples were collected. Moreover, the

outlier concentration of 20.317 ppmC is not shown in the figure, since this data point

appears to reflect unique or “episodic” air quality conditions. Overall, Figure 6-4

clearly shows that, during the morning hours, the wind at El Paso International Airport

most often blew from the north to northeast. However, the figure does not indicate any

noteworthy clustering of elevated concentrations about a particular wind direction. A

similar finding was observed from the data collected at JUMX during the 1997 program: 

Wind at El Paso International Airport almost always blew from wind directions

0 degrees to 180 degrees, but total NMOC concentrations did not appear to be notably

higher when winds blew from any specific direction. In short, the total NMOC

monitoring data from the 1997 and 1998 programs suggest that ambient air

concentrations of total NMOC at JUMX are not significantly correlated with the wind

direction observed at the El Paso International Airport. This absence of correlations

might result, to a certain extent, from surface wind patterns at the El Paso International

Airport that differ from those at JUMX.

Though the previous discussion describes apparent associations between total NMOC

concentrations at JUMX and selected meteorological conditions, readers should note that the

analyses presented in this section are only a small subset of the numerous types of graphical,

numerical, and statistical analyses that could be performed on this data set. For greater insight

into subtle trends among the total NMOC monitoring data and meteorological data, researchers

are encouraged to examine these data sets further using more sophisticated analyses, such as

multivariate statistical analyses. Such analyses are not included in the scope of this report.

6.1.3 Annual Variations

The JUMX monitoring station has participated in the NMOC/SNMOC Monitoring

Program every year since 1995, thus providing 4 years of monitoring data that characterize

levels of air pollution during the summertime morning hours. To put annual variations in air

quality into perspective, this section describes how average levels of total NMOC and peak

levels of total NMOC have changed at JUMX from year to year. Though the monitoring
More specifically, air samples were collected at JUMX from July 13 to September 28 during the 1995 program, from 1

June 6 to September 26 during the 1996 program, from July 15 to September 30 during the 1997 program, and from August 25

to September 29 during the 1998 program.

6-7

schedules at JUMX varied slightly between the 1995 and 1998 programs , these differing 1

schedules are not expected to bias the analysis of annual variations.

An overview of the key findings regarding annual variations in air quality at JUMX

follows:

C Changes in average concentrations of total NMOC. Figure 6-5 illustrates how average

levels of total NMOC at JUMX have changed from the summer of 1995 through the

summer of 1998. According to the figure, the average concentrations of total NMOC at

JUMX increased between the 1995 and 1997 programs, but the increases between 1995

and 1996 and between 1996 and 1997 were marginal and not statistically significant. On

the other hand, the total NMOC levels during the 1998 program were, on average, more

than three times higher than the levels observed during the 1995–1997 programs. This

considerable increase, which was statistically significant, largely resulted from an

outlier concentration measured during the 1998 program (20.317 ppmC). However,

even when the outlier concentration is omitted from the analysis, the average

concentration of total NMOC during the 1998 program is still more than twice as high as

the average concentrations measured during the 1995, 1996, and 1997 programs; this

concentration difference is also statistically significant. Overall, the annual variations

indicate that concentrations of total NMOC at JUMX, on average, were virtually

unchanged between the summers of 1995, 1996, and 1997, but increased considerably in

the summer of 1998.

C Changes in peak concentrations of total NMOC. As another indicator of annual

variations in air quality, Figure 6-6 indicates how often total NMOC concentrations at

JUMX exceeded 1.0 ppmC during the 1995, 1996, 1997, and 1998 programs. The figure

clearly illustrates that the frequency of elevated concentrations of total NMOC

(arbitrarily defined here as exceeding 1.0 ppmC) has increased dramatically at JUMX

over the last four summers. More specifically, during the 1995 and 1996 programs,

concentrations of total NMOC were higher than 1.0 ppmC in roughly 1 out of every 20

samples; during the 1997 and 1998 programs, however, concentrations of total NMOC

were higher than 1.0 ppmC in roughly 1 out of every 5 samples. The reason for this

considerable increase in the frequency of elevated concentrations is not known, but

Section 6.2.2 provides evidence that the increase is probably a result of episodic

releases from emissions sources other than motor vehicles.
6-8

Overall, the trends shown in Figure 6-5 and 6-6 indicate that not only have average

levels of total NMOC at JUMX increased in recent years, but the frequency of elevated

concentrations of total NMOC has also increased at JUMX over the same time frame. Though

the reasons for the increasing concentrations are not known and warrant further investigation, the

analyses in the remainder of this section provide additional insight into the factors that seem to

contribute to the elevated concentrations of total NMOC measured at JUMX.

6.2 SNMOC Monitoring Data

During the 1998 program, valid SNMOC samples were collected at JUMX on 21 days. 

Laboratory analysis of these samples measured ambient air concentrations of 80 different

organic compounds (all hydrocarbons) as well as the concentration of total NMOC. The

remainder of this section uses the data analysis methodology that was described in Section 3 to

put the SNMOC monitoring data from JUMX into perspective: Section 6.2.1 presents a concise

overview of the data; Section 6.2.2 characterizes the composition of the SNMOC samples;

Section 6.2.3 reviews the annual variations in ambient air concentrations for selected SNMOC;

and Section 6.2.4 qualitatively assesses the reactivity of the air mass at JUMX.

6.2.1 Data Summary

Using the four data summary parameters that were defined in Section 3.1, Table 6-2

summarizes the SNMOC measurements made at JUMX during the summer of 1998. A review of

this data summary follows:

• Prevalence. According to Table 6-2, 76 of the 80 hydrocarbons identified by the

SNMOC sampling and analytical method were detected in more than half of the samples

collected at JUMX during the 1998 program. In other words, the prevalence for these

76 compounds was higher than 50 percent. Summary statistics for these 76 compounds

are believed to be highly representative of actual air quality trends during the morning

hours of the summer months, since the majority of samples had quantified concentrations

instead of nondetect observations. For the remaining four compounds (1-decene,

2-ethyl-1-butene, 1-heptene, and 1-tridecene), however, the summary statistics might not

be representative of actual air quality trends due to potential biases introduced by the

frequent nondetect observations, which were replaced in the air monitoring database
6-9

with an estimated concentration of one-half the detection limit. The summary statistics

for these four compounds should be interpreted with caution. Overall, the prevalence

data confirm that a wide range of organic compounds is consistently found at detectable

levels in the ambient air at JUMX.

• Concentration range. Table 6-2 indicates that the concentration ranges for SNMOC

vary considerably from compound to compound. The highest SNMOC concentrations

were measured for propane (242.48 ppbC), toluene (188.03 ppbC), 2,3,4-

trimethylpentane (113.85 ppbC), cyclohexane (110.41 ppbC), and isopentane (51.10

ppbC). The highest concentrations measured for the 75 other SNMOC were all lower

than 50 ppbC.

Though the concentration range data in Table 6-2 are useful for identifying the

compounds that tend to have the highest concentrations at JUMX, readers should note that

the ranges listed in Table 6-2 only represent ambient air concentrations measured

between 6:00 a.m. and 9:00 a.m. during the summer. During other times of the day, and

during other times of year, ambient levels of many SNMOC might have reached higher

levels and lower levels than the concentration range data in Table 6-2 indicate.

• Central tendency. Like the concentration ranges, the central tendency concentrations in

Table 6-2 varied greatly from one SNMOC to the next. Only five compounds had

geometric mean concentrations greater than 10 ppbC: toluene (41.63 ppbC), propane

(31.51 ppbC), isopentane (21.11 ppbC), 2,3,4-trimethylpentane (18.22 ppbC), and

ethane (11.10 ppbC). Combined, the geometric mean concentrations of these five

compounds account for 42 percent of the geometric mean concentration of the total

identified SNMOC. Therefore, though the ambient air samples collected at JUMX

consistently contained more than 70 organic compounds, a small subset of these

compounds accounted for a large portion of the total NMOC concentrations. 

As noted above, readers should remember that the central tendency data for JUMX

characterize air quality during only the morning hours of summer months. Comparisons

of these central tendency data to data based on samples collected during other times of

day and other times of year should be made with caution.

• Variability. According to Table 6-2, coefficients of variation for most SNMOC

measured at JUMX were comparable and lower than 1.0. The compounds with the most

variable air monitoring data, as gauged by the coefficient of variation, were 3-methyl-1-

butene (2.78), cyclohexane (2.41), n-dodecane (1.91), and n-tridecane (1.51). The

greater variability for n-dodecane and n-tridecane likely results from the fact that these

compounds contain more than 10 carbon atoms, and the calculation of coefficients of

variation from concentrations measured in units of ppbC inherently gives greater weight

to compounds with more carbon atoms. The greater variability for 3-methyl-1-butene

and cyclohexane appears to be linked to outlier concentrations.
6-10

6.2.2 Composition of Air Samples

As previous NMOC/SNMOC reports have explained, the composition of air pollution at

a given location can provide insight into the probable origins of certain contaminants. As

examples of such analyses, this section examines the relative quantities of “identified” and

“unknown” SNMOC in the air sampled at JUMX as well as the relative quantities of alkanes,

olefins, and aromatic compounds in this air to reveal subtle, yet meaningful, trends among the

monitoring data.

6.2.2.1 “Identified” vs. “Unknown” Compounds

As noted earlier, the SNMOC sampling and analytical method measures the ambient air

concentration of total NMOC and concentrations of 80 hydrocarbons (i.e., the “identified”

compounds). In any given sample, the difference between the total NMOC concentration and the

sum of the 80 concentrations of hydrocarbons is the ambient air concentrations of the many

different organic compounds that the SNMOC method does not identify (i.e., the “unknown”

compounds). These unknown compounds include, but are not limited to, hydrocarbons with

functional groups containing halogens, oxygen, and nitrogen. The relative amounts of identified

compounds and unknown compounds are a useful indicator of the composition of ambient air.

During the 1998 NMOC/SNMOC Monitoring Program, the sum of the concentrations of

the identified compounds at JUMX accounted for, on average, only 16 percent of the total

NMOC concentrations—the lowest composition of identified compounds that has been observed

at any monitoring station that participated in the 1995, 1996, 1997, and 1998 programs. As

Figure 6-7 shows, the composition of ambient air at JUMX on days with elevated total NMOC

concentrations differed considerably from the composition on days with lower total NMOC

levels. In fact, on days when total NMOC concentrations at JUMX exceeded 1.0 ppmC,

identified compounds accounted for only 11 percent of the total NMOC levels. Therefore, the

higher frequency of elevated air concentrations of total NMOC at JUMX during the 1998

program (see Figure 6-6) appears to be linked to compounds that the SNMOC sampling and

analytical method does not identify, rather than to the 80 hydrocarbons listed in Table 6-2. 
6-11

Since motor vehicles emit many of the compounds identified by the SNMOC analytical method,

the presence of a large portion of unknown compounds on days with elevated total NMOC

concentrations suggests that emissions sources other than motor vehicles probably contributed to

the highest total NMOC concentrations measured at JUMX. Section 6.3 comments further on the

unknown compounds at JUMX.

6.2.2.2 Alkanes, Olefins, and Aromatic Compounds

The relative amounts of alkanes, olefins, and aromatic compounds in ambient air have

been used to characterize the reactivity and sources of pollution within airsheds. As Table 3-1

shows, alkanes are generally less reactive in ambient air than olefins, and aromatic compounds

exhibit a relatively wide range of reactivities. Based on this information, air samples with

relatively high concentrations of reactive compounds (such as olefins) are likely to characterize

“newer” air masses (i.e., air masses near the predominant emissions sources), and air samples

with relatively low concentrations of reactive compounds are likely to characterize “older” air

masses (e.g., those influenced by long-range transport).

During the 1998 NMOC/SNMOC Monitoring Program, alkanes, olefins, and aromatics

accounted for 63 percent, 17 percent, and 20 percent, respectively, of the total concentration of

identified compounds at JUMX. This composition is virtually identical to that presented in the

1997 report for JUMX: 63 percent alkanes, 24 percent olefins, and 13 percent aromatics. 

Though the relative amounts of alkanes were virtually unchanged between the 1997 and 1998

programs, the relative amounts of olefins decreased and the relative amounts of aromatics

increased. The changing amounts of olefins and aromatics appears to be largely due to

decreasing levels of ethylene and increasing levels of toluene—a trend that is illustrated in the

following section. The factors that caused the composition of the air mass at JUMX to change

slightly between the summer of 1997 and the summer of 1998, however, are not known.

Note: The composition data presented for JUMX in the 1996 NMOC/SNMOC report

(40 percent alkanes, 26 percent olefins, and 34 percent aromatics) are considerably
The difference between the average concentration of toluene during the 1998 program (46.46 ppbC) and during the 2

1996 program (41.55 ppbC) was not found to be statistically significant.

6-12

different from the composition data presented above. This difference results almost

entirely from differences in computational approaches: the composition presented in

the 1996 report is based on concentration data in units of ppbC, and the compositions

presented in the 1997 report and in this report are based on concentrations in units of

ppbv.

6.2.3 Annual Variations

The JUMX monitoring station has collected SNMOC samples in four consecutive

NMOC/SNMOC Monitoring Programs, thus allowing an analysis of long-term trends in air

quality. For an overview of these trends, Figure 6-8 depicts annual variations for the 14

SNMOC that had the highest concentrations. Though annual average concentrations for the

compounds shown in Figure 6-8 clearly changed, to a certain extent, from year to year, none of

the compounds exhibited steady upward or downward trends over the past 4 years of monitoring

at JUMX. 

The average concentration during the 1998 program for every compound shown in

Figure 6-8 (except for isopentane, toluene, and 2,3,4-trimethylpentane) was lower than that

measured in the previous year. In fact, for some compounds (benzene, ethylene, isobutane,

n-pentane, and m,p-xylene), the average concentration during the 1998 program was the lowest

that has been observed at JUMX over the last four summers. However, the exact reasons for

observing these lower levels during the summer of 1998 are not known.

For the three compounds—isopentane, toluene, and 2,3,4-trimethylpentane—that had

higher concentrations at JUMX during the summer of 1998 compared to those from earlier years,

statistical analyses show that, with one exception, the concentration differences between the

1998 and earlier programs are all statistically significant. Thus, the increasing air 2

concentrations for these compounds do not appear to be anomalous. In the case of isopentane,
6-13

the magnitude of the increase from the 1997 to 1998 program is 40 percent, which is moderate

when compared to the magnitude of the increases over the same time frame for toluene (118

percent) and for 2,3,4-trimethylpentane (1,040 percent). A review of local emissions

inventories, if available, is needed to determine the reasons why concentrations increased for

these hydrocarbons but decreased for the others. Moreover, additional monitoring at this

location might help determine whether the increasing concentrations for these compounds are

part of a continuing trend or whether they are merely fluctuations that typically occur over multiyear cycles.

6.2.4 Reactivity of the Air Mass

This section assesses the chemical reactivity of the individual SNMOC measured in the

air mass at JUMX. Because photochemical reactions involving hydrocarbons contribute to

ozone formation, the relative reactivities of SNMOC are an important consideration for ozone

control strategies. As one method for evaluating each compound’s reactivity, or ozone

formation potential, this report uses an “ozone index,” or a reactivity-weighted concentration,

defined as the product of a compound’s maximum incremental reactivity (MIR) (see Section 3.4)

and its geometric mean ambient air concentration. 

Figure 6-9 presents the ozone indices for the 20 SNMOC with highest geometric mean

concentrations at JUMX, excluding compounds for which MIRs are not readily available. The

figure, which lists compounds in order of decreasing concentration, clearly illustrates that

compounds with the highest potential for forming ozone at JUMX (e.g., toluene, m,p-xylene, and

ethylene) are not necessarily the compounds with the highest geometric mean concentration. 

This analysis of chemical reactivity suggests that pollution control strategies aimed at reducing

emissions of the compounds with the highest concentration (e.g., toluene, propane, and

isopentane) might not be as effective at reducing local ozone concentrations as strategies aimed

at reducing emissions of compounds with the highest ozone indices. However, since this

analysis is based on one researcher’s assessment of chemical reactivity (Carter, 1994),

environmental agencies are encouraged to perform additional analyses of chemical reactivity,
6-14

possibly through the use of photochemical modeling, to confirm the findings reported in this

section.

6.3 Carbonyl Monitoring Data

During the 1998 NMOC/SNMOC Monitoring Program, the JUMX station collected

carbonyl samples on four days, all in the month of September. Though these four sampling

events clearly do not provide an extensive account of ambient air concentrations at JUMX

throughout the summer of 1998, they are useful for providing insight into airborne levels of

16 organic compounds that the SNMOC sampling and analytical method cannot identify. Since

three of the carbonyl samples were collected on days with elevated total NMOC concentrations

(levels greater than 1.0 ppmC), the carbonyl monitoring data are particularly useful for

characterizing the unusually high levels of air pollution measured at JUMX on certain days of the

1998 program. The following discussion first summarizes the 1998 carbonyl monitoring data

for JUMX, then comments specifically on carbonyl levels on sampling days with elevated total

NMOC concentrations.

Using the four data summary parameters that were defined in Section 3.1, Table 6-4

presents a thorough, yet concise, overview of the four carbonyl sampling results from JUMX

during the summer of 1998. Key findings follow:

• Prevalence. As Table 6-4 shows, 12 of the 16 compounds identified by the carbonyl

sampling and analytical method were detected in at least 75 percent of the samples

collected in Juarez during the 1998 program. Summary statistics for these 12 compounds

are expected to accurately represent the actual carbonyl levels on the 4 sampling days,

since few data points (or no data points) were replaced with concentrations of one-half

the detection limit. Only crotonaldehyde and tolualdehydes were detected less

frequently. These compounds’ summary statistics are essentially meaningless, since both

crotonaldehyde and the tolualdehyde isomers were never detected at JUMX during the

1998 program.

• Concentration range. Of the 16 compounds identified by the carbonyl sampling and

analytical method, acetaldehyde, acetone, and formaldehyde had the broadest ranges of

measured concentrations. These compounds also had the highest concentrations of the
6-15

16 carbonyls; the other carbonyls never had concentrations greater than 1.0 ppbv at

JUMX. Though these general trends were observed at the other NMOC/SNMOC

monitoring stations that collected carbonyl samples, readers are encouraged to interpret

the carbonyl concentration range data in proper context. For example, with studies

reporting that ambient levels of many carbonyls peak during the early afternoon hours

(Brimblecombe 1996) and not during the sampling times for this program (between

6:00 a.m. and 9:00 a.m.), the concentration ranges shown in Table 6-4 are likely not to

be representative of the ranges observed for other times of day. In addition, since

carbonyl sampling was conducted infrequently at JUMX during the 1998 program,

ambient levels of carbonyls at JUMX almost certainly rose to higher levels and fell to

lower levels during the summer of 1998 than the concentration range data indicate.

• Central tendency. Table 6-4 indicates that most carbonyls had central tendency

concentrations lower than 0.5 ppbv. As exceptions, the geometric mean concentrations

for acetaldehyde (1.46 ppbv), acetone (2.93 ppbv), and formaldehyde (2.51 ppbv) all

were greater than this level. Moreover, the geometric mean concentrations of these three

compounds, combined, accounted for nearly 85 percent of the total concentration of all

16 carbonyls at JUMX—a trend that has been observed in other extensive ambient air

monitoring programs in urban centers (ERG 1999).

• Variability. As Table 6-2 indicates, the coefficients of variation for the 16 carbonyls

measured at JUMX were less than 0.7 and were generally comparable in magnitude. 

The relatively low coefficients of variation suggest that carbonyls are consistently found

in the Juarez ambient air during the morning hours, regardless of changing wind

directions. However, results from more extensive sampling efforts must be evaluated to

confirm this hypothesis.

As noted earlier, three of the four carbonyl sampling events occurred on days when total

NMOC concentrations at JUMX exceeded 1.0 ppmC. Careful examination of the monitoring

data reveals, however, that the 16 compounds identified by the carbonyl sampling and analytical

method accounted for only a very small portion of the elevated total NMOC levels at JUMX. 

For example, for the sampling event on September 9, 1998, the ambient air concentration of total

NMOC was 4.857 ppmC, of which 4.355 ppmC were “unknown” compounds. On the same

date, carbonyl sampling results indicated that the ambient air concentration of the 16 carbonyls

combined was 27.98 ppbC—an amount that is less than 1 percent of the concentration of the

unknown compounds. The sampling events on September 22, 1998, and on September 29, 1998,

had similar results. Overall, the coincidental carbonyl and SNMOC sampling clearly indicate
6-16

that the unusually high levels of total NMOC measured at JUMX during the summer of 1998

were not the result of elevated concentrations of the 16 carbonyls considered in this program.

6.4 Chapter Summary

The 1998 NMOC/SNMOC monitoring data collected at JUMX thoroughly characterize

levels of air pollution in one Juarez location during the summertime morning hours. The

monitoring data indicate that levels of total NMOC at JUMX were, on average, considerably

higher than those observed in previous years, as was the frequency with which total NMOC

concentrations exceeded 1.0 ppmC. The SNMOC and carbonyl sampling results strongly

suggest that motor vehicle emissions were not the primary cause of the elevated levels of total

NMOC at JUMX. The factors contributing to these elevated concentrations might be identified

through a review of local emissions inventories, if available, or through ongoing sampling

efforts that consider a wider range of compounds.

The daily SNMOC measurements allowed for a detailed analysis of associations

between selected meteorological parameters and levels of air pollution. This analysis found no

statistically significant trends between total NMOC concentrations at JUMX and concurrent

observations of humidity, temperature, and wind direction at the El Paso International Airport. 

Wind speed, on the other hand, had a statistically significant association with total NMOC

levels: Concentrations of total NMOC were considerably lower on windier days, and higher

when winds were calm or light. This trend was also observed at JUMX during the 1997

program.

The SNMOC measurements provided insight into the chemical composition of ambient

air at JUMX. These measurements found that “unknown” compounds (i.e., compounds that the

SNMOC sampling and analytical method does not identify) accounted for nearly 90 percent of

the airborne organic compounds on days when total NMOC concentrations exceeded 1.0 ppmC. 

The measurements also found that, excluding the days with elevated total NMOC levels, the

composition of alkanes, olefins, and aromatics in the ambient air at JUMX were not notably

different from the composition observed during the 1997 program. Analysis of the chemical
6-17

reactivity of the air mass at JUMX confirmed a finding of the 1996 NMOC/SNMOC report: The

compounds with the greatest potential for forming ozone are not always the compounds with the

highest ambient air concentration.

As noted several times in this report, the analyses of ambient air monitoring data

presented in this section are only a small subset of the many different numerical and statistical

analyses that could be performed. Therefore, though this section provides an extensive and

meaningful review of levels of air pollution at JUMX, researchers are encouraged to supplement

this review with additional analyses on the large volume of air monitoring data collected at this

station.
6-18

Figure 6-1

Juarez, Mexico (JUMX), Monitoring Station

Source: SGD 1996.
0

1

2 2

0

5

4

0 0

2

5

0

1

2

3

4

5

6

<=0.1 >0.1 and

<=0.2

>0.2 and

<=0.3

>0.3 and

<=0.4

>0.4 and

<=0.5

>0.5 and

<=0.6

>0.6 and

<=0.7

>0.7 and

<=0.8

>0.8 and

<=0.9

>0.9 and

<=1.0

>1.0

Concentration Range (ppmC)

Number of Observations in Listed Range

6-19

Figure 6-2

Distribution of Total NMOC Concentrations Measured at JUMX
NMOC Concentration vs. Humidity

0.0

0.3

0.6

0.9

1.2

1.5

<=55 >55

Relative Humidity (percent range)

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

NMOC Concentration vs. Temperature

0.0

0.5

1.0

1.5

2.0

<=75 >75

Tempe rature Range (degrees Fahrenheit)

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

NMOC Concentration vs. Wind Speed

0.0

0.5

1.0

1.5

2.0

2.5

<=5 >5

W ind Speed (mph)

Av

erage 

Concentr

ation of 

Total NMOC (ppmC)

6-20

Figure 6-3

Comparison of NMOC Concentrations at JUMX to Selected Meteorological Parameters
0

1

2

3

4

5

6

0 60 120 180 240 300 360

Wind Direction (degrees)

Total NMOC Concentration (ppmC)

6-21

Figure 6-4

Comparison of Total NMOC Concentrations at JUMX to Wind Direction

Notes: Wind direction is the direction from which wind blows. Observations with calm or variable winds are not included in this figure. As Section 6.1.2 notes, the outlier

concentration of 20.317 ppmC was not included in this analysis. For reference, the wind direction on the morning of this outlier concentration was 90 degrees.
0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

1995 1996 1997 1998

Year

Average NMOC Concentration, ppmC

6-22

Figure 6-5

Annual Variations in Average Concentrations of Total NMOC at JUMX

Note: The “error bars” in the graph indicate the 95-percent confidence intervals of the average concentrations. All valid sampling results (including suspected data outliers)

are considered in this figure.
4.1%

6.5%

20.0%

23.8%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

1995 1996 1997 1998

Year

Percent of Sampling Days when Total NMOC 

Concentrations Exceeded 1.0 ppmC

6-23

Figure 6-6

Annual Variations in the Frequency of Peak Concentrations of Total NMOC at JUMX
Bre a kdown o f Tota l NMOC on Days when 

Conce ntra tions Exceeded 1.0 ppm C

"Unknow n" 

Com pounds

89%

"Identifie d " 

Com pounds

11%

Bre a kdown o f Tota l NMOC on Days when 

Conce ntra tions W e re Less Than 1.0 ppm C

"Unknow n" 

Com pounds

43%

"Identifie d " 

Com pounds

57%

6-24

Figure 6-7

Contribution of “Identified” and “Unknown” Compounds to 

Total NMOC Concentrations at JUMX
Acetylene and Ethane

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

Benzene

0.0

2.0

4.0

6.0

8.0

10.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

n -Butane

0.0

5.0

10.0

15.0

20.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation, ppbC

6-25

Figure 6-8 (Page 1 of 4)

Annual Variations in Concentrations of Selected SNMOC at JUMX

Note: Acetylene and ethane are presented in the same graph because the sampling and analytical method used during the

1996 program could not differentiate these compounds.

Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Ethylene

0.0

3.0

6.0

9.0

12.0

15.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

Isobutane

0.0

2.0

4.0

6.0

8.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

Isopentane

0.0

8.0

16.0

24.0

32.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

6-26

Figure 6-8 (Page 2 of 4)

Annual Variations in Concentrations of Selected SNMOC at JUMX

Note: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
n -Pentane

0.0

5.0

10.0

15.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

Propane

0.0

30.0

60.0

90.0

120.0

150.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

Propylene

0.0

5.0

10.0

15.0

20.0

25.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

6-27

Figure 6-8 (Page 3 of 4)

Annual Variations in Concentrations of Selected SNMOC at JUMX

Note: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
Toluene

0.0

18.0

36.0

54.0

72.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

2,3,4-T rimethylpentane

0.0

10.0

20.0

30.0

40.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

m ,p -Xylene

0.0

5.0

10.0

15.0

20.0

25.0

1995 1996 1997 1998

Year

Av

erage 

Concentr

ation (ppbC)

6-28

Figure 6-8 (Page 4 of 4)

Annual Variations in Concentrations of Selected SNMOC at JUMX

Note: Every graph is shown on a different scale.

The “error bars” indicate 95-percent confidence intervals of the average concentrations.
0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

tolu

propa

ispna

234tmp

etha

nbuta

m/pxy

npnta

acetyl

ethylbenz

2mpna

nhexa

isbta

224tmp

ebenz

124tmb

3mpna

cyhex

prpyl

Compound

Geometric Mean Concentration (ppbC)

0

5

10

15

20

25

30

35

"Ozone Index" (see Section 6.2.4)

Geometric Mean Concentration

Ozone Index

6-29

Figure 6-9

Ozone Indices for the 20 SNMOC with Highest Geometric Mean Concentration at JUMX

Notes: Only those compounds with MIR values listed in Table 3-1 were considered.

Table 6-3 lists the abbreviations used for the compounds.
6-30

Table 6-1

Summary Statistics for Concentrations of Total NMOC at JUMX

Category Parameter Monitoring Station JUMX

Prevalence Number of nondetects 0

Number of valid sampling days 21

Frequency of detection 100%

Concentration

Range

Lowest concentration (ppmC) 0.173

25th percentile concentration (ppmC) 0.531

50th percentile concentration (ppmC) 0.633

75th percentile concentration (ppmC) 0.944

Highest concentration (ppmC) 20.317

Central Tendency Arithmetic mean concentration (ppmC) 2.060

Median concentration (ppmC) 0.633

Geometric mean concentration (ppmC) 0.845

Variability

Standard deviation (ppmC) 4.414

Coefficient of variation 2.14
ND = nondetect

Note: Due to the limited sample size, data for all compounds should be interpreted with caution, since they may not be representative of SNMOC concentrations in the morning

hours throughout the summer.

6-31

Table 6-2

Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 21 Days with Valid Samples)

Compound detects Detections (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) Variation

Prevalence of

Compound in Range of Measured Central Tendency of Variability in Measured

Ambient Air Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Lowest Highest Median Mean Mean Deviation Coefficient of

Acetylene 0 100% 1.14 17.42 5.28 6.36 5.08 4.12 0.65

Benzene 0 100% 1.39 14.34 4.88 5.93 4.85 3.69 0.62

1,3-Butadiene 0 100% 0.10 1.47 0.55 0.64 0.49 0.43 0.67

n-Butane 0 100% 2.25 27.41 10.11 12.00 9.41 7.74 0.65

cis-2-Butene 0 100% 0.33 1.39 0.62 0.70 0.63 0.34 0.49

trans-2-Butene 0 100% 0.22 1.32 0.43 0.59 0.52 0.32 0.54

Cyclohexane 0 100% 0.72 110.41 2.08 10.78 3.09 26.00 2.41

Cyclopentane 0 100% 0.31 2.33 0.83 0.96 0.84 0.52 0.54

Cyclopentene 0 100% 0.11 1.04 0.41 0.43 0.36 0.25 0.58

n-Decane 0 100% 0.46 4.20 1.46 1.66 1.43 0.95 0.57

1-Decene 21 0% ND ND 0.14 0.14 0.14 0.00 0.00

m-Diethylbenzene 0 100% 0.26 0.86 0.46 0.47 0.45 0.13 0.28

p-Diethylbenzene 0 100% 0.30 0.85 0.49 0.50 0.48 0.14 0.28

2,2-Dimethylbutane 0 100% 0.43 1.62 0.79 0.88 0.82 0.34 0.38

2,3-Dimethylbutane 0 100% 0.71 9.00 2.42 2.67 2.19 1.90 0.71

2,3-Dimethylpentane 0 100% 0.80 7.11 2.49 3.04 2.60 1.71 0.56

2,4-Dimethylpentane 0 100% 0.55 4.61 1.63 1.99 1.67 1.18 0.59

n-Dodecane 0 100% 0.15 9.72 0.43 1.14 0.54 2.18 1.91
Table 6-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 21 Days with Valid Samples)

Compound detects Detections (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) Variation

Prevalence of

Compound in Range of Measured Central Tendency of Variability in Measured

Ambient Air Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Lowest Highest Median Mean Mean Deviation Coefficient of

ND = nondetect

Note: Due to the limited sample size, data for all compounds should be interpreted with caution, since they may not be representative of SNMOC concentrations in the morning

hours throughout the summer.

6-32

1-Dodecene 1 95% ND 1.07 0.32 0.37 0.31 0.23 0.63

Ethane 0 100% 3.43 31.80 11.32 13.07 11.10 7.76 0.59

Ethylbenzene 0 100% 1.11 7.34 3.87 3.90 3.46 1.79 0.46

2-Ethyl-1-Butene 21 0% ND ND 0.12 0.12 0.12 0.00 0.00

Ethylene 0 100% 1.28 13.87 4.89 6.05 5.02 3.56 0.59

m-Ethyltoluene 0 100% 0.71 5.20 2.17 2.28 2.01 1.15 0.51

o-Ethyltoluene 0 100% 0.36 1.97 0.86 0.93 0.84 0.41 0.45

p-Ethyltoluene 0 100% 0.53 2.78 1.29 1.31 1.20 0.57 0.43

n-Heptane 0 100% 0.50 5.73 2.13 2.22 1.89 1.27 0.57

1-Heptene 17 19% ND 0.94 0.26 0.36 0.31 0.22 0.63

n-Hexane 0 100% 1.03 12.20 4.09 4.88 3.84 3.33 0.68

1-Hexene 1 95% ND 0.56 0.21 0.25 0.21 0.14 0.55

cis-2-Hexene 2 90% ND 1.10 0.17 0.28 0.19 0.25 0.91

trans-2-Hexene 1 95% ND 1.01 0.22 0.30 0.21 0.26 0.87

Isobutane 0 100% 0.92 11.73 4.07 4.35 3.53 2.71 0.62

Isobutene/1-Butene 0 100% 1.18 4.37 2.47 2.68 2.51 0.95 0.35

Isopentane 0 100% 8.83 51.10 18.42 24.17 21.11 13.11 0.54

Isoprene 0 100% 0.34 1.21 0.72 0.71 0.67 0.24 0.34
Table 6-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 21 Days with Valid Samples)

Compound detects Detections (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) Variation

Prevalence of

Compound in Range of Measured Central Tendency of Variability in Measured

Ambient Air Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Lowest Highest Median Mean Mean Deviation Coefficient of

ND = nondetect

Note: Due to the limited sample size, data for all compounds should be interpreted with caution, since they may not be representative of SNMOC concentrations in the morning

hours throughout the summer.

6-33

Isopropylbenzene 0 100% 0.27 0.65 0.40 0.43 0.42 0.11 0.25

2-Methyl-1-Butene 0 100% 0.13 2.72 0.88 1.08 0.81 0.79 0.73

2-Methyl-2-Butene 0 100% 0.14 4.32 0.84 1.24 0.78 1.21 0.97

3-Methyl-1-Butene 2 90% ND 26.14 0.62 2.01 0.51 5.58 2.78

Methylcyclohexane 0 100% 0.58 4.21 1.66 1.83 1.53 1.09 0.59

Methylcyclopentane 0 100% 0.62 7.94 2.31 2.94 2.38 1.90 0.65

2-Methylheptane 0 100% 0.46 2.03 1.14 1.22 1.15 0.41 0.33

3-Methylheptane 0 100% 0.49 2.26 1.17 1.27 1.20 0.45 0.35

2-Methylhexane 0 100% 0.93 5.32 2.38 2.39 2.13 1.17 0.49

3-Methylhexane 0 100% 0.64 6.07 2.69 2.64 2.28 1.40 0.53

2-Methylpentane 0 100% 1.22 14.64 4.51 5.59 4.57 3.55 0.63

3-Methylpentane 0 100% 0.91 9.29 3.05 3.75 3.09 2.29 0.61

2-Methyl-1-Pentene 1 95% ND 0.93 0.27 0.33 0.25 0.23 0.70

4-Methyl-1-Pentene 10 52% ND 0.21 0.12 0.11 0.11 0.03 0.29

n-Nonane 0 100% 0.40 2.06 0.91 1.09 0.99 0.49 0.45

1-Nonene 0 100% 0.87 11.49 2.44 3.19 2.65 2.49 0.78

n-Octane 0 100% 0.48 2.26 1.09 1.20 1.12 0.47 0.39

1-Octene 1 95% ND 0.46 0.18 0.21 0.19 0.11 0.50
Table 6-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 21 Days with Valid Samples)

Compound detects Detections (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) Variation

Prevalence of

Compound in Range of Measured Central Tendency of Variability in Measured

Ambient Air Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Lowest Highest Median Mean Mean Deviation Coefficient of

ND = nondetect

Note: Due to the limited sample size, data for all compounds should be interpreted with caution, since they may not be representative of SNMOC concentrations in the morning

hours throughout the summer.

6-34

n-Pentane 0 100% 1.68 21.58 6.32 8.06 6.37 5.44 0.68

1-Pentene 0 100% 0.29 1.84 0.76 0.82 0.71 0.46 0.56

cis-2-Pentene 0 100% 0.28 1.99 0.73 0.83 0.71 0.50 0.60

trans-2-Pentene 0 100% 0.37 3.73 1.00 1.34 1.07 0.94 0.71

"-Pinene 1 95% ND 2.12 0.37 0.58 0.41 0.53 0.93

$-Pinene 0 100% 0.10 3.32 1.23 1.35 1.08 0.81 0.60

Propane 0 100% 7.34 242.48 28.64 51.09 31.51 59.79 1.17

n-Propylbenzene 0 100% 0.39 1.76 0.86 0.86 0.80 0.34 0.39

Propylene 0 100% 0.68 8.76 2.84 3.48 2.81 2.23 0.64

Propyne 6 71% ND 0.51 0.22 0.24 0.21 0.12 0.49

Styrene 0 100% 1.48 9.50 3.53 4.04 3.56 2.17 0.54

Toluene 0 100% 11.30 188.03 38.18 48.46 41.63 36.08 0.74

n-Tridecane 1 95% ND 1.42 0.11 0.24 0.14 0.37 1.51

1-Tridecene 16 24% ND 0.14 0.14 0.13 0.12 0.03 0.20

1,2,3-Trimethylbenzene 0 100% 0.26 2.02 0.77 0.84 0.74 0.43 0.52

1,2,4-Trimethylbenzene 0 100% 1.00 8.53 3.17 3.60 3.14 1.90 0.53

1,3,5-Trimethylbenzene 0 100% 0.57 3.29 1.68 1.69 1.55 0.67 0.40

2,2,3-Trimethylpentane 0 100% 0.57 7.28 1.83 2.16 1.90 1.38 0.64
Table 6-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 21 Days with Valid Samples)

Compound detects Detections (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) (ppbC) Variation

Prevalence of

Compound in Range of Measured Central Tendency of Variability in Measured

Ambient Air Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Lowest Highest Median Mean Mean Deviation Coefficient of

ND = nondetect

Note: Due to the limited sample size, data for all compounds should be interpreted with caution, since they may not be representative of SNMOC concentrations in the morning

hours throughout the summer.

6-35

2,2,4-Trimethylpentane 0 100% 1.06 9.44 3.62 4.21 3.52 2.41 0.57

2,3,4-Trimethylpentane 0 100% 6.03 113.85 17.03 23.90 18.22 24.69 1.03

n-Undecane 0 100% 0.47 5.06 1.24 1.51 1.23 1.17 0.77

1-Undecene 5 76% ND 0.28 0.14 0.15 0.13 0.06 0.40

m,p-Xylene 0 100% 2.83 22.71 9.80 10.75 9.29 5.59 0.52

o-Xylene 0 100% 1.52 10.89 5.33 5.41 4.97 2.18 0.40

TNMOC (w/ unknowns) 0 100% 172.92 20,317.32 633.12 2,060.40 844.76 4,414.40 2.14

TNMOC (speciated) 0 100% 87.60 552.87 332.57 324.89 294.26 136.34 0.42
6-36

Table 6-3

Abbreviations Used in Figure 6-9

Abbreviation Compound

tolu Toluene

propa Propane

ispna Isopentane

234tmp 2,3,4-Trimethylpentane

etha Ethane

nbuta n-Butane

m/pxy m,p-Xylene

npnta n-Pentane

acetyl Acetylene

ethyl Ethylene

benz Benzene

2mpna 2-Methylpentane

nhexa n-Hexane

isbta Isobutane

224tmp 2,2,4-Trimethylpentane

ebenz Ethylbenzene

124tmb 1,2,4-Trimethylbenzene

3mpna 3-Methylpentane

cyhex Cyclohexane

prpyl Propylene

Note: Abbreviations in this table are presented in the same order as in Figure 6-9 (i.e., in the order of compounds with

decreasing concentration at JUMX).
6-37

Table 6-4

Summary Statistics for Carbonyl Concentrations Measured at Juarez, Mexico (JUMX)

(Based on 4 Days with Valid Samples)

Compound

Prevalence of

Compound in

Ambient Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetaldehyde 0 100% 1.07 2.18 1.39 1.51 1.46 0.47 0.31

Acetone 0 100% 1.62 5.01 3.02 3.17 2.93 1.39 0.44

Acrolein 0 100% 0.06 0.20 0.10 0.12 0.10 0.06 0.55

Benzaldehyde 0 100% 0.10 0.17 0.16 0.15 0.15 0.03 0.21

Butyr/Isobutyraldehyde 0 100% 0.31 0.57 0.46 0.45 0.44 0.11 0.24

Crotonaldehyde 4 0% ND ND 0.00 0.00 0.00 0.00 0.00

2,5-Dimethylbenzaldehyde 1 75% ND 0.23 0.21 0.16 0.08 0.11 0.66

Formaldehyde 0 100% 2.09 3.24 2.42 2.54 2.51 0.53 0.21

Hexanaldehyde 1 75% ND 0.07 0.06 0.05 0.03 0.03 0.60

Isovaleraldehyde 1 75% ND 0.11 0.09 0.07 0.04 0.05 0.64

Propionaldehyde 0 100% 0.21 0.29 0.23 0.24 0.24 0.04 0.15

Tolualdehydes 4 0% ND ND 0.01 0.01 0.01 0.00 0.00

Valeraldehyde 0 100% 0.06 0.30 0.28 0.23 0.19 0.12 0.51

ND = nondetect

Note: Due to the limited sample size (only 4 days with valid samples), the summary statistics for all compounds should be interpreted with caution, since they might not be

representative of carbonyl concentrations in the morning hours throughout the summer.
.
7-1

7.0 Monitoring Results for Long Island, New York (LINY)

This section summarizes and interprets the total NMOC monitoring data collected at the

Long Island, NY (LINY), monitoring station during the 1998 NMOC/SNMOC Monitoring

Program. This section also evaluates total NMOC data from previous years for the purpose of

investigating annual variations. As Table 2-1 noted, SNMOC, VOC, and carbonyl data were not

collected at this location.

The map in Figure 7-1 indicates the location of the LINY monitoring station and land use in

its vicinity. Located on a golf course in a suburban area, the monitoring station is surrounded by

open space and mostly single-story buildings. New York City is approximately 15 miles west of

the station. Emissions from many different sources impact the ambient levels of total NMOC at

LINY. These sources likely include three heavily traveled roads and many other roads that pass

within 1 mile of the station and numerous industrial facilities located in the area. Transport of

emissions from the densely populated New York City area also affects air quality at LINY.

During the 1998 program, total NMOC samples were attempted on 84 days; 81 of these

samples generated valid results, and 3 of the samples were voided. The data completeness, which

is defined as the percentage of attempted samples that are valid, was therefore 96 percent. The

high completeness figure suggests that the 1998 NMOC/SNMOC Monitoring Program was

efficiently managed at LINY.

The remainder of this section provides a summary of the 1998 total NMOC monitoring data

for LINY (Section 7.1), compares the measured concentrations to meteorological parameters

(Section 7.2), characterizes how total NMOC concentrations have changed at this station since

1990 (Section 7.3), and briefly summarizes the key findings for LINY (Section 7.4).

7.1 Data Summary

Using the four data summary parameters defined in Section 3.1, Table 7-1 presents an

overview of the total NMOC monitoring data collected in the summer of 1998 at LINY. When
7-2

reviewing these data, it is important to remember that total NMOC includes a wide range of

organic compounds (e.g., alkanes, olefins, aromatics, oxygenates, halogenated hydrocarbons), thus

providing a composite measure of the air pollution that is known to affect ozone formation

processes. Since total NMOC does not include many pollutants typically found in urban ambient

air, such as inorganic acids, particulate matter, and heavier organic compounds, the total NMOC

concentrations should not be considered the only measure of overall levels of air pollution.

An overview of the data summary presented in Table 7-1 follows:

• Prevalence. In every sample collected at LINY during the 1998 program, total NMOC

was measured at levels at least an order of magnitude higher than the estimated method

detection limit, 0.005 ppmC (or 5 ppbC). The prevalence of total NMOC was therefore

100 percent, and none of the air quality measurements collected at LINY were affected by

nondetect observations. Due to the high prevalence, completeness, and measurement

precision, the summary statistics presented in Table 7-1 are believed to represent air

quality at LINY accurately.

• Concentration range. According to Table 7-1, total NMOC concentrations at LINY

during the morning hours of the summer of 1998 ranged from 0.067 ppmC to 0.643 ppmC. 

The quartile concentrations listed in Table 7-1 indicate that three-fourths of the total

NMOC concentrations were lower than 0.300 ppmC. Figure 7-2, which presents the

distribution of total NMOC concentrations measured at LINY, offers a better visual

perspective on the range of concentrations. The data presented in Figure 7-2 indicate that

90 percent of the total NMOC levels at LINY were lower than 0.400 ppmC. Figure 7-2

also illustrates that none of the total NMOC concentrations at LINY appeared to be

outliers. (Sections 6 and 8 present examples of outlier concentrations of total NMOC.)

Not shown in either Table 7-1 or Figure 7-2 is an apparent association between elevated

total NMOC concentrations at LINY and elevated total NMOC concentrations at NWNJ, 

which is located approximately 20 miles west of the LINY station. More specifically, the

dates on which two of the three highest total NMOC concentrations were measured at

LINY (June 25 and September 25) are the same as the dates on which the nearby NWNJ

monitoring station measured its two highest total NMOC concentrations. The coincidence

of these dates suggests that certain regional phenomena contribute to the highest levels of

total NMOC measured in the Newark–New York City metropolitan area. These

phenomena might include unique meteorological conditions or enhanced long-range

transport of air pollution from other areas. The associations between selected

meteorological conditions and total NMOC concentrations are addressed in Section 7.2.
7-3

• Central tendency. As Table 7-1 shows, the geometric mean concentration of total NMOC

at LINY during the 1998 program was 0.195 ppmC—the lowest geometric mean

concentration that has been observed at LINY since this monitoring station first started

collecting total NMOC samples in 1990. Section 7.3, which evaluates annual variations in

air quality at LINY, shows that the total NMOC levels observed during the 1998 program

continue a statistically significant downward trend in average total NMOC concentration.

In addition to evaluating the program-average central tendency concentrations, monthlyaverage central tendencies were calculated and evaluated. During the 1998 program, the

total NMOC concentrations were, on average, higher during the morning hours of

September than during the morning hours of June, July, or August. However, none of these

concentration differences were found to be statistically significant.

• Variability. As Table 7-1 shows, the standard deviation of total NMOC concentrations

during the 1998 program was 0.137 ppmC, which is 60 percent of the arithmetic mean

concentration. This finding is notably consistent with the coefficients of variation

observed at LINY in the past three summers. More specifically, the coefficient of variation

for total NMOC concentrations was 0.62 in 1995, 0.67 in 1996, 0.64 in 1997, and 0.60 in

1998. This similarity suggests that the variability in total NMOC levels at LINY does not

change considerably from year to year, even though the average concentration does (see

Section 7.3).

7.2 Comparison to Selected Meteorological Conditions

To provide greater insight into the trends and patterns among the total NMOC

concentrations at LINY, the following discussion identifies associations between levels of total

NMOC and selected meteorological parameters. This analysis considers 3-hour average

observations of relative humidity, precipitation, temperature, wind direction, and wind speed, all

of which were measured between 7:00 and 10:00 a.m. at nearby John F. Kennedy International

Airport. Due to the close proximity of this meteorological station to the LINY monitoring station,

the meteorological data are believed to represent typical conditions at the LINY site.

To facilitate comparison of data trends from the 1998 program to those identified

previously, the following analyses of meteorological conditions are presented in a format almost

identical to that used in Section 4.2.1.1 of the 1997 NMOC/SNMOC report. As a notable

improvement, however, the analyses in this report differentiate the data trends that were found to
7-4

be statistically significant from those that were not. The following discussion puts the associations

between total NMOC at LINY and local meteorological conditions into perspective:

• Humidity. The graph in Figure 7-3 shows that, during the summer of 1998, levels of total

NMOC at LINY tended to be lower on mornings when the relative humidity was high. 

However, the concentration differences shown in the figure are marginal, and none of them

are statistically significant. In short, total NMOC levels at LINY were observed to be

lower, on average, on the more humid mornings, but the association between humidity and

total NMOC concentrations was found to be relatively weak and possibly anomalous.

This general finding is notably different from that reported in the 1997 NMOC/SNMOC

report. During the summer of 1997, total NMOC concentrations at LINY on mornings

when the relative humidity was less than 60 percent were, on average, nearly 1.5 times

higher than NMOC concentrations on mornings when relative humidity was greater than or

equal to 60 percent. The different findings between the 1997 and 1998 programs highlight

an inherent difficulty with assessing and understanding the impacts of local meteorological

conditions on air quality: Since so many different factors influence levels of air pollution,

a single factor’s effect on air quality might be masked in years when other conditions

(e.g., temperature or precipitation) have unusually high or low values. As a result,

researchers are encouraged to conduct multivariate statistical analyses on the total NMOC

monitoring data to understand how different combinations of conditions affect local air

quality. Such analyses, however, are not included in the scope of this project.

• Precipitation. Measurable rain was observed at John F. Kennedy International Airport

during 5 of the 81 valid sampling events at the LINY station. The average concentration of

total NMOC for the 5 days with measurable precipitation was 0.111 ppmC, and the

average concentration for all other days was 0.237 ppmC. In short, total NMOC

concentrations during hours with measurable precipitation were, on average, less than half

of the total NMOC concentrations on other days; this difference in concentrations was

found to be statistically significant. This general trend—total NMOC levels being lower

on rainy days—not only is consistent with the data trends of the 1997 program, but is also

consistent with “wet deposition” algorithms in EPA-approved dispersion models

(USEPA 1995). These algorithms indicate that precipitation removes portions of gases

and particles from ambient air.

• Temperature. Figure 7-3 shows that, during the 1998 program, total NMOC

concentrations at LINY were generally higher on warmer mornings. More specifically,

average levels of total NMOC on mornings when temperatures exceed 80 F were roughly o

50 percent higher than levels on cooler mornings; this difference in concentrations was

statistically significant. Though this trend of higher concentrations of total NMOC on

warmer mornings was also observed during the 1997 program, no such trend was observed
7-5

during the summer of 1996 (i.e., concentrations of total NMOC were completely uncorrelated with

temperature). Continued review of ambient air monitoring data and meteorological data can

confirm the existence of a relationship between total NMOC and temperature. 

• Wind Speed. According to Figure 7-3, total NMOC concentrations at LINY were, on

average, lower on windier mornings than they were on mornings with light or no winds. 

The roughly 15 percent difference between NMOC concentrations on the windiest days

(wind speeds greater than or equal to 14 mph) and concentrations on the moderately windy

days (wind speeds greater than or equal to 9 mph, but less than 14 mph) was not

statistically significant; however, the 25 percent difference between NMOC concentration

on the windiest days and on the least windy days (wind speeds less than 9 mph) was

statistically significant. This statistically significant trend is consistent both with findings

presented in the 1997 report and dispersion modeling algorithms, which predict that

dispersion of pollutants increases with wind speed (USEPA 1995).

• Wind Direction. To examine associations between wind direction and total NMOC

concentrations, the scatter plot in Figure 7-4 indicates how levels of total NMOC at LINY

varied with wind direction during the 1998 program. (The figure does not present

sampling results collected when winds were calm or variable.) As Figure 7-4 shows, no

particularly strong correlation between total NMOC concentrations and any specific wind

direction was observed. Though some of the highest levels of total NMOC were observed

when winds were blowing from the south (wind directions between 150 and 210 degrees),

the average concentration of total NMOC for this subset of wind directions (0.27 ppmC)

was not considerably higher than the average concentration of total NMOC for all other

wind directions (0.21 ppmC). Moreover, the difference in these concentrations was not

statistically significant.

The absence of statistically significant data correlations between wind direction and total

NMOC concentration suggests that the direction of the wind has little bearing on ambient

levels of total NMOC at LINY during the morning hours. The absence of notable

correlations is best explained by the hypothesis that the primary components of total

NMOC are emitted from sources that are found in all directions from the LINY monitoring

station, such as motor vehicles. The analyses in the 1997 report reached the same

conclusion.

When interpreting associations between meteorological conditions and total NMOC

monitoring data for LINY, it is important to note that this section presents only a small subset of the

numerous data analyses that could be performed on this data set. Greater insight into the factors
7-6

that affect levels of air pollution can be gained by examining meteorological conditions from

longer time frames (e.g., are total NMOC concentrations considerably lower or higher after

24 hours of warmer temperatures?) and by using multivariate statistical techniques (e.g., do higher

levels of total NMOC occur when both humidity and temperature are high?). Researchers are

encouraged to conduct such additional analyses to identify data trends that are not readily apparent

from the analyses presented in this section.

7.3 Annual Variations

Several different measures can be used to evaluate how air quality at a particular location

varies from year to year. To put the annual variations for the LINY monitoring stations into

perspective, the following discussion examines how average levels of total NMOC and peak

levels of total NMOC have changed from the 1990 to the 1998 NMOC/SNMOC Monitoring

Programs. (Note: Total NMOC monitoring data from LINY are not available from the 1992

program.)

C Changes in average concentrations of total NMOC. Figure 7-5 indicates how the

average concentration of total NMOC has changed at LINY since the 1990

NMOC/SNMOC Monitoring Program. Note that the figure presents the average

concentrations of total NMOC measured during the morning hours of the summer months,

which are likely quite different from annual average concentrations. Clearly, average

levels of total NMOC at LINY increased in some years and decreased in others.

Several important observations can be drawn from the figure. For example, the average

concentration of total NMOC observed during the 1998 program is the lowest level that

has been observed at LINY over the last 9 years. This trend was found to be statistically

significant, except that the average concentration observed in the 1997 program was not

found to be statistically different from that of the 1998 program. Furthermore, closer

inspection of the diagram reveals that the average concentrations of total NMOC for the

1995, 1997, and 1998 programs are all lower than the average concentrations observed

prior to 1995, but the concentration differences in some cases were not statistically

significant. It is interesting to note that this apparent decline in concentrations of total

NMOC began after motor vehicles in the New York City–Newark metropolitan area began

using reformulated fuels. In fact, the average concentration of total NMOC measured in the

summer months between 1995 and 1998 is 23 percent lower than the average concentration

measured in the summer months between 1990 and 1994; this decrease was statistically

significant. The exact causes of the decreasing concentrations are not known, but are likely

to include some combination of motor vehicle fuel usage, changes in traffic patterns, and
7-7

impacts from various pollution control initiatives. It is also possible that the statistically

significant decline in total NMOC concentrations over the last 4 years is merely part of

longer-term fluctuations in levels of air pollution. Results from continued monitoring at the

same location are needed to determine if the apparent downward trend in levels of total

NMOC persists, if the downward trend levels off, or if the average levels of total NMOC

increase back to their 1990–1994 levels.

C Changes in peak concentrations of total NMOC. Since many environmental statues

regulate both long-term average and short-term peak (or “episodic”) levels of air pollution,

annual variations in the frequency of peak concentrations were evaluated. As one measure

of the changing frequency of peak concentrations at LINY, Figure 7-6 shows the number of

total NMOC concentrations measured at levels greater than 1.0 ppmC in the 1990–1998

NMOC/SNMOC Monitoring Programs. According to the figure, total NMOC

concentrations have not exceeded 1 ppmC during the summer morning hours at LINY since

1996. However, unlike the annual variations of the average concentrations, no downward

long-term trend in the peak concentrations is readily apparent. Analyses of continued

monitoring are needed to confirm if the frequency and magnitude of peak concentrations of

total NMOC at LINY have indeed decreased.

7.4 Chapter Summary

Generally, the total NMOC data collected at the LINY monitoring station are consistent

with the data from other years and support the conclusions made in previous reports. For instance,

the data collected during the 1998 program indicated that ambient air concentrations of total

NMOC were lower on more humid days, on cooler days, on rainier days, and on windier

days—all of these trends were observed, to a certain extent, at LINY during the 1997 program. 

The associations between total NMOC concentration and temperature, precipitation, and wind

speed were all found to be statistically significant, but the apparent association between total

NMOC concentration and humidity was not. No obvious correlation between wind direction and

total NMOC concentration was observed.

On average, the 3-hour average concentrations of total NMOC during 1998 were the

lowest that have been observed during the summer months since the station first sampled for this

pollutant. Moreover, in the years since 1994, a statistically significant downward trend in

concentrations of total NMOC are apparent for the LINY monitoring station. This trend might be

due, at least in part, to the introduction of reformulated fuels between the 1994 and 1995
7-8

NMOC/SNMOC Monitoring Programs. Continued monitoring at LINY is encouraged to

characterize trends in air quality over the longer term.
7-9

Figure 7-1

Long Island, New York (LINY), Monitoring Station

Source: USGS 7.5 Minute Series. Map scale: 1:24,000.
9

32

19

13

3

2

3

0

05

10

15

20

25

30

35

<=0.1 >0.1 and <=0.2 >0.2 and <=0.3 >0.3 and <=0.4 >0.4 and <=0.5 >0.5 and <=0.6 >0.6 and <=0.7 >0.7

Conc e n tration Range (ppmC)

Number of Observations in Listed Range

7-10

Figure 7-2

Distribution of Total NMOC Concentrations Measured at LINY
NMOC Concentration vs. Humidity

0.000

0.050

0.100

0.150

0.200

0.250

0.300

<50 >=50 and <70 >=70

Relative Hum idity (p e rce nt range)

Av

erage Concentration 

of Tot

al NMOC (ppmC)

NMOC Concentration vs. Temperature

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

<=70 >70 and <=80 >80

T empe rature Range (degrees Fahrenheit)

Av

erage Concentration 

of Tot

al NMOC (ppmC)

NMOC Concentration vs. Wind Speed

0.000

0.050

0.100

0.150

0.200

0.250

0.300

<9 >=9 and <14 >=14

W ind Speed (mph)

Av

erage Concentration 

of Tot

al NMOC (ppmC)

7-11

Figure 7-3

Comparison of NMOC Concentrations at LINY to Selected Meteorological Parameters
0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0 60 120 180 240 300 360

Wind Direction (degrees)

Total NMOC Concentration (ppmC)

7-12

Figure 7-4

Comparison of Total NMOC Concentrations at LINY to Wind Direction

Note: Wind direction is the direction from which wind blows. Observations with calm or variable winds are not included in this figure.
0.00

0.10

0.20

0.30

0.40

0.50

0.60

1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

Average NMOC Concentration (ppmC)

7-13

Figure 7-5

Annual Variations in Average Concentrations of Total NMOC at LINY

Note: Total NMOC data from 1992 are not available for the LINY monitoring station.

The “error bars” in the graph indicate the 95-percent confidence intervals of the average concentrations.
5

1

0

5

0

1

0 0

0

2

4

6

8

1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

Number of Days with Total NMOC

Concentrations Greater Than 1 ppmC

7-14

Figure 7-6

Annual Variations in Peak Concentrations of Total NMOC at LINY

Note: Total NMOC data from 1992 are not available for the LINY monitoring station.
7-15

Table 7-1

Summary Statistics for Concentrations of Total NMOC at LINY

Category Parameter Value

Prevalence Number of nondetects 0

Number of valid sampling days 81

Frequency of detection 100%

Concentration

Range

Lowest concentration (ppmC) 0.067

25th percentile concentration (ppmC) 0.122

50th percentile concentration (ppmC) 0.196

75th percentile concentration (ppmC) 0.300

Highest concentration (ppmC) 0.643

Central Tendency Arithmetic mean concentration (ppmC) 0.225

Median concentration (ppmC) 0.196

Geometric mean concentration (ppmC) 0.195

Variability

Standard deviation (ppmC) 0.137

Coefficient of variation 0.60
.
8-1

8.0 Monitoring Results for Newark, New Jersey (NWNJ)

This section summarizes and interprets the total NMOC, SNMOC, VOC, and carbonyl

monitoring data collected at the NWNJ monitoring station during the 1998 NMOC/SNMOC

Monitoring Program; total NMOC data from previous years are also included for the purpose of

investigating annual variations.

Figure 8-1 indicates the location of the NWNJ monitoring station, which is in an area of

mixed industrial, commercial, and residential land use. Many transportation-related emissions

sources are in the immediate vicinity of NWNJ: Interstate 95, U.S. Highway 1, numerous surface

streets, and several railroads pass within 1 mile of the monitoring station, and the Newark

International Airport is approximately 2 miles southwest of the station. In addition, for the 1996

Toxics Release Inventory (TRI), more than 30 industrial facilities within the city limits of Newark

reported using large quantities of toxic chemicals and emitting air pollutants. Further, many other

industrial facilities operate in this area (i.e., facilities that are not subject to TRI reporting). 

Therefore, emissions from a great variety of sources impact the air quality at NWNJ. 

During the 1998 NMOC/SNMOC Monitoring Program, the NWNJ station collected total

NMOC samples every weekday morning, and collected SNMOC, VOC, and carbonyl samples

periodically. Overall, valid total NMOC samples were collected on 75 of the 77 days when

sampling events were scheduled. Thus, the completeness for the total NMOC measurements,

defined as the percentage of attempted samples that are valid, was 97 percent. For the other

monitoring options (SNMOC, VOC, and carbonyl), every attempted sampling event was valid, but

fewer than 10 samples were scheduled for these three groups of compounds. The analyses in this

section focus on interpreting trends and patterns among the daily measurements of total NMOC,

with a lesser emphasis placed on evaluating the periodic measurements of SNMOC, VOC, and

carbonyls.

The remainder of this section puts the monitoring data collected at NWNJ into perspective. 

Section 8.1 provides detailed analyses of the total NMOC monitoring data, including comparisons
8-2

to selected meteorological conditions and evaluations of long-term trends in total NMOC levels. 

Sections 8.2, 8.3, and 8.4 summarize the SNMOC, VOC, and carbonyl monitoring results,

respectively. Readers should note that Section 8.3 addresses two topics that have not been

addressed in earlier NMOC/SNMOC reports: air quality trends for methyl tert-butyl ether

(MTBE) and a comparison of monitoring results for compounds that are identified by both the

SNMOC and VOC sampling and analytical methods. For quick reference, Section 8.5 highlights

the most notable data trends observed at NWNJ.

8.1 Total NMOC Monitoring Data

To highlight key findings of the total NMOC monitoring data collected at NWNJ, the

following discussion reviews data summary parameters (Section 8.1.1), associations between total

NMOC levels and selected meteorological conditions (Section 8.1.2), and annual variations in

total NMOC concentrations (Section 8.1.3). When reading these sections, it is important to

remember that the total NMOC sampling and analytical method detects a wide range of organic

compounds (e.g., alkanes, olefins, aromatics, oxygenates, halogenated hydrocarbons), thus

providing a measure of overall levels of a large group of “ozone precursors.” However, this

method does not characterize total levels of air pollution, because the method does not measure

other pollutants common to urban air, such as inorganic acids, particulate matter, and heavier

organic compounds.

Note: The SNMOC analytical method also measures the concentration of total NMOC. 

Section 8.2 compares how total NMOC concentrations differed when measured with the

total NMOC and SNMOC sampling and analytical methods.

8.1.1 Data Summary

Using the data summary parameters that were defined in Section 3.1, Table 8-1 presents a

concise overview of the total NMOC measurements at NWNJ during the summer of 1998. A

review of this data summary follows:
8-3

• Prevalence. In each of the 75 valid samples collected at NWNJ, concentrations of total

NMOC were at least an order of magnitude higher than the estimated method detection

limit of 0.005 ppmC (or 5 ppbC). Therefore, the prevalence of total NMOC at NWNJ was

100 percent. With no nondetect observations among the total NMOC measurements, the

summary statistics presented in Table 8-1 are believed to accurately portray air quality

trends at NWNJ.

• Concentration range. According to Table 8-1, total NMOC concentrations at NWNJ

during the 1998 program ranged from 0.091 ppmC to 6.941 ppmC. The 75th percentile

concentration reveals that most samples at NWNJ contained less than 0.386 ppmC of total

NMOC. Only two total NMOC concentrations exceeded 1 ppmC during the summer of

1998; these observations are believed to be “outliers” that probably represent anomalous

air pollution episodes. In some cases, these two outliers greatly influenced statistical

analyses of the monitoring data. As a result, the two outlier concentrations were omitted

from certain analyses in this section. (Note, this section clearly indicates which analyses

omitted the concentration outliers.)

As Section 7.1 noted, the dates on which the outlier concentrations were observed at

NWNJ (June 25, 1998, and September 25, 1998) correspond to the dates on which two of

the highest total NMOC concentrations were observed at LINY. This coincidence suggests

that levels of air pollution throughout the Newark–New York City metropolitan area might

have been elevated on these two days, but monitoring data from other locations in the area

are needed to confirm this hypothesis.

For greater insight into the concentration distribution, Figure 8-2 presents a histogram of

the total NMOC monitoring data collected at NWNJ. As the figure shows, nearly

90 percent of the total NMOC concentrations fell in the range of 0.1–0.5 ppmC. This

observation suggests that levels of total NMOC at NWNJ during the morning hours on

summer days tend to fall within a fairly narrow range of concentrations, with notably

higher or lower concentrations occurring infrequently.

• Central tendency. During the 1998 program, the geometric mean concentration for total

NMOC at NWNJ was 0.303 ppmC—the lowest geometric mean concentration that has

been observed at this site for more than 10 years (see Section 8.1.3). For greater insight

into the central tendency concentrations, monthly-average central tendencies were

calculated and evaluated. When considering the entire set of total NMOC measurements

from NWNJ, the monthly-average concentrations for June and September were notably

higher than those for July and August. When considering the data set without the two

outlier concentrations, however, no statistically significant differences were observed

between the average concentrations of total NMOC for any 2 months. Therefore, the data

collected during the 1998 program showed no evidence of considerable monthly variations

in concentrations of total NMOC at NWNJ during the morning hours.
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• Variability. According to Table 8-1, the standard deviation of the total NMOC monitoring

data at NWNJ was 0.799 ppmC, and the coefficient of variation was 1.93. This data

variability is notably greater than the variability observed at NWNJ during previous

monitoring programs. More specifically, the coefficients of variation observed during the

1995, 1996, and 1997 NMOC/SNMOC Monitoring Programs were 0.49, 0.59, and 0.70,

respectively. Not surprisingly, the greater variability during the 1998 program appears to

be linked to the two outlier concentrations. Omitting these observations from the

variability calculation, the coefficient of variation for the 1998 data set at NWNJ is 0.44,

which is more comparable to the previous data trends.

8.1.2 Comparison to Selected Meteorological Conditions

To provide greater insight into the trends and patterns among the total NMOC

concentrations at NWNJ, this section compares the measured levels of NMOC to selected

meteorological parameters. The analysis considers 3-hour average observations of relative

humidity, precipitation, temperature, wind direction, and wind speed, all of which were measured

between 7:00 and 10:00 a.m. at the Newark International Airport. Since the airport is

approximately 2 miles from the ambient air monitoring station, the meteorological data are

believed to represent conditions at the NWNJ site.

To enable readers to compare data trends from the 1998 program to those from earlier

programs, the following analyses of associations between local meteorological conditions and

total NMOC concentrations are presented in a format almost identical to that used in

Section 4.2.1.2 of the 1997 NMOC/SNMOC report. Since the following analyses rely on the

grouping of meteorological data and total NMOC monitoring data into subsets on the order of ten

to twenty observations, the subsets can be significantly influenced by the values of outliers. To

avoid this potential bias, the two outliers of total NMOC concentrations were not considered when

evaluating correlations between meteorological conditions and the ambient air monitoring data.

An overview of the comparisons of meteorological conditions to total NMOC levels at

NWNJ follows:
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• Humidity. According to Figure 8-3, concentrations of total NMOC at NWNJ, on average,

tended to be higher on days with higher relative humidity. However, the concentration

differences for the different categories of humidity shown in the figure are all less than

20 percent, and none of these differences were found to be statistically significant. 

Therefore, the association between total NMOC concentrations at NWNJ during the

morning hours and humidity was found to be very weak and possibly anomalous.

It is interesting to note that the 1997 report showed that levels of total NMOC tended to be

lower on days with higher relative humidity, contrary to the trend illustrated in Figure 8-3

for the 1998 data. The discrepancy in trends between the 1997 and 1998 programs might

result from several factors, such as the possibility that the association between humidity

and total NMOC levels is weak and might have been overshadowed during the 1998

program by other influences or that the trend observed in either 1997 or 1998 was atypical. 

Further research is needed to better understand the relationship between total NMOC

levels at NWNJ and humidity, if such a relationship exists.

• Precipitation. Measurable rain was observed at the Newark International Airport during 7

of the 75 valid sampling events at NWNJ. The average concentration of total NMOC for

the 7 days with measurable precipitation was 0.320 ppmC, and the average concentration

for all other days (excluding the two days with outlier concentrations) was 0.308 ppmC. 

Therefore, levels of total NMOC on rainy mornings were, on average, 4 percent higher

than the levels on days without rain, but this concentration difference was not found to be

statistically significant.

The relationship between precipitation and total NMOC levels in Newark during the 1998

program contradicts the data presented in the 1997 report: At every station that

participated in the 1997 program (including NWNJ), total NMOC levels on rainy days

were notably lower than they were on days without measurable precipitation. The

inconsistent trends at NWNJ during the 1998 program might result from many factors,

including the fact that only trace amounts of precipitation (0.01 inches or less) were

recorded at Newark International Airport on 4 of the 7 days with measurable rain. This

trace precipitation was not likely to remove considerable portions of the airborne organic

compounds, thus explaining the apparent lack of association between precipitation events

and total NMOC concentrations. Additional data from NWNJ must be collected and

reviewed to better understand how precipitation events affect local air quality.

• Temperature. As Figure 8-3 shows, ambient air concentrations of total NMOC at NWNJ

on warmer mornings were, on average, higher than those measured on cooler mornings. 

The differences in concentrations for the three categories of temperature, however, were

only marginal, and none were statistically significant. The temperature in the morning

hours, therefore, appears to have minimal impact on levels of total NMOC at NWNJ—a

finding that is consistent with conclusions reached in the 1997 report. It should be noted

that total NMOC concentrations at NWNJ during the afternoon hours, or during other times
8-6

of year, might be temperature-dependent, despite the apparent lack of temperature

dependence observed during the past two NMOC/SNMOC Monitoring Programs, which

focused on characterizing air quality only during the morning hours. Continued review of

temperature and total NMOC concentrations can help clarify the relationship, if any,

between these two measurements.

• Wind Speed. Figure 8-3 shows that, similar to findings in previous years and at other

monitoring stations, total NMOC concentrations at NWNJ tended to be lower on the

windiest mornings. In fact, levels of total NMOC when wind speeds were greater than or

equal to 14 mph were almost 40 percent lower than levels of total NMOC when wind

speeds were less than 9 mph; this concentration difference was statistically significant. 

This association between wind speed and total NMOC concentration is generally

consistent with the analyses presented in the 1997 report and is also supported by the

science of atmospheric dispersion, which suggests that pollutants disperse more efficiently

as wind speed increases (USEPA 1995).

• Wind Direction. The scatter plot in Figure 8-4 shows how total NMOC concentrations

varied with wind direction at NWNJ. The figure does not include results from the

12 samples that were collected when the winds were calm or variable, and, to avoid

distorting the scale of the figure, the two outlier concentrations also are not shown. On the

dates the outliers were detected, winds were blowing from directions of 240 degrees and

280 degrees.

According to the figure, low to moderate levels of total NMOC were detected at NWNJ,

regardless of the direction that the wind was blowing, and total NMOC concentrations do

not appear to be strongly correlated with any single span of wind directions. Though the

average concentration of total NMOC for some wind directions (e.g., 240 to 310 degrees)

was higher than the average concentration for others, the differences in concentrations for

the various subsets of wind directions were modest, typically 30 percent or less. The

absence of notable associations between total NMOC concentrations and any specific wind

direction suggests that emissions sources throughout the Newark–New York City

metropolitan area contribute to the levels of total NMOC at NWNJ.

Though average levels of total NMOC did not vary significantly with wind direction, some

of the highest concentrations of total NMOC appeared to be linked to specific wind

patterns. More specifically, the three highest total NMOC concentrations at NWNJ

occurred primarily during westerly winds (i.e., wind directions of 240 to 300 degrees),

and five of the six highest total NMOC concentrations occurred during similar conditions. 

This trend is somewhat consistent with a trend observed during the 1997 program, when

almost every total NMOC concentration greater than 0.5 ppmC occurred when winds blew

either from the west to northwest (i.e., wind directions between 270 and 300 degrees) or

from the north to northeast (i.e., wind directions between 0 and 60 degrees). Analyses of
8-7

additional monitoring data will help confirm whether wind direction in the Newark area is

indeed linked with elevated concentrations of total NMOC at NWNJ.

As noted in Section 7.2, the analyses comparing selected meteorological conditions and

total NMOC concentrations in this report are only a small subset of the numerous types of

graphical and statistical analyses that could be performed on this data set. Use of multivariate

statistical techniques and consideration of meteorological conditions from longer time frames

(e.g., for the 24 hours prior to a sampling event) might provide greater insight into the many

complex factors that affect levels of air pollution at NWNJ.

8.1.3 Annual Variations

The NWNJ monitoring station has measured total NMOC concentrations on weekday

mornings every summer since 1988, thus providing 11 years of data to consider for evaluating

annual variations. To put the past data into perspective, this section examines how average levels

of total NMOC and peak levels of total NMOC have changed at NWNJ from the 1988 to 1998

NMOC/SNMOC Monitoring Programs. A summary of the key findings regarding annual variations

follows:

C Changes in average concentrations of total NMOC. Figure 8-5 indicates how the

average concentration of total NMOC has changed at NWNJ since the 1988

NMOC/SNMOC Monitoring Program. It is important to remember that the figure depicts

annual variations in levels of air pollution during the morning hours of the summer and

annual variations for other time frames (e.g., annual-average concentrations) might differ

from those shown in Figure 8-5.

In general, Figure 8-5 shows that average concentrations of total NMOC have increased at

NWNJ in some years and decreased in others; the figure also clearly shows that average

levels of total NMOC from 1995 to 1998 rank among the lowest observed at this station

over the last 11 years. The downward trend likely results from many factors, including the

requirement that all motor vehicles in the Newark–New York City metropolitan area use

reformulated fuels as of January 1, 1995. To examine the potential impact of motor

vehicles switching from conventional fuels to reformulated fuels, average concentrations of

total NMOC from 1988 to 1994 were compared to those from 1995 to 1998. On average,

the levels of total NMOC in the last 4 years (0.418 ppmC) was 31 percent lower than the

levels observed between 1988 and 1994 (0.603 ppmC), and this concentration difference
8-8

was found to be statistically significant. Though the use of reformulated fuels might have

caused, to a certain extent, the considerable decrease in total NMOC concentrations at

NWNJ, other factors likely contributed to this decrease as well. These other factors might

include state and local pollution prevention initiatives, declining emissions from industrial

sources, and long-term patterns in meteorological conditions.

C Changes in peak concentrations of total NMOC. For additional insight into annual

variations in levels of total NMOC, Figure 8-6 indicates how the frequency of peak

concentrations of total NMOC (defined here as concentrations greater than 1.0 ppmC) has

changed at NWNJ between the 1988 and 1998 programs. Clearly, the frequency of peak

concentrations of total NMOC was considerably higher between 1988 and 1994 than it was

between 1995 and 1998. Though this notable decline in total NMOC concentrations

greater than 1.0 ppmC might be linked to the use of reformulated fuels, it is extremely

difficult to determine the extent to which the decline in peak concentrations is linked to any

one factor.

Overall, the two different measures of annual variations—considering average and peak

concentrations—indicate that levels of total NMOC at NWNJ have decreased over the last

11 years and that the levels of total NMOC between 1995 and 1998, in particular, are lower than

those measured between 1988 and 1994.

For greater insight into the specific compounds that constitute total NMOC at NWNJ, the

remainder of this section summarizes the monitoring results for SNMOC, VOC, and carbonyls. 

Since fewer than 10 samples were collected at NWNJ for these categories of compounds, the

analyses in Sections 8.2, 8.3, and 8.4 are less detailed than those presented in Section 8.1 for the

extensive total NMOC sampling.

8.2 SNMOC Monitoring Data

During the 1998 program, SNMOC samples were collected at NWNJ on seven days. As

Section 2.3.2 explained, the SNMOC sampling and analytical method measures ambient air

concentrations of 80 different hydrocarbons as well as the concentration of total NMOC, thus

providing extensive information on the composition and magnitude of selected components of air

pollution. The following discussion summarizes the SNMOC data, comments on the composition
8-9

of the SNMOC samples, and compares the total NMOC concentrations measured by the total

NMOC sampling and analytical method to those measured concurrently by the SNMOC sampling

and analytical method.

8.2.1 Data Summary

Table 8-2 presents the data summary parameters, which Section 3.1 defined, for SNMOC

measurements at NWNJ in 1998. An overview of these summary parameters follows:

• Prevalence. According to Table 8-2, 73 of the 80 hydrocarbons identified by the SNMOC

sampling and analytical method were detected in all seven samples collected at NWNJ

during the 1998 program. These compounds, therefore, have a prevalence of 100 percent

and their summary statistics are not biased by nondetect observations. Only three

compounds (1-decene, 2-ethyl-1-butene, and 1-heptene) were detected in fewer than

50 percent of the SNMOC samples. Summary statistics for these compounds should be

interpreted with caution, as they might be significantly biased by a high fraction of

nondetect observations. In general, however, the high prevalence for almost every

SNMOC confirms that air pollution at the NWNJ monitoring station during the summer

months is a complex mixture of numerous hydrocarbons.

• Concentration range. As Table 8-2 indicates, concentration ranges for SNMOC vary

greatly from one compound to the next, and the highest concentrations at NWNJ were

observed for ethylene (23.20 ppbC), ethane (32.92 ppbC), propane (35.70 ppbC),

isopentane (42.52 ppbC), and toluene (33.54 ppbC). The highest concentrations for the

remaining 75 SNMOC were all lower than 20 ppbC.

Readers should note two limitations when interpreting the concentration range data in

Table 8-2. First, because air concentrations were measured only between 6:00 a.m. and

9:00 a.m., local time, the concentration range data in Table 8-2 only represent the span of

concentrations during the morning hours. It is highly likely that ambient levels of many

compounds rose to higher levels or fell to lower levels during other times of day. Second,

since the NWNJ station collected SNMOC samples on only 7 days of the monitoring

program, the concentration range data might not even characterize the actual lowest and

highest concentrations between 6:00 and 9:00 a.m.

• Central tendency. Not surprisingly, the central tendency concentrations in Table 8-2 also

vary widely among the compounds detected at NWNJ. For the most prevalent compounds,

the measures of central tendency shown in Table 8-2 are believed to accurately represent

actual central tendency levels. However, for the three compounds detected in fewer than

half of the SNMOC samples, the magnitude of the central tendency values is influenced by
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nondetects, which were all replaced with concentrations equal to one-half their

corresponding detection limits.

On average, the 80 compounds identified by the SNMOC sampling and analytical method

accounted for 79 percent of the total NMOC concentrations. The geometric mean

concentration for almost every individual compound was less than 10 ppbC. Only the

following nine compounds, presented in order of decreasing concentration, had geometric

mean levels greater than 10 ppbC: isopentane (30.13 ppbC), ethane (20.44 ppbC), toluene

(20.13 ppbC), propane (19.28 ppbC), ethylene (14.21 ppbC), propylene (11.16 ppbC),

2,3-dimethylbutane (11.13 ppbC), and m,p-xylene (10.87 ppbC). Combined, the

concentrations of these compounds comprised nearly 40 percent of the total NMOC

collected in the seven SNMOC samples at NWNJ.

Readers should keep in mind an important data limitation regarding the central tendency

concentrations: Since only 7 SNMOC samples were collected at NWNJ, each sample

contributes approximately 14 percent to the arithmetic mean concentrations. Therefore,

results from each individual sample at NWNJ have a considerable influence on the central

tendency concentrations. Central tendency estimates for the stations that collected SNMOC

samples every day, however, are believed to be much more representative of the actual

central tendencies (see Sections 5.2 and 6.2).

• Variability. According to Table 8-2, coefficients of variation for most SNMOC measured

at NWNJ were comparable and lower than 1.0. The compounds with the most variable air

monitoring data, as gauged by the coefficient of variation, were 1-dodecene (2.20),

cis-2-hexene (1.60), and 1-undecene (1.57). The greater variability for 1-dodecene and

1-undecene likely results from the fact that these compounds contain more than 10 carbon

atoms, and the calculation of coefficients of variation from concentrations measured in

units of ppbC inherently gives greater weight to compounds with more carbon atoms. The

reason for the greater variability in the cis-2-hexene concentrations is not known.

For greater insight into the SNMOC sampling, the following analyses comment on the

composition of the air samples (Section 8.3.2) and on the accuracy of the SNMOC measurements

(Section 8.3.3).

8.2.2 Composition of Air Samples

As previous NMOC/SNMOC reports have explained, the composition of air samples is

an important consideration when evaluating sources of pollution within airsheds. For instance,

air samples collected near significant emissions sources typically contain relatively high
8-11

concentrations of reactive compounds that are known to decompose readily in ambient air (such

as olefins). On the other hand, air samples collected in locations far downwind from emissions

sources typically contain lower levels of the reactive compounds and higher levels of their

decomposition products. In general, olefinic and aromatic compounds tend to be much more

reactive in ambient air than alkanes.

During the 1998 NMOC/SNMOC Monitoring Program, the identified SNMOC at NWNJ

contained, on average, 57 percent alkanes, 30 percent olefins, and 13 percent aromatic

compounds. This composition was calculated from a database of SNMOC concentrations that

had been converted to a volume basis (i.e., units of ppbv) in order to avoid artificially weighing

the composition by the number of carbons in different compounds. The composition of SNMOC

samples at NWNJ during the 1998 program was nearly identical to that observed at NWNJ

during the 1997 program (55 percent alkanes, 31 percent olefins, and 14 percent aromatic

compounds), and was quite similar to that observed at the other NMOC/SNMOC monitoring

stations. Results from monitoring conducted in earlier and future years should be reviewed to

determine if the composition of air at NWNJ has changed considerably over the years;

researchers should be sure to make such comparisons on a consistent basis (e.g., either on a

ppbC or a ppbv basis).

8.2.3 Comparison of Total NMOC Concentrations Measured by Two Different Methods

As Section 2.3 explained, both the total NMOC and the SNMOC sampling and analytical

methods measure concentrations of total NMOC. Of the six monitoring stations that participated

in the 1998 program, only the NWNJ monitoring station collected samples by both methods. 

More specifically, on 6 of the 7 days when SNMOC samples were collected at NWNJ, total

NMOC samples were also collected. These common sampling events provide a basis for

comparing the total NMOC concentrations measured by two different methods. Overall, the

total NMOC concentration measured by the SNMOC sampling and analytical method and that

measured by the total NMOC sampling and analytical method differed, on average, by
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 21 percent. This reasonable agreement in concentrations suggests that both methods are capable

of measuring levels of total NMOC accurately.

8.3 VOC Monitoring Data

This section summarizes results of the seven VOC sampling events conducted at NWNJ

during the 1998 NMOC/SNMOC program. As Section 8.2.1 noted, the 80 hydrocarbons

identified in the SNMOC samples, on average, accounted for nearly 80 percent of the airborne

total NMOC. The VOC monitoring data are useful for characterizing ambient levels of certain

organic compounds (e.g., selected halogenated hydrocarbons, nitriles, and oxygenated

compounds) that the SNMOC analytical method cannot identify: Of the 47 compounds that the

VOC analytical method identifies, 11 are currently identified by the SNMOC method, and the

remaining 36 are not. The following discussion highlights notable trends among the VOC

monitoring data.

8.3.1 Data Summary

Using the data summary parameters that were defined in Section 3.1, Table 8-3 provides

a concise summary of the VOC monitoring data collected at NWNJ during the 1998 program. 

An overview of the data summary parameters follows:

• Prevalence. According to Table 8-3, 21 of the 47 VOC were detected in more than

50 percent of the samples collected at the NWNJ monitoring station. The high

prevalence for these compounds, many of which are not identified by the SNMOC

analytical method, confirms that air pollution at the NWNJ monitoring station during the

summer months contains a complex mixture of numerous organic compounds. These

compounds’ high prevalence suggests that their summary statistics are not significantly

affected by nondetect observations. Conversely, summary statistics for the

26 compounds detected in less than 50 percent of the samples should be interpreted with

caution, as they might be significantly biased by nondetects, which were replaced within

the air monitoring database with an estimated concentration of one-half the detection

limit. Of the 26 compounds detected in less than 50 percent of the samples, 22 were not

detected in a single sample. The analyses in the remainder of this section focus on the

most prevalent compounds.
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• Concentration range. As Table 8-3 indicates, the highest VOC concentrations measured

in the seven sampling events were for propylene (8.04 ppbv), acetylene (7.15 ppbv),

toluene (6.92 ppbv), and MTBE (6.21 ppbv). Concentrations of the other compounds

were all less than 3.0 ppbv during the seven valid sampling events, and concentrations of

many compounds never exceeded 1.0 ppbv. 

The limitations regarding the concentration range of SNMOC (see Section 8.2.1) also

apply to the analysis of VOC concentrations. These limitations include the following: 

Because sampling only occurred during the morning hours, the concentration ranges do

not characterize the highest and lowest concentrations that might have occurred during

other times of day; and due to the limited number of VOC samples collected, the

concentration range data probably do not even characterize the actual highest and lowest

concentrations during the morning hours on summer days.

• Central tendency. Table 8-3 presents the median, arithmetic mean, and geometric mean

concentrations as different measures of the central tendency concentration. Overall, only

seven compounds had geometric mean concentrations greater than 1.0 ppbv: propylene

(4.08 ppbv), acetylene (3.98 ppbv), toluene (3.04 ppbv), MTBE (2.51 ppbv),

m,p-xylene (1.32 ppbv), and methyl ethyl ketone (1.15 ppbv). Two of these seven

compounds (MTBE and methyl ethyl ketone) are believed to account for a notable

portion of the total NMOC that could not be identified by the SNMOC analytical method. 

The majority of the remaining VOC has geometric mean concentrations less than

0.5 ppbv.

• Variability. The coefficient of variation for all of the most prevalent VOC compounds

detected at NWNJ during the 1998 program was less than 1.0. This consistently low

indicator of variability suggests that concentrations of many VOC do not change

considerably from one summer morning to the next. This result is consistent with VOC

originating from sources throughout the Newark area (e.g., motor vehicles), as emissions

would be detected regardless of wind direction. The relatively low data variability is

not consistent with emissions originating primarily from a single source at a discrete

location, since emissions would be expected to be highly variable (i.e., dependent upon

wind direction) from day to day. The impact of motor vehicle emissions is investigated

further in the following section.

8.3.2 Data Trends for MTBE

Ambient air quality trends for MTBE are expected to be influenced by requirements that

motor vehicles in selected metropolitan areas use reformulated fuels. As of January 1, 1995,

EPA required all motor vehicle fuels sold in the Newark–New York City area to be

reformulated gasoline (Main et al. 1998). Though the composition of reformulated gasoline

varies among urban centers, reformulated gasoline in the Newark area contains approximately
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11 percent MTBE, by weight (Main et al. 1998). As a result, motor vehicle emissions in this

area are expected to contain MTBE, along with the many other pollutants typically found in car

exhaust.

In support of this hypothesis, ambient air concentrations of MTBE were found to be

much more strongly correlated with concentrations of benzene, toluene, ethylbenzene, and xylene

isomers (i.e., compounds known to be found in motor vehicle exhaust) than with concentrations

of any other compound. To illustrate this correlation, Figure 8-7 compares concentrations of

benzene and toluene to concentrations of MTBE. Though the correlation between MTBE and the

other compounds is certainly not perfect and is somewhat uncertain due to the limited number of

samples, the figure indicates that concentrations of MTBE were generally higher when levels of

benzene and toluene were higher, and vice versa. As quantitative evidence of this trend, the

Pearson correlation coefficient for MTBE and benzene was 0.84, and for MTBE and toluene

was 0.94. These highly correlated data strongly suggest that emissions from motor vehicles

probably account for a large portion of the MTBE measured at NWNJ. However, a larger

volume of monitoring data is needed to establish statistically significant correlations between

these compounds’ concentrations.

For purposes of comparison, Figure 8-7 also shows how concentrations of ethylbenzene

and toluene varied during the monitoring program. Though the figure does not show correlations

between all possible pairings of compounds typically associated with motor vehicle exhaust, the

trends displayed in Figure 8-7 suggest that correlations between MTBE and selected aromatic

hydrocarbons are weaker than correlations between pairs of aromatic hydrocarbons (the

correlation between toluene and ethylbenzene is 0.98), but the difference in data correlations

appears to be marginal. Further research is needed to explain the relatively weaker correlations

involving MTBE and to characterize the many different sources of MTBE in the Newark area

(e.g., motor vehicles, gasoline stations, refineries).
8-15

8.3.3 Comparison of VOC and SNMOC Analytical Methods

As noted previously, the VOC analytical method identifies 11 compounds that the

SNMOC analytical method can also identify, thus providing a basis for comparing

concentrations measured by these two methods. During the 1998 program, air samples collected

at NWNJ on 7 days were analyzed for both SNMOC and VOC. Table 8-4 lists the 11

compounds identified by both methods, as well as the average concentrations measured by the

VOC and SNMOC analytical methods for these 7 days. 

According to Table 8-4, the average concentrations for 9 of the 11 compounds identified

by both methods were not more than 15 percent different when measured by both the VOC and

SNMOC analytical methods. Only two compounds, styrene and o-xylene, had higher

concentration differences for the two analytical methods, but neither of these differences were

statistically significant. The notable concentration difference observed for styrene is believed to

result, to a certain extent, from the fact that the average concentration measured by the VOC

method (0.14 ppbv) is only marginally higher than the corresponding detection limit

(0.11 ppbv). It has long been established that laboratory analytical methods are least precise

when measuring concentrations near their limits of detection. Overall, the absence of

statistically significant differences among the concentrations shown in Table 8-4, and the low

concentration differences themselves, suggest that the VOC and SNMOC analytical methods are

in excellent agreement when measuring ambient air concentrations of selected hydrocarbons.

8.4 Carbonyl Monitoring Data

Since neither the VOC nor the SNMOC analytical methods currently identify carbonyls,

the carbonyl monitoring option measures ambient air concentrations of an entire group of

compounds not characterized by other monitoring options of the NMOC/SNMOC Monitoring

Program. Ambient air concentrations of carbonyls are of particular interest because this group

of compounds is both formed by, and consumed by, the complex series of photochemical

reactions that produce ozone. During the 1998 program, carbonyl samples were collected at

NWNJ on 8 days between June and September. Due to the limited number of samples, extensive
8-16

analyses of the carbonyl monitoring data were not conducted. Rather, this section only presents

data summary parameters for the carbonyl monitoring results (see Table 8-5). An overview of

this data summary follows:

• Prevalence. According to Table 8-5, 11 of the 16 compounds identified by the carbonyl

analytical method were detected in more than half of the samples collected at NWNJ

during the 1998 program. Summary statistics for these compounds are expected to

accurately represent the actual distribution of concentrations, since few data points were

replaced with concentrations of one-half the detection limit. Since the remaining

5 compounds were not detected in any of the samples, the summary statistics for those

compounds shown in Table 8-5 are essentially meaningless.

• Concentration range. Referring again to Table 8-5, the highest ambient air

concentrations for carbonyls were observed for formaldehyde (25.34 ppbv), acetone

(8.83 ppbv), and acetaldehyde (5.43 ppbv). Every concentration measured for the

remaining carbonyls was lower than 5.0 ppbv, and concentrations of many carbonyls

never exceeded 1.0 ppbv. Since ambient air concentrations of many carbonyl

compounds are known to reach their highest levels during the early afternoon hours

(Brimblecombe 1996), and not during the scheduled sampling times for this program

(between 6:00 a.m. and 9:00 a.m.), the concentration ranges shown in Table 8-5

probably do not characterize the actual span of ambient air concentrations during the

summertime. Moreover, the concentration ranges in Table 8-5 might not be

representative of the ranges observed in other seasons.

• Central tendency. The central tendency data in Table 8-5 indicate that acetaldehyde,

acetone, and formaldehyde account for more than 90 percent of the carbonyls detected in

the air at NWNJ. This result is consistent with previous measurements at NWNJ and

with measurements at the other NMOC/SNMOC monitoring stations. Of the remaining

carbonyls, only butyr/isobutyraldehyde had a geometric mean concentration greater than

1.0 ppbv, and the remaining compounds had considerably lower geometric mean

concentrations.

To put the central tendency figures into perspective, the geometric mean concentrations

of the 16 carbonyls were compared to those for the 47 VOC and the 80 SNMOC. This

analysis found that the geometric mean concentration of formaldehyde (12.46 ppbv) was

higher than that of any other compound measured at NWNJ. Moreover, the geometric

mean concentrations of acetone (5.99 ppbv) and acetaldehyde (3.21 ppbv) had the sixth

highest and ninth highest geometric mean concentrations of all compounds, respectively. 

This analysis shows that certain carbonyls are among the most abundant organic

compounds found in the Newark ambient air.
8-17

• Variability. As Table 8-5 shows, the coefficient of variation for all 16 carbonyls was

less than 1.0. This relatively low coefficient of variation suggests that carbonyls were

consistently measured in the air at NWNJ, regardless of changing wind directions. This

trend is not consistent with carbonyls originating primarily from a single emissions

source at a discrete location, since this scenario would be likely to lead to carbonyls

being detected only under certain wind conditions. Rather, the relatively low data

variability is consistent with carbonyls being emitted from sources throughout the

Newark–New York City area (e.g., motor vehicles) or being formed by photochemical

reactions throughout this airshed.

The carbonyl monitoring data collected at NWNJ provide important context for

understanding the composition of air pollution during the morning hours. Greater insight into the

air quality trends for carbonyls can be gained through additional air monitoring efforts that

collect samples more frequently than was done during the 1998 program.

8.5 Chapter Summary

The ambient air monitoring data collected at NWNJ during the 1998 program provide a

wealth of information on the composition and magnitude of air pollution in the Newark area. 

Characterizing ambient air concentrations of more than 125 compounds, the NMOC/SNMOC

monitoring data from NWNJ identified the subset of compounds consistently found at highest

levels during the morning hours. The compounds with the highest concentrations include several

hydrocarbons (ethane, ethylene, propane, isopentane, acetylene, propylene, and toluene),

carbonyls (formaldehyde, acetone, and acetaldehyde), and other oxygenated compounds

(MTBE). Emissions from motor vehicles are believed to account for much of the airborne

hydrocarbons and MTBE at NWNJ.

The daily total NMOC measurements allowed for a detailed analysis of associations

between selected meteorological parameters and levels of air pollution. In general, no

statistically significant trends were observed between total NMOC concentrations and humidity,

precipitation, temperature, and wind direction. However, the absence of statistically significant

trends does not mean that these meteorological parameters have no impact on air quality. 

Rather, the effect of these parameters on total NMOC concentrations at NWNJ might have been
8-18

masked by other factors that exhibit a stronger influence on levels of air pollution. Wind speed

was the only meteorological parameter that had a statistically significant association with levels

of total NMOC: concentrations of total NMOC tended to be lower on windier days, and higher

when winds were calm or light. This trend was also observed at NWNJ during the 1997

program.

On average, the 3-hour average concentrations of total NMOC during the 1998 program

ranked among the lowest observed during the summer months since 1988—the year that the

NWNJ monitoring station first sampled for total NMOC. In the years since 1994, levels of total

NMOC at NWNJ have been, on average, more than 30 percent lower than the levels measured in

the years 1988–1994, and the concentration difference was found to be statistically significant. 

Furthermore, the frequency with which total NMOC concentrations exceed 1.0 ppmC has also

decreased considerably since 1994. The decreasing average and peak levels of total NMOC

might be due, at least in part, to the introduction of reformulated fuels between the 1994 and

1995 NMOC/SNMOC Monitoring Programs. Ongoing monitoring at NWNJ is needed,

however, to determine whether future levels of total NMOC continue to decrease, stay roughly

the same, or rise back to their 1988–1994 levels.
8-19

Figure 8-1

Newark, New Jersey (NWNJ), Monitoring Station

Source: USGS 7.5 Minute Series. Map scale: 1:24,000.
1

14

24

19

9

3

2

0

1

0

2

0

5

10

15

20

25

30

<=0.1 >0.1 and

<=0.2

>0.2 and

<=0.3

>0.3 and

<=0.4

>0.4 and

<=0.5

>0.5 and

<=0.6

>0.6 and

<=0.7

>0.7 and

<=0.8

>0.8 and

<=0.9

>0.9 and

<=1.0

>1.0

Concentration Range (ppmC)

Number of Observations in Listed Range

8-20

Figure 8-2

Distribution of Total NMOC Concentrations Measured at NWNJ

Note: The two concentrations higher than 1.0 ppmC were 1.208 ppmC and 6.941 ppmC.
NMOC Concentration vs. Humidity

0.0

0.1

0.2

0.3

0.4

<50 >=50 and <70 >=70

Relative Humidity (percent range)

Av

erage 

Concentr

ation of Tot

al 

NMOC (ppmC)

NMOC Concentration vs. Temperature

0.0

0.1

0.2

0.3

0.4

<=70 >70 and <=80 >80

Tempe rature Range (degrees Fahrenheit)

Av

erage 

Concentr

ation of Tot

al 

NMOC (ppmC)

NMOC Concentration vs. Wind Speed

0.0

0.1

0.2

0.3

0.4

<9 >=9 and <14 >=14

W ind Speed (mph)

Av

erage 

Concentr

ation of Tot

al 

NMOC (ppmC)

8-21

Figure 8-3

Comparison of NMOC Concentrations at NWNJ to Selected Meteorological Parameters
0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 60 120 180 240 300 360

Wind Direction (degrees)

Total NMOC Concentration (ppmC)

8-22

Figure 8-4

Comparison of Total NMOC Concentrations at NWNJ to Wind Direction

Notes: Wind direction is the direction from which wind blows. Observations with calm or variable winds are not included in this figure. As Section 8.1.2 notes, two outlier

concentrations are not included in this figure: When the total NMOC concentration was 1.208 ppmC, the wind direction was 280 degrees; when the total NMOC

concentration was 6.941 ppmC, the wind direction was 240 degrees.
0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

Average NMOC Concentration (ppmC)

8-23

Figure 8-5

Annual Variations in Average Concentrations of Total NMOC at NWNJ

Note: The “error bars” in the graph indicate the 95-percent confidence intervals of the average concentrations. All valid sampling results are considered in this figure,

including suspected data outliers.
16

13

2

3

11

1

10

1

2

3

2

0

5

10

15

20

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

Number of Days with Total NMOC

Concentrations Greater Than 1 ppmC

8-24

Figure 8-6

Annual Variations in Peak Concentrations of Total NMOC at NWNJ
0.00

0.50

1.00

1.50

2.00

2.50

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Concentra tion of MTBE (ppbv)

Concentr

ation of Benzene 

(ppbv)

0.00

2.00

4.00

6.00

8.00

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00

Concentra tion of MTBE (ppbv)

Concentr

ation of Toluene 

(ppbv)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

Concentra tion of Toluene (ppbv)

Concentr

ation of 

Ethylbenzene (ppbv)

8-25

Figure 8-7

Data Correlations for Ambient Air Concentrations of Selected Compounds

Note: Refer to Section 8.3.2 for interpretations of these plots.
8-26

Table 8-1

Summary Statistics for Concentrations of Total NMOC at NWNJ

Category Parameter Monitoring Station NWNJ

Prevalence Number of nondetects 0

Number of valid sampling days 75

Frequency of detection 100%

Concentration

Range

Lowest concentration (ppmC) 0.091

25th percentile concentration (ppmC) 0.216

50th percentile concentration (ppmC) 0.292

75th percentile concentration (ppmC) 0.386

Highest concentration (ppmC) 6.941

Central Tendency Arithmetic mean concentration (ppmC) 0.411

Median concentration (ppmC) 0.292

Geometric mean concentration (ppmC) 0.303

Variability

Standard deviation (ppmC) 0.799

Coefficient of variation 1.93
ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-27

Table 8-2

Summary Statistics for SNMOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

Acetylene 0 100% 5.38 12.75 8.80 8.69 8.40 2.41 0.28

Benzene 0 100% 3.84 9.33 5.73 5.98 5.78 1.75 0.29

1,3-Butadiene 0 100% 0.33 1.53 0.76 0.76 0.69 0.39 0.51

n-Butane 0 100% 6.25 19.43 9.12 10.23 9.55 4.49 0.44

cis-2-Butene 0 100% 0.87 2.33 1.12 1.32 1.24 0.55 0.41

trans-2-Butene 0 100% 0.84 2.57 1.08 1.33 1.23 0.62 0.46

Cyclohexane 0 100% 1.03 2.01 1.38 1.50 1.45 0.42 0.28

Cyclopentane 0 100% 0.67 1.66 0.95 1.10 1.06 0.33 0.30

Cyclopentene 0 100% 0.39 1.50 0.98 0.95 0.85 0.43 0.45

n-Decane 0 100% 1.41 4.14 1.67 2.35 2.14 1.14 0.48

1-Decene 7 0% ND ND 0.14 0.14 0.14 0.00 0.00

m-Diethylbenzene 0 100% 0.53 2.19 0.85 1.00 0.90 0.57 0.57

p-Diethylbenzene 0 100% 0.34 1.66 0.75 0.79 0.70 0.43 0.55

2,2-Dimethylbutane 0 100% 1.25 2.31 1.72 1.64 1.60 0.38 0.23

2,3-Dimethylbutane 0 100% 5.90 19.30 10.09 11.90 11.13 4.60 0.39

2,3-Dimethylpentane 0 100% 1.32 2.39 1.87 1.90 1.85 0.44 0.23

2,4-Dimethylpentane 0 100% 0.94 1.92 1.32 1.37 1.34 0.32 0.23

n-Dodecane 0 100% 0.41 1.05 0.64 0.69 0.65 0.24 0.35
Table 8-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-28

1-Dodecene 1 86% ND 5.46 0.15 0.91 0.24 2.01 2.20

Ethane 0 100% 11.59 32.92 21.47 21.50 20.44 7.27 0.34

Ethylbenzene 0 100% 2.35 5.83 3.33 3.76 3.56 1.35 0.36

2-Ethyl-1-Butene 7 0% ND ND 0.12 0.12 0.12 0.00 0.00

Ethylene 0 100% 10.42 23.20 12.61 14.84 14.21 5.00 0.34

m-Ethyltoluene 0 100% 1.80 4.89 2.77 3.13 2.95 1.14 0.36

o-Ethyltoluene 0 100% 0.93 2.44 1.46 1.54 1.46 0.56 0.37

p-Ethyltoluene 0 100% 1.13 2.92 1.68 1.97 1.86 0.73 0.37

n-Heptane 0 100% 1.62 3.84 1.94 2.29 2.20 0.77 0.34

1-Heptene 6 14% ND 0.89 0.26 0.35 0.30 0.24 0.69

n-Hexane 0 100% 2.83 5.93 3.60 4.15 4.02 1.15 0.28

1-Hexene 0 100% 0.23 0.51 0.30 0.33 0.32 0.11 0.32

cis-2-Hexene 0 100% 0.09 2.46 0.22 0.53 0.28 0.85 1.60

trans-2-Hexene 0 100% 0.15 0.74 0.30 0.33 0.30 0.20 0.59

Isobutane 0 100% 4.88 14.71 6.16 8.44 7.82 3.69 0.44

Isobutene/1-Butene 0 100% 3.31 9.51 5.04 5.51 5.22 2.04 0.37

Isopentane 0 100% 20.05 42.52 29.00 30.91 30.13 7.45 0.24

Isoprene 0 100% 0.32 2.61 1.25 1.30 1.13 0.68 0.53
Table 8-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-29

Isopropylbenzene 0 100% 0.55 1.59 0.84 0.90 0.85 0.35 0.39

2-Methyl-1-Butene 0 100% 0.66 2.64 1.28 1.34 1.22 0.66 0.49

2-Methyl-2-Butene 0 100% 0.86 3.92 1.69 1.85 1.66 1.02 0.55

3-Methyl-1-Butene 1 86% ND 3.37 0.53 1.39 0.64 1.44 1.03

Methylcyclohexane 0 100% 1.18 2.06 1.44 1.58 1.55 0.33 0.21

Methylcyclopentane 0 100% 1.68 3.51 2.25 2.50 2.43 0.66 0.26

2-Methylheptane 0 100% 0.84 1.87 1.17 1.23 1.18 0.37 0.30

3-Methylheptane 0 100% 0.80 1.52 1.04 1.14 1.11 0.28 0.25

2-Methylhexane 0 100% 1.91 4.22 2.54 2.81 2.68 0.92 0.33

3-Methylhexane 0 100% 1.96 3.79 2.46 2.77 2.69 0.71 0.26

2-Methylpentane 0 100% 3.84 9.25 5.62 6.30 6.05 1.94 0.31

3-Methylpentane 0 100% 2.35 5.59 3.50 3.78 3.64 1.14 0.30

2-Methyl-1-Pentene 0 100% 0.23 0.65 0.31 0.36 0.34 0.14 0.39

4-Methyl-1-Pentene 0 100% 0.06 0.17 0.11 0.11 0.10 0.03 0.32

n-Nonane 0 100% 1.15 2.50 1.92 1.75 1.67 0.56 0.32

1-Nonene 0 100% 0.23 0.58 0.31 0.37 0.35 0.16 0.42

n-Octane 0 100% 1.27 2.73 1.58 1.87 1.80 0.57 0.31

1-Octene 1 86% ND 0.28 0.18 0.19 0.18 0.07 0.38
Table 8-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-30

n-Pentane 0 100% 5.02 11.32 7.14 8.09 7.73 2.59 0.32

1-Pentene 0 100% 0.66 1.84 1.14 1.29 1.22 0.45 0.35

cis-2-Pentene 0 100% 0.68 1.76 1.05 1.14 1.08 0.40 0.35

trans-2-Pentene 0 100% 0.94 3.02 1.58 1.76 1.64 0.71 0.40

"-Pinene 0 100% 0.32 1.82 0.74 0.99 0.84 0.60 0.60

$-Pinene 0 100% 0.21 3.75 0.81 1.14 0.83 1.18 1.03

Propane 0 100% 14.05 35.70 19.56 20.28 19.28 7.59 0.37

n-Propylbenzene 0 100% 0.81 2.04 1.07 1.26 1.19 0.47 0.37

Propylene 0 100% 6.74 18.22 10.60 11.82 11.16 4.45 0.38

Propyne 0 100% 0.14 0.52 0.28 0.31 0.29 0.13 0.41

Styrene 0 100% 1.11 5.10 1.83 2.16 1.94 1.32 0.61

Toluene 0 100% 13.03 33.54 20.91 21.44 20.13 8.37 0.39

n-Tridecane 0 100% 0.09 1.36 0.18 0.39 0.25 0.46 1.17

1-Tridecene 3 57% ND 0.61 0.14 0.17 0.11 0.20 1.14

1,2,3-Trimethylbenzene 0 100% 0.72 2.47 1.32 1.41 1.29 0.64 0.45

1,2,4-Trimethylbenzene 0 100% 2.94 8.17 4.37 5.06 4.75 1.93 0.38

1,3,5-Trimethylbenzene 0 100% 1.14 3.23 1.84 2.23 2.06 0.91 0.41

2,2,3-Trimethylpentane 0 100% 0.58 1.64 0.98 1.03 0.98 0.34 0.33
Table 8-2 (Continued)

Summary Statistics for SNMOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of

Compound in Ambient

Air

Range of Measured Central Tendency of Variability in Measured

Concentrations Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbC) (ppbC) (ppbC)

Lowest Highest Median Coefficient of

(ppbC) (ppbC) (ppbC) Variation

8-31

2,2,4-Trimethylpentane 0 100% 2.86 7.67 4.49 4.93 4.72 1.57 0.32

2,3,4-Trimethylpentane 0 100% 1.05 2.83 1.77 1.77 1.70 0.57 0.32

n-Undecane 0 100% 1.09 2.94 1.52 1.90 1.78 0.75 0.39

1-Undecene 0 100% 0.04 2.02 0.25 0.45 0.22 0.70 1.57

m,p-Xylene 0 100% 7.10 18.74 10.78 11.63 10.87 4.69 0.40

o-Xylene 0 100% 2.71 6.50 4.06 4.43 4.20 1.56 0.35

TNMOC (w/ unknowns) 0 100% 239.93 518.03 312.97 367.31 351.72 116.80 0.32

TNMOC (speciated) 0 100% 198.22 420.63 260.37 291.18 280.26 88.80 0.30

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-32

Table 8-3

Summary Statistics for VOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetonitrile 7 0% ND ND 0.11 0.11 0.11 0.00 0.00

Acetylene 0 100% 1.76 7.15 3.74 4.28 3.98 1.66 0.39

Acrylonitrile 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Benzene 0 100% 0.50 2.23 0.69 0.98 0.87 0.59 0.60

Bromochloromethane 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Bromodichloromethane 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Bromoform 7 0% ND ND 0.06 0.06 0.06 0.00 0.00

Bromomethane 6 14% ND 0.02 0.02 0.02 0.02 0.00 0.10

1,3-Butadiene 2 71% ND 0.46 0.09 0.16 0.10 0.15 0.97

Carbon tetrachloride 0 100% 0.06 0.11 0.11 0.09 0.09 0.02 0.22

Chlorobenzene 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Chloroethane 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Chloroform 2 71% ND 0.10 0.03 0.04 0.04 0.03 0.68

Chloromethane 0 100% 0.39 0.89 0.57 0.62 0.60 0.17 0.27

Chloroprene 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Dibromochloromethane 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

m-Dichlorobenzene 7 0% ND ND 0.05 0.05 0.05 0.00 0.00

o-Dichlorobenzene 6 14% ND 0.05 0.05 0.04 0.04 0.01 0.22
Table 8-3 (Continued)

Summary Statistics for VOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).

8-33

p-Dichlorobenzene 1 86% ND 0.26 0.07 0.10 0.08 0.08 0.79

1,1-Dichloroethane 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

1,2-Dichloroethane 7 0% ND ND 0.04 0.04 0.04 0.00 0.00

trans-1,2-Dichloroethylene 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

1,2-Dichloropropane 7 0% ND ND 0.05 0.05 0.05 0.00 0.00

cis-1,3-Dichloropropene 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

trans-1,3-Dichloropropene 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Ethyl Acrylate 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Ethylbenzene 0 100% 0.31 0.96 0.45 0.51 0.47 0.23 0.45

Ethyl tert-Butyl Ether 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Methylene Chloride 1 86% ND 1.25 0.50 0.60 0.42 0.42 0.70

Methyl Ethyl Ketone 0 100% 0.79 1.88 1.09 1.18 1.15 0.34 0.28

Methyl Isobutyl Ketone 3 57% ND 0.31 0.12 0.12 0.09 0.10 0.84

Methyl Methacrylate 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Methyl tert-Butyl Ether 0 100% 1.28 6.21 2.31 2.85 2.51 1.69 0.59

n-Octane 2 71% ND 0.35 0.15 0.16 0.13 0.11 0.66

Propylene 0 100% 1.92 8.04 3.77 4.54 4.08 2.24 0.49

Styrene 2 71% ND 0.24 0.16 0.14 0.12 0.07 0.48
Table 8-3 (Continued)

Summary Statistics for VOC Concentrations Measured at Newark, NJ (NWNJ)

(Based on 7 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

8-34

tert-Amyl Methyl Ether 5 29% ND 0.16 0.03 0.06 0.05 0.05 0.88

1,1,2,2-Tetrachloroethane 7 0% ND ND 0.03 0.03 0.03 0.00 0.00

Tetrachloroethylene 1 86% ND 0.42 0.20 0.18 0.14 0.13 0.73

Toluene 0 100% 1.87 6.92 2.95 3.37 3.04 1.79 0.53

1,1,1-Trichloroethane 0 100% 0.42 1.01 0.62 0.63 0.61 0.19 0.30

1,1,2-Trichloroethane 7 0% ND ND 0.02 0.02 0.02 0.00 0.00

Trichloroethylene 4 43% ND 0.37 0.03 0.09 0.05 0.13 1.39

Vinyl Chloride 7 0% ND ND 0.04 0.04 0.04 0.00 0.00

m,p-Xylene 0 100% 0.85 2.88 1.32 1.45 1.32 0.73 0.51

o-Xylene 0 100% 0.46 1.43 0.63 0.73 0.68 0.34 0.47

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
8-35

Table 8-4

Comparison of Concentrations for Compounds Measured by 

Both the VOC and SNMOC Analytical Methods

(Based on 7 Days with Valid VOC and SNMOC Samples at NWNJ)

Compound Measured by the Measured by the RPD Two Methods

Average Average Is the Concentration

Concentration Concentration Difference Between the

VOC Method SNMOC Method Statistically

(ppbv) (ppbv) Significant?

Acetylene 4.28 4.35 2 % No

Benzene 0.98 1.00 2 % No

1,3-Butadiene 0.16 0.19 11 % No

Ethylbenzene 0.51 0.47 8 % No

n-Octane 0.16 0.23 12 % No

Propylene 4.54 3.94 14 % No

Styrene 0.14 0.27 44 % No

Toluene 3.37 3.06 10 % No

m,p-Xylene 1.45 1.45 1 % No

o-Xylene 0.73 0.55 28 % No

Notes: Concentrations measured by the SNMOC method were converted to units of ppbv for this analysis.

RPD = relative percent difference (see sidebar in Section 2.3 for a definition).

Nondetect observations were omitted from the calculation of RPDs.
8-36

Table 8-5

Summary Statistics for Carbonyl Concentrations Measured at Newark, NJ (NWNJ)

(Based on 8 Days with Valid Samples)

Compound

Prevalence of Range of

Compound in Ambient Measured

Air Concentrations

Central Tendency of Variability in Measured

Measured Concentrations Concentrations

Number Frequency Arithmetic Geometric Standard

of Non- of Mean Mean Deviation

detects Detections (ppbv) (ppbv) (ppbv)

Lowest Highest Median Coefficient of

(ppbv) (ppbv) (ppbv) Variation

Acetaldehyde 0 100% 1.92 5.43 3.24 3.38 3.21 1.18 0.35

Acetone 0 100% 3.80 8.83 6.31 6.18 5.99 1.61 0.26

Acrolein 0 100% 0.13 1.26 0.48 0.55 0.45 0.35 0.64

Benzaldehyde 3 63% ND 0.46 0.30 0.23 0.07 0.20 0.85

Butyr/Isobutyraldehyde 0 100% 0.28 3.54 1.53 1.64 1.09 1.29 0.79

Crotonaldehyde 8 0% ND ND 0.00 0.00 0.00 0.00 0.00

2,5-Dimethylbenzaldehyde 8 0% ND ND 0.00 0.00 0.00 0.00 0.00

Formaldehyde 0 100% 3.79 25.34 19.22 15.28 12.46 8.55 0.56

Hexanaldehyde 0 100% 0.11 0.49 0.32 0.29 0.25 0.15 0.51

Isovaleraldehyde 2 75% ND 0.30 0.20 0.17 0.08 0.13 0.73

Propionaldehyde 0 100% 0.13 0.46 0.29 0.29 0.27 0.12 0.42

Tolualdehydes 8 0% ND ND 0.01 0.01 0.01 0.00 0.00

Valeraldehyde 2 75% ND 0.24 0.14 0.13 0.07 0.09 0.72

ND = nondetect

Note: Data for compounds detected in less than 50 percent of the samples should be interpreted with caution, since their summary statistics might be influenced by low

prevalence (see Section 3.1).
9-1

9.0 Conclusions and Recommendations

The National 1998 NMOC/SNMOC Monitoring Program thoroughly characterized the

magnitude and composition of ozone precursors during the summer months at six monitoring

locations. The following discussion reviews the main conclusions of this report and recommends

several improvements for ongoing NMOC/SNMOC monitoring efforts.

9.1 Conclusions

Several different graphical, numerical, and statistical analyses were used to identify and

interpret trends and patterns in the data collected during the 1998 program, as well as data

collected during earlier NMOC/SNMOC programs. Though these analyses offer an extensive

account of air quality near the monitoring stations, they should not be viewed as comprehensive. 

An overview of key findings from the data analyses follows:

C Total NMOC Monitoring Data. During the 1998 program, concentrations of total NMOC

were measured on summer weekday mornings at six monitoring stations. Results from

duplicate samples and replicate analyses indicated that these measurements were highly

precise. Overall, total NMOC concentrations at JUMX were notably higher than those at

the other five stations. More specifically, the average concentration of total NMOC at

JUMX was 2.06 ppmC, while average levels at the other stations were less than

0.55 ppmC. The relatively high concentrations at JUMX resulted, in part, from several

outliers. In fact, one air sample collected at JUMX had a total NMOC concentration higher

than 20 ppmC—a level far higher than any other total NMOC concentration measured

during the past five NMOC/SNMOC Monitoring Programs.

At all six stations, total NMOC levels were lower on windier days and higher on days with

calm or light winds, but no consistent trends were observed between total NMOC

concentrations and other meteorological parameters (i.e., humidity, precipitation,

temperature, and wind direction). Even the record high temperatures in Dallas and Fort

Worth during the 1998 program appeared to have little bearing on the total NMOC levels

in these cities. The trend of decreasing total NMOC levels with increasing wind speed is

consistent with a fundamental principle of atmospheric dispersion: High wind speeds

enhance the dispersion of pollution.

The annual variations in total NMOC levels provided insight into long-term trends in air

quality at the six monitoring stations. No consistent annual variations were observed

among the 4 years of monitoring data available for the three stations in Dallas and Fort

Worth: At some stations (CAMS5 and DLTX), total NMOC levels decreased from 1995
9-2

to 1998; at the other station (CAMS13), total NMOC levels increased over this time frame. 

At the monitoring station in Juarez, Mexico, concentrations of total NMOC during the 1998

program were, on average, roughly four times higher than those measured during the 1995,

1996, and 1997 programs. Even when the outlier concentrations were omitted from the

analysis, the total NMOC levels at JUMX during 1998 were higher than those during

previous years. At the two monitoring stations in the Newark–New York City area (LINY

and NWNJ), total NMOC levels have steadily decreased over the last 10 summers. 

Moreover, the average concentration of total NMOC at LINY during the 1998 program was

the lowest level observed at this station since 1990, and the average concentration at

NWNJ during the 1998 program was the second lowest observed at the station since 1988. 

The factors that accounted for each station’s unique annual variations were not considered

in this report.

C SNMOC Monitoring Data. Four of the monitoring stations that participated in the 1998

program collected SNMOC samples every weekday morning during the summer, thus

providing a wealth of information on the composition of airborne hydrocarbons. The

SNMOC monitoring data were shown to be highly precise, based on the results of

39 duplicate samples that were analyzed in replicate. An overview of key findings for the

El Paso–Juarez and Dallas–Fort Worth areas follows.

At JUMX, the SNMOC monitoring data offered insight into the unusually high levels of

total NMOC that were measured during the 1998 program. For example, the SNMOC

monitoring data revealed an interesting pattern on the composition of the air mass at

JUMX: On days when total NMOC levels exceeded 1.0 ppmC, the 80 hydrocarbons

identified by the SNMOC sampling and analytical method accounted for only 11 percent of

the total NMOC; on all other sampling days, however, these 80 hydrocarbons accounted

for 57 percent of the total NMOC. Thus, the many observations of elevated total NMOC

levels at JUMX were highly influenced by compounds that the SNMOC sampling and

analytical method does not currently identify. For the most abundant SNMOC, average

concentrations during the 1998 program were not notably higher or lower than those

measured during the 1995, 1996, and 1997 programs.

In the Dallas–Fort Worth area, ambient air concentrations of the most abundant SNMOC at

CAMS13 were considerably higher than concentrations of the same compounds at CAMS5

and DLTX. Closer examination of the data revealed that the air mass at CAMS13

contained the greatest proportion of alkanes, while the air mass at DLTX contained the

greatest proportion of olefins. This trend was found to be very consistent with the

hypothesis that gasoline vapor emissions have a relatively greater influence on air quality

at CAMS13 and that mobile source emissions have a relatively greater influence on air

quality at DLTX—a hypothesis that should be verified by comparing the SNMOC

monitoring data to local emissions inventories for these three stations. With few

exceptions, the annual variations for the most abundant SNMOC tended to parallel each

station’s annual variations in total NMOC levels. In other words, at stations where total
9-3

NMOC levels gradually increased from 1995 to 1998, concentrations of the most abundant

SNMOC generally increased as well. As one exception to this general trend, the ambient

air concentrations of 2,3-dimethylbutane at all three monitoring stations in Dallas and Fort

Worth during the 1998 program were significantly higher than those during previous years. 

This notable increase throughout the Dallas–Fort Worth area might be linked to the record

high temperatures observed during the 1998 program, but detailed evaluations of additional

monitoring data are needed to verify this association.

At all four stations that collected daily SNMOC samples, data analyses revealed that the

compounds with the greatest potential for forming ozone were often not the compounds

with the highest ambient air concentrations. This same finding was presented in the 1996

NMOC/SNMOC report.

C VOC Monitoring Data. Only one station (NWNJ) collected VOC samples during the 1998

NMOC/SNMOC Monitoring Program. The VOC monitoring data provided insight into air

quality trends for many compounds that the SNMOC sampling and analytical method does

not identify. Of these compounds, methyl ethyl ketone and MTBE had geometric mean

concentrations that ranked among the highest levels measured at NWNJ. Closer evaluation

of the monitoring data revealed that mobile source emissions likely accounted for a large

portion of the airborne MTBE in the Newark area. Due to the limited number of VOC

samples collected during the 1998 program, further analysis of trends and patterns among

the VOC data were not performed.

The precision of the VOC monitoring data was not known, because too few duplicate

samples were collected to quantify the measurement precision. However, comparison of

the VOC and SNMOC sampling results from NWNJ showed that the VOC and SNMOC

sampling and analytical methods generated very consistent results for the 11 compounds

that can be identified by both methods.

C Carbonyl Monitoring Data. The limited carbonyl sampling performed during the 1998

program characterized ambient air concentrations for an entire group of compounds that the

SNMOC sampling and analytical method does not identify. Results from four duplicate

sampling events demonstrate that the carbonyl monitoring data were highly precise. 

Further, some noteworthy data trends were identified that appeared to be common to the

five stations that collected carbonyl samples (CAMS5, CAMS13, DLTX, JUMX, NWNJ). 

For instance, at all five stations, acetaldehyde, acetone, and formaldehyde accounted for a

large portion—80 percent or higher—of the combined concentration of the 18 carbonyls

that the sampling and analytical method can identify. Moreover, at many stations, the

average air concentrations of these compounds ranked among the ten highest average

concentrations measured during the program (including the 80 SNMOC). Therefore,

carbonyls were shown to account for a substantial portion of the total NMOC that was not

identified by the SNMOC sampling and analytical method.
9-4

9.2 Recommendations

Based on lessons learned from analyzing the 1998 NMOC/SNMOC monitoring data, a

number of improvements are recommended for future national ambient air monitoring efforts:

C Conduct more extensive statistical analyses on the data. Though this report highlighted

numerous trends and patterns in the large volume of monitoring data collected during the

1998 program, the analyses in this report should not be viewed as an exhaustive evaluation

of the data collected at the six monitoring stations. Additional statistical analyses of the

NMOC/SNMOC monitoring data could reveal subtle trends that were not identified by the

data analysis methodology used in this report. Examples of such additional analyses

include the use of multivariate statistics to understand how many different parameters affect

air quality and the use of factor analyses to determine the extent to which certain emissions

profiles are reflected in the air monitoring data.

C Compare ambient air monitoring data to emissions data. Though several air quality

trends identified in this report appeared to be consistent with emissions profiles for certain

types of sources, the link between emissions and ambient air concentrations could not be

verified since site-specific emissions inventories were not considered in this report. 

Consequently, a comparison of air quality trends documented in this report to local

emissions inventories should be performed. Understanding the extent to which emissions

from specific sources affect air quality is a critical step in developing effective air

pollution control strategies.

C Encourage stations to include the VOC (i.e., Air Toxics) monitoring option. The VOC

monitoring data collected during the 1998 program provided important insight into ambient

air quality in the Newark area, primarily by measuring concentrations of many compounds

that the SNMOC sampling and analytical method does not identify. Of particular interest,

the VOC sampling and analytical method measures concentrations of MTBE—a compound

that has gained recent attention in the environmental field—and other oxygenates that are

present in photochemical smog (e.g., methyl ethyl ketone). For a more complete picture of

air quality in their jurisdictions, agencies that sponsor NMOC/SNMOC monitoring stations

are encouraged to have all samples analyzed for both SNMOC and VOC, rather than having

samples analyzed for only SNMOC.

C Encourage long-term participation in the program. As noted in other NMOC/SNMOC

reports, state and local agencies can assess long-term trends in air pollution only by

evaluating the results of ongoing ambient air monitoring efforts. These long-term data

trends can answer important questions often asked of sponsoring agencies, such as: To

what extent has a certain pollution control strategy affected air quality? Is air quality in our

city improving or degrading? How can we best reduce ozone levels? To help answer

these and other important questions, sponsoring agencies are encouraged to continue

measuring levels of air pollutants at the same monitoring locations used in this program.
10-1

10.0 References

Brimblecombe, 1996. Air Composition & Chemistry. Second edition. University Press: 

Cambridge, England. 1996.

Carter, 1994. Development of Ozone Reactivity Scales for Volatile Organic Compounds. Journal

of the Air and Waste Management Association 44: 881–899. 1994.

Conner, Lonneman, Seila, 1995. Transportation-Related Volatile Hydrocarbon Source Profiles

Measured in Atlanta. Teri L. Conner, William A. Lonneman, Robert L. Seila. Journal of

the Air and Waste Management Association 45: 383–394. 1995.

ERG, 1996. 1995 Nonmethane Organic Compounds and Speciated Nonmethane Organic

Compounds Monitoring Programs. Eastern Research Group, Inc. Prepared for

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. 

December 1996.

ERG, 1997a. 1995 Urban Air Toxics Monitoring Program. Eastern Research Group, Inc. 

Prepared for U.S Environmental Protection Agency, Office of Air Quality Planning and

Standards. January 1997.

ERG, 1997b. 1996 Nonmethane Organic Compound and Speciated Nonmethane Organic

Compound Monitoring Program. Eastern Research Group, Inc. Prepared for

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. 

November 1997.

ERG, 1999. 1997 Nonmethane Organic Compounds (NMOC) and Speciated Nonmethane Organic

Compounds (SNMOC) Monitoring Program. Eastern Research Group, Inc. Prepared for

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. 

January 1999.

FR, 1984. Definition and Procedure for the Determination of the Method Detection Limit—

Revision 1.1. Federal Register 49/209. October 26, 1984.

Harnett, 1982. Statistical Methods. Donald L. Harnett. Addison-Wesley Publishing Company: 

Reading, Massachusetts. 1982.

Grosjean, 1991. Daniel Grosjean. Ambient Levels of Formaldehyde, Acetaldehyde, and Formic

Acid in Southern California: Results of a One-Year Base-Line Study. Environmental

Science and Technology 25:710–715. 1991.
10-2

Main et al., 1998. Analysis of Photochemical Assessment Monitoring Station (PAMS) Data to

Evaluate a Reformulated Gasoline (RFG) Effect. Hilary H. Main, Paul T. Roberts,

Richard Reiss. Prepared for U.S. Environmental Protection Agency, Office of Mobile

Sources. April 1998.

Scheff and Wadden, 1993. Receptor Modeling of Volatile Organic Compounds: 1. Emission

Inventory and Validation. Peter A. Scheff and Richard A. Wadden. Environmental

Science and Technology. 27: 617–625. 1993.

SGD, 1996. Street Guide and Directory: Ciudad Juarez, Chihuahua, Mexico. Index Publications,

Inc., El Paso, TX. 1996.

Sonoma, 1996. PAMS Data Analysis Workshop: Illustrating the Use of PAMS Data to Support

Ozone Control Programs. Sonoma Technology, Inc. Prepared for U.S. Environmental

Protection Agency, Office of Air Quality Planning and Standards. October 1996.

Sterrett, 1995. Alternative Fuels and the Environment. Edited by Frances Sterrett. Lewis

Publishers, Inc. 1995.

USDOC, 1993. 1990 Census of Population and Housing. U.S. Department of Commerce, Bureau

of the Census. July 1993.

USEPA, 1988. Method for the Determination of Non-Methane Organic Compounds (NMOC) in

Ambient Air Using Cryogenic Preconcentration and Direct Flame Ionization Detection

(PDFID). U.S. Environmental Protection Agency, Quality Assurance Division,

Environmental Monitoring Systems Laboratory. May 1988.

USEPA, 1989. Determination of C2 to C12 Ambient Air Hydrocarbons in 39 U.S. Cities from 1984

through 1986. U.S. Environmental Protection Agency, Atmospheric Research and

Exposure Assessment Laboratory. March 1989.

USEPA, 1995. User’s Guide for the Industrial Source Complex (ISC3) Dispersion Models:

Volume II - Description of Model Algorithms. U.S. Environmental Protection Agency,

Office of Air Quality Planning and Standards. October 1996.

USEPA, 1996a. PAMS Data Analysis Workshop: Illustrating the Use of PAMS Data to Support

Ozone Control Programs. Prepared by Sonoma Technology, Inc., for U.S. Environmental

Protection Agency. October 1996.

USEPA, 1996b. Photochemical Assessment Monitoring Stations: 1996 Data Analysis Results

Report. U.S. Environmental Protection Agency, Office of Air Quality Planning and

Standards. October 1996.
10-3

USEPA, 1999a. Compendium 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). U.S. Environmental Protection Agency,

Center for Environmental Research and Information. January 1999.

USEPA, 1999b. Compendium Method TO-11A: Determination of Formaldehyde in Ambient Air

Using Adsorbent Cartridge Followed by High Performance Liquid Chromatography

(HPLC) [Active Sampling Methodology]. U.S. Environmental Protection Agency, Center

for Environmental Research and Information. January 1999.
.
Long Island, NY

Eisenhower Park Monitoring Station

NMOC Results 1998

SITE SAMPLE COLLECTION AVERAGE

CODE ID DATE CONC.

LINY 12832 6/4/98 0.148

LINY 12853 6/5/98 0.084

LINY 12856 6/9/98 0.221

LINY 12890 6/10/98 0.072

LINY 12911 6/11/98 0.110

LINY 12912 6/12/98 0.093

LINY 12938 6/16/98 0.208

LINY 12940 6/17/98 0.220

LINY 12966 6/18/98 0.213

LINY 12933 6/19/98 0.331

LINY 12995 6/22/98 0.116

LINY 13013 6/23/98 0.112

LINY 13025 6/24/98 0.159

LINY 13026 6/24/98 0.148

LINY 13025 6/24/98 0.144

LINY 13026 6/24/98 0.139

LINY 13046 6/25/98 0.642

LINY 13070 6/26/98 0.300

LINY 13080 6/29/98 0.148

LINY 13173 6/30/98 0.122

LINY 13174 7/1/98 0.140

LINY 13196 7/2/98 0.149

LINY 13197 7/2/98 0.147

LINY 13196 7/2/98 0.152

LINY 13197 7/2/98 0.150

LINY 13209 7/3/98 0.313

LINY 13250 7/6/98 0.100

LINY 13318 7/7/98 0.241

LINY 13326 7/8/98 0.118

LINY 13344 7/9/98 0.229

LINY 13365 7/10/98 0.508

LINY 13375 7/13/98 0.353

LINY 13529 7/14/98 0.239

LINY 13257 7/15/98 0.177

LINY 13558 7/16/98 0.273

LINY 13594 7/17/98 0.216

LINY 13595 7/17/98 0.210

LINY 13594 7/17/98 0.208

LINY 13595 7/17/98 0.204

LINY 13581 7/20/98 0.127

LINY 13617 7/21/98 0.383

LINY 13705 7/22/98 0.361

LINY 13731 7/23/98 0.339

LINY 13760 7/24/98 0.187

LINY 13776 7/27/98 0.244

LINY 13890 7/28/98 0.109

LINY 13891 7/28/98 0.112

LINY 13890 7/28/98 0.113

LINY 13891 7/28/98 0.117

LINY 13780 7/29/98 0.162

LINY 13898 7/30/98 0.272

LINY 13916 7/31/98 0.094

Long Island, NY, NMOC Results, June 1998

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

6/4/986/6/986/8/98

6/10/986/12/986/14/986/16/986/18/986/20/986/22/986/24/986/26/986/28/986/30/98

Date

NMOC Conc. in ppmC

Long Island, NY, NMOC Results, July 1998

0.000

0.100

0.200

0.300

0.400

0.500

0.600

7/1/987/3/987/5/987/7/987/9/98

7/11/987/13/98

Date 7/15/98 7/17/98

7/19/987/21/987/23/987/25/987/27/987/29/987/31/98

NMOC Conc. in ppmC

1 of 2
Long Island, NY

Eisenhower Park Monitoring Station

NMOC Results 1998

SITE SAMPLE COLLECTION AVERAGE

CODE ID DATE CONC.

LINY 13923 8/3/98 0.326

LINY 13968 8/4/98 0.467

LINY 13969 8/4/98 0.522

LINY 13968 8/4/98 0.540

LINY 13969 8/4/98 0.426

LINY 12853 8/6/98 0.643

LINY 14054 8/7/98 0.230

LINY 14060 8/10/98 0.113

LINY 14094 8/11/98 0.260

LINY 14178 8/13/98 0.077

LINY 14239 8/14/98 0.089

LINY 14237 8/14/98 0.117

LINY 14230 8/17/98 0.169

LINY 14221 8/18/98 0.425

LINY 14238 8/20/98 0.111

LINY 14353 8/24/98 0.178

LINY 14364 8/25/98 0.248

LINY 14485 8/26/98 0.129

LINY 14496 8/27/98 0.116

LINY 14498 8/28/98 0.077

LINY 14564 8/31/98 0.205

LINY 14548 9/1/98 0.180

LINY 14549 9/1/98 0.208

LINY 14548 9/1/98 0.199

LINY 14549 9/1/98 0.198

LINY 14563 9/2/98 0.350

LINY 14692 9/3/98 0.170

LINY 14676 9/4/98 0.552

LINY 14694 9/8/98 0.303

LINY 14707 9/9/98 0.115

LINY 14708 9/9/98 0.074

LINY 14707 9/9/98 0.116

LINY 14708 9/9/98 0.141

LINY 14768 9/10/98 0.130

LINY 14779 9/11/98 0.357

LINY 14798 9/14/98 0.147

LINY 14807 9/15/98 0.209

LINY 14826 9/16/98 0.278

LINY 14832 9/17/98 0.190

LINY 14833 9/17/98 0.109

LINY 14832 9/17/98 0.208

LINY 14833 9/17/98 0.102

LINY 14892 9/18/98 0.132

LINY 14900 9/21/98 0.216

LINY 14964 9/22/98 0.170

LINY 14979 9/23/98 0.067

LINY 14991 9/24/98 0.355

LINY 15005 9/25/98 0.553

LINY 15006 9/25/98 0.611

LINY 15005 9/25/98 0.642

LINY 15006 9/25/98 0.644

LINY 15026 9/28/98 0.134

LINY 15027 9/28/98 0.096

LINY 15026 9/28/98 0.142

LINY 15027 9/28/98 0.156

LINY 15039 9/29/98 0.289

LINY 15040 9/29/98 0.307

LINY 15039 9/29/98 0.295

LINY 15040 9/29/98 0.301

LINY 15044 9/30/98 0.476

Long Island, NY, NMOC Results, August 1998

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

8/3/988/5/988/7/988/9/98

8/11/988/13/988/15/988/17/988/19/988/21/988/23/988/25/988/27/988/29/988/31/98

Date

NMOC Conc. in ppmC

Long Island, NY, NMOC Results, September, 1998

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

9/1/989/3/989/5/989/7/989/9/98

9/11/989/13/989/15/989/17/989/19/989/21/989/23/989/25/989/27/989/29/98

Date

NMOC Conc. in ppmC

2 of 2
Newark, NJ

SNMOC 1998 Results

SNMOC OPTION REPORT

SITE CODE: NWNJ

Reported in ppbC

Sample No.: 13179 13899 14059 14468 14487D1 14487R1

Sampling Date: 6/29/98 7/29/98 8/6/98 8/24/98 8/25/98 8/25/98

Analysis Date: 7/23/98 12/1/98 9/21/98 9/23/98 9/24/98 12/1/98

Compound

Ethylene 12.61 10.42 20.71 11.84 15.29 11.80

Acetylene 8.80 9.88 9.78 6.93 8.79 6.16

Ethane 0.00 @ 11.59 32.92 16.69 23.72 17.90

Propylene 10.60 6.74 18.22 9.08 12.43 9.36

Propane 14.05 14.41 35.70 19.90 22.77 17.05

Propyne 0.28 0.23 0.43 0.26 0.37 0.25

Isobutane 11.66 4.88 9.76 6.16 6.93 5.14

Isobutene/1-Butene 6.45 4.08 5.69 4.48 5.88 4.48

1,3-Butadiene 0.76 0.67 0.81 0.33 0.95 0.70

n-Butane 10.83 7.20 11.45 9.12 8.50 6.23

trans-2-Butene 1.49 0.84 1.56 0.92 1.29 0.97

cis-2-Butene 1.66 0.87 1.53 0.90 1.27 1.00

3-Methyl-1-butene 3.37 0.29 2.82 ND 0.85 0.17

Isopentane 31.04 29.00 42.52 27.96 30.14 27.33

1-Pentene 1.84 0.91 1.61 1.12 1.40 0.89

2-Methyl-1-butene 1.51 0.85 1.54 0.92 1.47 1.21

n-Pentane 10.08 5.56 11.32 6.71 8.23 6.14

Isoprene 2.61 1.28 1.42 0.32 1.41 1.03

trans-2-Pentene 2.11 1.28 2.09 1.27 1.85 1.35

cis-2-Pentene 1.56 0.83 1.24 0.86 1.26 0.90

2-Methyl-2-butene 1.87 1.30 2.20 1.13 2.03 1.39

2,2-Dimethylbutane 1.30 1.25 1.73 1.84 2.01 1.50

Cyclopentene 1.37 0.39 1.50 0.98 1.17 0.72

4-Methyl-1-pentene 0.12 0.09 0.11 0.06 0.10 0.10

Cyclopentane 1.66 0.95 1.38 0.95 0.93 0.81

2,3-Dimethylbutane 13.46 8.63 15.92 10.09 11.56 8.58

2-Methylpentane 6.87 4.74 8.30 5.50 6.50 5.38

3-Methylpentane 3.75 2.90 5.01 3.50 3.95 2.87

2-Methyl-1-pentene 0.31 0.31 0.43 0.27 0.42 0.26

1-Hexene 0.30 0.25 0.45 0.30 0.35 0.27

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.60 3.24 5.29 3.58 4.38 3.05

trans-2-Hexene 0.30 0.23 0.41 0.20 0.34 0.34

cis-2-Hexene 0.32 0.19 0.31 0.14 0.19 0.19

Methylcyclopentane 2.61 2.03 3.24 2.25 2.56 1.93

2,4-Dimethylpentane 1.50 1.23 1.54 1.17 1.69 1.11

Benzene 6.66 4.76 6.19 5.33 6.61 4.82

Cyclohexane 1.84 1.15 2.01 1.03 1.25 1.04

2-Methylhexane 4.22 2.10 3.41 1.91 2.60 2.13

2,3-Dimethylpentane 2.39 1.54 2.29 1.55 2.08 1.72

3-Methylhexane 3.13 2.18 3.54 2.31 2.84 2.14

1-Heptene 0.89 ND ND ND ND ND

2,2,4-Trimethylpentane 5.42 3.81 5.92 4.31 5.27 3.77

n-Heptane 2.44 1.62 2.58 1.76 2.21 1.64

Methylcyclohexane 1.83 1.29 2.06 1.44 1.54 1.16

2,2,3-Trimethylpentane 0.99 0.85 1.27 0.90 1.25 0.75

2,3,4-Trimethylpentane 1.78 1.38 2.06 1.53 2.03 1.50

Toluene 21.00 14.71 33.54 14.80 22.36 16.42

2-Methylheptane 1.31 0.93 1.52 0.96 1.34 1.02

3-Methylheptane 1.32 0.80 1.40 1.02 1.06 0.92

1-Octene 0.28 0.12 0.26 0.13 0.16 0.11

n-Octane 2.42 1.34 2.18 1.56 1.90 1.27

Ethylbenzene 4.26 2.93 5.83 2.50 3.76 2.95

m-Xylene/p-Xylene 12.30 8.25 18.74 7.24 12.34 9.47

Styrene 5.10 1.11 1.79 1.61 1.92 1.89

o-Xylene 5.02 3.30 6.35 3.05 4.52 3.62

1-Nonene 0.58 0.24 0.58 0.23 0.28 0.20

n-Nonane 1.92 1.17 2.22 1.25 1.48 1.15

Isopropylbenzene 1.59 1.05 0.85 0.83 0.59 0.59

a-Pinene 1.82 0.64 1.80 0.32 0.70 0.48

n-Propylbenzene 2.04 0.94 1.53 0.84 1.13 1.04

m-Ethyltoluene 3.61 2.51 4.21 2.12 2.94 2.65

p-Ethyltoluene 2.92 1.55 2.54 1.29 1.75 1.69

1,3,5-Trimethylbenzene 3.23 1.71 3.05 1.41 2.01 1.76

o-Ethyltoluene 2.44 1.46 1.79 0.95 1.31 1.20

b-Pinene 3.75 0.21 0.71 0.87 0.66 1.02

1,2,4-Trimethylbenzene 6.09 4.26 6.52 3.08 4.60 4.38

1-Decene ND ND ND ND ND ND

n-Decane 2.50 1.44 3.68 1.41 1.81 1.66

1,2,3-Trimethylbenzene 2.47 1.32 1.95 0.73 1.10 1.31

m-Diethylbenzene 2.19 1.10 0.72 0.53 0.65 1.03

p-Diethylbenzene 1.66 0.85 0.75 0.34 0.49 0.88

1-Undecene 0.25 0.13 0.25 2.02 0.09 0.12

n-Undecane 2.94 1.52 2.50 1.09 1.17 1.47

1-Dodecene 5.46 0.15 ND 0.17 0.02 0.38

n-Dodecane 1.05 0.72 0.64 0.41 0.32 0.68

1-Tridecene 0.61 ND 0.03 0.04 ND 0.06

n-Tridecane 0.57 1.36 0.12 0.18 0.07 0.28

TNMOC (w/ unknowns) 437.60 259.34 518.03 299.17 346.79 289.73

TNMOC (speciated) 307.94 217.98 400.35 232.78 293.15 230.90

@ For the 6/29/98 sample, ethane was not quantitated due to an analytical problem.

1 of 2
Newark, NJ

SNMOC 1998 Results

SNMOC OPTION REPORT

SITE CODE: NWNJ

Reported in ppbC

Sample No.:

Sampling Date:

Analysis Date:

Compound

Ethylene

Acetylene

Ethane

Propylene

Propane

Propyne

Isobutane

Isobutene/1-Butene

1,3-Butadiene

n-Butane

trans-2-Butene

cis-2-Butene

3-Methyl-1-butene

Isopentane

1-Pentene

2-Methyl-1-butene

n-Pentane

Isoprene

trans-2-Pentene

cis-2-Pentene

2-Methyl-2-butene

2,2-Dimethylbutane

Cyclopentene

4-Methyl-1-pentene

Cyclopentane

2,3-Dimethylbutane

2-Methylpentane

3-Methylpentane

2-Methyl-1-pentene

1-Hexene

2-Ethyl-1-butene

n-Hexane

trans-2-Hexene

cis-2-Hexene

Methylcyclopentane

2,4-Dimethylpentane

Benzene

Cyclohexane

2-Methylhexane

2,3-Dimethylpentane

3-Methylhexane

1-Heptene

2,2,4-Trimethylpentane

n-Heptane

Methylcyclohexane

2,2,3-Trimethylpentane

2,3,4-Trimethylpentane

Toluene

2-Methylheptane

3-Methylheptane

1-Octene

n-Octane

Ethylbenzene

m-Xylene/p-Xylene

Styrene

o-Xylene

1-Nonene

n-Nonane

Isopropylbenzene

a-Pinene

n-Propylbenzene

m-Ethyltoluene

p-Ethyltoluene

1,3,5-Trimethylbenzene

o-Ethyltoluene

b-Pinene

1,2,4-Trimethylbenzene

1-Decene

n-Decane

1,2,3-Trimethylbenzene

m-Diethylbenzene

p-Diethylbenzene

1-Undecene

n-Undecane

1-Dodecene

n-Dodecane

1-Tridecene

n-Tridecane

TNMOC (w/ unknowns)

TNMOC (speciated)

@ For the 6/29/98 sample, ethane was not quantitated due to an analytical problem.

14488D2 14488R2 14984 15058

8/25/98 8/25/98 9/18/98 9/30/98

9/24/98 12/1/98 11/3/98 10/28/98

14.75 12.14 11.58 23.20

8.30 6.08 5.38 12.75

23.35 18.04 22.19 24.86

11.59 9.29 9.57 17.87

21.33 17.10 15.18 23.18

0.38 0.26 0.14 0.52

6.84 5.20 5.89 14.71

5.46 4.36 3.31 9.51

0.88 0.68 0.43 1.53

8.22 6.31 6.25 19.43

1.18 0.87 0.86 2.57

1.23 0.98 0.87 2.33

0.92 0.16 0.15 2.50

28.02 24.10 20.05 38.38

1.31 0.97 0.66 1.74

1.35 1.10 0.66 2.64

8.06 6.13 5.02 10.78

1.37 1.05 0.99 1.25

1.78 1.35 0.94 3.02

1.17 0.88 0.68 1.76

1.89 1.43 0.86 3.92

1.84 1.54 1.31 2.31

1.11 0.66 0.41 1.07

0.14 0.08 0.08 0.17

1.05 0.80 0.67 1.18

11.26 8.48 5.90 19.30

6.00 4.59 3.84 9.25

3.80 2.82 2.35 5.59

0.35 0.30 0.23 0.65

0.29 0.23 0.23 0.51

ND ND ND ND

4.09 2.88 2.83 5.93

0.34 0.25 0.15 0.74

0.32 0.20 0.09 2.46

2.38 1.92 1.68 3.51

1.39 1.10 0.94 1.92

6.42 5.06 3.84 9.33

1.27 1.04 1.38 1.94

3.06 2.37 1.93 3.55

2.08 1.62 1.32 2.33

2.82 2.06 1.96 3.79

ND ND ND ND

5.16 3.77 2.86 7.67

2.30 1.60 1.86 3.84

1.59 1.30 1.18 1.85

1.16 0.75 0.58 1.64

2.05 1.47 1.05 2.83

24.01 20.85 13.03 32.08

1.36 0.96 0.84 1.87

1.25 0.94 0.85 1.52

0.10 0.06 ND 0.26

1.86 1.30 1.27 2.73

3.71 2.91 2.35 5.15

12.00 9.33 7.10 17.03

1.82 1.75 1.88 1.83

4.44 3.65 2.71 6.50

0.26 0.24 0.31 0.44

2.01 3.62 1.15 2.50

0.58 0.58 0.55 0.84

0.69 0.47 0.74 0.99

1.08 1.02 0.81 1.60

2.88 2.61 1.80 4.89

1.68 1.61 1.13 2.71

1.84 1.74 1.14 3.21

1.20 1.20 0.93 2.00

0.63 0.70 0.87 0.81

4.33 4.17 2.94 8.17

ND ND ND ND

1.72 1.50 1.60 4.14

1.02 1.14 0.72 1.51

0.65 1.05 0.56 1.06

0.44 0.89 0.41 0.85

0.10 0.12 0.04 0.32

1.23 1.55 1.31 2.57

0.02 0.12 0.25 0.07

0.41 0.65 0.52 0.96

ND ND ND ND

0.10 0.25 0.09 0.23

336.57 278.78 239.93 504.13

285.08 232.34 198.22 420.63

2 of 2
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13011 13012 13021D1 13021R1 13022D2 13022R2

Sampling Date: 6/22/98 6/23/98 6/24/98 6/24/98 6/24/98 6/24/98

Analysis Date: 7/9/98 7/10/98 7/8/98 @ 7/8/98 7/9/98

Compound

Ethylene 1.99 2.63 2.01 1.88 1.94

Acetylene 1.28 2.14 1.71 1.63 1.23

Ethane 3.10 2.73 2.58 2.07 2.78

Propylene 1.00 1.24 1.21 1.29 1.10

Propane 2.27 3.04 3.64 3.55 3.07

Propyne 0.11 0.19 0.13 0.14 0.07

Isobutane 1.28 3.00 1.75 1.79 1.49

Isobutene/1-Butene 1.81 2.35 1.87 2.16 1.83

1,3-Butadiene ND 0.19 0.19 0.19 0.16

n-Butane 4.89 19.41 9.49 9.51 8.84

trans-2-Butene 0.36 1.29 0.61 0.65 0.55

cis-2-Butene 0.44 1.50 0.70 0.74 0.63

3-Methyl-1-butene 0.82 1.42 0.62 0.62 0.80

Isopentane 18.41 44.13 24.05 24.94 20.35

1-Pentene 0.58 2.20 1.06 0.97 0.89

2-Methyl-1-butene 1.12 3.65 1.76 1.75 1.58

n-Pentane 4.61 14.79 7.31 7.55 6.24

Isoprene 1.36 1.58 1.09 1.14 1.23

trans-2-Pentene 1.16 4.08 1.88 1.95 1.67

cis-2-Pentene 0.55 2.09 0.95 1.00 0.79

2-Methyl-2-butene 1.52 5.58 2.50 2.67 2.13

2,2-Dimethylbutane 0.55 1.88 0.96 1.00 0.78

Cyclopentene 0.48 1.19 0.54 0.61 0.50

4-Methyl-1-pentene 0.03 0.27 0.11 0.12 0.10

Cyclopentane 0.62 1.93 0.94 0.97 0.88

2,3-Dimethylbutane 9.67 28.62 13.87 14.33 12.75

2-Methylpentane 5.13 14.86 7.40 7.55 6.51

3-Methylpentane 2.73 9.70 4.61 4.77 3.89

2-Methyl-1-pentene 0.22 0.85 0.43 0.46 0.31

1-Hexene 0.19 0.43 0.27 0.25 0.23

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 3.16 10.68 5.22 5.28 4.43

trans-2-Hexene 0.18 0.87 0.32 0.32 0.35

cis-2-Hexene 0.12 0.46 0.19 0.20 0.14

Methylcyclopentane 1.42 4.42 2.28 2.34 1.95

2,4-Dimethylpentane 0.46 1.28 0.70 0.71 0.62

Benzene 2.18 4.73 2.90 2.98 2.53

Cyclohexane 0.41 1.13 0.71 0.66 0.56

2-Methylhexane 1.81 4.36 2.57 2.43 2.13

2,3-Dimethylpentane 0.68 1.58 0.83 0.85 0.82

3-Methylhexane 1.44 4.04 2.18 2.32 1.75

1-Heptene ND ND ND ND ND

2,2,4-Trimethylpentane 1.92 4.38 2.60 2.72 2.21

n-Heptane 0.99 3.06 1.76 1.81 1.37

Methylcyclohexane 0.54 1.31 0.90 0.93 0.71

2,2,3-Trimethylpentane 0.47 1.04 0.65 0.70 0.54

2,3,4-Trimethylpentane 0.57 1.27 0.84 0.87 0.70

Toluene 6.12 12.87 8.68 9.04 7.50

2-Methylheptane 0.32 0.85 0.51 0.56 0.45

3-Methylheptane 0.29 0.63 0.40 0.42 0.34

1-Octene 0.08 0.11 0.06 0.06 0.05

n-Octane 0.44 0.98 0.62 0.69 0.56

Ethylbenzene 1.02 2.21 1.42 1.46 1.21

m-Xylene/p-Xylene 3.29 7.64 4.87 4.96 4.05

Styrene 0.95 1.12 1.14 1.19 0.86

o-Xylene 1.27 2.77 1.80 1.87 1.53

1-Nonene 0.11 0.14 0.11 0.10 0.06

n-Nonane 0.31 0.51 0.39 0.42 0.32

Isopropylbenzene 0.07 0.15 0.09 0.10 0.07

a-Pinene 0.27 0.29 0.22 0.21 0.17

n-Propylbenzene 0.32 0.69 0.41 0.42 0.35

m-Ethyltoluene 1.05 2.32 1.38 1.70 1.42

p-Ethyltoluene 0.49 1.38 0.71 0.85 0.67

1,3,5-Trimethylbenzene 0.47 1.29 0.73 0.75 0.59

o-Ethyltoluene 0.48 1.00 0.73 0.67 0.44

b-Pinene 0.62 0.60 0.69 0.66 0.51

1,2,4-Trimethylbenzene 1.41 3.47 1.88 2.04 1.65

1-Decene ND ND ND ND ND

n-Decane 0.26 0.41 0.52 0.47 0.31

1,2,3-Trimethylbenzene 0.31 0.68 0.36 0.45 0.35

m-Diethylbenzene 0.09 0.16 0.09 0.12 0.08

p-Diethylbenzene 0.10 0.16 0.12 0.15 0.08

1-Undecene ND ND ND ND ND

n-Undecane 0.49 0.31 0.15 0.18 0.13

1-Dodecene ND ND ND ND ND

n-Dodecane 3.74 4.35 1.97 1.08 0.11

1-Tridecene ND 0.11 0.54 0.57 1.12

n-Tridecane 0.06 ND 0.77 0.80 2.22

TNMOC (w/ unknowns) 159.79 329.08 200.25 210.54 184.62

TNMOC (speciated) 109.03 270.80 152.20 155.36 133.32

@ The replicate sample file was lost at the lab, and could not be reanalyzed.
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13054 13091 13093 13195 13194D1 13194R1 

Sampling Date: 6/25/98 6/29/98 6/30/98 7/1/98 7/2/98 7/2/98

Analysis Date: 7/10/98 7/11/98 7/11/98 7/10/98 7/8/98 7/8/98

Compound

Ethylene 2.41 4.20 2.15 6.18 4.91 6.00

Acetylene 1.91 3.30 2.05 5.86 4.60 4.14

Ethane 7.07 7.04 2.72 9.24 4.75 6.53

Propylene 1.47 1.95 1.45 3.66 2.83 2.63

Propane 12.00 11.74 4.49 10.42 7.28 6.56

Propyne 0.19 0.28 0.18 0.59 0.45 0.38

Isobutane 2.08 6.09 4.42 7.68 3.97 3.54

Isobutene/1-Butene 2.05 3.19 2.77 6.30 4.14 4.01

1,3-Butadiene 0.22 0.33 0.22 0.74 0.28 0.40

n-Butane 6.44 32.87 28.89 51.86 18.87 19.51

trans-2-Butene 0.14 ND 1.95 3.90 1.63 1.48

cis-2-Butene 0.16 2.29 2.15 4.15 1.72 1.57

3-Methyl-1-butene 1.25 2.43 1.99 3.51 2.02 2.22

Isopentane 14.84 70.43 57.88 108.20 53.13 47.82

1-Pentene 0.24 3.34 3.04 5.92 2.61 2.37

2-Methyl-1-butene 0.43 5.58 5.12 9.83 4.07 3.80

n-Pentane 3.77 26.07 21.22 41.12 19.92 18.03

Isoprene 1.13 1.24 1.19 2.03 1.58 1.52

trans-2-Pentene 0.42 6.12 5.70 11.11 5.07 4.65

cis-2-Pentene 0.19 3.17 3.13 6.01 2.67 2.31

2-Methyl-2-butene 0.51 8.82 8.26 16.20 6.87 6.30

2,2-Dimethylbutane 0.30 3.00 2.73 5.41 2.59 2.37

Cyclopentene 0.49 1.64 1.62 3.05 1.70 1.65

4-Methyl-1-pentene 0.03 0.44 0.42 0.78 0.30 0.36

Cyclopentane 0.34 3.62 3.27 6.29 2.96 2.68

2,3-Dimethylbutane 3.23 47.71 44.78 88.82 39.41 35.80

2-Methylpentane 3.18 24.80 23.80 46.28 21.28 20.03

3-Methylpentane 1.42 15.94 14.77 29.87 13.65 12.36

2-Methyl-1-pentene 0.09 1.46 1.27 2.60 1.30 1.26

1-Hexene 0.13 0.76 0.81 1.62 0.76 0.63

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.98 17.97 16.39 32.42 16.18 14.65

trans-2-Hexene 0.07 1.43 1.30 2.64 1.37 1.24

cis-2-Hexene 0.05 0.77 0.70 1.46 0.74 0.67

Methylcyclopentane 1.18 7.67 6.88 13.86 7.23 6.52

2,4-Dimethylpentane 0.37 2.33 2.09 4.39 2.55 2.29

Benzene 2.24 7.61 6.41 13.22 9.91 8.86

Cyclohexane 0.62 14.20 1.72 2.69 9.69 8.79

2-Methylhexane 1.54 6.68 5.98 12.03 8.44 7.18

2,3-Dimethylpentane 0.49 2.71 2.26 4.30 3.23 2.97

3-Methylhexane 1.12 6.51 6.39 13.12 8.37 7.65

1-Heptene ND 1.13 ND ND ND ND

2,2,4-Trimethylpentane 1.90 6.00 6.49 14.16 12.88 11.69

n-Heptane 0.97 5.25 4.60 9.42 7.06 6.41

Methylcyclohexane 0.89 2.37 1.94 3.76 3.30 2.89

2,2,3-Trimethylpentane 0.48 1.76 1.55 3.44 3.48 3.16

2,3,4-Trimethylpentane 0.67 2.20 1.98 4.68 5.40 4.92

Toluene 7.16 21.73 17.80 38.86 34.12 31.48

2-Methylheptane 0.43 1.54 1.31 2.70 2.73 2.54

3-Methylheptane 0.26 1.42 1.26 2.66 2.74 2.51

1-Octene 0.09 0.17 0.09 0.15 0.19 0.17

n-Octane 0.51 1.69 1.39 2.82 3.19 2.94

Ethylbenzene 1.24 3.57 3.08 6.65 6.25 5.67

m-Xylene/p-Xylene 4.00 12.25 10.84 23.25 20.43 18.78

Styrene 0.94 1.45 1.04 1.76 1.75 1.55

o-Xylene 1.41 4.57 4.05 8.77 7.48 6.97

1-Nonene 0.08 0.24 0.15 0.28 0.39 0.54

n-Nonane 0.29 0.97 0.72 1.35 1.94 1.76

Isopropylbenzene 0.04 0.34 0.25 0.54 0.39 0.36

a-Pinene 0.60 0.45 0.35 0.67 0.63 0.56

n-Propylbenzene 0.28 1.19 1.03 2.17 1.79 1.64

m-Ethyltoluene 1.92 3.90 3.49 7.77 6.10 5.68

p-Ethyltoluene 0.71 2.06 1.80 3.81 3.03 2.77

1,3,5-Trimethylbenzene 0.44 1.95 1.62 3.52 3.05 2.83

o-Ethyltoluene 0.49 1.76 1.45 3.16 2.82 2.43

b-Pinene 0.56 0.54 0.78 1.26 1.53 1.34

1,2,4-Trimethylbenzene 1.48 5.37 4.72 10.00 8.32 7.55

1-Decene ND ND ND ND ND ND

n-Decane 0.21 1.67 0.58 1.02 1.56 1.30

1,2,3-Trimethylbenzene 0.27 1.10 1.06 1.89 1.57 1.42

m-Diethylbenzene 0.07 0.88 0.21 0.53 0.58 0.51

p-Diethylbenzene 0.06 0.57 0.22 0.61 0.60 0.54

1-Undecene ND 1.02 ND 0.07 0.20 0.17

n-Undecane 0.29 24.37 0.29 0.87 1.14 0.94

1-Dodecene ND ND ND ND ND ND

n-Dodecane 2.21 3.19 ND 0.43 ND 0.26

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.09 ND ND 0.07 0.12 0.10

TNMOC (w/ unknowns) 153.89 637.34 454.51 883.78 561.44 507.04

TNMOC (speciated) 108.88 486.39 380.70 762.46 451.78 418.12
SNMOC 1998 REPORT

SITE CODE: CAMS13

All concentrations reported in ppbC

Sample No.: 13207D2 13207R2 13202 13249 13324 13328

Sampling Date: 7/2/98 7/2/98 7/3/98 7/6/98 7/7/98 7/8/98

Analysis Date: 7/9/98 7/10/98 7/11/98 VOID 7/15/98 7/16/98

Compound

Ethylene 2.05 4.97 5.10 3.00 2.59

Acetylene 4.01 3.59 5.13 1.97 3.12

Ethane 6.09 5.92 9.85 3.91 4.67

Propylene 2.23 2.17 3.66 1.22 1.87

Propane 6.67 6.86 15.77 4.02 6.22

Propyne 0.29 0.28 0.50 0.06 0.27

Isobutane 3.10 3.07 10.67 4.13 3.19

Isobutene/1-Butene 3.31 3.21 4.52 2.52 2.41

1,3-Butadiene 0.39 0.37 0.11 0.22 0.32

n-Butane 16.33 16.12 46.28 30.48 20.17

trans-2-Butene 1.11 1.11 3.52 2.47 1.45

cis-2-Butene 1.21 1.19 3.70 2.67 1.62

3-Methyl-1-butene 1.13 1.85 3.22 1.65 1.07

Isopentane 39.07 37.25 100.52 64.14 45.79

1-Pentene 1.72 1.82 5.73 3.92 2.57

2-Methyl-1-butene 2.83 2.92 8.76 6.30 3.95

n-Pentane 15.58 14.53 43.40 26.22 18.06

Isoprene 1.35 1.72 1.52 0.66 0.83

trans-2-Pentene 3.65 3.50 11.38 8.13 5.09

cis-2-Pentene 1.79 1.69 5.93 4.22 2.56

2-Methyl-2-butene 4.74 4.29 15.34 9.38 6.61

2,2-Dimethylbutane 1.75 1.86 5.00 3.26 2.20

Cyclopentene 1.18 1.19 3.21 2.23 1.81

4-Methyl-1-pentene 0.23 0.23 0.74 0.50 0.34

Cyclopentane 1.97 2.12 6.32 4.18 2.86

2,3-Dimethylbutane 28.75 27.35 81.45 58.21 34.07

2-Methylpentane 15.60 15.70 43.88 29.73 20.33

3-Methylpentane 10.11 9.66 27.53 18.41 12.39

2-Methyl-1-pentene 0.94 0.92 2.68 1.89 1.19

1-Hexene 0.54 0.49 1.53 1.04 0.74

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 11.56 11.46 34.61 22.63 15.16

trans-2-Hexene 0.76 0.93 2.93 2.04 1.31

cis-2-Hexene 0.37 0.50 1.55 1.08 0.69

Methylcyclopentane 5.34 5.06 13.69 8.73 5.97

2,4-Dimethylpentane 1.73 1.80 4.25 2.74 1.89

Benzene 6.37 6.28 16.99 10.77 7.77

Cyclohexane 7.47 7.73 4.81 1.63 1.30

2-Methylhexane 4.84 5.67 12.98 7.26 4.17

2,3-Dimethylpentane 1.98 2.32 4.84 2.77 1.72

3-Methylhexane 5.96 5.79 13.83 8.18 5.54

1-Heptene ND ND ND 0.72 0.74

2,2,4-Trimethylpentane 9.68 9.20 15.95 8.59 5.85

n-Heptane 5.14 4.98 11.45 6.75 4.52

Methylcyclohexane 2.33 2.40 5.01 2.58 1.89

2,2,3-Trimethylpentane 2.48 2.52 4.55 2.46 1.66

2,3,4-Trimethylpentane 4.13 3.96 7.33 3.49 2.25

Toluene 26.84 26.03 57.39 33.77 25.09

2-Methylheptane 2.11 2.10 4.21 2.08 1.32

3-Methylheptane 1.70 2.02 3.91 2.00 1.01

1-Octene 0.08 0.13 0.36 0.15 0.16

n-Octane 2.44 2.38 5.29 2.76 1.79

Ethylbenzene 5.46 5.27 11.14 6.96 4.47

m-Xylene/p-Xylene 18.62 18.18 38.01 25.61 16.06

Styrene 1.47 1.64 1.79 1.13 0.62

o-Xylene 5.91 5.68 13.40 8.92 5.42

1-Nonene 0.34 0.39 0.58 0.32 0.23

n-Nonane 1.82 1.82 3.21 1.95 1.12

Isopropylbenzene 0.37 0.37 0.99 0.46 0.28

a-Pinene 1.00 1.30 0.82 0.28 0.31

n-Propylbenzene 1.19 1.36 3.14 2.14 1.21

m-Ethyltoluene 4.50 4.60 10.68 7.41 4.07

p-Ethyltoluene 2.15 2.23 5.45 3.73 2.14

1,3,5-Trimethylbenzene 2.30 2.33 5.30 3.62 1.87

o-Ethyltoluene 1.79 2.01 4.38 2.87 1.67

b-Pinene 0.77 0.94 0.87 0.40 0.33

1,2,4-Trimethylbenzene 6.01 5.53 14.15 10.32 5.33

1-Decene ND ND ND ND ND

n-Decane 3.81 4.21 2.20 1.54 0.78

1,2,3-Trimethylbenzene 1.27 1.68 2.62 1.83 1.12

m-Diethylbenzene 0.36 0.42 0.86 0.55 0.23

p-Diethylbenzene 0.39 0.42 0.95 0.55 0.29

1-Undecene 0.18 0.20 0.16 0.98 ND

n-Undecane 6.13 5.98 0.98 0.53 0.15

1-Dodecene ND ND 0.05 ND ND

n-Dodecane 1.69 1.55 0.46 ND ND

1-Tridecene ND ND 0.05 ND ND

n-Tridecane 0.13 0.06 0.02 ND ND

TNMOC (w/ unknowns) 405.16 436.80 1011.96 609.15 398.21

TNMOC (speciated) 350.69 349.40 825.15 516.02 349.87
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13369 13531 13371 13530 13523 13584

Sampling Date: 7/9/98 7/10/98 7/13/98 7/14/98 7/15/98 7/16/98

Analysis Date: 7/16/98 8/7/98 7/16/98 8/7/98 8/8/98 8/8/98

Compound

Ethylene 1.73 14.58 1.50 7.76 9.02 16.71

Acetylene 0.89 4.68 8.84 4.75 6.27 10.22

Ethane 4.72 21.61 12.70 19.01 18.16 25.52

Propylene 0.74 10.33 7.98 3.17 4.06 7.46

Propane 3.97 27.95 16.42 22.23 24.00 20.29

Propyne 0.07 0.29 0.95 0.34 0.41 0.73

Isobutane 1.04 5.83 19.84 9.41 4.89 6.88

Isobutene/1-Butene 1.59 4.95 8.89 3.71 5.00 8.98

1,3-Butadiene 0.10 0.91 1.06 0.52 0.86 1.71

n-Butane 3.51 6.85 33.96 29.55 27.64 34.87

trans-2-Butene 0.19 1.09 3.74 2.76 2.68 3.25

cis-2-Butene 0.19 1.15 3.69 2.41 2.91 3.67

3-Methyl-1-butene 0.18 2.07 3.53 1.75 1.72 2.20

Isopentane 13.13 27.14 76.12 77.10 78.75 104.80

1-Pentene 0.37 1.21 3.41 3.64 4.34 5.61

2-Methyl-1-butene 0.63 1.08 4.83 4.71 6.00 8.02

n-Pentane 2.96 6.21 17.29 27.37 28.62 55.52

Isoprene 0.40 1.94 2.99 1.19 1.38 1.85

trans-2-Pentene 0.70 1.59 5.04 6.68 8.18 10.57

cis-2-Pentene 0.31 1.07 2.61 3.66 4.45 5.67

2-Methyl-2-butene 0.70 1.61 4.95 7.83 10.01 13.97

2,2-Dimethylbutane 0.29 1.14 3.21 3.08 3.71 4.98

Cyclopentene 0.82 1.18 1.83 3.51 1.87 2.19

4-Methyl-1-pentene 0.04 ND 0.47 0.38 0.42 0.58

Cyclopentane 0.29 0.72 1.89 3.22 3.80 5.37

2,3-Dimethylbutane 4.12 10.37 35.99 44.57 49.81 65.26

2-Methylpentane 3.61 5.39 15.18 22.19 26.04 34.45

3-Methylpentane 1.72 3.06 8.44 15.23 16.61 21.99

2-Methyl-1-pentene 0.16 0.38 0.86 1.37 1.62 2.36

1-Hexene 0.20 0.34 0.64 1.07 0.93 1.24

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.47 3.38 7.55 19.92 20.85 26.36

trans-2-Hexene 0.23 0.34 1.10 1.32 1.45 1.96

cis-2-Hexene 0.11 0.17 0.49 0.86 0.95 1.30

Methylcyclopentane 1.01 1.98 4.92 7.78 8.36 10.90

2,4-Dimethylpentane 0.31 1.28 1.85 2.73 3.09 4.27

Benzene 2.01 4.85 9.26 11.92 12.35 17.00

Cyclohexane 0.37 1.39 1.91 2.47 2.21 3.94

2-Methylhexane 1.93 2.22 4.87 7.09 6.99 9.01

2,3-Dimethylpentane 0.60 1.50 2.66 3.23 2.85 3.72

3-Methylhexane 1.09 2.45 5.40 7.78 7.80 10.85

1-Heptene 0.22 ND 0.62 0.18 ND 0.33

2,2,4-Trimethylpentane 1.40 4.10 8.80 9.39 10.17 15.03

n-Heptane 0.93 1.93 4.39 7.29 7.38 9.35

Methylcyclohexane 0.61 1.46 2.82 3.05 2.89 3.41

2,2,3-Trimethylpentane 0.40 1.01 2.11 2.62 2.49 3.87

2,3,4-Trimethylpentane 0.50 1.46 2.92 3.82 3.61 5.50

Toluene 6.40 19.74 34.33 42.53 39.34 56.63

2-Methylheptane 0.28 1.17 1.83 2.61 2.44 3.29

3-Methylheptane 0.24 1.27 1.51 2.68 2.54 3.20

1-Octene 0.12 0.18 0.19 0.24 0.15 0.17

n-Octane 0.52 2.05 2.13 3.79 3.17 4.12

Ethylbenzene 1.19 3.26 4.60 8.03 7.78 11.37

m-Xylene/p-Xylene 4.33 10.05 14.79 28.60 26.93 39.33

Styrene 0.96 2.86 1.47 2.05 1.65 1.60

o-Xylene 1.46 4.17 5.73 9.97 9.31 13.85

1-Nonene 0.13 0.47 0.64 0.58 0.45 0.28

n-Nonane 0.37 1.72 2.10 2.90 2.46 2.79

Isopropylbenzene 0.06 0.53 0.08 1.13 0.86 1.12

a-Pinene 0.24 1.87 1.53 0.37 0.46 1.02

n-Propylbenzene 0.31 1.07 1.21 2.53 2.44 3.39

m-Ethyltoluene 1.10 2.91 4.09 8.40 7.81 11.14

p-Ethyltoluene 0.58 1.82 2.09 4.67 4.27 5.73

1,3,5-Trimethylbenzene 0.48 1.88 2.46 4.32 4.24 5.79

o-Ethyltoluene 0.39 1.39 2.23 3.31 2.97 4.21

b-Pinene 0.48 2.35 1.15 1.45 1.16 1.37

1,2,4-Trimethylbenzene 1.57 4.70 6.73 12.52 11.32 16.14

1-Decene ND ND ND ND ND ND

n-Decane 0.58 2.57 3.65 2.09 2.29 2.51

1,2,3-Trimethylbenzene 0.28 1.45 1.56 3.23 2.82 3.86

m-Diethylbenzene 0.09 0.54 0.59 1.13 1.08 1.59

p-Diethylbenzene 0.12 0.62 0.38 1.21 1.32 1.18

1-Undecene ND 0.16 0.15 0.17 0.16 0.32

n-Undecane 2.78 2.34 1.77 1.72 1.77 2.28

1-Dodecene ND 0.50 ND 0.29 0.46 0.29

n-Dodecane 1.12 0.96 ND 1.14 0.92 1.34

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.04 0.37 ND 0.34 0.19 0.34

TNMOC (w/ unknowns) 113.97 350.43 571.38 686.14 685.36 934.38

TNMOC (speciated) 89.77 271.17 469.51 579.62 590.36 813.96
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13703D1 13703R1 13704D2 13704R2 13604 13727

Sampling Date: 7/17/98 7/17/98 7/17/98 7/17/98 7/20/98 7/21/98

Analysis Date: 8/8/98 8/19/98 8/8/98 8/19/98 8/8/98 8/20/98

Compound

Ethylene 13.28 10.96 13.74 11.43 2.89 3.84

Acetylene 8.48 7.64 8.43 7.55 1.65 3.56

Ethane 26.23 20.08 26.13 20.36 12.35 6.11

Propylene 5.53 5.19 5.58 5.02 1.54 2.10

Propane 26.19 23.59 26.15 23.86 9.27 4.81

Propyne 0.58 0.33 0.55 0.39 0.67 0.05

Isobutane 11.87 10.96 12.12 11.05 2.45 2.75

Isobutene/1-Butene 6.13 5.46 6.21 5.83 2.17 2.76

1,3-Butadiene 1.17 0.95 1.18 1.10 0.13 0.42

n-Butane 36.53 32.81 36.47 33.65 5.48 13.53

trans-2-Butene 2.91 2.49 2.62 2.64 0.59 1.42

cis-2-Butene 3.04 2.79 3.14 2.78 0.61 1.65

3-Methyl-1-butene 1.73 1.55 2.36 2.06 ND 0.78

Isopentane 85.59 81.49 86.40 84.58 17.59 44.26

1-Pentene 4.32 3.97 4.21 4.01 0.90 2.33

2-Methyl-1-butene 5.72 5.19 5.73 5.33 0.57 3.51

n-Pentane 38.88 35.65 38.97 35.91 7.10 15.85

Isoprene 1.45 1.30 1.46 1.33 0.86 1.01

trans-2-Pentene 7.45 6.80 7.50 6.82 1.15 4.93

cis-2-Pentene 3.94 3.62 4.08 3.66 0.75 2.64

2-Methyl-2-butene 9.29 8.38 9.49 8.69 0.96 6.08

2,2-Dimethylbutane 4.37 4.16 4.50 3.99 0.98 2.49

Cyclopentene 2.75 2.06 3.85 3.69 0.48 1.62

4-Methyl-1-pentene 0.39 0.44 0.36 0.41 0.07 0.31

Cyclopentane 4.10 3.92 4.03 4.10 0.67 2.68

2,3-Dimethylbutane 46.90 42.82 51.09 46.26 7.27 30.44

2-Methylpentane 25.29 23.36 27.03 25.35 4.83 15.98

3-Methylpentane 16.60 15.19 16.67 15.22 2.97 9.59

2-Methyl-1-pentene 1.51 1.29 1.62 1.15 0.16 0.85

1-Hexene 0.98 0.86 0.83 0.81 0.19 0.51

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 20.59 18.90 20.11 18.76 4.10 11.53

trans-2-Hexene 1.41 1.40 1.28 1.37 0.26 0.84

cis-2-Hexene 0.91 0.87 0.97 0.76 0.05 0.54

Methylcyclopentane 8.16 7.56 8.30 7.59 1.83 4.67

2,4-Dimethylpentane 3.26 2.81 3.36 2.72 0.95 1.90

Benzene 12.79 11.58 12.89 12.24 3.44 7.28

Cyclohexane 2.43 2.35 2.47 2.12 0.69 1.34

2-Methylhexane 7.32 6.97 7.21 6.57 1.43 4.20

2,3-Dimethylpentane 3.10 2.87 3.07 2.74 0.96 1.99

3-Methylhexane 8.10 7.25 8.02 7.20 1.97 4.25

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 11.40 10.43 11.40 10.41 2.75 5.51

n-Heptane 7.25 6.60 7.30 6.63 1.63 3.72

Methylcyclohexane 3.34 2.74 3.20 2.90 1.09 1.47

2,2,3-Trimethylpentane 2.78 2.51 2.95 2.60 0.61 1.28

2,3,4-Trimethylpentane 4.05 3.62 3.98 3.73 1.13 1.98

Toluene 42.74 39.26 42.82 39.67 10.77 20.00

2-Methylheptane 2.61 2.36 2.66 2.45 0.81 1.28

3-Methylheptane 2.65 2.21 2.63 1.90 0.81 1.27

1-Octene 0.22 0.19 0.34 0.18 0.09 0.07

n-Octane 3.41 3.18 3.78 3.27 1.16 1.66

Ethylbenzene 11.07 10.38 11.23 10.40 2.28 3.92

m-Xylene/p-Xylene 39.92 37.27 40.12 37.36 7.15 13.72

Styrene 2.16 1.91 2.58 2.22 4.50 1.66

o-Xylene 11.97 11.07 12.13 11.18 2.59 4.89

1-Nonene 0.45 0.38 0.42 0.44 0.17 0.22

n-Nonane 2.48 2.40 2.52 2.36 1.18 1.27

Isopropylbenzene 0.90 0.84 1.07 1.03 0.55 0.68

a-Pinene 1.25 1.17 1.24 1.18 0.12 0.13

n-Propylbenzene 2.36 2.31 2.38 2.21 0.88 1.40

m-Ethyltoluene 7.77 7.16 7.79 7.35 2.17 4.25

p-Ethyltoluene 4.19 3.87 4.28 4.01 1.58 2.34

1,3,5-Trimethylbenzene 4.15 3.66 4.35 3.94 1.34 2.25

o-Ethyltoluene 3.02 2.86 3.06 2.94 1.01 1.82

b-Pinene 1.30 1.22 1.68 1.36 2.28 1.19

1,2,4-Trimethylbenzene 10.98 10.29 10.96 10.19 3.21 6.08

1-Decene ND ND ND ND ND ND

n-Decane 2.61 2.35 2.55 2.45 1.26 0.88

1,2,3-Trimethylbenzene 3.37 2.61 3.22 2.56 0.60 1.47

m-Diethylbenzene 0.90 1.01 0.79 0.77 0.51 0.84

p-Diethylbenzene 1.03 1.09 1.01 1.00 0.61 0.71

1-Undecene 0.22 0.16 0.10 0.15 0.06 0.10

n-Undecane 2.07 1.99 2.17 1.93 1.16 0.81

1-Dodecene 0.11 0.08 0.20 0.19 ND 0.17

n-Dodecane 0.98 0.96 1.02 0.77 0.32 0.51

1-Tridecene ND ND ND ND ND 0.05

n-Tridecane 0.21 0.25 0.25 0.27 0.22 0.13

TNMOC (w/ unknowns) 765.83 692.66 785.93 712.71 214.50 372.37

TNMOC (speciated) 667.20 608.27 678.34 623.04 159.57 317.15
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13729 13763 13762 13781 13803D1 13803R1

Sampling Date: 7/22/98 7/23/98 7/24/98 7/27/98 7/28/98 7/28/98

Analysis Date: 8/20/98 8/20/98 8/21/98 8/21/98 8/28/98 9/14/98

Compound

Ethylene 3.11 2.34 2.69 2.61 2.53 2.49

Acetylene 1.97 1.32 1.54 1.18 2.57 2.47

Ethane 4.70 3.33 3.77 4.10 4.98 4.99

Propylene 1.55 1.12 1.24 1.28 1.22 1.37

Propane 4.16 3.20 42.22 4.17 4.66 5.01

Propyne 0.10 0.08 ND 0.06 0.05 0.10

Isobutane 2.14 1.96 13.28 1.78 1.89 1.94

Isobutene/1-Butene 2.04 1.68 1.83 1.76 1.59 1.67

1,3-Butadiene 0.25 0.20 0.23 0.20 0.25 0.24

n-Butane 10.85 9.65 37.08 9.05 7.77 7.91

trans-2-Butene 1.15 1.01 0.94 0.94 0.87 0.77

cis-2-Butene 1.37 1.21 1.18 1.10 0.92 0.94

3-Methyl-1-butene 0.67 0.65 0.77 0.65 0.49 0.49

Isopentane 34.92 34.18 35.31 36.97 30.03 31.11

1-Pentene 2.12 1.83 1.88 1.92 1.75 1.70

2-Methyl-1-butene 2.99 2.54 2.71 2.61 2.01 2.07

n-Pentane 13.08 11.56 12.23 11.56 9.40 9.58

Isoprene 1.03 0.98 0.92 1.10 0.87 0.92

trans-2-Pentene 4.14 3.62 3.42 3.32 2.78 2.78

cis-2-Pentene 2.26 2.07 1.93 1.93 1.61 1.60

2-Methyl-2-butene 5.32 4.70 4.45 4.36 3.40 3.48

2,2-Dimethylbutane 2.03 1.70 2.20 1.96 1.61 1.51

Cyclopentene 1.14 1.14 1.12 1.13 0.94 0.88

4-Methyl-1-pentene 0.23 0.21 0.10 0.23 0.16 0.16

Cyclopentane 1.94 1.99 2.14 2.01 1.59 1.67

2,3-Dimethylbutane 24.16 22.73 24.79 24.06 17.50 18.75

2-Methylpentane 13.07 12.31 12.80 12.21 9.13 9.63

3-Methylpentane 8.18 7.28 7.93 7.59 5.93 6.39

2-Methyl-1-pentene 0.88 0.76 0.79 0.67 0.62 0.61

1-Hexene 0.41 0.41 0.31 0.46 0.29 0.31

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 9.89 8.71 8.47 8.22 7.28 7.26

trans-2-Hexene 0.78 0.62 0.59 0.59 0.57 0.47

cis-2-Hexene 0.37 0.36 0.40 0.34 0.28 0.29

Methylcyclopentane 4.10 3.60 3.49 3.33 2.82 3.11

2,4-Dimethylpentane 1.70 1.29 1.42 1.47 1.17 1.25

Benzene 5.79 4.61 3.97 3.77 3.96 4.52

Cyclohexane 1.21 1.16 1.12 1.17 3.00 3.36

2-Methylhexane 3.37 3.21 2.93 2.85 2.50 2.85

2,3-Dimethylpentane 1.52 1.62 1.49 1.66 1.37 1.54

3-Methylhexane 3.54 3.17 2.98 2.83 2.65 2.89

1-Heptene ND 0.79 ND ND ND ND

2,2,4-Trimethylpentane 4.44 4.13 3.91 3.61 3.35 3.54

n-Heptane 2.74 2.62 2.02 2.09 1.93 2.30

Methylcyclohexane 1.25 1.17 1.02 0.91 1.06 1.15

2,2,3-Trimethylpentane 1.04 0.84 0.80 0.72 0.72 0.80

2,3,4-Trimethylpentane 1.58 1.47 1.36 1.24 1.22 1.28

Toluene 16.87 14.14 9.94 8.93 11.77 12.16

2-Methylheptane 1.10 0.92 0.88 0.87 0.83 0.86

3-Methylheptane 1.17 1.00 0.95 0.86 0.95 0.71

1-Octene 0.15 0.08 0.06 0.08 0.05 0.05

n-Octane 1.47 1.37 1.13 1.08 1.08 1.13

Ethylbenzene 3.43 2.92 2.07 1.73 2.27 2.34

m-Xylene/p-Xylene 11.64 9.99 6.07 5.35 7.47 7.56

Styrene 1.15 1.34 1.23 1.35 1.22 0.97

o-Xylene 4.05 3.58 2.38 2.11 2.73 2.75

1-Nonene 0.19 0.13 ND ND 0.13 0.12

n-Nonane 1.17 1.22 0.92 0.82 0.86 0.82

Isopropylbenzene 0.65 0.61 0.52 0.52 0.53 0.48

a-Pinene 0.29 0.20 0.23 0.28 0.17 0.14

n-Propylbenzene 1.23 1.33 0.88 0.84 0.93 0.93

m-Ethyltoluene 3.50 3.31 2.22 1.95 2.37 2.32

p-Ethyltoluene 2.03 2.04 1.44 1.36 1.47 1.47

1,3,5-Trimethylbenzene 1.86 1.80 1.31 1.15 1.30 1.16

o-Ethyltoluene 1.47 1.53 1.17 0.92 1.06 1.14

b-Pinene 1.06 1.16 1.16 1.27 0.89 0.82

1,2,4-Trimethylbenzene 5.16 4.90 3.31 2.80 3.36 3.13

1-Decene ND ND ND ND ND ND

n-Decane 1.01 1.18 0.94 0.63 0.67 0.65

1,2,3-Trimethylbenzene 1.26 1.07 0.93 0.70 0.90 0.84

m-Diethylbenzene 0.71 0.81 0.76 0.65 0.56 0.50

p-Diethylbenzene 0.61 0.71 0.63 0.51 0.43 0.41

1-Undecene 0.13 0.06 ND ND 0.04 0.04

n-Undecane 0.78 0.83 0.78 0.64 0.91 0.95

1-Dodecene 0.38 0.13 0.37 0.23 0.08 0.10

n-Dodecane 0.41 0.38 0.35 0.26 0.51 0.54

1-Tridecene ND 0.03 ND ND ND ND

n-Tridecane 0.13 0.10 0.11 0.09 0.17 0.14

TNMOC (w/ unknowns) 306.00 279.41 345.64 267.56 228.33 237.64

TNMOC (speciated) 260.31 236.02 300.53 214.69 199.00 205.39
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13804D2 13804R2 13905 13897 13914 13918

Sampling Date: 7/28/98 7/28/98 7/29/98 7/30/98 7/31/98 8/3/98

Analysis Date: 8/28/98 9/14/98 8/18/98 8/18/98 8/18/98 8/19/98

Compound

Ethylene 2.54 2.55 1.90 1.56 2.90 2.41

Acetylene 2.55 2.46 1.46 1.73 1.48 6.60

Ethane 5.08 5.08 3.03 2.99 3.92 16.04

Propylene 1.24 1.33 1.10 1.04 1.45 4.92

Propane 4.59 4.77 2.95 3.15 3.51 18.32

Propyne 0.11 0.13 ND ND ND 0.61

Isobutane 1.77 1.88 1.72 1.51 1.76 5.54

Isobutene/1-Butene 1.64 1.69 1.72 1.50 1.98 5.94

1,3-Butadiene 0.23 0.24 0.19 0.12 0.22 1.06

n-Butane 7.52 7.60 10.05 7.89 9.97 25.04

trans-2-Butene 0.84 0.84 0.97 0.88 1.06 3.12

cis-2-Butene 0.86 0.92 1.25 1.06 1.36 2.89

3-Methyl-1-butene 0.48 0.48 ND 0.49 0.80 ND

Isopentane 27.78 29.34 33.30 28.49 34.85 90.38

1-Pentene 1.58 1.77 2.19 1.64 2.11 4.98

2-Methyl-1-butene 1.86 2.03 2.96 2.28 3.17 7.30

n-Pentane 9.12 9.61 13.38 10.40 13.61 35.84

Isoprene 0.93 0.96 0.88 0.93 1.58 1.51

trans-2-Pentene 2.65 2.77 4.10 3.24 4.37 9.88

cis-2-Pentene 1.55 1.59 2.30 1.86 2.46 5.21

2-Methyl-2-butene 3.34 3.38 5.28 4.10 5.88 12.88

2,2-Dimethylbutane 1.55 1.66 1.91 1.35 2.19 4.61

Cyclopentene 1.05 0.99 1.03 0.86 1.24 2.66

4-Methyl-1-pentene 0.14 0.17 0.20 0.16 0.25 0.67

Cyclopentane 1.48 1.63 1.73 1.76 2.41 5.12

2,3-Dimethylbutane 17.00 18.55 25.03 20.23 26.73 62.87

2-Methylpentane 9.05 9.86 12.93 10.96 14.39 33.79

3-Methylpentane 5.79 6.31 8.78 6.91 9.18 21.52

2-Methyl-1-pentene 0.58 0.61 0.87 0.71 0.97 2.13

1-Hexene 0.34 0.36 0.48 0.37 0.51 1.21

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 6.81 7.18 10.67 8.24 11.07 25.61

trans-2-Hexene 0.43 0.47 0.87 0.57 0.87 2.56

cis-2-Hexene 0.29 0.30 0.45 0.33 0.47 ND

Methylcyclopentane 2.79 3.22 4.11 3.35 4.13 10.36

2,4-Dimethylpentane 1.22 1.35 1.55 1.43 1.59 3.62

Benzene 4.55 5.00 5.02 4.23 5.54 15.45

Cyclohexane 3.00 3.37 1.88 1.01 1.35 2.47

2-Methylhexane 2.59 2.79 2.61 2.95 3.65 8.66

2,3-Dimethylpentane 1.40 1.51 1.35 1.53 1.86 3.16

3-Methylhexane 2.55 2.74 3.19 2.71 3.55 9.00

1-Heptene ND ND ND ND ND 0.30

2,2,4-Trimethylpentane 3.39 3.57 4.05 3.24 4.39 11.70

n-Heptane 2.10 2.01 2.95 2.13 3.10 8.11

Methylcyclohexane 1.11 1.25 1.10 0.95 1.32 3.47

2,2,3-Trimethylpentane 0.78 0.86 0.96 0.40 0.93 2.75

2,3,4-Trimethylpentane 1.22 1.28 1.36 1.27 1.57 4.07

Toluene 11.54 12.12 15.07 12.03 16.16 42.74

2-Methylheptane 0.84 0.92 1.01 0.90 1.07 2.66

3-Methylheptane 0.84 0.87 1.01 0.87 1.06 2.64

1-Octene 0.09 0.08 0.06 0.12 0.14 ND

n-Octane 1.05 1.15 1.42 1.19 1.46 3.41

Ethylbenzene 2.23 2.30 2.92 2.35 3.20 7.91

m-Xylene/p-Xylene 7.32 7.57 10.08 8.04 10.89 27.39

Styrene 1.34 1.50 1.15 1.17 1.01 1.81

o-Xylene 2.72 2.72 3.41 2.77 3.72 9.43

1-Nonene 0.11 0.14 0.30 ND 0.10 0.35

n-Nonane 0.85 0.85 1.11 0.84 1.08 2.75

Isopropylbenzene 0.48 0.52 0.66 0.52 0.62 0.94

a-Pinene 0.21 0.19 0.25 0.15 0.30 1.04

n-Propylbenzene 0.86 0.84 1.07 0.94 1.12 2.54

m-Ethyltoluene 2.34 2.28 2.79 2.36 3.08 8.32

p-Ethyltoluene 1.40 1.43 1.80 1.54 1.91 4.67

1,3,5-Trimethylbenzene 1.29 1.17 1.50 1.26 1.63 4.59

o-Ethyltoluene 1.17 1.07 1.19 0.81 1.36 3.24

b-Pinene 1.17 1.31 0.97 1.18 0.90 1.71

1,2,4-Trimethylbenzene 3.35 3.14 4.08 3.53 4.40 11.97

1-Decene ND ND ND ND ND ND

n-Decane 0.62 0.57 0.80 0.64 0.87 2.47

1,2,3-Trimethylbenzene 0.86 0.78 1.04 0.81 1.12 3.34

m-Diethylbenzene 0.46 0.48 0.46 0.59 0.62 0.98

p-Diethylbenzene 0.45 0.46 0.43 0.46 0.56 1.14

1-Undecene 0.09 0.09 0.05 ND 0.05 ND

n-Undecane 0.54 0.57 0.71 0.59 0.67 1.61

1-Dodecene 0.25 0.13 ND ND ND ND

n-Dodecane 0.27 0.18 0.26 0.14 0.29 0.79

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.10 0.08 0.10 0.05 0.10 0.24

TNMOC (w/ unknowns) 230.11 247.18 284.64 239.25 309.49 768.76

TNMOC (speciated) 194.28 203.96 241.51 200.37 261.20 657.01
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 13972 13977D1 13977R1 13978D2 13978R2 14052

Sampling Date: 8/4/98 8/5/98 8/5/98 8/5/98 8/5/98 8/6/98

Analysis Date: 8/28/98 8/28/98 9/16/98 8/28/98 10/20/98 8/28/98

Compound

Ethylene 12.78 4.10 3.00 4.12 3.57 2.23

Acetylene 10.92 4.02 2.75 3.97 2.86 2.39

Ethane 26.32 17.10 9.69 17.36 14.02 26.57

Propylene 5.46 1.85 1.47 1.76 1.59 1.25

Propane 40.68 17.85 11.75 18.22 15.65 30.60

Propyne 0.52 0.17 0.10 0.14 0.17 0.08

Isobutane 12.14 4.40 3.33 4.51 3.87 7.12

Isobutene/1-Butene 6.63 2.27 1.62 2.28 1.98 1.70

1,3-Butadiene 0.98 0.33 0.21 0.39 0.35 0.27

n-Butane 42.85 13.88 8.01 14.31 12.19 22.77

trans-2-Butene 3.14 0.92 0.55 0.98 0.80 1.12

cis-2-Butene 3.84 1.11 0.69 1.09 0.93 1.39

3-Methyl-1-butene 2.55 0.60 0.36 0.57 0.57 0.81

Isopentane 156.62 45.61 46.32 45.45 40.79 44.27

1-Pentene 7.10 1.97 1.26 2.16 1.62 2.40

2-Methyl-1-butene 9.70 2.74 1.50 2.84 2.33 3.60

n-Pentane 55.00 15.12 8.13 15.82 13.29 20.84

Isoprene 1.69 0.61 2.94 0.67 0.52 0.69

trans-2-Pentene 12.75 3.61 1.94 3.78 3.06 5.06

cis-2-Pentene 6.91 2.02 1.17 2.06 1.74 2.80

2-Methyl-2-butene 15.84 4.44 2.15 4.55 3.78 6.76

2,2-Dimethylbutane 7.17 2.26 1.57 2.37 2.11 2.58

Cyclopentene 4.61 1.06 1.06 1.07 0.88 0.98

4-Methyl-1-pentene 0.74 0.22 0.12 0.21 0.19 0.32

Cyclopentane 7.34 2.37 1.25 2.40 2.14 2.82

2,3-Dimethylbutane 93.66 27.28 13.98 28.17 24.33 31.10

2-Methylpentane 50.29 15.47 9.16 15.83 13.94 17.89

3-Methylpentane 30.79 9.54 6.00 10.02 8.80 12.11

2-Methyl-1-pentene 2.96 0.84 0.45 0.89 0.75 1.09

1-Hexene 1.73 0.48 0.28 0.56 0.48 0.64

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 37.18 11.69 7.84 12.09 10.49 15.27

trans-2-Hexene 2.32 0.68 0.33 0.73 0.73 0.96

cis-2-Hexene 1.53 0.48 1.90 0.51 0.40 0.62

Methylcyclopentane 14.28 4.63 3.05 4.82 4.43 6.01

2,4-Dimethylpentane 5.08 1.77 1.37 1.87 1.74 2.08

Benzene 21.87 7.10 4.57 7.19 6.12 7.00

Cyclohexane 22.40 1.64 1.61 1.83 1.79 2.46

2-Methylhexane 11.87 3.71 3.27 4.04 3.68 4.68

2,3-Dimethylpentane 5.42 1.64 1.66 1.94 1.83 2.19

3-Methylhexane 12.81 4.02 3.10 4.29 3.89 4.80

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 15.67 5.91 4.02 6.06 5.09 5.68

n-Heptane 11.21 3.66 2.40 3.86 3.00 4.69

Methylcyclohexane 4.32 1.75 1.42 0.45 1.67 2.44

2,2,3-Trimethylpentane 3.74 1.38 0.88 1.41 1.21 1.30

2,3,4-Trimethylpentane 5.19 1.96 1.46 1.99 1.82 1.79

Toluene 59.45 18.94 15.81 19.52 16.40 19.19

2-Methylheptane 3.79 1.23 1.08 1.34 1.07 1.42

3-Methylheptane 3.50 1.27 0.85 1.19 1.05 1.31

1-Octene 0.29 0.15 0.10 0.12 0.11 0.13

n-Octane 4.89 1.59 1.76 1.67 1.45 2.12

Ethylbenzene 10.40 3.47 2.39 3.60 2.92 3.59

m-Xylene/p-Xylene 35.07 11.17 7.30 11.60 9.68 12.46

Styrene 3.81 1.32 1.67 1.22 1.15 0.94

o-Xylene 11.85 3.99 2.72 4.11 3.31 4.09

1-Nonene 0.71 0.10 0.21 0.14 0.11 0.24

n-Nonane 3.56 1.11 1.13 1.21 0.97 1.19

Isopropylbenzene 1.37 0.58 0.52 0.61 0.45 0.49

a-Pinene 2.02 0.21 1.91 0.26 0.11 0.41

n-Propylbenzene 3.16 1.21 0.85 1.14 0.99 1.13

m-Ethyltoluene 9.92 3.28 2.16 3.29 2.62 3.23

p-Ethyltoluene 5.73 1.96 1.34 1.97 1.61 1.93

1,3,5-Trimethylbenzene 4.93 1.58 1.22 1.67 1.23 1.66

o-Ethyltoluene 4.20 1.34 1.10 1.41 1.14 1.28

b-Pinene 2.76 1.12 1.88 1.15 0.94 0.81

1,2,4-Trimethylbenzene 13.68 4.47 4.08 4.65 3.62 4.48

1-Decene ND ND ND ND ND ND

n-Decane 3.22 0.76 0.95 0.74 0.65 0.64

1,2,3-Trimethylbenzene 3.23 1.09 0.72 1.22 0.88 1.21

m-Diethylbenzene 1.46 0.64 0.50 0.62 0.46 0.49

p-Diethylbenzene 1.62 0.68 0.47 0.61 0.47 0.45

1-Undecene 0.17 0.04 0.05 ND 0.04 ND

n-Undecane 3.63 0.68 0.79 0.71 0.61 0.54

1-Dodecene 0.27 0.14 0.36 0.16 0.34 0.11

n-Dodecane 2.20 0.27 0.30 0.29 0.27 0.16

1-Tridecene ND ND 0.06 0.05 0.04 ND

n-Tridecane 0.55 0.12 0.15 0.12 0.07 0.12

TNMOC (w/ unknowns) 1164.63 367.51 289.91 375.79 322.55 429.12

TNMOC (speciated) 1010.04 320.82 236.11 328.02 281.97 382.02
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14057 14090 14174 14173 14195 14233D1

Sampling Date: 8/7/98 8/10/98 8/11/98 8/12/98 8/13/98 8/14/98

Analysis Date: 8/28/98 8/29/98 9/2/98 10/19/98 9/2/98 9/11/98

Compound

Ethylene 3.65 1.90 1.75 5.82 6.59 7.68

Acetylene 3.96 1.61 1.49 3.99 7.13 7.92

Ethane 11.64 2.68 12.42 15.56 13.88 12.52

Propylene 1.82 1.11 0.92 2.46 2.91 3.57

Propane 7.87 3.79 14.15 20.48 14.60 9.78

Propyne 0.12 0.04 ND 0.24 0.28 0.32

Isobutane 2.74 1.10 4.24 4.30 5.27 2.68

Isobutene/1-Butene 2.28 1.87 1.45 2.85 3.67 4.29

1,3-Butadiene 0.36 0.20 0.13 0.42 0.54 0.86

n-Butane 5.57 2.59 16.17 16.00 19.70 12.96

trans-2-Butene 0.47 0.36 1.07 1.16 1.65 1.30

cis-2-Butene 0.55 0.44 1.34 1.39 1.99 1.41

3-Methyl-1-butene 0.19 0.09 0.69 0.90 1.19 0.98

Isopentane 19.19 11.53 44.61 58.55 83.82 49.53

1-Pentene 0.74 0.55 2.24 2.88 3.56 2.65

2-Methyl-1-butene 0.64 0.40 3.00 3.84 5.11 4.03

n-Pentane 6.04 2.89 22.46 22.68 36.60 20.60

Isoprene 1.75 1.69 0.67 0.96 0.92 1.00

trans-2-Pentene 0.99 0.75 4.39 5.37 6.75 5.53

cis-2-Pentene 0.67 0.51 2.47 2.86 3.81 3.01

2-Methyl-2-butene 0.87 0.66 5.56 7.36 8.88 7.09

2,2-Dimethylbutane 0.88 0.58 2.82 3.00 3.61 3.12

Cyclopentene 0.33 0.44 1.30 1.81 2.05 1.20

4-Methyl-1-pentene ND ND 0.23 0.29 0.40 0.35

Cyclopentane 0.75 0.52 2.83 3.39 4.13 3.54

2,3-Dimethylbutane 7.72 4.11 31.31 40.03 51.64 43.49

2-Methylpentane 4.80 2.90 16.65 23.06 26.94 23.17

3-Methylpentane 2.97 1.77 10.53 14.18 17.49 15.32

2-Methyl-1-pentene 0.23 0.16 1.07 1.31 1.71 1.35

1-Hexene 0.19 0.14 0.50 0.76 0.91 0.86

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 3.36 2.35 13.23 17.43 21.36 18.13

trans-2-Hexene 0.18 0.12 1.00 1.28 1.67 1.25

cis-2-Hexene 0.12 0.11 0.58 0.66 0.87 0.80

Methylcyclopentane 1.75 1.07 5.18 7.25 8.59 8.03

2,4-Dimethylpentane 0.87 0.60 2.31 2.62 3.18 3.02

Benzene 3.90 2.05 5.73 9.64 11.52 10.86

Cyclohexane 0.67 0.62 2.00 2.52 5.78 2.11

2-Methylhexane 1.43 1.42 4.13 5.82 7.77 6.27

2,3-Dimethylpentane 0.94 1.00 2.34 2.51 3.47 2.81

3-Methylhexane 1.94 1.21 4.27 6.36 9.40 7.41

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 3.22 1.80 7.38 7.81 9.74 9.80

n-Heptane 1.82 0.96 3.93 5.47 7.34 6.09

Methylcyclohexane 1.12 0.78 2.17 2.64 2.74 2.55

2,2,3-Trimethylpentane 0.73 0.24 1.49 1.98 2.32 2.31

2,3,4-Trimethylpentane 1.26 0.74 2.61 2.75 3.47 3.41

Toluene 12.82 6.93 17.99 30.40 36.84 34.09

2-Methylheptane 0.89 0.51 1.22 1.60 1.97 1.97

3-Methylheptane 0.84 0.57 1.22 1.76 1.91 2.02

1-Octene ND ND 0.07 0.11 0.10 0.15

n-Octane 1.09 0.60 1.78 2.33 2.66 2.45

Ethylbenzene 2.76 1.39 3.13 5.47 5.94 6.39

m-Xylene/p-Xylene 8.92 4.23 11.02 19.13 20.53 21.61

Styrene 0.98 0.84 1.30 2.03 1.86 1.26

o-Xylene 2.98 1.61 3.54 6.35 6.76 7.28

1-Nonene 0.11 ND 0.20 0.17 0.28 0.22

n-Nonane 1.00 0.62 1.13 1.56 1.78 1.50

Isopropylbenzene 0.51 0.44 0.50 0.63 0.69 0.72

a-Pinene 0.58 0.25 0.70 1.24 0.83 0.27

n-Propylbenzene 0.90 0.61 1.09 1.61 1.90 1.80

m-Ethyltoluene 2.38 1.34 2.53 4.92 5.62 5.70

p-Ethyltoluene 1.50 0.96 1.59 2.70 3.15 3.09

1,3,5-Trimethylbenzene 1.45 0.81 1.25 2.26 2.80 2.72

o-Ethyltoluene 1.13 0.65 0.93 2.16 2.08 2.33

b-Pinene 0.60 0.70 1.01 1.67 0.75 0.46

1,2,4-Trimethylbenzene 3.70 2.00 3.50 6.66 7.82 7.79

1-Decene ND ND ND ND ND ND

n-Decane 1.28 0.57 0.71 1.06 1.63 1.04

1,2,3-Trimethylbenzene 1.17 0.54 0.73 1.59 1.99 1.91

m-Diethylbenzene 0.46 0.50 0.56 0.72 0.64 0.71

p-Diethylbenzene 0.51 0.39 0.59 0.59 0.69 0.59

1-Undecene 0.08 ND 0.05 0.10 0.08 0.10

n-Undecane 1.10 0.56 0.61 0.96 1.75 0.93

1-Dodecene ND 0.08 0.21 0.26 0.21 0.13

n-Dodecane 0.33 0.19 0.18 0.49 0.96 0.40

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.14 0.09 0.08 0.14 0.25 0.16

TNMOC (w/ unknowns) 198.60 117.88 382.27 523.94 636.59 510.68

TNMOC (speciated) 163.51 90.45 326.17 445.28 551.37 446.75
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14233R1 14234D2 14234R2 14217 14223 14236

Sampling Date: 8/14/98 8/14/98 8/14/98 8/17/98 8/18/98 8/20/98

Analysis Date: 9/11/98 9/11/98 9/11/98 9/10/98 9/10/98 10/19/98

Compound

Ethylene 7.79 7.58 7.81 5.03 4.65 5.92

Acetylene 8.10 7.92 8.03 4.52 4.31 4.94

Ethane 12.62 12.44 12.69 8.40 11.30 34.32

Propylene 3.73 3.66 3.74 2.70 2.27 2.88

Propane 9.95 9.78 9.90 5.20 13.25 26.80

Propyne 0.40 0.30 0.28 0.19 0.15 0.18

Isobutane 2.77 2.77 2.87 2.69 3.66 12.85

Isobutene/1-Butene 4.34 4.28 4.38 3.48 2.72 5.48

1,3-Butadiene 0.78 0.79 0.88 0.50 0.44 0.70

n-Butane 13.12 13.19 13.30 15.16 12.94 53.24

trans-2-Butene 1.46 1.37 1.37 1.63 1.11 5.42

cis-2-Butene 1.52 1.53 1.59 1.94 1.25 5.20

3-Methyl-1-butene 0.93 0.92 0.94 1.21 0.66 3.26

Isopentane 49.97 48.77 50.04 64.65 39.60 136.35

1-Pentene 2.72 2.74 2.75 3.71 2.20 8.35

2-Methyl-1-butene 4.18 4.00 4.23 5.52 3.13 10.28

n-Pentane 20.73 20.68 20.95 25.81 16.06 64.36

Isoprene 0.94 0.95 0.96 0.87 0.81 1.17

trans-2-Pentene 5.43 5.51 5.53 7.99 4.75 13.89

cis-2-Pentene 3.03 3.00 3.04 4.31 2.50 7.13

2-Methyl-2-butene 7.26 7.23 7.29 10.52 6.29 16.56

2,2-Dimethylbutane 3.13 3.09 3.10 3.73 2.42 10.00

Cyclopentene 1.29 1.24 1.25 2.17 1.46 3.45

4-Methyl-1-pentene 0.39 0.37 0.34 0.48 0.26 0.84

Cyclopentane 3.50 3.46 3.54 4.57 2.82 6.36

2,3-Dimethylbutane 43.70 43.62 44.12 59.50 32.89 77.65

2-Methylpentane 23.30 23.19 23.62 30.63 17.99 40.48

3-Methylpentane 15.39 15.33 15.53 20.35 11.68 24.30

2-Methyl-1-pentene 1.49 1.37 1.48 2.04 1.13 2.39

1-Hexene 0.77 0.88 0.82 1.03 0.65 1.41

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 18.24 18.60 18.68 24.34 14.60 27.27

trans-2-Hexene 1.27 1.39 1.27 1.92 1.22 2.26

cis-2-Hexene 0.81 0.84 0.80 1.08 0.63 1.23

Methylcyclopentane 8.01 7.99 8.03 9.74 6.16 11.81

2,4-Dimethylpentane 3.00 2.92 2.92 3.42 2.34 5.01

Benzene 11.73 10.67 11.07 13.17 8.10 12.14

Cyclohexane 2.39 2.50 2.58 2.71 2.52 3.09

2-Methylhexane 6.63 6.80 6.69 7.59 5.25 8.71

2,3-Dimethylpentane 3.16 2.82 2.82 3.08 2.45 4.81

3-Methylhexane 7.49 7.36 7.37 8.28 5.50 9.27

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 9.98 10.00 10.10 9.77 6.41 16.34

n-Heptane 6.11 6.08 6.09 7.08 4.79 7.60

Methylcyclohexane 2.59 2.55 2.65 2.93 2.28 3.25

2,2,3-Trimethylpentane 2.34 2.36 2.38 2.37 1.60 3.21

2,3,4-Trimethylpentane 3.49 3.54 3.55 3.48 2.37 5.54

Toluene 34.66 34.46 35.00 36.75 25.73 45.84

2-Methylheptane 2.11 2.01 2.09 2.11 1.52 2.20

3-Methylheptane 1.93 1.98 2.10 2.06 1.53 2.15

1-Octene 0.13 0.18 0.21 0.13 0.10 0.11

n-Octane 2.40 2.45 2.44 2.76 1.92 2.72

Ethylbenzene 6.42 6.44 6.52 6.22 4.52 5.78

m-Xylene/p-Xylene 22.09 21.93 22.21 22.20 15.30 19.35

Styrene 1.29 3.23 3.04 2.17 1.28 1.31

o-Xylene 7.46 7.32 7.53 7.13 5.05 6.42

1-Nonene 0.20 0.40 0.37 0.20 0.14 0.37

n-Nonane 1.51 1.57 1.52 1.79 1.41 1.94

Isopropylbenzene 0.83 0.88 0.84 0.70 0.56 0.63

a-Pinene 0.27 0.19 0.26 0.30 0.47 1.23

n-Propylbenzene 1.86 1.80 1.88 1.89 1.39 1.49

m-Ethyltoluene 5.82 5.71 5.87 5.57 4.03 4.52

p-Ethyltoluene 3.26 3.22 3.40 3.15 2.35 2.65

1,3,5-Trimethylbenzene 2.95 2.74 2.86 2.58 2.02 2.43

o-Ethyltoluene 2.43 2.20 2.45 2.22 1.76 1.75

b-Pinene 0.50 1.97 2.28 1.10 0.89 0.66

1,2,4-Trimethylbenzene 7.95 8.61 8.86 7.42 5.61 6.40

1-Decene ND ND ND ND ND ND

n-Decane 1.06 1.01 1.03 1.02 1.39 2.14

1,2,3-Trimethylbenzene 1.86 1.59 1.80 1.67 1.35 1.54

m-Diethylbenzene 0.70 0.67 0.67 0.71 0.59 0.72

p-Diethylbenzene 0.74 0.66 0.60 0.63 0.51 0.62

1-Undecene 0.08 3.33 3.46 0.17 0.09 0.08

n-Undecane 0.95 5.34 5.32 0.97 0.92 1.58

1-Dodecene 0.10 8.61 8.52 0.83 0.47 0.22

n-Dodecane 0.47 9.56 9.55 0.92 0.67 0.60

1-Tridecene ND 10.55 10.35 0.37 0.38 0.09

n-Tridecane 0.17 9.62 9.49 0.54 0.51 0.28

TNMOC (w/ unknowns) 519.65 568.81 577.04 606.19 426.39 918.61

TNMOC (speciated) 454.20 498.63 505.84 517.73 356.01 825.55
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14350 14838D1 14383R1 14384D2 14384R2 14486

Sampling Date: 8/21/98 8/24/98 8/24/98 8/24/98 8/24/98 8/25/98

Analysis Date: 9/22/98 9/23/98 9/24/98 9/23/98 9/24/98 9/24/98

Compound

Ethylene 7.50 5.64 7.12 5.87 7.05 12.69

Acetylene 7.92 5.55 7.27 5.76 6.92 12.03

Ethane 53.72 9.89 9.45 10.17 11.83 19.33

Propylene 3.52 2.48 3.20 2.88 3.16 6.40

Propane 18.96 9.19 11.87 10.05 11.59 17.95

Propyne 0.28 0.19 0.18 0.24 0.20 0.55

Isobutane 7.35 3.13 4.09 3.41 3.93 6.28

Isobutene/1-Butene 5.19 2.89 3.70 3.16 3.60 6.86

1,3-Butadiene 0.79 0.52 0.67 0.57 0.64 1.29

n-Butane 32.49 9.42 12.29 9.92 11.81 27.21

trans-2-Butene 3.13 0.93 1.14 1.00 1.04 3.21

cis-2-Butene 3.55 1.08 1.32 1.08 1.27 2.94

3-Methyl-1-butene 2.26 0.56 0.66 0.53 0.44 4.05

Isopentane 95.08 29.78 38.38 34.30 39.63 101.24

1-Pentene 6.81 1.74 2.17 1.70 1.93 5.67

2-Methyl-1-butene 9.12 2.50 3.29 2.59 3.14 9.12

n-Pentane 46.97 12.59 16.51 13.29 15.64 43.76

Isoprene 1.24 0.86 0.99 0.83 0.96 1.59

trans-2-Pentene 11.07 3.57 4.61 3.73 4.41 12.78

cis-2-Pentene 5.95 1.98 2.58 2.11 2.43 6.83

2-Methyl-2-butene 14.25 4.62 6.02 4.92 5.70 17.48

2,2-Dimethylbutane 6.12 2.12 2.75 2.19 2.79 6.24

Cyclopentene 4.97 1.28 1.66 1.56 1.81 3.95

4-Methyl-1-pentene 0.74 0.20 0.31 0.24 0.23 0.86

Cyclopentane 5.81 2.29 2.84 2.40 2.81 7.40

2,3-Dimethylbutane 73.78 26.50 33.99 28.23 32.62 97.60

2-Methylpentane 36.98 14.68 19.26 15.61 18.46 52.49

3-Methylpentane 23.64 9.75 12.77 10.33 12.27 34.60

2-Methyl-1-pentene 2.25 0.93 1.25 0.96 1.22 3.27

1-Hexene 1.49 0.55 0.66 0.64 0.65 2.01

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 28.22 12.10 15.48 12.50 15.25 41.99

trans-2-Hexene 2.18 0.92 1.09 0.87 1.24 3.45

cis-2-Hexene 1.18 0.53 0.70 0.56 0.66 1.87

Methylcyclopentane 11.89 5.21 6.80 5.51 6.49 17.09

2,4-Dimethylpentane 4.30 2.04 2.53 2.10 2.42 5.93

Benzene 13.99 7.87 9.93 8.46 9.81 23.43

Cyclohexane 3.09 1.74 2.24 1.90 2.26 5.07

2-Methylhexane 9.04 4.90 6.16 5.05 5.92 13.99

2,3-Dimethylpentane 3.96 2.07 2.52 2.33 2.77 5.59

3-Methylhexane 9.92 4.86 6.38 5.35 6.30 15.51

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 11.69 6.06 7.88 6.46 7.76 18.47

n-Heptane 8.13 4.19 5.42 4.52 5.23 12.99

Methylcyclohexane 3.20 1.76 2.32 2.05 2.30 5.14

2,2,3-Trimethylpentane 2.88 1.52 2.02 1.60 1.88 5.02

2,3,4-Trimethylpentane 4.12 2.12 2.73 2.33 2.77 6.56

Toluene 43.68 25.14 33.04 27.16 31.93 75.99

2-Methylheptane 2.49 1.42 1.91 1.59 1.81 3.99

3-Methylheptane 2.49 1.47 1.48 1.55 1.88 3.90

1-Octene 0.14 0.08 0.17 0.11 0.15 0.29

n-Octane 3.11 1.81 2.27 1.90 2.22 4.94

Ethylbenzene 7.25 4.27 5.37 4.77 5.53 12.33

m-Xylene/p-Xylene 24.60 13.74 17.51 15.20 17.74 41.63

Styrene 1.44 0.96 0.90 1.19 1.19 1.85

o-Xylene 8.03 4.75 5.98 5.40 6.27 13.66

1-Nonene 0.39 0.16 0.23 0.24 0.16 0.39

n-Nonane 3.01 1.12 1.39 1.22 1.37 3.24

Isopropylbenzene 0.82 0.58 0.64 0.56 0.69 1.12

a-Pinene 0.95 0.19 0.22 0.14 0.21 0.55

n-Propylbenzene 1.96 1.23 1.43 1.38 1.51 3.22

m-Ethyltoluene 5.68 3.64 4.40 3.89 4.36 10.16

p-Ethyltoluene 3.53 2.09 2.46 2.21 2.53 5.53

1,3,5-Trimethylbenzene 3.61 1.86 2.25 2.00 2.29 4.90

o-Ethyltoluene 2.07 1.65 1.99 1.75 1.74 4.23

b-Pinene 0.71 0.45 0.20 0.52 0.24 0.64

1,2,4-Trimethylbenzene 8.07 4.95 5.68 5.25 5.75 13.62

1-Decene ND ND ND ND ND ND

n-Decane 3.89 0.89 1.01 1.68 1.81 2.24

1,2,3-Trimethylbenzene 1.83 1.16 1.35 1.13 1.39 3.06

m-Diethylbenzene 0.86 0.47 0.48 0.56 0.51 1.03

p-Diethylbenzene 0.79 0.41 0.45 0.51 0.41 0.94

1-Undecene 0.11 0.09 0.05 0.08 0.05 0.11

n-Undecane 1.70 0.64 0.59 0.67 0.62 1.12

1-Dodecene 0.19 0.11 0.02 0.06 0.03 0.18

n-Dodecane 0.56 0.32 0.16 0.33 0.16 0.49

1-Tridecene 0.05 0.09 ND ND 0.02 ND

n-Tridecane 0.21 0.10 0.04 0.07 0.02 0.09

TNMOC (w/ unknowns) 846.84 348.76 430.52 435.83 477.70 1059.09

TNMOC (speciated) 744.90 301.13 380.86 325.00 377.88 925.21
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14495 14494 14516 14540 14561D1 14561R1

Sampling Date: 8/26/98 8/27/98 8/28/98 8/31/98 9/1/98 9/1/98

Analysis Date: 9/24/98 10/19/98 10/16/98 10/16/98 10/16/98 10/22/98

Compound

Ethylene 5.50 7.14 4.85 7.25 5.50 8.51

Acetylene 5.03 5.90 1.86 5.85 6.50 6.69

Ethane 12.05 10.61 7.82 17.17 15.40 15.59

Propylene 2.56 3.25 2.71 4.30 4.21 4.33

Propane 11.63 10.72 6.51 43.50 45.47 46.81

Propyne 0.26 0.31 0.18 0.27 0.27 0.33

Isobutane 3.72 3.05 1.67 4.21 4.14 4.27

Isobutene/1-Butene 2.99 3.86 2.10 3.87 3.68 3.93

1,3-Butadiene 0.49 0.79 0.45 0.74 0.76 0.84

n-Butane 14.82 11.13 8.23 14.43 11.03 11.43

trans-2-Butene 1.18 1.09 1.23 1.18 0.93 0.99

cis-2-Butene 1.43 1.20 0.96 1.37 1.07 1.17

3-Methyl-1-butene 0.71 0.70 0.51 0.70 0.55 0.52

Isopentane 53.50 43.09 35.02 55.69 47.13 48.85

1-Pentene 2.53 2.08 1.82 2.55 1.65 2.27

2-Methyl-1-butene 4.05 3.30 2.53 3.31 2.40 2.46

n-Pentane 20.12 16.28 12.03 19.66 47.25 48.70

Isoprene 0.98 0.87 0.66 0.83 0.71 0.76

trans-2-Pentene 5.40 4.38 3.38 4.88 3.37 3.39

cis-2-Pentene 2.99 2.41 1.96 2.59 1.79 1.89

2-Methyl-2-butene 6.78 5.44 4.63 5.82 4.32 4.37

2,2-Dimethylbutane 3.16 2.67 1.86 3.15 2.40 2.50

Cyclopentene 2.11 1.46 1.29 1.98 1.62 1.51

4-Methyl-1-pentene 0.34 0.29 0.24 0.34 0.24 0.22

Cyclopentane 3.60 2.92 2.29 3.20 2.89 3.02

2,3-Dimethylbutane 45.46 34.05 27.38 38.07 26.15 26.68

2-Methylpentane 24.73 19.40 15.68 21.12 15.38 16.09

3-Methylpentane 16.36 12.76 10.07 14.00 9.78 10.14

2-Methyl-1-pentene 1.49 1.29 0.99 1.30 0.80 0.83

1-Hexene 0.87 0.71 0.59 0.76 0.61 0.59

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 19.97 15.04 12.21 16.97 11.63 12.01

trans-2-Hexene 1.53 1.07 0.78 1.26 0.75 0.77

cis-2-Hexene 0.90 0.68 0.49 0.75 0.47 0.49

Methylcyclopentane 8.18 6.66 5.01 7.43 5.33 5.52

2,4-Dimethylpentane 2.94 2.28 1.79 2.60 2.11 2.18

Benzene 11.19 10.19 7.67 11.79 9.09 9.56

Cyclohexane 2.64 2.41 1.38 2.32 1.94 1.91

2-Methylhexane 6.96 5.84 3.83 6.48 4.97 4.93

2,3-Dimethylpentane 3.22 2.46 1.70 0.10 2.48 2.27

3-Methylhexane 7.56 6.41 4.23 7.03 5.36 5.42

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 8.79 7.57 4.82 8.27 7.56 7.73

n-Heptane 6.23 5.29 3.66 5.80 4.39 4.50

Methylcyclohexane 2.62 2.28 1.64 2.60 2.19 2.25

2,2,3-Trimethylpentane 2.17 1.99 1.27 2.11 1.87 1.88

2,3,4-Trimethylpentane 2.94 2.70 1.70 2.90 2.67 2.82

Toluene 35.39 34.60 19.58 35.70 32.65 33.17

2-Methylheptane 1.91 1.82 1.10 1.99 1.65 1.70

3-Methylheptane 1.98 1.82 1.08 2.03 1.62 1.76

1-Octene 0.22 0.15 0.14 0.24 0.10 0.15

n-Octane 2.60 2.20 1.60 2.51 1.98 2.11

Ethylbenzene 6.00 5.61 3.49 5.99 6.51 6.66

m-Xylene/p-Xylene 19.74 18.44 12.11 19.71 21.51 22.30

Styrene 1.38 1.25 1.16 1.80 1.84 2.06

o-Xylene 6.47 6.31 3.97 6.77 7.47 7.60

1-Nonene 0.25 0.28 0.16 0.21 0.22 0.23

n-Nonane 1.61 1.40 1.06 1.81 1.59 1.63

Isopropylbenzene 0.62 0.66 0.51 0.67 0.67 0.70

a-Pinene 0.17 0.26 0.23 0.34 1.54 1.59

n-Propylbenzene 1.63 1.56 1.09 1.68 1.49 1.57

m-Ethyltoluene 4.68 4.89 2.93 5.10 4.87 5.01

p-Ethyltoluene 2.70 2.70 1.75 2.79 2.66 2.74

1,3,5-Trimethylbenzene 2.17 2.38 1.34 2.52 2.63 2.70

o-Ethyltoluene 1.90 2.11 1.10 2.26 2.13 2.22

b-Pinene 0.37 0.73 0.92 0.87 0.99 1.13

1,2,4-Trimethylbenzene 6.02 6.84 4.01 7.10 6.70 7.05

1-Decene ND ND ND ND ND ND

n-Decane 0.94 1.01 0.48 1.39 1.73 1.89

1,2,3-Trimethylbenzene 1.37 1.68 0.91 1.96 1.43 1.82

m-Diethylbenzene 0.45 0.76 0.51 0.82 0.77 0.73

p-Diethylbenzene 0.50 0.72 0.48 0.84 0.57 0.81

1-Undecene 0.08 0.10 0.09 0.13 0.09 0.14

n-Undecane 0.59 0.86 0.50 1.07 1.44 1.43

1-Dodecene 0.04 0.42 0.27 0.29 0.13 0.24

n-Dodecane 0.18 0.51 0.35 0.64 0.67 0.70

1-Tridecene ND 0.09 ND ND 0.04 0.10

n-Tridecane 0.03 0.17 0.07 0.20 0.26 0.37

TNMOC (w/ unknowns) 519.41 453.32 331.65 562.94 503.30 523.23

TNMOC (speciated) 446.69 388.35 276.72 471.91 438.77 440.63
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14562D2 14562R2 14666 14673 14679 14701

Sampling Date: 9/1/98 9/1/98 9/2/98 9/3/98 9/4/98 9/8/98

Analysis Date: 10/16/98 10/22/98 10/2/98 10/3/98 10/4/98 10/9/98

Compound

Ethylene 8.45 8.60 5.08 19.51 9.08 11.34

Acetylene 6.49 6.73 3.33 14.51 6.57 9.59

Ethane 15.54 16.03 10.43 25.47 17.51 16.66

Propylene 4.29 4.30 2.36 9.75 4.61 5.88

Propane 45.53 46.81 13.34 21.36 19.75 19.46

Propyne 0.26 0.33 0.16 0.89 0.44 0.34

Isobutane 4.14 4.29 3.21 10.15 7.68 8.72

Isobutene/1-Butene 3.69 3.93 1.91 10.35 5.45 7.10

1,3-Butadiene 0.81 0.87 0.33 2.04 0.97 1.20

n-Butane 11.19 11.52 6.50 38.78 29.41 36.64

trans-2-Butene 1.10 1.00 0.40 2.74 1.79 2.47

cis-2-Butene 1.11 1.15 0.46 2.75 1.86 2.54

3-Methyl-1-butene 0.61 0.56 0.17 1.10 0.90 1.20

Isopentane 45.04 47.54 23.15 120.06 83.64 119.83

1-Pentene 1.93 1.89 0.61 3.45 1.99 3.70

2-Methyl-1-butene 2.44 2.50 0.28 4.74 2.83 4.97

n-Pentane 47.59 49.00 8.59 51.21 33.67 48.88

Isoprene 0.73 0.85 0.51 1.39 0.80 1.12

trans-2-Pentene 3.38 3.55 0.59 9.74 6.40 11.42

cis-2-Pentene 1.86 1.93 0.43 4.56 2.99 5.31

2-Methyl-2-butene 4.46 4.63 0.34 9.10 5.59 11.07

2,2-Dimethylbutane 2.40 2.55 1.31 4.43 2.73 4.11

Cyclopentene 1.73 1.53 0.85 2.74 1.81 3.51

4-Methyl-1-pentene 0.20 0.24 ND 0.53 0.37 0.61

Cyclopentane 2.92 3.08 0.96 6.47 4.20 6.23

2,3-Dimethylbutane 26.07 27.39 6.13 50.32 31.31 58.22

2-Methylpentane 15.42 16.07 5.06 36.34 23.53 38.53

3-Methylpentane 9.97 10.29 3.13 22.15 14.03 22.63

2-Methyl-1-pentene 0.89 0.87 0.12 2.29 1.36 2.73

1-Hexene 0.55 0.64 0.16 1.07 0.74 1.13

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 11.83 12.42 3.66 24.20 14.79 25.09

trans-2-Hexene 0.79 0.94 0.07 2.35 1.31 2.82

cis-2-Hexene 0.47 0.52 0.07 1.27 0.84 1.56

Methylcyclopentane 5.35 5.64 1.94 13.90 8.96 14.16

2,4-Dimethylpentane 2.15 2.37 0.98 3.97 2.43 3.90

Benzene 9.40 9.48 3.26 15.82 8.69 16.06

Cyclohexane 2.01 2.10 1.00 4.97 3.37 5.19

2-Methylhexane 4.81 5.26 1.75 10.39 6.00 10.06

2,3-Dimethylpentane 2.19 2.57 1.18 3.95 2.36 3.74

3-Methylhexane 5.34 5.65 2.04 11.69 6.40 10.89

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 7.64 7.87 3.39 14.02 7.71 14.18

n-Heptane 4.47 4.64 1.50 8.85 5.25 8.89

Methylcyclohexane 2.20 2.26 1.14 4.56 2.88 4.52

2,2,3-Trimethylpentane 1.91 1.91 0.78 3.60 1.93 3.56

2,3,4-Trimethylpentane 2.72 2.85 1.25 4.78 2.91 4.87

Toluene 32.83 33.87 11.12 60.50 31.11 58.99

2-Methylheptane 1.68 1.67 0.74 3.14 1.89 3.05

3-Methylheptane 1.68 1.75 0.75 3.29 1.78 3.12

1-Octene 0.12 0.13 0.05 0.17 0.13 0.16

n-Octane 1.99 2.07 0.94 3.19 1.96 3.33

Ethylbenzene 6.57 6.74 1.99 8.96 4.51 8.74

m-Xylene/p-Xylene 21.86 22.80 5.85 28.75 15.11 28.52

Styrene 1.96 2.09 0.72 1.67 1.20 2.18

o-Xylene 7.47 7.73 2.18 10.24 5.53 9.76

1-Nonene 0.24 0.24 0.10 0.30 0.20 0.28

n-Nonane 1.57 1.65 0.76 1.92 1.20 1.97

Isopropylbenzene 0.63 0.66 0.38 0.79 0.55 0.82

a-Pinene 1.58 1.67 0.79 0.56 0.21 0.53

n-Propylbenzene 1.45 1.59 0.60 2.16 1.22 2.27

m-Ethyltoluene 4.84 5.03 1.70 7.12 3.92 7.28

p-Ethyltoluene 2.63 2.75 1.05 3.70 2.02 3.74

1,3,5-Trimethylbenzene 2.64 2.77 0.96 3.84 2.06 3.51

o-Ethyltoluene 1.86 2.20 0.73 2.82 1.84 3.10

b-Pinene 0.72 1.11 0.80 0.62 0.85 1.28

1,2,4-Trimethylbenzene 6.76 7.36 2.31 9.82 5.80 10.01

1-Decene ND ND ND ND ND ND

n-Decane 1.77 1.92 0.84 1.52 0.76 1.51

1,2,3-Trimethylbenzene 1.30 1.69 0.56 2.31 1.37 2.29

m-Diethylbenzene 0.78 0.84 0.35 0.72 0.42 0.84

p-Diethylbenzene 0.75 0.70 0.37 0.76 0.45 0.92

1-Undecene 0.13 0.15 ND 0.10 0.09 0.11

n-Undecane 1.34 1.42 0.67 1.11 0.73 1.23

1-Dodecene 0.14 0.29 0.19 0.34 0.16 0.17

n-Dodecane 0.64 0.67 0.33 0.71 0.45 0.60

1-Tridecene 0.09 0.10 ND ND ND ND

n-Tridecane 0.16 0.28 0.16 0.24 0.17 0.30

TNMOC (w/ unknowns) 508.71 534.08 197.41 885.00 555.63 881.90

TNMOC (speciated) 442.25 461.07 161.92 779.69 487.52 757.23
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14775D1 14775R1 14776D2 14776R2 14786 14797

Sampling Date: 9/9/98 9/9/98 9/9/98 9/9/98 9/10/98 9/11/98

Analysis Date: 10/9/98 10/26/98 10/9/98 10/26/98 10/17/98 10/12/98

Compound

Ethylene 5.39 4.76 4.91 4.61 3.23 1.58

Acetylene 4.12 3.47 3.64 3.30 3.39 1.71

Ethane 14.36 13.11 12.82 12.85 30.32 14.29

Propylene 2.64 2.32 2.41 2.18 1.62 0.90

Propane 16.06 14.32 14.87 13.94 10.53 6.10

Propyne 0.23 0.17 0.08 0.07 0.12 ND

Isobutane 10.78 9.71 9.81 9.34 4.66 3.07

Isobutene/1-Butene 3.47 2.98 3.22 2.98 2.06 1.27

1,3-Butadiene 0.36 0.34 0.36 0.36 0.24 0.09

n-Butane 34.93 31.73 33.23 31.39 20.38 12.27

trans-2-Butene 2.38 2.08 2.21 2.08 1.21 1.07

cis-2-Butene 2.86 2.51 2.65 2.47 1.32 0.87

3-Methyl-1-butene 1.34 1.26 1.26 1.24 0.72 0.35

Isopentane 116.04 106.26 108.10 104.74 59.60 38.55

1-Pentene 3.18 2.85 2.88 2.72 1.77 1.08

2-Methyl-1-butene 4.54 4.05 4.24 3.94 2.33 1.35

n-Pentane 33.01 29.94 31.24 29.67 31.24 16.70

Isoprene 0.90 0.62 0.68 0.66 0.47 0.38

trans-2-Pentene 6.88 6.00 6.30 5.84 5.54 3.29

cis-2-Pentene 3.65 3.07 3.21 3.02 2.65 1.60

2-Methyl-2-butene 7.19 6.45 6.58 6.21 4.99 2.70

2,2-Dimethylbutane 3.28 2.83 3.04 2.83 2.02 1.36

Cyclopentene 3.05 2.83 2.72 2.62 1.58 1.08

4-Methyl-1-pentene 0.34 0.31 0.34 0.35 0.30 0.18

Cyclopentane 3.51 3.16 3.33 3.19 3.14 1.91

2,3-Dimethylbutane 35.12 31.22 32.24 30.70 27.52 16.24

2-Methylpentane 23.24 20.94 21.66 20.35 18.08 10.78

3-Methylpentane 13.57 12.09 12.86 11.91 10.57 6.32

2-Methyl-1-pentene 1.30 1.08 1.18 1.12 1.27 0.76

1-Hexene 0.65 0.63 0.58 0.50 0.60 0.35

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 14.99 12.90 14.04 12.70 11.81 6.99

trans-2-Hexene 1.32 0.96 1.21 0.96 1.18 0.65

cis-2-Hexene 0.64 0.57 0.62 0.58 0.73 0.50

Methylcyclopentane 7.15 6.41 6.67 6.36 6.74 4.15

2,4-Dimethylpentane 2.57 2.22 2.14 2.24 1.85 1.27

Benzene 8.58 8.40 7.74 8.25 6.74 4.08

Cyclohexane 3.55 3.07 2.44 2.79 2.70 1.70

2-Methylhexane 5.19 4.59 4.31 4.91 4.53 2.66

2,3-Dimethylpentane 2.41 1.98 1.94 1.93 1.99 1.14

3-Methylhexane 5.52 4.85 4.95 4.65 4.47 2.67

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 7.02 6.30 6.59 6.22 5.24 3.13

n-Heptane 4.63 4.05 4.17 3.96 3.79 2.54

Methylcyclohexane 2.80 2.26 2.40 2.25 2.07 1.67

2,2,3-Trimethylpentane 1.65 1.46 1.44 1.39 1.20 0.81

2,3,4-Trimethylpentane 2.36 2.02 2.11 2.07 1.85 1.13

Toluene 28.34 25.69 25.20 24.36 22.12 19.50

2-Methylheptane 1.72 1.40 1.50 1.35 1.29 0.92

3-Methylheptane 1.65 1.41 1.46 1.35 1.00 0.91

1-Octene 0.19 0.13 0.12 0.11 ND 0.06

n-Octane 2.05 1.79 1.81 1.73 1.60 1.21

Ethylbenzene 3.64 3.44 3.28 3.35 3.41 2.74

m-Xylene/p-Xylene 11.55 11.00 10.43 10.74 11.98 9.35

Styrene 1.97 2.05 1.53 1.77 1.14 1.19

o-Xylene 4.02 3.90 3.64 3.80 3.90 3.07

1-Nonene 0.29 0.21 0.19 0.15 0.21 0.11

n-Nonane 1.48 1.31 1.26 1.32 1.62 0.96

Isopropylbenzene 0.57 0.48 0.47 0.47 0.58 0.43

a-Pinene 0.88 0.81 0.78 0.77 0.40 0.13

n-Propylbenzene 1.08 1.08 0.90 1.04 1.08 0.75

m-Ethyltoluene 2.82 2.82 2.51 2.77 2.75 1.90

p-Ethyltoluene 1.76 1.74 1.47 1.71 1.84 1.27

1,3,5-Trimethylbenzene 1.73 1.62 1.40 1.55 1.67 1.06

o-Ethyltoluene 1.12 1.16 1.01 1.17 1.18 1.05

b-Pinene 0.86 1.03 0.94 0.77 0.56 0.76

1,2,4-Trimethylbenzene 4.07 4.15 3.62 4.04 4.07 2.72

1-Decene ND ND ND ND ND ND

n-Decane 1.68 1.66 1.44 1.57 1.88 1.28

1,2,3-Trimethylbenzene 1.13 1.19 0.99 0.81 0.89 0.60

m-Diethylbenzene 0.55 0.51 0.53 0.62 0.53 0.39

p-Diethylbenzene 0.54 0.51 0.47 0.53 0.42 0.37

1-Undecene 0.10 0.13 0.07 0.08 0.05 ND

n-Undecane 1.33 1.26 1.13 1.26 0.86 0.63

1-Dodecene 0.16 0.22 0.08 0.09 ND 0.06

n-Dodecane 0.60 0.68 0.54 0.65 0.28 0.17

1-Tridecene ND ND ND ND ND 0.01

n-Tridecane 0.10 0.18 0.09 0.15 0.07 0.04

TNMOC (w/ unknowns) 568.95 515.03 517.86 500.43 432.92 275.20

TNMOC (speciated) 506.75 458.65 464.26 435.69 377.69 236.92
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14796 14806 14828 14906D1 14906R1 14907D2

Sampling Date: 9/14/98 9/15/98 9/16/98 9/17/98 9/17/98 9/17/98

Analysis Date: 10/17/98 10/17/98 10/23/98 10/20/98 10/26/98 10/20/98

Compound

Ethylene 6.04 2.08 3.66 2.42 2.52 2.29

Acetylene 7.04 1.27 2.98 2.03 1.96 1.98

Ethane 9.15 7.67 5.80 5.30 5.16 5.25

Propylene 3.01 1.34 2.04 1.39 1.40 1.35

Propane 9.26 11.61 6.80 9.22 9.32 8.97

Propyne 0.23 ND 0.09 ND 0.08 0.05

Isobutane 5.55 7.19 5.63 5.88 5.85 5.70

Isobutene/1-Butene 3.66 1.84 2.57 2.41 2.64 2.60

1,3-Butadiene 0.60 0.12 0.36 0.27 0.25 0.29

n-Butane 23.07 28.93 22.81 29.14 29.16 28.40

trans-2-Butene 1.62 2.01 1.76 2.03 2.01 2.05

cis-2-Butene 1.66 1.78 1.63 2.25 2.23 2.24

3-Methyl-1-butene 0.84 0.94 0.85 1.17 1.14 1.23

Isopentane 68.96 77.48 66.38 102.92 106.08 91.85

1-Pentene 2.05 2.31 1.98 3.39 3.31 3.36

2-Methyl-1-butene 3.14 3.20 2.85 4.05 3.92 4.06

n-Pentane 30.09 34.58 28.09 34.03 33.80 33.12

Isoprene 0.87 0.56 0.58 1.08 0.99 0.96

trans-2-Pentene 7.63 8.25 6.83 7.68 7.46 7.78

cis-2-Pentene 3.51 3.80 3.15 3.71 3.55 3.70

2-Methyl-2-butene 7.47 8.06 6.55 7.50 7.22 7.49

2,2-Dimethylbutane 2.46 2.54 2.32 2.81 2.82 2.82

Cyclopentene 1.83 2.07 1.58 1.90 1.86 1.94

4-Methyl-1-pentene 0.40 0.45 0.35 0.42 0.39 0.43

Cyclopentane 3.91 4.26 3.59 4.02 3.92 3.95

2,3-Dimethylbutane 37.00 38.84 32.64 39.27 38.83 32.97

2-Methylpentane 23.99 25.27 21.69 22.87 22.98 22.53

3-Methylpentane 14.31 14.83 12.69 13.83 13.65 13.49

2-Methyl-1-pentene 1.88 1.69 1.47 1.68 1.65 1.65

1-Hexene 0.85 0.94 0.67 0.73 0.75 0.76

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 15.85 16.75 13.56 15.29 15.32 14.91

trans-2-Hexene 1.83 1.90 1.53 1.47 1.45 1.51

cis-2-Hexene 1.12 1.16 0.93 0.87 0.82 0.89

Methylcyclopentane 9.23 9.43 7.88 8.13 8.07 7.98

2,4-Dimethylpentane 2.79 3.20 2.33 2.35 2.34 2.28

Benzene 9.27 7.97 7.76 6.81 6.80 6.71

Cyclohexane 3.36 3.60 2.97 34.74 34.07 32.28

2-Methylhexane 6.27 5.24 4.80 5.22 4.78 5.18

2,3-Dimethylpentane 2.31 2.41 1.84 2.29 1.87 2.28

3-Methylhexane 6.78 5.74 5.12 5.39 5.14 5.31

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 8.02 11.12 6.23 5.89 5.71 5.73

n-Heptane 5.72 4.95 4.35 4.18 4.14 4.10

Methylcyclohexane 2.93 2.54 2.41 2.19 2.22 2.19

2,2,3-Trimethylpentane 2.00 2.25 1.50 1.35 1.37 1.46

2,3,4-Trimethylpentane 3.00 3.82 2.29 1.99 2.10 1.99

Toluene 32.41 26.89 24.69 21.75 22.07 21.34

2-Methylheptane 2.03 1.48 1.37 1.24 1.29 1.24

3-Methylheptane 2.17 1.49 1.46 1.25 1.27 1.26

1-Octene 0.10 0.11 0.08 0.08 0.09 0.09

n-Octane 2.14 1.87 1.69 1.46 1.60 1.40

Ethylbenzene 5.50 4.09 3.89 3.12 4.08 3.09

m-Xylene/p-Xylene 18.52 14.88 13.64 10.01 11.62 9.84

Styrene 1.14 0.89 1.06 1.37 4.25 1.19

o-Xylene 6.40 4.74 4.58 3.41 4.45 3.22

1-Nonene 0.15 0.09 0.15 0.15 0.09 0.10

n-Nonane 1.22 1.13 1.10 0.91 1.07 0.87

Isopropylbenzene 0.65 0.50 0.49 0.55 1.79 0.50

a-Pinene 0.30 2.34 0.42 0.54 0.42 0.53

n-Propylbenzene 1.61 1.22 1.21 0.95 2.19 0.91

m-Ethyltoluene 5.19 3.58 3.52 2.86 3.76 2.60

p-Ethyltoluene 2.77 2.06 2.04 1.60 2.88 1.47

1,3,5-Trimethylbenzene 2.44 1.66 1.74 1.28 2.21 1.24

o-Ethyltoluene 2.04 1.41 1.45 1.26 2.25 1.10

b-Pinene 0.60 1.00 0.38 0.74 0.76 0.71

1,2,4-Trimethylbenzene 7.04 4.87 5.01 3.95 5.20 3.40

1-Decene ND ND ND ND ND ND

n-Decane 0.85 0.85 0.88 0.85 1.10 0.68

1,2,3-Trimethylbenzene 1.73 1.06 1.17 0.91 1.67 0.83

m-Diethylbenzene 0.68 0.54 0.55 0.50 1.21 0.45

p-Diethylbenzene 0.64 0.49 0.48 0.42 0.97 0.43

1-Undecene 0.09 0.07 0.06 0.11 0.10 0.06

n-Undecane 0.73 0.71 0.66 1.32 1.64 0.99

1-Dodecene 0.21 0.04 0.04 0.06 0.04 0.08

n-Dodecane 0.49 0.32 0.31 1.03 1.11 0.28

1-Tridecene 0.06 0.02 ND ND 0.07 ND

n-Tridecane 0.16 0.08 0.05 0.27 0.38 0.03

TNMOC (w/ unknowns) 538.41 520.27 440.30 531.94 550.03 504.48

TNMOC (speciated) 462.62 458.49 390.07 477.52 494.74 449.96
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 14907R2 14898 14901 14982 14980 14995

Sampling Date: 9/17/98 9/18/98 9/21/98 9/22/98 9/23/98 9/24/98

Analysis Date: 10/26/98 10/21/98 10/21/98 10/21/98 10/21/98 10/22/98

Compound

Ethylene 2.49 3.22 3.16 6.34 1.56 4.43

Acetylene 2.09 2.41 2.85 5.62 1.18 3.83

Ethane 5.24 76.21 7.77 14.81 9.10 11.31

Propylene 1.43 1.92 1.68 3.14 0.89 2.25

Propane 9.10 74.41 7.57 16.03 13.70 11.98

Propyne 0.06 0.07 0.09 0.30 ND 0.17

Isobutane 5.74 20.71 4.55 6.17 4.92 5.74

Isobutene/1-Butene 2.66 2.02 2.15 20.42 1.27 2.62

1,3-Butadiene 0.28 0.23 0.30 0.60 0.09 0.38

n-Butane 28.69 54.25 16.47 22.31 17.41 19.29

trans-2-Butene 2.04 1.62 1.31 1.53 0.90 1.13

cis-2-Butene 2.26 1.64 1.14 1.58 0.93 1.23

3-Methyl-1-butene 1.17 0.87 0.49 0.67 0.39 0.58

Isopentane 92.10 88.84 47.76 60.20 36.67 52.10

1-Pentene 3.26 2.09 1.49 2.06 1.09 1.63

2-Methyl-1-butene 4.06 2.88 1.88 1.78 1.32 2.13

n-Pentane 33.35 49.53 20.94 29.25 16.35 22.87

Isoprene 0.96 0.68 0.56 0.78 0.96 0.59

trans-2-Pentene 7.56 7.83 4.57 6.01 3.38 4.88

cis-2-Pentene 3.72 3.62 2.20 4.94 1.65 2.36

2-Methyl-2-butene 7.44 7.45 4.17 12.75 3.07 4.65

2,2-Dimethylbutane 2.76 2.79 1.72 2.21 1.33 2.00

Cyclopentene 1.90 1.69 1.26 1.98 0.88 1.86

4-Methyl-1-pentene 0.40 0.39 0.27 0.36 0.19 0.25

Cyclopentane 3.99 4.74 2.67 3.72 2.11 2.83

2,3-Dimethylbutane 32.91 37.81 23.59 7.58 16.90 25.14

2-Methylpentane 22.46 29.00 15.82 20.64 11.82 17.39

3-Methylpentane 13.55 17.35 9.45 12.32 7.18 10.49

2-Methyl-1-pentene 1.54 1.60 1.14 0.95 0.81 1.14

1-Hexene 0.83 0.51 0.45 0.80 0.44 0.59

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 14.99 22.67 10.42 13.78 8.47 12.46

trans-2-Hexene 1.48 1.84 1.10 1.40 0.79 1.19

cis-2-Hexene 0.80 1.07 0.70 0.83 0.50 0.71

Methylcyclopentane 7.96 11.89 6.14 8.25 4.83 7.02

2,4-Dimethylpentane 2.31 3.08 1.87 2.61 1.67 2.06

Benzene 7.72 9.73 7.15 9.88 4.96 8.40

Cyclohexane 32.31 52.49 6.54 3.41 20.22 13.73

2-Methylhexane 4.86 6.49 3.90 5.81 3.55 5.01

2,3-Dimethylpentane 1.95 2.33 1.60 2.61 1.81 2.14

3-Methylhexane 5.04 7.21 4.25 6.08 3.32 5.07

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 5.68 8.45 5.31 7.43 5.32 5.67

n-Heptane 4.09 7.38 3.60 5.14 2.83 4.38

Methylcyclohexane 2.18 7.38 1.95 2.86 1.82 2.40

2,2,3-Trimethylpentane 1.45 2.08 1.25 1.71 1.04 1.58

2,3,4-Trimethylpentane 2.06 2.83 1.95 2.82 1.83 2.16

Toluene 21.18 26.94 20.44 29.29 14.93 28.43

2-Methylheptane 1.28 2.21 1.18 1.72 0.94 1.45

3-Methylheptane 1.28 1.52 1.20 1.76 0.90 1.41

1-Octene 0.09 0.19 0.06 0.08 0.09 0.10

n-Octane 1.47 2.93 1.42 2.77 1.25 1.82

Ethylbenzene 3.00 4.24 3.48 4.95 2.30 3.68

m-Xylene/p-Xylene 9.63 14.83 12.07 17.14 7.73 12.69

Styrene 1.97 1.30 0.89 1.28 0.78 1.13

o-Xylene 3.35 4.81 4.02 5.89 2.61 4.23

1-Nonene 0.12 0.20 0.10 0.17 0.12 0.14

n-Nonane 0.84 1.41 0.90 1.34 0.79 1.28

Isopropylbenzene 0.73 0.54 0.48 0.60 0.48 0.57

a-Pinene 0.60 0.69 0.10 ND 0.50 0.23

n-Propylbenzene 1.60 1.23 1.10 1.50 0.80 1.19

m-Ethyltoluene 3.36 3.56 3.10 4.57 1.99 3.43

p-Ethyltoluene 2.63 2.06 1.84 2.56 1.28 2.02

1,3,5-Trimethylbenzene 2.28 1.79 1.57 2.30 1.03 1.78

o-Ethyltoluene 2.21 1.53 1.34 1.93 0.91 1.53

b-Pinene 0.78 0.47 0.49 0.29 0.48 0.56

1,2,4-Trimethylbenzene 5.26 4.98 4.44 6.34 2.80 4.89

1-Decene ND ND ND ND ND ND

n-Decane 0.81 1.16 0.68 1.15 0.62 1.24

1,2,3-Trimethylbenzene 2.01 1.20 1.12 1.73 0.59 1.27

m-Diethylbenzene 2.22 0.52 0.51 0.69 0.48 0.66

p-Diethylbenzene 1.39 0.51 0.53 0.64 0.38 0.60

1-Undecene 0.06 0.18 ND 0.11 ND 0.07

n-Undecane 1.25 1.31 0.69 0.87 0.60 1.06

1-Dodecene 0.07 0.15 0.12 0.16 0.28 0.25

n-Dodecane 0.31 0.69 0.35 0.47 0.31 0.87

1-Tridecene 0.04 0.05 ND ND 0.04 0.05

n-Tridecane 0.10 0.10 0.07 0.21 0.12 0.34

TNMOC (w/ unknowns) 519.00 808.26 370.42 492.81 311.73 436.77

TNMOC (speciated) 457.62 728.59 311.52 434.99 267.61 366.92
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 15018D1 15018R1 15019D2 15019R2 15032 15030

Sampling Date: 9/25/98 9/25/98 9/25/98 9/25/98 9/28/98 9/29/98

Analysis Date: 10/23/98 10/27/98 10/23/98 10/27/98 10/24/98 10/27/98

Compound

Ethylene 3.24 3.19 3.21 3.33 9.57 6.56

Acetylene 2.78 2.84 2.81 2.76 8.43 4.46

Ethane 8.01 8.03 8.10 8.05 35.49 11.38

Propylene 1.53 1.49 1.55 1.56 6.13 3.29

Propane 8.94 8.81 8.80 8.93 19.46 13.91

Propyne 0.08 0.07 0.14 0.11 0.46 0.25

Isobutane 4.61 4.67 4.69 4.74 9.36 7.64

Isobutene/1-Butene 1.59 1.63 1.74 1.77 9.57 3.19

1,3-Butadiene 0.25 0.23 0.28 0.26 1.27 0.62

n-Butane 15.16 15.14 15.18 15.41 37.08 30.46

trans-2-Butene 0.92 0.85 0.96 1.02 2.30 1.96

cis-2-Butene 0.87 0.85 0.94 0.93 2.40 1.83

3-Methyl-1-butene 0.42 0.32 0.47 0.40 0.91 0.97

Isopentane 42.22 42.86 42.43 43.12 94.52 76.30

1-Pentene 1.04 1.04 1.21 1.15 3.25 2.61

2-Methyl-1-butene 1.33 1.30 1.47 1.50 3.96 3.13

n-Pentane 15.99 15.85 16.05 16.23 52.27 32.85

Isoprene 0.55 0.51 0.57 0.60 1.25 0.81

trans-2-Pentene 3.00 3.06 3.33 3.31 9.53 7.25

cis-2-Pentene 1.51 1.51 1.67 1.66 4.58 3.39

2-Methyl-2-butene 2.51 2.46 2.77 2.81 13.64 6.88

2,2-Dimethylbutane 1.52 1.62 1.60 1.52 3.62 2.80

Cyclopentene 1.10 1.04 1.07 1.02 2.25 1.78

4-Methyl-1-pentene 0.18 0.22 0.18 0.21 0.56 0.43

Cyclopentane 2.16 2.00 2.16 2.21 5.57 4.31

2,3-Dimethylbutane 18.57 18.04 20.71 20.92 39.37 40.27

2-Methylpentane 12.90 12.50 13.13 13.24 32.05 26.19

3-Methylpentane 7.85 7.84 7.92 7.95 19.46 15.92

2-Methyl-1-pentene 0.72 0.71 0.81 0.85 1.96 1.72

1-Hexene 0.38 0.37 0.37 0.44 1.33 0.82

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 8.91 8.71 8.77 8.84 21.24 18.24

trans-2-Hexene 0.86 0.71 0.83 0.78 2.32 2.15

cis-2-Hexene 0.46 0.48 0.54 0.56 1.38 1.11

Methylcyclopentane 5.10 5.15 5.20 5.23 12.95 10.31

2,4-Dimethylpentane 1.42 1.50 1.52 1.50 4.45 3.20

Benzene 5.84 5.91 6.02 6.29 15.95 10.49

Cyclohexane 4.21 4.26 4.29 4.13 4.65 4.22

2-Methylhexane 3.67 3.47 3.76 3.78 9.43 7.40

2,3-Dimethylpentane 1.71 1.48 1.74 1.41 4.33 3.19

3-Methylhexane 3.84 3.70 3.83 3.83 9.84 7.73

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 4.67 4.62 4.71 4.87 16.98 10.44

n-Heptane 3.05 3.02 3.08 3.12 8.19 6.24

Methylcyclohexane 1.72 1.68 1.71 1.81 4.20 3.28

2,2,3-Trimethylpentane 1.07 1.14 1.15 1.12 3.68 2.62

2,3,4-Trimethylpentane 1.63 1.65 1.74 1.72 6.62 3.64

Toluene 16.64 16.70 17.10 17.16 52.02 37.22

2-Methylheptane 1.10 1.11 0.97 1.14 2.80 2.13

3-Methylheptane 1.13 1.15 1.15 1.16 2.85 2.12

1-Octene 0.09 0.11 0.16 0.16 0.24 0.11

n-Octane 1.36 1.35 1.35 1.39 3.52 2.39

Ethylbenzene 2.89 2.91 3.03 3.05 8.04 6.00

m-Xylene/p-Xylene 9.35 9.28 10.06 10.35 27.79 20.64

Styrene 0.92 0.74 1.06 1.16 1.71 0.99

o-Xylene 3.35 3.35 3.57 3.67 9.83 7.08

1-Nonene 0.11 0.12 0.12 0.14 0.43 0.21

n-Nonane 0.86 0.88 0.89 0.95 2.87 1.58

Isopropylbenzene 0.49 0.45 0.51 0.48 0.99 0.67

a-Pinene ND ND ND ND 0.25 1.22

n-Propylbenzene 0.94 0.86 1.07 1.08 2.48 1.78

m-Ethyltoluene 2.52 2.41 2.93 2.95 8.41 5.49

p-Ethyltoluene 1.51 1.44 1.75 1.66 4.41 3.02

1,3,5-Trimethylbenzene 1.27 1.21 1.55 1.62 4.39 2.73

o-Ethyltoluene 1.19 0.96 1.28 1.32 2.95 2.38

b-Pinene 0.56 0.44 0.81 0.82 0.90 1.68

1,2,4-Trimethylbenzene 3.64 3.50 4.50 4.62 11.84 7.65

1-Decene ND ND ND ND ND ND

n-Decane 0.76 0.59 0.75 0.64 3.93 1.33

1,2,3-Trimethylbenzene 0.81 0.75 1.19 0.99 3.12 1.71

m-Diethylbenzene 0.41 0.46 0.49 0.51 1.14 0.75

p-Diethylbenzene 0.46 0.40 0.50 0.55 1.14 0.68

1-Undecene ND ND 0.10 0.09 0.59 0.12

n-Undecane 0.60 0.51 0.67 0.61 2.13 1.07

1-Dodecene 0.17 0.07 0.33 0.28 0.28 0.19

n-Dodecane 0.31 0.24 0.46 0.38 1.17 0.60

1-Tridecene ND ND ND 0.06 0.05 0.07

n-Tridecane 0.09 0.05 0.13 0.15 0.36 0.23

TNMOC (w/ unknowns) 303.19 297.64 322.95 324.90 836.20 640.48

TNMOC (speciated) 263.65 260.61 273.69 276.14 720.46 522.08
SNMOC 1998 REPORT

SITE CODE: CAMS 13

All concentrations reported in ppbC

Sample No.: 15049D1 15049R1 15050D2 15050R2

Sampling Date: 9/30/98 9/30/98 9/30/98 9/30/98

Analysis Date: 10/28/98 10/28/98 10/28/98 10/28/98

Compound

Ethylene 18.55 18.62 18.63 19.00

Acetylene 15.44 15.27 14.98 15.26

Ethane 45.81 44.68 45.24 45.36

Propylene 8.96 8.98 9.06 9.10

Propane 25.01 25.01 24.95 25.39

Propyne 0.80 0.72 0.74 0.80

Isobutane 17.75 17.78 17.70 17.96

Isobutene/1-Butene 11.56 11.64 11.48 11.68

1,3-Butadiene 2.35 2.33 2.29 2.32

n-Butane 86.04 85.41 85.55 86.58

trans-2-Butene 5.71 5.06 5.68 5.01

cis-2-Butene 5.41 5.49 5.33 5.44

3-Methyl-1-butene 2.83 2.97 2.98 2.76

Isopentane 152.75 151.76 167.90 170.97

1-Pentene 7.26 7.38 7.13 7.61

2-Methyl-1-butene 9.02 9.06 8.71 9.09

n-Pentane 72.40 71.91 72.08 72.90

Isoprene 1.83 1.91 1.83 1.91

trans-2-Pentene 12.87 12.89 12.45 12.89

cis-2-Pentene 6.49 6.49 6.26 6.59

2-Methyl-2-butene 13.09 13.00 12.55 13.16

2,2-Dimethylbutane 6.99 6.91 6.85 7.13

Cyclopentene 2.79 2.74 2.75 2.90

4-Methyl-1-pentene 0.68 0.71 0.73 0.70

Cyclopentane 6.65 6.64 6.56 6.70

2,3-Dimethylbutane 62.99 63.21 62.24 64.72

2-Methylpentane 37.39 37.34 37.92 39.18

3-Methylpentane 22.49 22.33 22.12 22.80

2-Methyl-1-pentene 2.21 2.28 2.22 2.31

1-Hexene 1.43 1.40 1.45 1.45

2-Ethyl-1-butene ND ND ND ND

n-Hexane 23.34 23.15 22.18 23.54

trans-2-Hexene 2.49 2.29 2.01 2.31

cis-2-Hexene 1.28 1.27 1.22 1.24

Methylcyclopentane 12.34 12.32 12.16 12.50

2,4-Dimethylpentane 4.52 4.62 4.31 4.46

Benzene 16.15 16.49 17.58 18.39

Cyclohexane 4.00 4.12 3.58 4.05

2-Methylhexane 9.69 10.27 9.52 9.97

2,3-Dimethylpentane 4.14 4.72 3.97 4.24

3-Methylhexane 10.68 11.04 10.72 11.14

1-Heptene ND ND ND ND

2,2,4-Trimethylpentane 16.23 16.04 15.96 16.32

n-Heptane 8.71 8.64 8.53 8.88

Methylcyclohexane 4.63 4.49 4.61 4.51

2,2,3-Trimethylpentane 3.80 4.21 3.76 3.88

2,3,4-Trimethylpentane 5.75 5.59 5.74 5.86

Toluene 58.00 58.06 56.61 58.32

2-Methylheptane 3.25 3.30 3.31 3.32

3-Methylheptane 3.29 3.30 3.24 3.38

1-Octene 0.25 0.23 0.32 0.25

n-Octane 3.52 3.44 3.41 3.42

Ethylbenzene 9.35 9.41 9.21 9.57

m-Xylene/p-Xylene 30.36 30.55 29.91 31.12

Styrene 2.54 2.78 3.57 3.50

o-Xylene 10.86 10.99 10.77 11.34

1-Nonene 0.45 0.45 0.54 0.80

n-Nonane 3.12 3.22 3.04 3.41

Isopropylbenzene 1.02 1.18 1.11 1.21

a-Pinene 1.74 1.74 2.06 1.72

n-Propylbenzene 2.69 2.83 2.61 2.71

m-Ethyltoluene 8.61 8.92 8.55 9.02

p-Ethyltoluene 4.84 4.96 4.83 4.96

1,3,5-Trimethylbenzene 5.32 5.53 5.24 5.48

o-Ethyltoluene 3.38 3.31 3.30 3.35

b-Pinene 1.65 1.73 2.27 2.56

1,2,4-Trimethylbenzene 12.77 13.14 12.44 13.23

1-Decene ND ND ND ND

n-Decane 4.69 4.71 4.57 4.78

1,2,3-Trimethylbenzene 3.02 3.28 3.07 3.19

m-Diethylbenzene 1.31 1.39 1.38 1.42

p-Diethylbenzene 1.14 1.22 1.11 1.35

1-Undecene 0.30 0.33 0.30 0.32

n-Undecane 2.77 2.83 2.70 2.82

1-Dodecene 0.26 0.37 0.30 0.52

n-Dodecane 1.23 1.41 1.10 1.24

1-Tridecene 0.08 0.06 0.10 0.07

n-Tridecane 0.41 0.48 0.36 0.39

TNMOC (w/ unknowns) 1105.03 1110.96 1129.62 1169.89

TNMOC (speciated) 975.52 976.35 983.55 1009.73
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 12967 12968 13015 13023D1 13023R1 13024D2

Sampling Date: 6/15/98 6/16/98 6/23/98 6/24/98 6/24/98 6/24/98

Analysis Date: VOID VOID 7/9/98 7/8/98 7/9/98 7/8/98

Compound

Ethylene 2.16 2.04 1.77 2.09

Acetylene 1.56 2.21 2.11 2.28

Ethane 3.12 5.81 5.71 5.56

Propylene 1.13 0.94 0.93 0.96

Propane 2.46 5.87 5.79 5.70

Propyne 0.15 0.10 0.10 0.11

Isobutane 0.83 1.60 1.58 1.55

Isobutene/1-Butene 3.27 3.73 3.77 2.71

1,3-Butadiene 0.12 0.13 0.14 0.13

n-Butane 3.36 4.90 5.07 4.90

trans-2-Butene 0.10 0.07 0.08 0.10

cis-2-Butene 0.12 0.11 0.10 0.11

3-Methyl-1-butene 1.03 0.57 0.60 0.64

Isopentane 17.56 15.08 15.30 14.10

1-Pentene 0.25 0.31 0.32 0.32

2-Methyl-1-butene 0.41 0.71 0.73 0.59

n-Pentane 2.34 4.65 4.52 4.29

Isoprene 2.52 2.01 1.93 1.96

trans-2-Pentene 0.45 0.64 0.64 0.60

cis-2-Pentene 0.21 0.32 0.33 0.30

2-Methyl-2-butene 0.51 0.97 0.94 0.72

2,2-Dimethylbutane 0.25 0.52 0.55 0.49

Cyclopentene 0.47 0.44 0.48 0.35

4-Methyl-1-pentene 0.05 0.11 0.13 0.10

Cyclopentane 0.26 0.39 0.38 0.38

2,3-Dimethylbutane 6.00 10.22 10.02 8.98

2-Methylpentane 3.95 5.98 6.74 5.40

3-Methylpentane 1.90 3.79 3.48 3.48

2-Methyl-1-pentene 0.21 0.45 0.42 0.39

1-Hexene 0.26 0.35 0.36 0.35

2-Ethyl-1-butene ND ND ND ND

n-Hexane 2.54 5.27 5.07 4.78

trans-2-Hexene 0.19 0.43 0.39 0.35

cis-2-Hexene 0.13 0.28 0.25 0.25

Methylcyclopentane 1.34 2.71 2.61 2.40

2,4-Dimethylpentane 0.56 1.08 1.05 0.91

Benzene 2.03 2.62 2.50 2.51

Cyclohexane 0.46 0.93 0.89 0.85

2-Methylhexane 2.33 3.78 3.52 3.55

2,3-Dimethylpentane 0.78 1.42 1.34 1.32

3-Methylhexane 1.75 3.44 3.29 3.14

1-Heptene 0.27 ND ND ND

2,2,4-Trimethylpentane 2.74 4.91 4.80 4.46

n-Heptane 1.66 3.14 3.04 2.87

Methylcyclohexane 0.82 1.64 1.60 1.53

2,2,3-Trimethylpentane 0.78 1.70 1.67 1.21

2,3,4-Trimethylpentane 1.23 1.87 1.81 1.73

Toluene 7.65 12.14 12.10 11.20

2-Methylheptane 0.65 1.03 1.03 0.95

3-Methylheptane 0.46 0.83 0.81 0.95

1-Octene 0.14 0.12 0.11 0.14

n-Octane 0.78 1.28 1.28 1.18

Ethylbenzene 1.63 2.85 2.80 2.52

m-Xylene/p-Xylene 5.16 9.48 9.31 8.40

Styrene 1.19 1.08 1.06 1.28

o-Xylene 2.05 3.74 3.68 3.23

1-Nonene 0.17 0.20 0.18 0.20

n-Nonane 0.41 0.64 0.59 0.57

Isopropylbenzene 0.08 0.15 0.14 0.12

a-Pinene 0.29 0.36 0.33 0.32

n-Propylbenzene 0.52 0.89 0.84 0.71

m-Ethyltoluene 1.97 3.06 3.06 2.50

p-Ethyltoluene 1.10 1.43 1.38 1.16

1,3,5-Trimethylbenzene 0.99 1.36 1.43 1.10

o-Ethyltoluene 0.70 1.26 1.35 0.99

b-Pinene 1.27 0.64 0.97 1.08

1,2,4-Trimethylbenzene 2.41 4.39 4.42 3.45

1-Decene ND ND ND ND

n-Decane 0.68 0.62 0.56 0.58

1,2,3-Trimethylbenzene 0.44 0.98 0.80 0.66

m-Diethylbenzene 0.23 0.35 0.34 0.21

p-Diethylbenzene 0.18 0.36 0.40 0.20

1-Undecene 0.05 ND ND ND

n-Undecane 0.77 0.75 0.77 0.61

1-Dodecene ND ND ND ND

n-Dodecane 2.62 1.71 1.24 3.64

1-Tridecene 0.08 ND ND ND

n-Tridecane 2.92 ND 0.10 0.07

TNMOC (w/ unknowns) 186.84 230.19 218.67 208.51

TNMOC (speciated) 114.25 161.93 159.95 149.50
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13024R2 13053 13084 13092 13211 13206

Sampling Date: 6/24/98 6/25/98 6/26/98 6/29/98 6/30/98 7/1/98

Analysis Date: 7/9/98 7/10/98 7/10/98 7/10/98 7/10/98 7/11/98

Compound

Ethylene 1.88 1.90 2.38 3.61 1.67 1.23

Acetylene 2.14 1.48 1.63 2.12 1.30 1.72

Ethane 5.70 5.40 6.14 8.09 3.88 4.93

Propylene 0.97 1.02 0.96 1.42 1.02 1.31

Propane 5.87 4.62 5.53 6.77 3.18 4.11

Propyne 0.10 0.09 0.14 0.11 0.08 0.15

Isobutane 1.60 1.31 2.54 3.01 0.93 1.45

Isobutene/1-Butene 2.77 2.10 2.27 2.73 1.94 2.47

1,3-Butadiene 0.13 0.16 0.11 0.13 0.14 0.19

n-Butane 4.77 3.45 5.84 4.85 2.89 3.65

trans-2-Butene 0.10 0.10 0.07 0.06 0.07 0.14

cis-2-Butene 0.12 0.11 0.09 0.10 0.09 0.14

3-Methyl-1-butene 0.75 1.00 1.05 0.70 0.21 1.04

Isopentane 14.47 11.75 15.13 14.31 9.84 16.66

1-Pentene 0.33 0.20 0.30 0.20 0.17 0.38

2-Methyl-1-butene 0.64 0.38 0.47 0.34 0.33 0.58

n-Pentane 4.53 3.20 2.96 3.19 2.18 3.28

Isoprene 1.93 2.11 2.35 1.33 1.07 1.33

trans-2-Pentene 0.64 0.39 0.33 0.27 0.32 0.55

cis-2-Pentene 0.31 0.16 0.14 0.12 0.16 0.24

2-Methyl-2-butene 0.66 0.40 0.28 0.20 0.34 0.50

2,2-Dimethylbutane 0.49 0.25 0.40 0.26 0.23 0.46

Cyclopentene 0.36 0.32 0.93 0.91 0.44 0.83

4-Methyl-1-pentene 0.10 ND ND ND 0.04 0.05

Cyclopentane 0.40 0.29 0.28 0.28 0.20 0.36

2,3-Dimethylbutane 9.23 4.84 4.21 3.98 3.69 5.62

2-Methylpentane 5.56 3.45 3.38 3.26 2.94 4.44

3-Methylpentane 3.48 1.64 1.68 1.50 1.35 1.97

2-Methyl-1-pentene 0.37 0.14 0.15 0.14 0.14 0.20

1-Hexene 0.40 0.22 0.16 0.19 0.16 0.22

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 5.11 2.44 2.26 2.48 1.86 2.79

trans-2-Hexene 0.48 0.19 0.11 0.13 0.16 0.23

cis-2-Hexene 0.24 0.09 0.07 0.08 0.08 0.12

Methylcyclopentane 2.44 1.21 1.14 1.18 0.97 1.30

2,4-Dimethylpentane 0.91 0.44 0.37 0.36 0.36 0.49

Benzene 2.43 1.77 2.13 2.34 1.97 2.52

Cyclohexane 0.81 10.14 0.53 0.72 0.33 1.07

2-Methylhexane 3.00 2.35 1.81 1.38 1.16 2.11

2,3-Dimethylpentane 0.91 0.75 0.57 0.33 0.31 0.77

3-Methylhexane 3.10 1.53 1.16 1.20 1.02 1.65

1-Heptene ND 0.22 0.36 0.20 0.27 0.40

2,2,4-Trimethylpentane 4.40 2.02 1.59 1.69 1.60 2.30

n-Heptane 2.98 1.17 1.13 1.21 1.10 1.46

Methylcyclohexane 1.57 0.83 0.75 0.90 0.57 0.77

2,2,3-Trimethylpentane 1.37 0.58 0.56 0.50 0.48 0.68

2,3,4-Trimethylpentane 1.77 0.79 0.68 0.63 0.68 0.95

Toluene 11.44 6.56 6.10 5.89 5.51 8.93

2-Methylheptane 0.96 0.42 0.48 0.41 0.35 0.50

3-Methylheptane 0.76 0.44 0.32 0.43 0.29 0.40

1-Octene 0.14 0.13 0.13 0.11 0.06 0.06

n-Octane 1.24 0.59 0.64 0.67 0.50 0.62

Ethylbenzene 2.60 1.32 1.14 1.18 1.14 1.67

m-Xylene/p-Xylene 8.72 4.11 3.49 3.64 3.68 5.36

Styrene 1.32 0.87 1.35 1.07 0.75 1.24

o-Xylene 3.40 1.61 1.41 1.41 1.42 2.08

1-Nonene 0.26 0.18 0.18 0.15 0.08 0.18

n-Nonane 0.60 0.43 0.39 0.38 0.30 0.50

Isopropylbenzene 0.12 0.06 0.05 0.09 0.06 0.10

a-Pinene 0.32 0.23 0.09 0.17 0.14 0.36

n-Propylbenzene 0.74 0.40 0.32 0.31 0.31 0.53

m-Ethyltoluene 2.66 1.45 1.16 1.09 1.22 1.85

p-Ethyltoluene 1.26 0.73 0.58 0.53 0.56 0.89

1,3,5-Trimethylbenzene 1.14 0.56 0.36 0.44 0.55 0.79

o-Ethyltoluene 1.04 0.60 0.51 0.42 0.47 0.76

b-Pinene 1.15 0.86 1.61 0.70 0.35 1.04

1,2,4-Trimethylbenzene 3.45 1.83 1.61 1.39 1.64 2.46

1-Decene ND ND ND ND ND ND

n-Decane 0.54 0.95 0.35 0.26 0.31 0.81

1,2,3-Trimethylbenzene 0.69 0.33 0.27 0.25 0.27 0.44

m-Diethylbenzene 0.23 0.18 0.15 0.07 0.09 0.21

p-Diethylbenzene 0.21 0.13 0.15 0.12 0.14 0.21

1-Undecene ND 0.25 ND ND ND ND

n-Undecane 0.57 2.80 0.28 0.46 0.27 0.69

1-Dodecene ND 0.51 ND ND ND ND

n-Dodecane 4.35 7.17 0.79 ND ND 0.55

1-Tridecene ND 0.06 0.04 ND ND ND

n-Tridecane 0.04 0.26 0.05 0.03 0.04 0.21

TNMOC (w/ unknowns) 206.39 159.68 143.86 150.39 115.25 164.41

TNMOC (speciated) 152.28 115.06 101.12 101.18 74.38 113.25
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13193D1 13193R1 13208D2 13208R2 13212 13248

Sampling Date: 7/2/98 7/2/98 7/2/98 7/2/98 7/3/98 7/6/98

Analysis Date: 7/8/98 7/8/98 7/10/98 7/10/98 7/11/98 7/11/98

Compound

Ethylene 0.82 2.11 0.87 2.31 1.95 1.75

Acetylene 1.51 1.54 1.56 1.58 1.05 1.92

Ethane 7.90 8.09 8.15 8.34 9.41 5.65

Propylene 1.07 1.11 1.05 1.10 0.89 1.08

Propane 7.11 7.33 7.44 7.46 7.99 5.49

Propyne 0.13 0.10 0.08 0.12 0.09 0.11

Isobutane 2.06 2.10 2.10 2.13 2.96 1.68

Isobutene/1-Butene 1.85 1.94 1.77 1.87 1.71 2.67

1,3-Butadiene 0.13 0.16 0.15 0.16 0.10 0.18

n-Butane 5.62 5.99 5.33 5.39 7.24 7.54

trans-2-Butene 0.13 0.13 0.10 0.11 0.20 0.28

cis-2-Butene 0.14 0.15 0.12 0.10 0.23 0.30

3-Methyl-1-butene 0.86 1.10 0.71 1.06 0.83 1.70

Isopentane 12.46 12.87 13.30 13.83 18.72 19.24

1-Pentene 0.18 0.25 0.22 0.21 0.40 0.60

2-Methyl-1-butene 0.37 0.42 0.43 0.48 0.69 0.80

n-Pentane 3.52 3.58 3.66 3.75 4.99 4.70

Isoprene 1.95 2.08 1.66 1.52 1.05 0.84

trans-2-Pentene 0.41 0.45 0.41 0.43 0.79 1.00

cis-2-Pentene 0.17 0.19 0.17 0.17 0.38 0.45

2-Methyl-2-butene 0.38 0.39 0.20 0.25 0.83 1.02

2,2-Dimethylbutane 0.27 0.32 0.34 0.36 0.51 0.48

Cyclopentene 1.01 1.01 0.99 1.04 1.63 1.24

4-Methyl-1-pentene ND ND ND ND 0.05 0.03

Cyclopentane 0.32 0.31 0.32 0.32 0.51 0.55

2,3-Dimethylbutane 3.75 3.81 3.73 3.88 5.69 6.32

2-Methylpentane 3.46 3.55 3.49 3.63 5.25 5.12

3-Methylpentane 1.50 1.53 1.52 1.56 2.55 2.40

2-Methyl-1-pentene 0.13 0.12 0.13 0.14 0.15 0.27

1-Hexene 0.12 0.12 0.14 0.15 0.26 0.25

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.91 1.96 2.15 2.14 3.70 3.72

trans-2-Hexene 0.09 0.11 0.18 0.11 0.22 0.31

cis-2-Hexene 0.07 0.07 0.07 0.07 0.11 0.14

Methylcyclopentane 1.07 1.09 1.08 1.12 1.46 1.56

2,4-Dimethylpentane 0.34 0.37 0.35 0.37 0.44 0.49

Benzene 1.92 2.08 2.15 2.35 3.14 2.98

Cyclohexane 0.58 0.61 0.46 0.52 0.66 0.50

2-Methylhexane 1.22 1.20 1.32 1.67 2.07 2.07

2,3-Dimethylpentane 0.35 0.35 0.34 0.57 0.74 0.76

3-Methylhexane 1.15 1.17 1.11 1.23 1.69 1.60

1-Heptene ND ND 0.23 ND 0.21 0.25

2,2,4-Trimethylpentane 1.88 2.01 1.73 2.04 1.64 2.07

n-Heptane 0.98 1.02 1.06 1.09 1.56 1.33

Methylcyclohexane 0.78 0.82 0.81 0.82 1.01 0.76

2,2,3-Trimethylpentane 0.50 0.52 0.47 0.53 0.58 0.58

2,3,4-Trimethylpentane 0.70 0.73 0.69 0.73 0.61 0.73

Toluene 7.15 7.21 7.12 7.40 8.08 9.10

2-Methylheptane 0.39 0.43 0.42 0.45 0.59 0.50

3-Methylheptane 0.30 0.39 0.30 0.31 0.39 0.33

1-Octene 0.05 0.06 0.05 0.06 0.08 0.08

n-Octane 0.59 0.60 0.64 0.65 0.84 0.65

Ethylbenzene 1.05 1.05 1.06 1.14 1.42 1.77

m-Xylene/p-Xylene 3.38 3.34 3.31 3.48 5.00 6.51

Styrene 2.89 2.88 3.07 3.31 1.45 1.19

o-Xylene 1.35 1.38 1.35 1.44 1.71 2.19

1-Nonene 0.09 0.09 0.09 0.11 0.11 0.16

n-Nonane 0.40 0.41 0.42 0.42 0.53 0.45

Isopropylbenzene 0.10 0.10 0.10 0.10 0.07 0.09

a-Pinene 0.38 0.37 0.39 0.42 0.16 0.22

n-Propylbenzene 0.45 0.43 0.41 0.46 0.41 0.49

m-Ethyltoluene 1.64 1.67 1.52 1.58 1.28 1.63

p-Ethyltoluene 0.77 0.81 0.72 0.76 0.72 0.86

1,3,5-Trimethylbenzene 0.78 0.80 0.78 0.69 0.52 0.73

o-Ethyltoluene 0.60 0.63 0.70 0.70 0.55 0.63

b-Pinene 0.79 0.81 0.77 0.96 1.31 0.88

1,2,4-Trimethylbenzene 2.22 2.34 2.19 2.32 1.83 2.35

1-Decene ND ND ND ND ND ND

n-Decane 0.53 0.47 0.47 0.50 0.46 0.40

1,2,3-Trimethylbenzene 0.45 0.46 0.35 0.47 0.38 0.40

m-Diethylbenzene 0.11 0.09 0.10 0.14 0.14 0.11

p-Diethylbenzene 0.11 0.12 0.13 0.15 0.14 0.16

1-Undecene ND ND ND 0.10 ND 0.04

n-Undecane 0.50 0.42 0.33 0.36 0.39 0.33

1-Dodecene ND ND ND ND ND ND

n-Dodecane ND 0.31 ND 0.41 ND 0.31

1-Tridecene 0.26 ND 0.10 0.17 ND ND

n-Tridecane 0.22 0.10 0.29 0.07 0.05 0.07

TNMOC (w/ unknowns) 142.63 141.01 148.16 145.00 176.29 182.84

TNMOC (speciated) 100.40 104.77 101.50 107.93 127.53 128.14
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13325 13327 13367 13373 13370 13526

Sampling Date: 7/7/98 7/8/98 7/9/98 7/10/98 7/13/98 7/14/98

Analysis Date: 7/11/98 7/16/98 8/7/98 7/16/98 7/16/98 8/7/98

Compound

Ethylene 1.76 1.52 2.71 1.44 1.86 5.93

Acetylene 2.13 2.65 1.32 2.19 1.29 1.16

Ethane 4.24 4.23 5.78 4.14 33.98 20.07

Propylene 0.94 1.71 1.47 1.55 0.92 1.34

Propane 4.18 5.05 4.60 6.32 38.32 17.80

Propyne 0.10 0.26 0.06 0.19 0.16 ND

Isobutane 1.31 3.41 2.84 2.22 9.35 6.22

Isobutene/1-Butene 1.87 2.70 2.29 2.12 1.64 5.46

1,3-Butadiene 0.13 0.31 0.24 0.29 ND 0.13

n-Butane 5.47 24.62 16.09 4.08 30.74 11.97

trans-2-Butene 0.25 1.77 1.51 0.19 1.08 0.44

cis-2-Butene 0.24 1.94 1.76 0.18 1.21 0.60

3-Methyl-1-butene 0.95 1.29 0.79 0.42 1.65 1.30

Isopentane 15.51 55.97 38.56 15.03 49.63 26.33

1-Pentene 0.41 3.20 2.24 0.32 2.09 0.71

2-Methyl-1-butene 0.88 4.84 3.14 0.59 3.16 0.13

n-Pentane 3.87 20.97 14.39 2.86 21.52 7.66

Isoprene 0.58 1.01 1.26 1.84 0.59 0.86

trans-2-Pentene 0.83 6.17 4.45 0.48 3.82 1.02

cis-2-Pentene 0.37 3.19 2.45 0.21 1.93 0.99

2-Methyl-2-butene 0.85 8.16 5.69 0.57 4.95 1.52

2,2-Dimethylbutane 0.39 2.64 2.25 0.34 1.93 1.03

Cyclopentene 1.01 2.32 1.46 0.92 1.61 2.48

4-Methyl-1-pentene ND 0.40 0.20 ND 0.30 ND

Cyclopentane 0.44 3.18 2.18 0.28 2.62 0.99

2,3-Dimethylbutane 5.18 44.66 27.81 3.46 30.25 3.16

2-Methylpentane 4.22 23.16 14.56 3.50 18.84 6.05

3-Methylpentane 2.08 14.95 9.38 2.04 11.21 3.25

2-Methyl-1-pentene 0.17 1.44 1.08 0.12 0.88 0.07

1-Hexene 0.24 0.90 0.53 0.13 0.64 0.51

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.92 18.34 11.52 5.19 15.69 6.98

trans-2-Hexene 0.25 1.59 0.89 0.10 0.99 0.23

cis-2-Hexene 0.11 0.85 0.47 0.06 0.52 ND

Methylcyclopentane 1.25 7.14 4.60 1.57 6.22 2.40

2,4-Dimethylpentane 0.40 2.32 1.92 0.34 1.62 1.01

Benzene 2.48 9.55 6.10 2.88 6.24 4.37

Cyclohexane 0.40 1.44 1.28 2.26 3.13 1.14

2-Methylhexane 1.77 5.17 3.60 1.81 5.22 1.99

2,3-Dimethylpentane 0.62 2.01 1.64 0.59 1.96 1.23

3-Methylhexane 1.23 6.63 3.92 2.45 5.53 2.04

1-Heptene 0.25 0.42 0.12 0.09 0.94 0.02

2,2,4-Trimethylpentane 1.65 7.39 4.98 1.55 4.89 2.07

n-Heptane 1.14 5.50 3.64 2.79 5.60 2.20

Methylcyclohexane 0.68 2.17 1.44 1.83 4.03 1.56

2,2,3-Trimethylpentane 0.50 2.01 1.25 0.53 1.59 0.62

2,3,4-Trimethylpentane 0.64 2.50 1.84 0.58 1.70 0.85

Toluene 7.48 29.69 18.37 8.81 18.64 8.58

2-Methylheptane 0.42 1.59 1.23 0.49 1.65 0.90

3-Methylheptane 0.28 1.52 1.28 0.41 1.25 0.71

1-Octene 0.10 0.18 0.06 0.07 0.30 0.10

n-Octane 0.55 2.10 1.68 0.67 2.37 2.38

Ethylbenzene 1.44 5.29 3.57 1.44 3.20 1.86

m-Xylene/p-Xylene 5.18 19.20 11.99 4.54 11.93 6.17

Styrene 1.13 0.91 1.25 1.05 2.59 1.84

o-Xylene 1.77 6.38 4.10 1.58 3.80 2.07

1-Nonene 0.17 0.25 0.14 0.08 0.21 0.22

n-Nonane 0.39 1.30 1.10 0.34 1.22 0.90

Isopropylbenzene 0.05 0.32 0.69 0.06 0.18 0.54

a-Pinene 0.15 0.40 0.24 0.72 0.34 ND

n-Propylbenzene 0.39 1.43 1.21 0.29 0.92 0.92

m-Ethyltoluene 1.36 4.80 3.40 1.11 2.98 1.75

p-Ethyltoluene 0.72 2.51 2.10 0.53 1.62 1.22

1,3,5-Trimethylbenzene 0.59 2.21 1.62 0.56 1.38 0.86

o-Ethyltoluene 0.53 2.01 1.48 0.55 1.10 0.72

b-Pinene 0.90 0.69 1.30 1.40 1.32 2.54

1,2,4-Trimethylbenzene 1.95 6.46 4.69 1.55 4.21 2.62

1-Decene ND ND ND ND ND ND

n-Decane 0.35 0.78 0.80 0.37 0.57 0.87

1,2,3-Trimethylbenzene 0.33 1.10 1.15 0.26 0.66 0.73

m-Diethylbenzene 0.10 0.31 0.57 0.09 0.22 0.58

p-Diethylbenzene 0.13 0.36 0.60 0.11 0.25 0.60

1-Undecene ND 0.04 ND ND ND ND

n-Undecane 0.25 0.25 0.75 0.19 0.45 0.87

1-Dodecene ND ND 0.48 ND ND 1.38

n-Dodecane 0.24 ND 0.22 0.07 ND 0.29

1-Tridecene ND ND ND 0.02 ND ND

n-Tridecane 0.03 ND 0.09 ND ND 0.08

TNMOC (w/ unknowns) 138.14 481.96 335.23 144.91 482.34 241.80

TNMOC (speciated) 103.85 415.74 288.48 109.99 407.42 200.21
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13525 13586 13614 13615 13752 13753

Sampling Date: 7/15/98 7/16/98 7/17/98 7/20/98 7/21/98 7/22/98

Analysis Date: 8/8/98 8/7/98 8/8/98 8/8/98 8/20/98 8/20/98

Compound

Ethylene 4.59 5.77 4.15 3.06 2.12 1.52

Acetylene 2.64 3.25 1.36 1.38 1.41 1.04

Ethane 11.05 28.09 22.70 11.70 7.88 5.39

Propylene 2.16 2.16 1.31 1.39 1.18 1.02

Propane 10.14 23.12 19.63 11.48 6.34 4.36

Propyne 0.15 0.22 0.10 0.02 0.09 ND

Isobutane 9.53 6.42 7.63 3.15 2.09 1.49

Isobutene/1-Butene 3.06 2.98 1.83 2.60 1.78 1.47

1,3-Butadiene 0.36 0.30 0.09 0.25 0.21 0.12

n-Butane 20.52 20.62 21.00 7.44 5.02 4.47

trans-2-Butene 1.92 2.23 1.46 0.53 0.44 0.39

cis-2-Butene 2.17 1.79 1.48 0.71 0.52 0.54

3-Methyl-1-butene 1.36 1.51 0.68 0.03 0.17 0.09

Isopentane 69.60 62.31 46.56 19.03 16.34 11.09

1-Pentene 3.68 3.13 2.22 0.64 0.58 0.66

2-Methyl-1-butene 4.80 3.44 2.66 0.60 0.56 0.45

n-Pentane 24.01 22.23 18.54 5.47 4.24 3.36

Isoprene 1.21 1.31 0.69 0.81 0.99 0.64

trans-2-Pentene 6.46 5.67 4.42 1.16 1.08 0.95

cis-2-Pentene 3.47 3.17 2.34 0.71 0.63 0.63

2-Methyl-2-butene 8.22 6.87 5.26 0.99 0.93 0.85

2,2-Dimethylbutane 2.95 2.19 1.88 0.69 0.65 0.65

Cyclopentene 1.82 2.10 2.64 0.79 0.88 0.50

4-Methyl-1-pentene 0.36 0.31 0.12 0.01 0.09 0.05

Cyclopentane 3.28 2.74 2.14 0.63 0.55 0.61

2,3-Dimethylbutane 39.55 35.16 25.93 6.39 4.19 4.49

2-Methylpentane 20.30 19.15 14.79 3.87 3.05 3.03

3-Methylpentane 13.06 12.61 10.01 2.60 2.20 1.77

2-Methyl-1-pentene 1.24 1.35 0.97 0.20 0.22 0.26

1-Hexene 0.72 1.03 0.70 0.21 0.26 0.15

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 17.52 18.78 15.98 3.56 2.93 2.27

trans-2-Hexene 1.13 1.36 1.10 0.19 0.20 0.16

cis-2-Hexene 0.68 0.97 0.61 0.14 0.09 0.16

Methylcyclopentane 6.49 7.15 5.57 1.68 1.33 4.10

2,4-Dimethylpentane 2.31 2.67 2.08 0.91 0.78 1.70

Benzene 8.51 11.66 9.51 3.07 2.76 5.79

Cyclohexane 25.20 2.29 2.03 4.04 2.13 1.21

2-Methylhexane 4.94 6.83 5.34 1.55 1.62 0.76

2,3-Dimethylpentane 2.21 2.97 2.30 1.00 1.05 0.69

3-Methylhexane 5.70 7.34 5.58 1.55 1.41 1.18

1-Heptene ND ND ND 0.12 0.14 0.11

2,2,4-Trimethylpentane 6.98 9.38 6.01 2.09 1.93 1.41

n-Heptane 5.12 7.79 6.32 1.55 1.26 1.07

Methylcyclohexane 2.19 3.12 2.88 1.10 0.89 0.71

2,2,3-Trimethylpentane 1.83 2.61 1.77 0.54 0.45 0.13

2,3,4-Trimethylpentane 2.39 3.66 2.51 0.89 0.78 0.64

Toluene 34.27 44.78 31.45 8.58 7.77 6.20

2-Methylheptane 1.93 2.90 1.96 0.51 0.34 0.58

3-Methylheptane 1.59 2.59 1.83 0.68 0.61 0.58

1-Octene 0.07 0.14 0.07 0.20 0.06 0.08

n-Octane 2.49 4.34 2.87 1.04 0.89 0.69

Ethylbenzene 5.29 8.77 5.99 1.81 1.87 1.41

m-Xylene/p-Xylene 18.32 30.43 22.17 5.99 5.80 4.55

Styrene 1.80 1.62 1.92 1.44 1.32 1.17

o-Xylene 6.55 10.42 7.19 2.23 2.00 1.65

1-Nonene 0.40 0.43 0.21 0.14 0.09 0.16

n-Nonane 1.89 3.57 1.83 0.76 0.76 0.66

Isopropylbenzene 0.79 1.55 0.70 0.58 0.48 0.52

a-Pinene 0.23 1.06 0.15 0.16 0.43 0.21

n-Propylbenzene 1.81 3.11 1.75 0.76 0.79 0.68

m-Ethyltoluene 5.52 8.45 5.48 1.87 1.69 1.41

p-Ethyltoluene 3.20 5.32 3.18 1.34 1.14 1.05

1,3,5-Trimethylbenzene 3.23 4.76 3.16 1.14 0.99 0.85

o-Ethyltoluene 2.24 3.42 2.28 0.83 0.83 0.57

b-Pinene 0.88 1.90 2.47 1.76 0.99 1.04

1,2,4-Trimethylbenzene 8.05 12.67 7.90 2.75 2.56 2.23

1-Decene ND ND ND ND ND ND

n-Decane 1.89 3.65 1.25 0.80 0.79 0.62

1,2,3-Trimethylbenzene 1.95 3.02 1.84 0.69 0.62 0.64

m-Diethylbenzene 0.71 1.98 0.73 0.50 0.50 0.40

p-Diethylbenzene 0.70 1.80 1.05 0.37 0.37 0.39

1-Undecene 0.10 0.20 0.11 ND 0.09 0.06

n-Undecane 1.71 3.46 1.26 1.01 0.98 0.71

1-Dodecene 0.27 0.31 1.21 0.56 ND 0.41

n-Dodecane 1.02 1.17 0.79 0.37 0.36 0.25

1-Tridecene ND ND 0.05 0.03 ND 0.05

n-Tridecane 0.33 0.31 0.17 0.36 0.13 0.13

TNMOC (w/ unknowns) 564.13 645.14 476.87 192.16 159.48 119.65

TNMOC (speciated) 476.78 539.96 407.85 151.75 121.72 104.01
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13754 13735 13779 13892D1 13892R1 13893D2

Sampling Date: 7/23/98 7/24/98 7/27/98 7/28/98 7/28/98 7/28/98

Analysis Date: 8/20/98 8/21/98 8/21/98 8/28/98 9/14/98 8/28/98

Compound

Ethylene 2.83 2.19 2.74 2.63 2.60 2.57

Acetylene 1.11 0.80 1.04 1.72 1.60 1.77

Ethane 4.93 4.55 3.24 3.40 3.40 3.56

Propylene 1.26 1.02 1.50 1.19 1.20 1.16

Propane 4.25 3.94 3.75 3.81 4.05 3.92

Propyne 0.11 0.06 0.05 0.05 0.03 0.06

Isobutane 1.38 1.31 1.22 1.09 1.21 1.16

Isobutene/1-Butene 1.96 1.61 2.02 1.51 1.54 1.53

1,3-Butadiene 0.32 0.17 0.20 0.18 0.15 0.20

n-Butane 3.45 3.11 3.22 2.93 3.00 3.06

trans-2-Butene 0.43 0.41 0.42 0.37 0.38 0.45

cis-2-Butene 0.62 0.53 0.61 0.55 0.54 0.50

3-Methyl-1-butene 0.11 ND 0.16 0.14 0.15 0.12

Isopentane 21.05 12.33 19.05 14.77 16.37 14.20

1-Pentene 0.62 0.64 0.72 0.64 0.66 0.61

2-Methyl-1-butene 0.49 0.52 0.52 0.50 0.49 0.44

n-Pentane 3.66 3.24 3.74 3.35 3.42 3.43

Isoprene 0.96 0.61 2.20 2.38 2.52 2.38

trans-2-Pentene 1.10 0.95 1.04 0.89 0.93 0.96

cis-2-Pentene 0.65 0.70 0.59 0.67 0.69 0.61

2-Methyl-2-butene 0.96 0.81 0.95 0.86 0.93 0.88

2,2-Dimethylbutane 0.58 0.55 0.86 0.68 0.72 0.67

Cyclopentene 0.89 0.66 0.98 0.72 0.75 0.72

4-Methyl-1-pentene ND ND ND 0.04 0.03 ND

Cyclopentane 0.59 0.49 0.58 0.56 0.62 0.56

2,3-Dimethylbutane 4.66 4.69 4.95 4.84 5.16 4.90

2-Methylpentane 2.93 3.05 3.68 3.22 3.54 3.51

3-Methylpentane 2.10 1.97 2.23 1.92 2.20 2.03

2-Methyl-1-pentene 0.26 0.25 0.26 0.19 0.19 0.22

1-Hexene 0.23 0.15 0.18 0.16 0.17 0.18

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 3.16 3.17 2.99 2.60 2.51 2.90

trans-2-Hexene 0.16 0.26 0.20 0.15 0.18 0.16

cis-2-Hexene 0.12 0.10 0.11 0.06 0.13 0.11

Methylcyclopentane 1.14 1.20 1.45 1.13 1.32 1.16

2,4-Dimethylpentane 0.71 0.78 0.77 0.74 0.78 0.69

Benzene 2.22 2.12 3.00 2.37 2.33 2.39

Cyclohexane 0.62 1.14 0.95 1.00 1.21 0.87

2-Methylhexane 1.36 1.51 1.50 1.44 1.51 1.43

2,3-Dimethylpentane 1.01 0.83 1.08 0.95 1.03 0.82

3-Methylhexane 2.24 1.21 2.02 1.32 1.45 1.34

1-Heptene 0.10 0.06 ND 0.20 0.17 0.05

2,2,4-Trimethylpentane 1.67 1.62 1.93 1.66 1.80 1.72

n-Heptane 1.24 1.16 1.26 1.10 1.31 1.19

Methylcyclohexane 0.92 0.87 0.85 0.83 0.87 0.78

2,2,3-Trimethylpentane 0.51 0.32 0.55 0.40 0.40 0.41

2,3,4-Trimethylpentane 0.70 0.68 0.80 0.71 0.89 0.76

Toluene 6.82 6.69 8.58 7.11 7.66 7.40

2-Methylheptane 0.57 0.57 0.61 0.56 0.52 0.61

3-Methylheptane 0.54 0.61 0.72 0.54 0.49 0.56

1-Octene 0.13 0.86 ND 0.08 0.09 0.04

n-Octane 0.79 0.88 0.91 0.76 0.76 0.75

Ethylbenzene 1.66 1.83 1.61 1.45 1.50 1.43

m-Xylene/p-Xylene 5.43 6.31 5.07 4.42 4.63 4.60

Styrene 2.15 1.19 2.47 1.07 1.10 0.93

o-Xylene 1.87 2.08 1.91 1.64 1.68 1.67

1-Nonene 0.13 0.06 ND 0.05 0.10 0.05

n-Nonane 0.75 0.82 0.72 0.59 0.65 0.65

Isopropylbenzene 0.55 0.47 0.46 0.46 0.42 0.49

a-Pinene 0.46 ND 0.23 0.23 0.28 0.32

n-Propylbenzene 0.77 0.78 0.75 0.62 0.60 0.62

m-Ethyltoluene 1.60 1.73 1.64 1.40 1.42 1.41

p-Ethyltoluene 1.20 1.10 1.12 0.93 0.97 0.97

1,3,5-Trimethylbenzene 0.94 1.07 0.87 0.80 0.80 0.85

o-Ethyltoluene 0.58 0.77 0.89 0.85 0.82 0.82

b-Pinene 1.71 1.17 2.03 0.84 0.86 0.70

1,2,4-Trimethylbenzene 2.53 2.57 2.35 2.02 2.06 2.12

1-Decene ND ND ND ND ND ND

n-Decane 0.63 0.85 0.70 0.62 0.66 0.65

1,2,3-Trimethylbenzene 0.61 0.65 0.68 0.59 0.55 0.67

m-Diethylbenzene 0.60 0.51 0.69 0.41 0.44 0.35

p-Diethylbenzene 0.61 0.52 0.48 0.38 0.34 0.35

1-Undecene 0.06 ND 0.12 0.06 0.05 ND

n-Undecane 0.79 0.80 0.70 0.72 0.73 0.62

1-Dodecene 0.47 0.34 0.71 0.09 0.03 0.07

n-Dodecane 0.26 0.23 0.19 0.33 0.30 0.16

1-Tridecene 0.06 ND ND ND ND ND

n-Tridecane 0.12 0.04 0.11 0.10 0.09 0.06

TNMOC (w/ unknowns) 172.52 133.95 158.32 124.50 132.15 124.23

TNMOC (speciated) 117.77 103.82 119.49 102.33 107.72 103.01
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13893R2 13901 13896 13911 13948 13970

Sampling Date: 7/28/98 7/29/98 7/30/98 7/31/98 8/3/98 8/4/98

Analysis Date: 9/14/98 8/18/98 8/18/98 8/19/98 8/19/98 8/28/98

Compound

Ethylene 2.57 2.50 1.78 2.35 4.31 4.52

Acetylene 1.65 1.39 0.93 1.61 2.38 3.24

Ethane ND 3.25 2.95 3.83 17.22 11.63

Propylene 1.23 1.29 1.03 1.23 2.14 1.77

Propane 4.20 3.38 3.38 3.90 16.10 11.33

Propyne ND ND ND ND 0.64 0.14

Isobutane 1.19 1.04 1.24 1.45 5.65 3.97

Isobutene/1-Butene 1.52 2.15 1.68 2.23 3.27 2.41

1,3-Butadiene 0.18 0.24 0.23 0.18 0.38 0.29

n-Butane 3.10 3.28 3.23 4.90 11.81 7.57

trans-2-Butene 0.44 0.48 0.41 0.58 1.53 0.43

cis-2-Butene 0.53 0.62 0.62 0.66 0.85 0.54

3-Methyl-1-butene 0.13 ND ND 0.11 ND 0.10

Isopentane 15.29 25.41 14.43 17.54 34.91 26.53

1-Pentene 0.61 0.72 0.68 0.78 1.18 0.73

2-Methyl-1-butene 0.53 0.48 0.43 0.88 1.41 0.65

n-Pentane 3.55 3.59 3.45 5.02 10.88 6.41

Isoprene 2.52 2.75 2.74 2.71 7.15 2.06

trans-2-Pentene 1.02 1.01 1.05 1.42 2.11 1.02

cis-2-Pentene 0.69 0.83 0.70 0.83 1.29 0.68

2-Methyl-2-butene 0.91 0.93 0.95 1.51 2.19 0.86

2,2-Dimethylbutane 0.77 0.72 0.65 0.87 1.55 0.85

Cyclopentene 0.80 0.52 0.36 0.84 3.71 1.27

4-Methyl-1-pentene ND ND ND 0.18 ND 0.07

Cyclopentane 0.64 0.53 0.40 0.85 1.61 0.83

2,3-Dimethylbutane 5.60 4.82 4.70 8.88 16.71 7.12

2-Methylpentane 3.80 3.20 3.01 5.23 9.77 5.43

3-Methylpentane 2.37 1.95 2.11 3.17 5.82 3.08

2-Methyl-1-pentene 0.18 0.23 0.19 0.28 0.49 0.24

1-Hexene 0.16 0.26 0.15 0.24 0.34 0.17

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.62 2.67 2.88 4.48 8.04 4.26

trans-2-Hexene 0.19 0.21 0.18 0.28 0.78 0.15

cis-2-Hexene 0.13 0.11 ND ND ND 0.17

Methylcyclopentane 1.37 1.34 1.23 2.04 3.22 1.91

2,4-Dimethylpentane 0.82 0.78 0.76 0.97 1.45 0.91

Benzene 2.49 2.44 2.34 3.48 7.35 4.61

Cyclohexane 1.00 0.85 0.88 7.92 1.39 1.40

2-Methylhexane 1.52 1.58 1.61 1.39 3.54 2.02

2,3-Dimethylpentane 0.94 1.01 1.12 0.91 1.57 1.08

3-Methylhexane 1.45 1.39 1.42 1.94 3.57 2.05

1-Heptene 0.15 0.49 0.08 0.13 ND 0.20

2,2,4-Trimethylpentane 1.91 1.70 1.67 2.55 4.84 2.58

n-Heptane 1.33 1.22 1.29 1.75 3.30 1.91

Methylcyclohexane 0.90 0.92 0.91 1.06 1.90 1.14

2,2,3-Trimethylpentane 0.48 0.27 0.35 0.49 1.28 0.66

2,3,4-Trimethylpentane 0.82 0.74 0.78 1.07 1.84 1.10

Toluene 7.82 7.47 7.62 11.02 18.92 12.10

2-Methylheptane 0.61 0.60 0.63 0.85 1.36 0.90

3-Methylheptane 0.63 0.52 0.65 0.75 1.41 0.86

1-Octene 0.04 0.22 0.14 ND 0.18 0.15

n-Octane 0.84 0.87 0.99 1.01 1.97 1.37

Ethylbenzene 1.53 1.83 2.01 2.16 3.68 2.41

m-Xylene/p-Xylene 4.66 6.23 6.43 6.90 12.26 7.30

Styrene 0.93 1.59 1.34 1.00 1.39 1.20

o-Xylene 1.71 2.10 2.09 2.49 4.46 2.69

1-Nonene 0.06 ND ND ND ND 0.26

n-Nonane 0.67 0.73 0.92 0.81 1.34 1.10

Isopropylbenzene 0.42 0.49 0.51 0.59 0.63 0.60

a-Pinene 0.25 0.36 0.33 0.34 0.52 0.29

n-Propylbenzene 0.65 0.83 0.75 0.77 1.27 0.79

m-Ethyltoluene 1.40 1.66 1.65 1.79 3.76 2.23

p-Ethyltoluene 0.96 1.15 1.06 1.19 2.16 1.43

1,3,5-Trimethylbenzene 0.83 0.94 1.00 0.97 1.81 1.23

o-Ethyltoluene 0.80 0.90 0.70 0.91 1.71 1.00

b-Pinene 0.85 1.71 1.92 0.83 1.11 0.77

1,2,4-Trimethylbenzene 2.01 2.65 2.56 2.62 5.21 3.07

1-Decene ND ND ND ND ND ND

n-Decane 0.58 0.71 0.85 0.69 1.18 1.10

1,2,3-Trimethylbenzene 0.65 0.81 0.65 0.72 1.43 0.96

m-Diethylbenzene 0.42 0.58 0.63 0.60 0.81 0.62

p-Diethylbenzene 0.39 0.45 0.44 0.45 0.81 0.53

1-Undecene ND 0.04 ND ND ND 0.07

n-Undecane 0.63 0.81 0.83 0.98 1.15 0.85

1-Dodecene 0.04 ND ND ND ND 0.32

n-Dodecane 0.19 0.49 0.29 1.02 0.53 0.36

1-Tridecene ND ND ND ND ND 0.16

n-Tridecane 0.06 0.27 0.11 0.31 0.24 61.56

TNMOC (w/ unknowns) 132.35 154.85 135.94 171.09 337.08 278.29

TNMOC (speciated) 104.94 122.29 108.07 146.47 282.79 240.41
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 13973D1 13973R1 13974D2 13974R2 14051 14053

Sampling Date: 8/5/98 8/5/98 8/5/98 8/5/98 8/6/98 8/7/98

Analysis Date: 8/28/98 9/16/98 8/28/98 10/20/98 8/28/98 8/28/98

Compound

Ethylene 5.99 5.67 5.82 4.88 5.02 7.55

Acetylene 4.67 4.64 4.73 3.47 5.34 18.45

Ethane 13.02 12.82 12.85 10.58 16.13 9.30

Propylene 2.52 2.54 2.41 2.26 2.45 3.96

Propane 14.04 14.64 13.88 12.30 20.27 11.88

Propyne 0.26 0.19 0.26 0.17 0.20 0.27

Isobutane 3.66 3.67 3.65 3.12 4.13 2.43

Isobutene/1-Butene 2.81 2.70 2.57 2.32 3.02 3.94

1,3-Butadiene 0.38 0.44 0.49 0.35 0.59 0.81

n-Butane 6.40 6.48 6.40 5.53 15.81 5.42

trans-2-Butene 0.66 0.57 0.56 0.45 1.45 0.59

cis-2-Butene 0.77 0.65 0.63 0.53 1.73 0.65

3-Methyl-1-butene 0.32 0.19 0.17 0.23 0.96 0.51

Isopentane 28.62 31.25 29.20 28.83 53.74 23.81

1-Pentene 0.84 0.88 0.91 0.76 2.90 0.69

2-Methyl-1-butene 0.74 0.84 0.79 0.67 4.45 0.90

n-Pentane 7.40 7.52 7.43 6.39 21.36 7.32

Isoprene 2.04 2.08 2.02 1.69 0.90 0.94

trans-2-Pentene 1.22 1.26 1.26 1.02 6.29 1.24

cis-2-Pentene 0.83 0.78 0.75 0.65 3.35 0.80

2-Methyl-2-butene 1.15 1.26 1.27 1.04 8.31 1.30

2,2-Dimethylbutane 1.47 1.37 0.95 1.06 3.08 1.14

Cyclopentene 0.70 0.89 0.77 0.61 1.37 0.47

4-Methyl-1-pentene 0.06 0.08 0.06 0.07 0.39 0.06

Cyclopentane 1.02 1.02 0.92 0.89 3.57 0.82

2,3-Dimethylbutane 9.41 10.09 9.65 8.43 42.12 8.77

2-Methylpentane 6.16 6.68 6.24 5.90 22.50 6.42

3-Methylpentane 3.76 3.89 3.71 3.29 14.32 3.77

2-Methyl-1-pentene 0.27 0.30 0.27 0.23 1.45 0.29

1-Hexene 0.36 0.22 0.24 0.22 0.82 0.26

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 5.10 4.96 5.27 4.38 17.37 4.26

trans-2-Hexene 0.21 0.23 0.22 0.25 1.25 0.20

cis-2-Hexene 0.13 0.13 0.10 0.14 0.81 0.15

Methylcyclopentane 2.33 2.46 2.33 2.08 6.83 2.38

2,4-Dimethylpentane 1.11 1.12 1.13 0.96 2.61 1.18

Benzene 5.12 5.33 5.16 4.54 9.33 5.72

Cyclohexane 6.85 7.74 1.17 1.14 2.03 1.04

2-Methylhexane 2.25 2.38 2.35 2.08 5.95 2.63

2,3-Dimethylpentane 1.15 1.32 1.29 1.10 2.73 1.23

3-Methylhexane 2.31 2.61 2.50 2.28 6.19 2.81

1-Heptene ND 0.78 ND ND ND ND

2,2,4-Trimethylpentane 3.70 4.07 3.78 3.31 8.35 4.36

n-Heptane 2.17 2.08 2.16 1.86 5.32 2.71

Methylcyclohexane 1.22 1.36 1.31 1.19 1.96 2.06

2,2,3-Trimethylpentane 0.88 0.99 1.01 0.80 2.09 1.06

2,3,4-Trimethylpentane 1.48 1.62 1.54 1.34 2.97 1.67

Toluene 17.69 18.57 18.16 15.56 29.91 18.02

2-Methylheptane 1.06 1.16 1.08 0.92 1.73 1.35

3-Methylheptane 1.01 0.88 1.00 0.88 1.37 1.15

1-Octene 0.06 0.07 0.14 0.08 0.11 0.16

n-Octane 1.42 1.49 1.41 1.29 2.18 1.43

Ethylbenzene 2.87 3.01 2.95 2.51 5.33 6.88

m-Xylene/p-Xylene 8.77 9.14 8.95 7.72 18.21 23.38

Styrene 1.15 1.26 1.12 1.27 1.14 2.85

o-Xylene 3.30 3.47 3.36 2.78 6.31 7.33

1-Nonene 0.14 0.34 0.14 0.17 0.21 0.14

n-Nonane 1.10 1.14 1.13 0.95 1.54 1.09

Isopropylbenzene 0.55 0.57 0.52 0.48 0.62 0.60

a-Pinene 0.43 0.41 0.32 0.27 1.51 0.95

n-Propylbenzene 1.01 1.07 1.00 0.85 1.67 1.07

m-Ethyltoluene 2.70 2.88 2.94 2.38 5.22 3.46

p-Ethyltoluene 1.74 1.79 1.72 1.37 3.01 2.03

1,3,5-Trimethylbenzene 1.59 1.65 1.65 1.26 2.62 2.11

o-Ethyltoluene 1.39 1.60 1.32 1.13 1.99 1.53

b-Pinene 0.59 0.89 0.67 0.77 1.76 1.15

1,2,4-Trimethylbenzene 3.90 4.17 4.06 3.29 7.35 5.32

1-Decene ND ND ND ND ND ND

n-Decane 1.26 1.39 1.20 1.03 1.18 1.40

1,2,3-Trimethylbenzene 1.11 1.09 1.03 0.95 1.89 1.42

m-Diethylbenzene 0.54 0.63 0.62 0.50 0.70 0.70

p-Diethylbenzene 0.52 0.51 0.60 0.54 0.65 0.61

1-Undecene 0.07 0.08 ND 0.09 0.11 0.10

n-Undecane 1.19 1.27 1.16 1.03 0.99 1.23

1-Dodecene 0.10 0.20 ND 0.17 ND 0.20

n-Dodecane 0.44 0.57 0.53 0.47 0.41 0.55

1-Tridecene 0.06 0.07 ND 0.02 ND ND

n-Tridecane 0.23 0.24 0.20 0.14 0.10 0.20

TNMOC (w/ unknowns) 255.93 270.21 253.02 226.92 515.66 313.23

TNMOC (speciated) 215.52 226.40 211.14 186.26 443.59 246.66
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14092 14176 14216 14229 14242D1 14242R1

Sampling Date: 8/10/98 8/11/98 8/12/98 8/13/98 8/14/98 8/14/98

Analysis Date: 9/21/98 9/2/98 9/2/98 9/2/98 9/10/98 9/11/98

Compound

Ethylene 2.54 4.02 10.51 2.96 5.12 5.00

Acetylene 1.99 3.35 9.75 2.31 4.18 4.22

Ethane 3.98 9.76 19.95 11.78 15.52 15.50

Propylene 1.44 1.71 4.43 1.23 2.21 2.25

Propane 4.95 12.87 13.47 11.14 15.60 15.47

Propyne ND 0.15 0.37 0.08 0.18 0.11

Isobutane 1.34 2.97 4.61 3.46 3.45 3.48

Isobutene/1-Butene 2.25 2.38 4.68 1.79 2.40 2.49

1,3-Butadiene 0.25 0.27 0.87 0.25 0.38 0.44

n-Butane 3.21 7.53 8.42 6.71 7.18 7.14

trans-2-Butene 0.43 0.53 0.85 0.39 0.47 0.55

cis-2-Butene 0.53 0.64 0.90 0.48 0.62 0.56

3-Methyl-1-butene 0.15 0.23 0.75 0.14 0.20 0.20

Isopentane 15.03 24.38 35.52 19.34 24.38 23.82

1-Pentene 0.58 0.70 1.26 0.55 0.72 0.75

2-Methyl-1-butene 0.54 0.75 1.45 0.44 0.62 0.73

n-Pentane 3.54 8.32 11.31 5.36 7.30 7.26

Isoprene 2.17 1.17 3.25 1.11 2.06 2.09

trans-2-Pentene 0.93 1.39 2.29 0.89 1.01 1.04

cis-2-Pentene 0.64 0.88 1.30 0.67 0.74 0.70

2-Methyl-2-butene 0.84 1.33 2.43 0.77 0.93 0.97

2,2-Dimethylbutane 0.79 0.92 1.71 0.87 1.07 1.02

Cyclopentene 0.58 0.63 0.74 0.75 0.41 0.46

4-Methyl-1-pentene ND ND 0.12 ND ND ND

Cyclopentane 0.63 1.07 1.48 0.68 1.00 1.01

2,3-Dimethylbutane 5.23 9.28 17.06 6.04 8.94 8.79

2-Methylpentane 3.62 5.98 10.66 4.32 5.71 5.79

3-Methylpentane 2.27 3.94 6.67 2.77 3.76 3.66

2-Methyl-1-pentene 0.27 0.29 0.50 0.20 0.27 0.26

1-Hexene 0.18 0.36 0.47 0.17 0.24 0.23

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.73 5.26 7.95 3.89 4.66 4.77

trans-2-Hexene 0.17 0.29 0.46 0.17 0.18 0.25

cis-2-Hexene 0.15 0.18 0.23 0.16 0.13 0.12

Methylcyclopentane 1.55 2.48 4.14 1.67 2.46 2.32

2,4-Dimethylpentane 0.83 1.18 1.83 0.86 1.16 1.03

Benzene 2.75 4.16 8.04 3.57 4.31 4.25

Cyclohexane 0.78 3.80 1.79 1.89 1.19 1.23

2-Methylhexane 1.46 2.40 3.76 1.90 2.03 2.12

2,3-Dimethylpentane 0.95 1.40 1.76 1.12 1.03 1.30

3-Methylhexane 1.45 2.61 4.06 1.82 2.36 2.39

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 2.06 3.28 6.91 2.12 3.43 3.27

n-Heptane 1.20 2.37 3.62 1.62 1.85 1.92

Methylcyclohexane 0.93 1.35 2.40 1.22 1.24 1.19

2,2,3-Trimethylpentane 0.42 0.90 1.61 0.55 0.78 0.77

2,3,4-Trimethylpentane 0.84 1.26 2.69 0.91 1.31 1.36

Toluene 8.77 14.79 27.86 8.46 15.51 15.52

2-Methylheptane 0.56 0.97 1.60 0.72 0.89 0.87

3-Methylheptane 0.63 0.86 1.67 0.78 0.91 0.87

1-Octene ND 0.09 0.14 ND 0.05 0.03

n-Octane 0.77 1.20 2.05 1.02 1.21 1.17

Ethylbenzene 1.55 2.39 4.76 1.55 2.52 2.57

m-Xylene/p-Xylene 5.03 7.24 15.08 4.82 7.77 7.81

Styrene 0.97 0.82 3.19 0.87 1.33 1.20

o-Xylene 1.79 2.58 5.38 1.71 2.86 2.87

1-Nonene ND 0.11 0.30 0.06 0.15 0.12

n-Nonane 0.66 0.91 1.85 0.73 0.93 0.93

Isopropylbenzene 0.36 0.44 0.58 0.41 0.52 0.54

a-Pinene 0.32 0.38 2.29 0.18 0.29 0.33

n-Propylbenzene 0.62 0.71 1.31 0.67 0.86 0.86

m-Ethyltoluene 1.42 2.02 4.29 1.44 2.19 2.22

p-Ethyltoluene 0.95 1.24 2.59 0.94 1.36 1.44

1,3,5-Trimethylbenzene 0.81 1.00 2.64 0.77 1.17 1.23

o-Ethyltoluene 0.88 0.88 1.92 0.67 1.04 1.20

b-Pinene 0.69 0.54 1.49 0.50 0.77 0.78

1,2,4-Trimethylbenzene 1.99 2.81 6.28 2.06 3.11 3.09

1-Decene ND ND ND ND ND ND

n-Decane 0.67 0.98 2.50 0.66 1.14 1.11

1,2,3-Trimethylbenzene 0.51 0.72 1.77 0.41 0.74 0.79

m-Diethylbenzene 0.35 0.48 0.73 0.43 0.51 0.52

p-Diethylbenzene 0.27 0.39 0.90 0.42 0.43 0.43

1-Undecene ND 0.06 0.16 0.04 0.05 0.03

n-Undecane 0.54 1.02 2.30 0.67 1.07 1.07

1-Dodecene ND 0.14 0.21 0.13 0.19 0.11

n-Dodecane 0.18 0.70 0.94 0.27 0.37 0.35

1-Tridecene ND 0.05 ND ND ND ND

n-Tridecane 0.04 0.28 0.33 0.11 0.13 0.15

TNMOC (w/ unknowns) 140.63 223.11 393.37 169.34 228.33 228.48

TNMOC (speciated) 110.47 187.53 326.11 142.56 194.86 194.45
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14245D2 14245R2 14220 14225 14248 14243

Sampling Date: 8/14/98 8/14/98 8/17/98 8/18/98 8/19/98 8/20/98

Analysis Date: 9/2/98 9/21/98 9/11/98 10/19/98 9/22/98 10/19/98

Compound

Ethylene 5.17 5.18 3.20 3.19 7.11 4.23

Acetylene 4.32 4.12 2.64 2.89 6.00 2.65

Ethane 15.46 15.45 5.49 11.02 13.08 10.35

Propylene 2.22 2.25 1.58 1.45 3.40 1.86

Propane 14.59 15.20 4.75 8.60 10.26 9.76

Propyne 0.24 0.16 0.11 0.07 0.22 0.09

Isobutane 3.43 3.43 1.46 2.40 4.02 3.60

Isobutene/1-Butene 2.49 2.45 2.36 2.09 4.15 2.18

1,3-Butadiene 0.38 0.37 0.26 0.27 0.61 0.28

n-Butane 7.02 7.11 4.17 5.62 12.13 6.18

trans-2-Butene 0.46 0.48 0.43 0.35 1.12 0.41

cis-2-Butene 0.58 0.57 0.56 0.51 1.33 0.51

3-Methyl-1-butene 0.17 0.26 0.08 0.17 0.65 0.18

Isopentane 26.22 27.68 16.93 12.94 41.02 21.45

1-Pentene 0.77 0.71 0.62 0.52 2.05 0.77

2-Methyl-1-butene 0.56 0.70 0.63 0.58 2.94 0.50

n-Pentane 7.01 7.19 4.33 4.57 16.57 5.85

Isoprene 1.95 1.97 1.80 2.18 3.32 1.65

trans-2-Pentene 1.03 1.00 1.01 0.90 4.12 0.91

cis-2-Pentene 0.72 0.70 0.70 0.58 2.26 0.63

2-Methyl-2-butene 0.82 0.83 0.94 0.78 5.53 0.80

2,2-Dimethylbutane 0.97 1.13 0.80 0.66 2.09 0.94

Cyclopentene 0.58 0.55 0.39 0.53 1.65 2.02

4-Methyl-1-pentene ND ND ND 0.05 0.23 ND

Cyclopentane 0.90 0.99 0.69 0.61 2.22 0.72

2,3-Dimethylbutane 8.54 8.60 5.86 5.32 27.68 6.81

2-Methylpentane 5.89 6.22 4.11 3.72 15.71 5.90

3-Methylpentane 3.57 3.64 2.51 2.28 10.01 3.09

2-Methyl-1-pentene 0.26 0.31 0.24 0.20 1.10 0.30

1-Hexene 0.21 0.23 0.19 0.15 0.73 0.19

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.45 4.30 2.94 2.88 14.16 4.16

trans-2-Hexene 0.16 0.14 0.19 0.16 1.19 0.20

cis-2-Hexene 0.09 0.09 0.13 0.10 0.62 0.08

Methylcyclopentane 2.38 2.40 1.64 1.54 5.98 1.92

2,4-Dimethylpentane 1.07 1.01 0.81 0.74 2.48 0.95

Benzene 4.21 4.26 3.11 2.83 10.68 4.06

Cyclohexane 1.27 1.36 1.43 0.90 1.99 3.49

2-Methylhexane 2.17 2.54 1.60 1.54 5.24 2.06

2,3-Dimethylpentane 1.22 1.32 0.98 0.92 2.28 1.14

3-Methylhexane 2.29 2.55 1.63 1.48 5.99 2.25

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 3.13 3.38 2.60 2.14 7.83 2.63

n-Heptane 1.79 1.84 1.34 1.25 5.77 1.81

Methylcyclohexane 1.30 1.25 0.88 1.00 2.70 1.19

2,2,3-Trimethylpentane 0.76 0.71 0.57 0.50 2.15 0.68

2,3,4-Trimethylpentane 1.21 1.28 1.00 0.88 3.06 1.04

Toluene 14.10 15.15 9.63 8.69 37.50 15.80

2-Methylheptane 0.81 0.82 0.68 0.63 2.25 0.74

3-Methylheptane 0.87 0.83 0.65 0.68 2.02 0.76

1-Octene 0.09 0.10 0.04 ND 0.17 0.07

n-Octane 1.16 1.22 0.86 0.87 2.96 1.22

Ethylbenzene 2.31 2.48 1.84 1.62 6.44 3.20

m-Xylene/p-Xylene 6.89 7.35 5.71 5.09 22.74 10.07

Styrene 1.41 1.64 1.22 0.95 1.54 2.40

o-Xylene 2.54 2.77 2.10 1.91 7.52 3.26

1-Nonene 0.10 0.15 0.07 0.08 0.31 0.07

n-Nonane 0.87 0.90 0.67 0.65 1.75 0.75

Isopropylbenzene 0.46 0.44 0.43 0.41 0.78 0.46

a-Pinene 0.28 0.19 0.35 0.27 0.49 0.18

n-Propylbenzene 0.89 0.82 0.73 0.66 1.77 0.80

m-Ethyltoluene 2.04 1.98 1.69 1.58 5.48 2.00

p-Ethyltoluene 1.23 1.27 1.11 1.04 3.10 1.22

1,3,5-Trimethylbenzene 0.92 1.10 0.95 0.92 2.78 1.05

o-Ethyltoluene 0.92 1.10 0.84 0.92 2.21 1.06

b-Pinene 0.78 0.81 0.73 0.48 0.85 1.81

1,2,4-Trimethylbenzene 2.80 2.76 2.40 2.35 7.69 2.76

1-Decene ND ND ND ND ND ND

n-Decane 0.97 1.07 0.77 0.86 1.53 0.94

1,2,3-Trimethylbenzene 0.74 0.66 0.57 0.54 1.84 0.74

m-Diethylbenzene 0.55 0.44 0.45 0.36 0.82 0.57

p-Diethylbenzene 0.53 0.32 0.37 0.34 0.64 0.59

1-Undecene 0.06 0.09 ND 0.03 0.11 0.08

n-Undecane 0.91 0.80 1.07 0.85 1.26 0.95

1-Dodecene 0.23 0.03 ND ND 0.09 0.47

n-Dodecane 0.25 0.23 0.60 0.36 0.49 0.56

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.08 0.07 0.13 0.09 0.10 0.18

TNMOC (w/ unknowns) 226.27 232.63 158.90 150.81 464.43 240.22

TNMOC (speciated) 189.77 195.50 126.34 127.31 392.65 177.28
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14354 14381D1 14381R1 14382D2 14382R2 14474

Sampling Date: 8/21/98 8/24/98 8/24/98 8/24/98 8/24/98 8/25/98

Analysis Date: 9/22/98 9/23/98 9/24/98 9/23/98 9/24/98 9/23/98

Compound

Ethylene 3.99 4.31 5.32 4.31 5.64 3.87

Acetylene 3.14 3.41 4.42 3.56 4.58 2.62

Ethane 6.57 8.92 11.07 9.06 11.51 13.15

Propylene 1.97 1.94 2.34 1.93 2.40 1.61

Propane 6.20 8.75 10.84 8.60 11.11 10.63

Propyne 0.18 0.12 0.13 0.11 0.14 0.11

Isobutane 2.27 4.79 5.97 4.53 5.85 3.93

Isobutene/1-Butene 2.52 2.37 2.90 2.29 2.88 2.20

1,3-Butadiene 0.34 0.38 0.47 0.42 0.46 0.27

n-Butane 4.76 7.11 8.89 7.33 9.42 5.94

trans-2-Butene 0.46 0.53 0.78 0.45 0.77 0.42

cis-2-Butene 0.55 0.55 0.73 0.61 0.72 0.52

3-Methyl-1-butene 0.22 0.18 0.29 0.09 0.80 0.17

Isopentane 21.72 23.12 28.29 22.59 29.11 18.08

1-Pentene 0.71 0.73 0.88 0.89 0.91 0.07

2-Methyl-1-butene 0.71 0.80 0.99 0.78 1.00 0.55

n-Pentane 5.05 7.97 9.90 7.58 9.96 5.86

Isoprene 1.78 2.03 2.56 2.07 2.64 2.78

trans-2-Pentene 0.97 1.19 1.46 1.24 1.56 0.94

cis-2-Pentene 0.71 0.72 0.98 0.82 1.00 0.61

2-Methyl-2-butene 0.90 1.19 1.55 1.21 1.70 0.76

2,2-Dimethylbutane 1.07 0.99 1.31 1.07 1.33 1.01

Cyclopentene 2.34 0.69 0.88 0.61 0.92 1.18

4-Methyl-1-pentene 0.03 0.05 0.07 0.08 0.08 ND

Cyclopentane 0.80 1.18 1.47 1.08 1.44 0.76

2,3-Dimethylbutane 6.40 7.72 9.51 7.63 9.87 6.09

2-Methylpentane 4.62 4.44 5.70 4.83 6.23 4.83

3-Methylpentane 2.82 2.99 3.70 3.06 3.96 2.82

2-Methyl-1-pentene 0.22 0.32 0.36 0.28 0.34 0.20

1-Hexene 0.19 0.22 0.25 0.24 0.34 0.15

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 3.45 3.94 4.97 3.98 5.38 3.61

trans-2-Hexene 0.18 0.19 0.27 0.25 0.39 0.16

cis-2-Hexene 0.14 0.11 0.18 0.20 0.20 0.14

Methylcyclopentane 1.62 1.97 2.41 2.01 2.59 1.75

2,4-Dimethylpentane 0.89 0.98 1.17 0.98 1.16 0.86

Benzene 4.12 4.08 5.02 4.22 5.29 4.19

Cyclohexane 0.89 15.09 18.85 13.23 17.15 1.13

2-Methylhexane 2.13 2.12 2.57 1.92 2.84 1.99

2,3-Dimethylpentane 1.15 1.12 1.33 1.26 1.50 1.04

3-Methylhexane 1.80 1.93 2.44 2.00 2.61 1.90

1-Heptene ND ND ND ND ND 0.41

2,2,4-Trimethylpentane 2.51 2.84 3.64 2.96 3.86 2.61

n-Heptane 1.85 1.71 2.14 1.57 2.24 1.58

Methylcyclohexane 0.98 1.12 1.43 1.14 1.46 1.19

2,2,3-Trimethylpentane 0.55 0.76 0.90 0.67 0.96 0.55

2,3,4-Trimethylpentane 1.02 1.21 1.54 1.21 1.55 0.97

Toluene 10.01 15.02 19.02 14.41 18.86 10.57

2-Methylheptane 0.73 1.21 1.28 1.01 1.29 0.79

3-Methylheptane 0.76 0.91 1.09 0.91 1.18 0.72

1-Octene 0.05 0.06 0.13 0.07 0.15 ND

n-Octane 0.99 1.41 1.81 1.53 1.86 1.03

Ethylbenzene 1.93 4.47 5.56 3.81 4.82 1.92

m-Xylene/p-Xylene 5.85 14.47 18.26 11.95 15.35 5.64

Styrene 0.86 1.83 2.25 1.15 1.08 2.38

o-Xylene 2.17 5.62 6.96 4.38 5.55 2.08

1-Nonene 0.11 0.29 0.26 0.19 0.24 0.08

n-Nonane 0.69 1.54 1.92 1.45 1.82 0.78

Isopropylbenzene 0.40 0.70 0.75 0.60 0.62 0.45

a-Pinene 0.17 0.47 0.59 0.45 0.68 0.20

n-Propylbenzene 0.68 1.89 2.38 1.18 1.40 0.67

m-Ethyltoluene 1.65 6.43 8.08 3.29 4.09 1.65

p-Ethyltoluene 1.07 3.33 4.14 1.92 2.30 1.15

1,3,5-Trimethylbenzene 0.93 3.54 4.43 1.86 2.20 0.98

o-Ethyltoluene 0.80 3.05 3.32 1.49 1.73 0.93

b-Pinene 0.29 0.64 0.72 0.41 0.54 0.44

1,2,4-Trimethylbenzene 2.33 11.70 14.49 4.89 5.95 2.38

1-Decene ND ND ND ND ND ND

n-Decane 0.68 1.93 2.73 1.25 1.82 0.79

1,2,3-Trimethylbenzene 0.61 2.95 3.42 1.14 1.38 0.52

m-Diethylbenzene 0.38 1.64 1.92 0.50 0.62 0.43

p-Diethylbenzene 0.29 1.48 2.48 0.44 0.48 0.33

1-Undecene ND 0.25 0.31 0.09 0.09 ND

n-Undecane 0.52 2.70 3.09 0.77 0.88 0.57

1-Dodecene ND 0.37 0.39 0.03 0.03 0.03

n-Dodecane 0.11 1.55 1.82 0.23 0.22 0.21

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.08 0.27 0.24 0.04 ND 0.04

TNMOC (w/ unknowns) 169.08 299.22 371.92 231.56 295.49 183.34

TNMOC (speciated) 142.68 230.60 286.70 198.40 255.07 140.78
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14492 14493 14515 14543 14565D1 14565R1

Sampling Date: 8/26/98 8/27/98 8/28/98 8/31/98 9/1/98 9/1/98

Analysis Date: VOID 10/19/98 10/15/98 10/15/98 10/16/98 10/22/98

Compound

Ethylene 4.69 7.12 4.74 7.46 7.43

Acetylene 3.61 4.27 3.27 4.91 5.01

Ethane 8.73 8.17 12.62 11.51 11.66

Propylene 2.17 3.19 2.22 3.36 3.45

Propane 8.50 11.19 9.83 11.72 11.96

Propyne 0.10 0.17 0.18 0.19 0.28

Isobutane 2.58 4.23 3.60 3.53 3.57

Isobutene/1-Butene 2.49 3.35 3.08 4.06 4.21

1,3-Butadiene 0.41 0.60 0.37 0.79 0.72

n-Butane 7.51 6.02 6.52 7.68 7.77

trans-2-Butene 0.80 0.55 0.44 0.59 0.61

cis-2-Butene 0.82 0.60 0.58 0.67 0.70

3-Methyl-1-butene 0.32 0.25 0.15 0.25 0.31

Isopentane 25.61 24.87 27.87 25.44 25.99

1-Pentene 1.19 0.84 0.65 0.85 0.96

2-Methyl-1-butene 1.54 0.93 0.76 1.09 1.16

n-Pentane 9.02 7.52 6.17 7.61 7.77

Isoprene 2.02 1.70 1.77 2.48 2.51

trans-2-Pentene 2.25 1.28 1.01 1.44 1.45

cis-2-Pentene 1.35 0.78 0.65 0.92 0.91

2-Methyl-2-butene 2.62 1.36 0.88 1.52 1.56

2,2-Dimethylbutane 1.44 1.42 1.13 1.33 1.30

Cyclopentene 1.11 0.70 0.64 1.77 1.72

4-Methyl-1-pentene 0.16 0.03 0.06 0.08 0.08

Cyclopentane 1.41 1.02 0.73 0.90 0.99

2,3-Dimethylbutane 15.18 9.54 7.62 10.82 12.06

2-Methylpentane 9.19 6.59 5.18 6.76 7.15

3-Methylpentane 5.88 3.93 3.21 4.26 4.29

2-Methyl-1-pentene 0.53 0.28 0.23 0.25 0.31

1-Hexene 0.41 0.24 0.24 0.24 0.24

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 7.86 4.81 3.96 5.16 5.29

trans-2-Hexene 0.53 0.31 0.16 0.36 0.34

cis-2-Hexene 0.35 0.17 0.16 0.21 0.20

Methylcyclopentane 3.60 2.50 1.98 2.55 2.54

2,4-Dimethylpentane 1.49 1.11 0.94 1.18 1.24

Benzene 6.52 5.13 4.56 6.45 6.52

Cyclohexane 1.34 1.15 1.24 1.78 1.91

2-Methylhexane 3.20 2.81 2.25 3.06 3.02

2,3-Dimethylpentane 1.51 1.37 1.29 1.51 1.45

3-Methylhexane 3.46 2.55 2.34 3.00 2.98

1-Heptene ND ND ND ND ND

2,2,4-Trimethylpentane 4.59 3.69 3.12 4.50 4.57

n-Heptane 3.22 1.87 1.94 2.41 2.50

Methylcyclohexane 1.53 1.35 1.28 1.33 1.42

2,2,3-Trimethylpentane 1.04 0.95 0.73 1.13 1.06

2,3,4-Trimethylpentane 1.83 1.53 1.28 1.79 1.85

Toluene 23.28 19.82 12.76 16.99 17.37

2-Methylheptane 1.13 0.96 0.80 0.97 1.03

3-Methylheptane 1.17 0.93 0.83 1.06 1.12

1-Octene 0.09 0.15 0.07 0.03 0.03

n-Octane 1.57 1.27 1.15 1.24 1.35

Ethylbenzene 4.05 2.98 2.29 3.02 3.09

m-Xylene/p-Xylene 13.26 9.24 6.92 9.18 9.35

Styrene 1.25 1.03 0.84 1.11 1.18

o-Xylene 4.65 3.38 2.68 3.48 3.61

1-Nonene 0.20 0.16 0.16 0.11 0.15

n-Nonane 1.07 0.97 0.90 0.90 0.95

Isopropylbenzene 0.53 0.44 0.43 0.42 0.52

a-Pinene 0.38 0.44 0.25 0.28 0.27

n-Propylbenzene 1.17 0.91 0.88 0.97 0.99

m-Ethyltoluene 3.51 2.74 2.17 2.75 2.87

p-Ethyltoluene 2.02 1.73 1.34 1.56 1.65

1,3,5-Trimethylbenzene 1.84 1.62 1.19 1.52 1.71

o-Ethyltoluene 1.83 1.18 1.11 1.34 1.43

b-Pinene 0.69 0.64 0.45 0.38 0.47

1,2,4-Trimethylbenzene 5.03 3.9392 3.15 4.21 4.35

1-Decene ND ND ND ND ND

n-Decane 1.06 1.27 1.06 0.91 0.93

1,2,3-Trimethylbenzene 1.21 0.98 0.70 0.96 1.07

m-Diethylbenzene 0.64 0.40 0.50 0.61 0.66

p-Diethylbenzene 0.55 0.53 0.43 0.50 0.49

1-Undecene 0.07 0.07 0.07 0.08 0.07

n-Undecane 0.89 1.20 0.98 0.95 1.03

1-Dodecene 0.23 0.24 0.12 0.09 0.20

n-Dodecane 0.41 0.68 0.40 0.45 0.51

1-Tridecene ND 0.04 0.05 0.04 0.06

n-Tridecane 0.12 0.17 0.10 0.10 0.22

TNMOC (w/ unknowns) 282.43 250.18 210.92 253.87 261.11

TNMOC (speciated) 239.65 204.20 178.35 217.12 223.76
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14566D2 14566R2 14670 14672 14700 14764

Sampling Date: 9/1/98 9/1/98 9/2/98 9/3/98 9/4/98 9/7/98

Analysis Date: 10/16/98 10/22/98 10/2/98 10/3/98 10/4/98 VOID

Compound

Ethylene 7.51 7.59 8.41 5.87 6.39

Acetylene 4.89 5.01 6.21 4.27 5.74

Ethane 11.46 11.75 13.37 15.50 12.68

Propylene 3.27 3.49 3.92 2.87 3.07

Propane 11.71 11.91 12.12 12.33 14.73

Propyne 0.25 0.14 0.29 0.23 0.19

Isobutane 3.46 3.54 3.93 3.82 3.97

Isobutene/1-Butene 3.84 4.10 4.45 3.08 3.84

1,3-Butadiene 0.72 0.73 0.67 0.48 0.55

n-Butane 7.52 7.66 7.66 7.65 14.46

trans-2-Butene 0.60 0.58 0.58 0.44 1.15

cis-2-Butene 0.67 0.70 0.73 0.56 1.24

3-Methyl-1-butene 0.27 0.27 ND 0.16 0.86

Isopentane 25.47 26.22 25.28 28.13 47.29

1-Pentene 0.86 0.96 2.22 0.84 2.16

2-Methyl-1-butene 1.04 1.08 0.97 0.66 2.66

n-Pentane 7.16 7.39 8.08 7.80 17.62

Isoprene 2.43 2.50 1.60 2.26 1.65

trans-2-Pentene 1.33 1.40 1.36 0.96 3.91

cis-2-Pentene 0.88 0.89 0.85 0.62 2.13

2-Methyl-2-butene 1.45 1.50 1.38 0.82 4.66

2,2-Dimethylbutane 1.32 1.37 1.33 1.12 2.33

Cyclopentene 1.77 1.78 1.38 1.78 1.62

4-Methyl-1-pentene 0.06 0.05 0.03 ND 0.28

Cyclopentane 0.95 0.91 1.07 1.05 2.74

2,3-Dimethylbutane 10.54 11.69 9.50 8.49 28.07

2-Methylpentane 6.54 6.83 6.96 6.54 18.51

3-Methylpentane 4.06 4.17 4.32 3.95 11.91

2-Methyl-1-pentene 0.27 0.32 0.30 0.24 1.08

1-Hexene 0.22 0.24 0.24 0.23 0.71

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 4.83 4.99 5.07 4.76 15.50

trans-2-Hexene 0.23 0.26 0.26 0.15 1.01

cis-2-Hexene 0.18 0.19 0.19 0.13 0.62

Methylcyclopentane 2.37 2.47 2.61 2.45 7.20

2,4-Dimethylpentane 1.16 1.21 1.18 1.11 2.56

Benzene 6.45 6.57 5.42 4.36 9.02

Cyclohexane 1.18 1.34 1.30 4.37 2.56

2-Methylhexane 2.91 3.19 2.77 2.74 7.24

2,3-Dimethylpentane 1.35 1.57 1.36 1.39 3.02

3-Methylhexane 2.89 2.98 2.79 2.53 7.14

1-Heptene ND ND ND ND ND

2,2,4-Trimethylpentane 4.30 4.50 4.20 3.67 10.66

n-Heptane 2.37 2.48 2.19 2.02 6.42

Methylcyclohexane 1.30 1.36 1.43 1.21 3.19

2,2,3-Trimethylpentane 1.14 1.15 1.06 0.91 2.80

2,3,4-Trimethylpentane 1.75 1.82 1.72 1.42 4.22

Toluene 16.37 16.86 16.63 13.39 34.85

2-Methylheptane 1.01 1.11 1.33 0.91 2.47

3-Methylheptane 0.97 1.11 1.21 0.93 2.37

1-Octene 0.06 0.06 0.10 0.04 0.14

n-Octane 1.16 1.22 1.56 1.18 2.72

Ethylbenzene 2.87 2.92 2.76 2.33 5.97

m-Xylene/p-Xylene 8.50 8.77 8.68 7.18 20.75

Styrene 0.90 1.11 1.06 1.03 0.65

o-Xylene 3.35 3.48 3.21 2.72 7.71

1-Nonene 0.09 0.18 0.12 0.12 0.33

n-Nonane 0.85 0.90 0.99 0.87 1.93

Isopropylbenzene 0.49 0.53 0.44 0.44 0.71

a-Pinene 0.25 0.22 0.28 0.41 0.44

n-Propylbenzene 0.91 0.96 0.79 0.76 1.68

m-Ethyltoluene 2.71 2.77 2.28 1.94 5.55

p-Ethyltoluene 1.59 1.57 1.34 1.12 2.85

1,3,5-Trimethylbenzene 1.47 1.40 1.32 1.13 3.23

o-Ethyltoluene 1.31 1.24 1.06 0.95 2.34

b-Pinene 0.39 0.45 0.48 0.54 0.51

1,2,4-Trimethylbenzene 3.86 4.09 3.40 2.76 8.16

1-Decene ND ND ND ND ND

n-Decane 0.75 0.94 1.15 0.99 1.68

1,2,3-Trimethylbenzene 0.93 1.04 0.79 0.55 1.60

m-Diethylbenzene 0.51 0.59 0.37 0.37 0.80

p-Diethylbenzene 0.50 0.50 0.44 0.31 0.64

1-Undecene 0.07 0.09 0.04 ND 0.14

n-Undecane 0.84 0.89 1.51 0.79 1.41

1-Dodecene 0.09 0.19 0.17 0.19 0.17

n-Dodecane 0.39 0.43 1.23 0.35 0.58

1-Tridecene 0.02 0.08 ND ND ND

n-Tridecane 0.13 0.20 0.27 0.13 0.18

TNMOC (w/ unknowns) 242.34 252.80 257.37 234.03 484.16

TNMOC (speciated) 210.28 218.77 217.71 200.46 413.90
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14704 14773D1 14773R1 14774D2 14774R2 14782

Sampling Date: 9/8/98 9/9/98 9/9/98 9/9/98 9/9/98 9/10/98

Analysis Date: 10/9/98 10/12/98 10/24/98 10/12/98 10/24/98 10/12/98

Compound

Ethylene 4.35 2.44 2.46 2.45 2.35 2.92

Acetylene 3.31 1.86 1.70 1.97 1.73 2.07

Ethane 8.91 5.41 5.45 5.56 5.36 3.63

Propylene 2.06 0.98 1.01 1.00 0.97 1.13

Propane 6.60 4.80 4.89 5.13 4.96 2.80

Propyne 0.12 ND ND ND ND 0.08

Isobutane 2.34 4.57 4.54 4.13 4.09 1.05

Isobutene/1-Butene 3.33 1.44 1.32 1.49 1.32 2.15

1,3-Butadiene 0.38 0.09 0.11 0.12 0.11 0.20

n-Butane 5.20 3.27 3.23 3.51 3.49 4.83

trans-2-Butene 0.48 0.31 0.32 0.30 0.30 0.66

cis-2-Butene 0.53 0.40 0.36 0.39 0.43 0.70

3-Methyl-1-butene 0.16 0.06 0.08 0.09 0.08 0.28

Isopentane 16.54 28.50 28.68 25.00 25.53 19.96

1-Pentene 0.59 0.37 0.34 0.49 0.39 1.12

2-Methyl-1-butene 0.68 0.39 0.36 0.47 0.38 1.20

n-Pentane 4.54 3.49 3.38 3.74 3.53 6.61

Isoprene 2.09 0.88 0.85 0.85 0.91 0.70

trans-2-Pentene 0.97 0.59 0.54 0.57 0.63 1.89

cis-2-Pentene 0.62 0.46 0.41 0.54 0.50 1.16

2-Methyl-2-butene 0.82 0.51 0.50 0.60 0.57 2.25

2,2-Dimethylbutane 0.94 0.76 0.66 0.65 0.78 0.98

Cyclopentene 1.17 0.13 1.14 1.13 1.18 0.84

4-Methyl-1-pentene 0.04 ND ND ND ND 0.11

Cyclopentane 0.75 0.58 0.47 0.56 0.55 1.05

2,3-Dimethylbutane 5.92 3.12 2.90 3.60 3.55 12.13

2-Methylpentane 4.04 2.87 2.92 2.87 3.06 7.07

3-Methylpentane 2.59 1.63 1.56 1.83 1.75 4.56

2-Methyl-1-pentene 0.19 0.11 0.14 0.13 0.14 0.49

1-Hexene 0.24 0.13 0.12 0.12 0.12 0.38

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 3.23 2.64 2.51 2.67 2.58 6.41

trans-2-Hexene 0.21 0.07 0.08 0.10 0.09 0.46

cis-2-Hexene 0.13 0.16 0.07 0.07 0.06 0.29

Methylcyclopentane 1.59 1.17 1.11 1.12 1.07 2.79

2,4-Dimethylpentane 0.81 0.65 0.60 0.65 0.67 1.18

Benzene 3.61 2.67 2.59 2.85 2.81 5.35

Cyclohexane 0.85 4.46 4.39 3.98 4.04 1.59

2-Methylhexane 2.00 1.55 1.52 1.52 1.96 3.01

2,3-Dimethylpentane 1.08 0.99 1.00 0.88 1.08 1.38

3-Methylhexane 1.79 1.79 1.68 1.72 1.73 2.67

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 2.53 1.58 1.42 1.56 1.53 3.35

n-Heptane 1.31 1.90 1.75 1.74 1.67 2.61

Methylcyclohexane 1.10 1.37 1.35 1.27 1.22 1.17

2,2,3-Trimethylpentane 0.61 0.42 0.47 0.46 0.51 0.85

2,3,4-Trimethylpentane 0.98 0.59 0.55 0.73 0.65 1.31

Toluene 9.71 16.04 15.45 14.30 14.10 14.55

2-Methylheptane 0.72 0.69 0.55 0.58 0.51 0.87

3-Methylheptane 0.74 0.64 0.55 0.49 0.63 0.88

1-Octene 0.05 0.06 0.08 0.08 0.04 0.13

n-Octane 0.97 0.82 0.79 0.80 0.82 1.19

Ethylbenzene 2.24 1.61 1.59 1.61 1.57 2.87

m-Xylene/p-Xylene 7.16 4.41 4.21 4.42 4.36 9.74

Styrene 1.14 1.68 1.69 1.04 1.14 1.04

o-Xylene 2.31 1.61 1.52 1.60 1.61 3.31

1-Nonene 0.12 0.15 0.12 0.14 0.14 0.17

n-Nonane 0.69 0.57 0.51 0.61 0.58 0.85

Isopropylbenzene 0.34 0.43 0.38 0.42 0.41 0.47

a-Pinene 0.22 0.08 0.07 0.07 0.10 0.09

n-Propylbenzene 0.61 0.56 0.52 0.56 0.53 0.85

m-Ethyltoluene 1.60 1.16 1.12 1.21 1.21 2.46

p-Ethyltoluene 0.94 0.87 0.82 0.84 0.90 1.49

1,3,5-Trimethylbenzene 0.91 0.68 0.62 0.64 0.69 1.21

o-Ethyltoluene 0.93 0.62 0.59 0.66 0.63 1.03

b-Pinene 0.34 0.87 0.87 0.77 0.83 0.54

1,2,4-Trimethylbenzene 2.40 1.68 1.69 1.65 1.69 3.42

1-Decene ND ND ND ND ND ND

n-Decane 0.72 0.79 0.63 0.68 0.54 0.63

1,2,3-Trimethylbenzene 0.51 0.42 0.37 0.44 0.35 0.66

m-Diethylbenzene 0.42 0.45 0.39 0.41 0.43 0.50

p-Diethylbenzene 0.29 0.39 0.26 0.37 0.37 0.43

1-Undecene 0.06 0.04 0.06 ND ND 0.07

n-Undecane 0.65 1.09 1.00 0.74 0.69 0.53

1-Dodecene 0.09 0.31 0.26 0.35 0.29 0.13

n-Dodecane 0.32 0.35 0.35 0.22 0.24 0.29

1-Tridecene ND 0.04 ND ND ND ND

n-Tridecane 0.05 0.07 0.05 0.04 0.06 0.02

TNMOC (w/ unknowns) 166.91 164.63 161.99 153.00 152.19 198.47

TNMOC (speciated) 139.58 131.36 128.63 126.32 125.90 169.83
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14794 14795 14803 14827 14904D1 14904R1

Sampling Date: 9/11/98 9/14/98 9/15/98 9/16/98 9/17/98 9/17/98

Analysis Date: 12/7/98 10/20/98 10/17/98 VOID 10/20/98 10/26/98

Compound

Ethylene 2.65 3.82 3.46 3.28 3.34

Acetylene 1.84 2.43 2.08 2.27 2.25

Ethane 4.83 14.55 5.68 3.66 3.57

Propylene 1.29 1.92 1.60 1.56 1.60

Propane 4.03 12.23 5.98 3.59 3.56

Propyne ND 0.08 0.08 0.06 0.06

Isobutane 1.30 3.05 2.24 1.48 1.43

Isobutene/1-Butene 2.02 2.86 2.05 2.27 2.33

1,3-Butadiene 0.19 0.36 0.31 0.29 0.34

n-Butane 2.71 7.06 4.27 6.26 6.27

trans-2-Butene 0.44 0.48 0.33 0.72 0.72

cis-2-Butene 0.50 0.54 0.50 0.93 0.88

3-Methyl-1-butene ND 0.20 0.11 0.37 0.37

Isopentane 15.97 14.92 11.72 23.91 24.24

1-Pentene 0.51 0.65 0.47 1.32 1.29

2-Methyl-1-butene 0.40 0.68 0.52 1.92 1.85

n-Pentane 2.53 5.45 3.59 13.44 13.37

Isoprene 0.60 1.05 0.93 1.21 1.17

trans-2-Pentene 0.66 1.03 0.81 2.83 2.78

cis-2-Pentene 0.54 0.65 0.57 1.58 1.52

2-Methyl-2-butene 0.41 1.01 0.80 3.53 3.47

2,2-Dimethylbutane 0.84 0.87 0.81 1.44 1.41

Cyclopentene 0.62 0.56 0.34 1.12 1.17

4-Methyl-1-pentene ND 0.05 ND 0.14 0.14

Cyclopentane 0.54 0.74 0.61 1.43 1.49

2,3-Dimethylbutane 3.03 5.46 4.44 16.31 16.38

2-Methylpentane 3.01 4.01 3.28 9.46 9.52

3-Methylpentane 1.53 2.47 2.03 6.22 6.10

2-Methyl-1-pentene 0.14 0.20 0.20 0.72 0.74

1-Hexene 0.13 0.16 0.15 0.47 0.43

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 2.00 3.15 2.44 8.72 8.68

trans-2-Hexene 0.07 0.19 0.14 0.71 0.71

cis-2-Hexene 0.04 0.09 0.07 0.46 0.44

Methylcyclopentane 1.10 1.61 1.37 3.61 3.62

2,4-Dimethylpentane 0.70 0.88 0.65 1.56 1.52

Benzene 2.53 3.50 3.17 6.66 6.16

Cyclohexane 0.81 1.14 0.80 15.08 15.33

2-Methylhexane 1.62 1.93 1.69 3.28 3.36

2,3-Dimethylpentane 0.97 1.01 0.88 1.41 1.47

3-Methylhexane 1.13 1.64 1.34 3.55 3.50

1-Heptene ND ND ND ND ND

2,2,4-Trimethylpentane 1.43 2.41 1.89 4.42 4.39

n-Heptane 1.01 1.42 1.10 3.61 3.56

Methylcyclohexane 0.70 1.07 0.79 1.58 1.56

2,2,3-Trimethylpentane 0.24 0.57 0.48 1.19 1.17

2,3,4-Trimethylpentane 0.72 1.02 0.79 1.85 1.76

Toluene 5.82 9.74 7.71 21.73 21.59

2-Methylheptane 0.54 0.73 0.60 1.14 1.24

3-Methylheptane 0.46 0.55 0.62 1.20 1.24

1-Octene 0.05 0.05 0.05 0.08 0.06

n-Octane 0.68 0.86 0.71 1.59 1.59

Ethylbenzene 1.37 1.86 1.55 4.09 4.02

m-Xylene/p-Xylene 3.84 5.58 4.84 14.07 13.87

Styrene 1.22 1.02 0.88 0.89 0.96

o-Xylene 1.53 2.14 1.81 4.80 4.75

1-Nonene ND 0.10 ND 0.13 0.14

n-Nonane 0.58 0.65 0.52 1.06 1.06

Isopropylbenzene 0.52 0.48 0.38 0.54 0.46

a-Pinene 0.64 0.80 0.41 0.35 0.38

n-Propylbenzene 0.66 0.71 0.58 1.13 1.08

m-Ethyltoluene 1.35 2.08 1.59 3.41 3.45

p-Ethyltoluene 1.00 1.16 1.03 2.02 2.00

1,3,5-Trimethylbenzene 0.80 0.94 0.89 1.64 1.72

o-Ethyltoluene 0.74 0.98 0.78 1.39 1.44

b-Pinene 0.58 0.51 0.41 0.27 0.32

1,2,4-Trimethylbenzene 1.54 2.68 2.20 4.59 4.91

1-Decene ND ND ND ND ND

n-Decane 0.43 0.70 0.48 0.90 0.90

1,2,3-Trimethylbenzene 0.38 0.71 0.56 1.04 1.27

m-Diethylbenzene 0.41 0.48 0.43 0.52 0.85

p-Diethylbenzene 0.64 0.44 0.29 0.50 0.74

1-Undecene 0.10 0.06 0.02 0.08 0.06

n-Undecane 0.60 0.67 0.56 0.92 1.06

1-Dodecene 0.23 0.10 0.10 0.10 0.04

n-Dodecane 0.20 0.33 0.22 0.28 0.29

1-Tridecene ND 0.02 ND ND ND

n-Tridecane 0.08 0.13 0.08 0.05 0.06

TNMOC (w/ unknowns) 120.63 174.50 128.72 272.21 273.96

TNMOC (speciated) 95.26 148.45 107.86 241.98 242.58
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 14905D2 14905R2 14902 14972 14973 14998

Sampling Date: 9/17/98 9/17/98 9/18/98 9/21/98 9/23/98 9/24/98

Analysis Date: 10/21/98 10/26/98 10/15/98 10/21/98 10/21/98 10/21/98

Compound

Ethylene 3.41 3.34 7.82 4.43 3.11 3.30

Acetylene 2.30 2.27 5.51 3.03 1.99 2.29

Ethane 3.64 3.61 8.25 16.59 5.93 11.19

Propylene 1.63 1.70 3.69 2.12 1.40 1.43

Propane 3.62 3.65 6.91 12.66 5.94 10.67

Propyne 0.11 0.11 0.32 0.08 0.06 0.11

Isobutane 1.48 1.52 2.92 3.65 1.53 3.83

Isobutene/1-Butene 2.26 2.25 4.38 2.85 2.25 2.26

1,3-Butadiene 0.31 0.31 0.79 0.39 0.23 0.24

n-Butane 6.20 6.25 5.79 6.88 4.58 13.17

trans-2-Butene 0.80 0.72 0.69 0.41 0.47 1.12

cis-2-Butene 0.87 0.88 0.80 0.48 0.56 1.16

3-Methyl-1-butene 0.39 0.38 0.28 0.15 0.20 0.61

Isopentane 25.88 25.89 27.09 19.23 19.10 38.34

1-Pentene 1.21 1.35 0.95 0.61 0.81 2.02

2-Methyl-1-butene 1.84 1.81 1.21 0.63 0.80 2.73

n-Pentane 14.87 14.79 7.23 5.78 5.41 15.44

Isoprene 1.21 1.16 1.05 1.50 0.77 1.00

trans-2-Pentene 2.72 2.65 1.75 0.95 1.27 4.13

cis-2-Pentene 1.53 1.51 1.02 0.64 0.80 2.28

2-Methyl-2-butene 3.40 3.36 1.78 0.84 1.38 5.19

2,2-Dimethylbutane 1.24 1.28 1.15 0.97 1.03 1.82

Cyclopentene 1.08 1.05 0.67 0.76 0.68 1.69

4-Methyl-1-pentene 0.14 0.14 0.09 ND ND 0.25

Cyclopentane 1.50 1.47 1.00 0.78 0.71 2.33

2,3-Dimethylbutane 16.02 15.86 11.17 6.10 7.45 27.55

2-Methylpentane 9.46 9.39 6.61 4.45 4.73 15.78

3-Methylpentane 6.07 6.02 4.19 2.70 3.03 10.14

2-Methyl-1-pentene 0.63 0.63 0.36 0.19 0.23 1.18

1-Hexene 0.43 0.43 0.30 0.18 0.21 0.79

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 8.57 8.88 4.78 3.36 3.90 14.98

trans-2-Hexene 0.70 0.85 0.34 0.14 0.27 1.13

cis-2-Hexene 0.44 0.44 0.21 0.11 0.19 0.71

Methylcyclopentane 3.63 3.71 2.61 1.85 1.84 5.98

2,4-Dimethylpentane 1.40 1.53 1.36 0.81 0.90 2.24

Benzene 6.86 6.07 6.48 4.06 4.15 10.64

Cyclohexane 20.05 19.97 1.21 0.96 20.39 2.24

2-Methylhexane 3.83 3.65 2.53 1.69 1.77 5.34

2,3-Dimethylpentane 1.61 1.48 1.48 0.98 0.98 2.12

3-Methylhexane 3.49 3.47 2.75 1.86 1.94 5.71

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 4.21 4.23 5.56 2.69 2.70 6.59

n-Heptane 3.56 3.48 2.32 1.52 1.88 6.06

Methylcyclohexane 1.57 1.54 1.52 1.10 1.05 2.64

2,2,3-Trimethylpentane 1.12 1.14 1.24 0.68 0.70 1.86

2,3,4-Trimethylpentane 1.71 1.83 2.18 1.10 1.12 2.50

Toluene 22.14 21.95 20.32 11.79 14.16 31.70

2-Methylheptane 1.13 1.14 1.22 0.72 0.77 1.73

3-Methylheptane 1.13 1.13 1.22 0.68 0.66 1.83

1-Octene 0.04 0.09 0.15 0.05 0.10 0.16

n-Octane 1.58 1.57 1.48 1.07 1.12 2.75

Ethylbenzene 4.15 4.07 3.48 2.21 2.88 6.02

m-Xylene/p-Xylene 14.11 13.88 11.08 6.80 9.31 21.98

Styrene 1.59 1.58 1.31 1.13 1.61 1.09

o-Xylene 4.89 4.79 4.21 2.56 3.24 7.09

1-Nonene 0.20 0.12 0.20 0.09 0.14 0.29

n-Nonane 1.08 1.09 1.33 0.93 0.92 1.61

Isopropylbenzene 0.52 0.52 0.55 0.48 0.57 0.65

a-Pinene 0.41 0.37 1.04 0.44 0.23 0.17

n-Propylbenzene 1.17 1.13 1.09 0.93 0.89 1.66

m-Ethyltoluene 3.43 3.40 3.55 2.28 2.32 5.03

p-Ethyltoluene 2.05 1.94 2.00 1.48 1.42 2.97

1,3,5-Trimethylbenzene 1.63 1.72 2.01 1.19 1.26 2.36

o-Ethyltoluene 1.35 1.34 1.42 1.14 1.05 1.94

b-Pinene 0.70 0.71 0.81 0.60 0.74 0.51

1,2,4-Trimethylbenzene 4.61 4.74 5.29 3.37 3.18 6.89

1-Decene ND ND ND ND ND ND

n-Decane 1.15 1.14 2.00 1.11 1.50 0.84

1,2,3-Trimethylbenzene 1.10 1.20 1.34 0.92 0.71 1.61

m-Diethylbenzene 0.54 0.73 0.73 0.60 0.42 0.69

p-Diethylbenzene 0.49 0.73 0.61 0.53 0.46 0.70

1-Undecene 0.04 0.06 0.12 0.06 0.10 0.10

n-Undecane 1.35 1.33 1.43 1.07 2.13 0.77

1-Dodecene 0.39 0.16 0.16 0.13 0.30 0.44

n-Dodecane 0.42 0.44 0.51 0.40 0.91 0.41

1-Tridecene ND ND 0.04 ND 0.05 0.07

n-Tridecane 0.04 0.06 0.16 0.10 0.23 0.24

TNMOC (w/ unknowns) 289.27 291.03 275.43 202.27 208.60 413.00

TNMOC (speciated) 252.43 251.16 223.20 167.77 173.84 347.88
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 15022D1 15022R1 15023D2 15023R2 15041D1 15041R1

Sampling Date: 9/25/98 9/25/98 9/25/98 9/25/98 9/28/98 9/28/98

Analysis Date: 10/24/98 10/27/98 10/24/98 10/27/98 10/27/98 10/28/98

Compound

Ethylene 3.75 3.65 3.69 3.63 8.36 8.67

Acetylene 2.39 2.28 2.34 2.32 4.75 4.87

Ethane 9.03 8.89 8.97 9.01 16.01 16.03

Propylene 1.46 1.56 1.50 1.58 3.91 3.91

Propane 8.79 8.67 8.65 8.63 12.80 12.94

Propyne 0.07 0.06 0.15 0.04 0.23 0.27

Isobutane 2.93 2.89 2.87 2.82 4.52 4.60

Isobutene/1-Butene 1.70 1.62 1.72 1.71 4.38 4.82

1,3-Butadiene 0.26 0.26 0.24 0.27 0.81 0.63

n-Butane 6.49 6.45 6.50 6.49 10.49 10.04

trans-2-Butene 0.36 0.32 0.33 0.33 0.67 0.65

cis-2-Butene 0.41 0.43 0.43 0.44 0.73 0.74

3-Methyl-1-butene 1.32 ND 0.51 ND 0.36 0.37

Isopentane 16.85 16.96 16.82 16.26 30.02 30.52

1-Pentene 0.52 0.61 0.44 0.53 1.01 1.12

2-Methyl-1-butene 0.48 0.47 0.44 0.45 1.26 1.32

n-Pentane 5.17 5.09 5.22 5.10 8.63 8.69

Isoprene 0.93 0.95 1.00 0.98 1.85 1.92

trans-2-Pentene 0.65 0.67 0.69 0.72 1.72 1.75

cis-2-Pentene 0.50 0.50 0.52 0.56 1.01 1.02

2-Methyl-2-butene 0.45 0.45 0.51 0.47 1.69 1.72

2,2-Dimethylbutane 0.74 0.77 0.80 0.81 1.41 1.49

Cyclopentene 0.47 0.44 0.49 0.49 1.27 1.23

4-Methyl-1-pentene ND ND ND ND 0.06 0.15

Cyclopentane 0.66 0.67 0.64 0.60 0.98 1.12

2,3-Dimethylbutane 4.76 4.77 4.92 4.89 11.54 11.80

2-Methylpentane 3.56 3.41 3.58 3.55 7.36 7.47

3-Methylpentane 2.39 2.39 2.45 2.45 4.52 4.71

2-Methyl-1-pentene 0.14 0.13 0.17 0.16 0.30 0.33

1-Hexene 0.14 0.15 0.20 0.23 0.27 0.45

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 3.62 3.73 3.62 3.52 5.15 5.44

trans-2-Hexene 0.12 0.18 0.15 0.13 0.31 0.32

cis-2-Hexene 0.08 0.11 0.09 0.09 0.21 0.21

Methylcyclopentane 1.56 1.57 1.61 1.55 2.80 2.88

2,4-Dimethylpentane 0.73 0.71 0.72 0.77 1.32 1.40

Benzene 3.16 3.09 3.18 3.20 6.71 6.82

Cyclohexane 6.54 6.42 5.85 5.83 1.18 1.25

2-Methylhexane 1.76 1.67 1.74 1.72 3.02 2.78

2,3-Dimethylpentane 0.98 0.93 0.90 0.89 1.42 1.45

3-Methylhexane 1.54 1.51 1.59 1.61 3.01 3.01

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 2.33 2.30 2.38 2.45 4.86 5.03

n-Heptane 1.28 1.30 1.31 1.37 2.39 2.50

Methylcyclohexane 0.98 1.00 1.03 1.00 1.33 1.42

2,2,3-Trimethylpentane 0.49 0.49 0.43 0.59 1.14 1.05

2,3,4-Trimethylpentane 0.90 0.90 0.93 0.94 1.99 1.98

Toluene 10.16 10.06 10.18 10.09 18.33 18.60

2-Methylheptane 0.63 0.67 0.56 0.65 1.13 1.28

3-Methylheptane 0.61 0.71 0.64 0.63 1.19 1.20

1-Octene 0.10 0.08 0.07 0.07 0.11 0.20

n-Octane 1.04 1.01 1.03 1.03 1.48 1.52

Ethylbenzene 1.81 1.77 1.76 1.79 3.56 3.58

m-Xylene/p-Xylene 5.33 5.16 5.58 5.43 11.44 11.39

Styrene 1.09 1.00 0.76 0.87 1.35 1.35

o-Xylene 1.98 1.91 2.00 2.00 4.25 4.33

1-Nonene 0.25 0.16 0.15 0.12 0.17 0.33

n-Nonane 0.82 0.84 0.79 0.80 0.97 1.00

Isopropylbenzene 0.41 0.40 0.41 0.40 0.57 0.56

a-Pinene ND ND 0.07 0.09 1.21 1.27

n-Propylbenzene 0.61 0.54 0.64 0.56 1.10 1.16

m-Ethyltoluene 1.53 1.41 1.48 1.47 3.45 3.52

p-Ethyltoluene 1.06 0.89 0.98 0.93 1.92 1.97

1,3,5-Trimethylbenzene 0.94 0.77 0.83 0.84 1.82 1.92

o-Ethyltoluene 0.83 0.65 0.87 0.63 1.79 1.63

b-Pinene 0.55 0.51 0.45 0.44 0.93 1.00

1,2,4-Trimethylbenzene 2.27 2.11 2.31 2.19 5.14 5.51

1-Decene ND ND ND ND ND ND

n-Decane 0.86 0.79 0.79 0.78 1.24 1.28

1,2,3-Trimethylbenzene 0.50 0.47 0.50 0.49 1.30 1.26

m-Diethylbenzene 0.39 0.39 0.35 0.42 0.71 0.69

p-Diethylbenzene 0.31 0.34 0.28 0.37 0.58 0.66

1-Undecene 0.02 0.03 0.09 0.06 0.13 0.29

n-Undecane 0.87 0.83 0.75 0.75 1.22 1.24

1-Dodecene 0.35 0.09 0.07 0.13 0.13 0.18

n-Dodecane 0.38 0.25 0.28 0.22 0.50 0.75

1-Tridecene ND ND ND ND ND 0.11

n-Tridecane 0.09 0.07 0.05 0.07 0.27 0.41

TNMOC (w/ unknowns) 172.61 168.22 164.15 163.50 292.76 300.22

TNMOC (speciated) 139.20 135.28 137.03 135.49 247.75 253.10
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 15042D2 15042R2 15081 15062D1 15062R1 15063D2

Sampling Date: 9/28/98 9/28/98 9/29/98 9/30/98 9/30/98 9/30/98

Analysis Date: 10/27/98 10/28/98 10/27/98 10/28/98 10/28/98 10/28/98

Compound

Ethylene 8.41 8.74 13.06 6.64 6.57 6.73

Acetylene 4.90 5.04 7.98 4.85 4.86 4.99

Ethane 15.88 16.17 18.67 16.06 15.72 16.28

Propylene 4.00 4.11 6.12 3.09 3.05 3.11

Propane 12.70 12.88 12.22 11.23 11.08 11.24

Propyne 0.28 0.25 0.46 0.25 0.19 0.20

Isobutane 4.53 4.57 6.51 3.34 3.34 3.25

Isobutene/1-Butene 4.37 4.62 6.77 3.32 3.17 3.30

1,3-Butadiene 0.75 0.87 1.32 0.54 0.58 0.54

n-Butane 10.36 10.62 24.52 9.27 9.23 9.36

trans-2-Butene 0.68 0.65 1.59 0.77 0.59 0.65

cis-2-Butene 0.73 0.73 1.50 0.77 0.66 0.72

3-Methyl-1-butene 0.34 0.35 0.71 0.36 0.34 0.36

Isopentane 31.49 32.31 54.50 27.91 27.86 29.63

1-Pentene 1.15 1.15 1.92 1.13 1.06 1.11

2-Methyl-1-butene 1.21 1.29 2.60 1.37 1.32 1.33

n-Pentane 8.39 8.62 16.16 9.26 9.19 9.35

Isoprene 1.85 1.93 3.08 1.62 1.59 1.63

trans-2-Pentene 1.70 1.72 3.85 1.83 1.84 1.95

cis-2-Pentene 1.02 1.03 2.03 1.10 1.06 1.12

2-Methyl-2-butene 1.68 1.74 4.03 1.87 1.84 1.96

2,2-Dimethylbutane 1.38 1.42 2.07 1.40 1.24 1.43

Cyclopentene 1.30 1.30 1.40 0.86 0.82 0.99

4-Methyl-1-pentene 0.11 0.08 0.24 0.11 0.12 0.13

Cyclopentane 1.00 1.17 1.81 1.27 1.27 1.28

2,3-Dimethylbutane 11.67 11.94 26.17 13.67 13.36 13.97

2-Methylpentane 7.45 7.59 13.49 8.31 8.31 8.64

3-Methylpentane 4.52 4.57 8.32 5.23 5.27 5.39

2-Methyl-1-pentene 0.34 0.37 0.77 0.40 0.43 0.46

1-Hexene 0.33 0.33 0.51 0.28 0.41 0.36

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.98 5.09 8.68 6.71 6.30 6.57

trans-2-Hexene 0.30 0.30 0.76 0.50 0.40 0.41

cis-2-Hexene 0.18 0.21 0.40 0.23 0.22 0.27

Methylcyclopentane 2.79 2.75 4.79 3.20 3.14 3.21

2,4-Dimethylpentane 1.36 1.21 2.17 1.31 1.32 1.30

Benzene 6.82 7.01 10.10 6.62 6.47 6.76

Cyclohexane 1.80 1.84 1.76 1.93 1.99 1.34

2-Methylhexane 3.07 3.26 4.51 3.41 3.43 3.25

2,3-Dimethylpentane 1.42 1.56 2.27 1.50 1.49 1.50

3-Methylhexane 2.89 3.04 5.05 3.42 3.36 3.44

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 4.88 4.89 9.01 4.94 4.86 5.36

n-Heptane 2.40 2.46 4.08 3.09 3.05 3.14

Methylcyclohexane 1.48 1.40 2.28 1.79 1.69 1.68

2,2,3-Trimethylpentane 1.00 1.08 2.04 1.24 1.22 1.29

2,3,4-Trimethylpentane 1.92 1.95 3.64 1.91 1.87 1.94

Toluene 18.11 18.40 33.99 26.35 25.87 22.42

2-Methylheptane 1.10 1.14 2.44 1.30 1.28 1.34

3-Methylheptane 1.16 1.23 2.19 1.30 1.28 1.27

1-Octene 0.11 0.09 0.17 0.15 0.08 0.08

n-Octane 1.46 1.51 2.74 1.67 1.62 1.64

Ethylbenzene 3.52 3.58 5.81 3.77 3.67 3.84

m-Xylene/p-Xylene 11.17 11.17 19.23 12.35 12.12 12.63

Styrene 1.41 1.38 1.92 1.90 2.11 2.42

o-Xylene 4.16 4.30 6.83 4.46 4.45 4.57

1-Nonene 0.17 0.23 0.29 0.15 0.26 0.15

n-Nonane 1.05 1.00 1.64 1.30 1.31 1.35

Isopropylbenzene 0.57 0.52 0.74 0.58 0.52 0.52

a-Pinene 1.14 1.12 1.52 0.48 0.64 0.41

n-Propylbenzene 1.14 1.21 1.69 1.22 1.27 1.32

m-Ethyltoluene 3.40 3.51 5.50 3.57 3.60 3.69

p-Ethyltoluene 1.96 1.97 3.01 2.12 2.09 2.27

1,3,5-Trimethylbenzene 1.88 1.96 3.10 2.05 2.04 2.13

o-Ethyltoluene 1.69 1.44 2.30 1.51 1.46 1.81

b-Pinene 0.93 0.94 1.04 0.50 0.56 0.65

1,2,4-Trimethylbenzene 5.21 5.21 8.25 5.21 5.22 5.60

1-Decene ND ND ND ND ND ND

n-Decane 1.30 1.27 2.31 1.59 1.51 1.51

1,2,3-Trimethylbenzene 1.44 1.52 2.14 1.38 1.26 1.38

m-Diethylbenzene 0.68 0.69 0.90 0.62 0.72 0.75

p-Diethylbenzene 0.62 0.58 0.78 0.55 0.65 0.53

1-Undecene 0.14 0.17 0.18 0.12 0.08 0.09

n-Undecane 1.21 1.24 1.72 1.22 1.22 1.38

1-Dodecene 0.14 0.20 0.19 0.15 0.17 0.34

n-Dodecane 0.42 0.61 0.84 0.55 0.58 0.62

1-Tridecene ND 0.09 ND ND 0.05 ND

n-Tridecane 0.14 0.15 0.23 0.16 0.13 0.11

TNMOC (w/ unknowns) 294.45 304.99 497.97 307.25 302.26 307.30

TNMOC (speciated) 249.22 254.63 419.58 242.14 254.99 243.45
SNMOC 1998 REPORT

SITE CODE: CAMS 5

All concentrations reported in ppbC

Sample No.: 15063R2

Sampling Date: 9/30/98

Analysis Date: 10/29/98

Compound

Ethylene 6.80

Acetylene 4.92

Ethane 15.80

Propylene 3.04

Propane 11.10

Propyne 0.19

Isobutane 3.26

Isobutene/1-Butene 3.31

1,3-Butadiene 0.58

n-Butane 9.19

trans-2-Butene 0.62

cis-2-Butene 0.75

3-Methyl-1-butene 0.33

Isopentane 30.01

1-Pentene 1.14

2-Methyl-1-butene 1.30

n-Pentane 9.15

Isoprene 1.57

trans-2-Pentene 1.88

cis-2-Pentene 1.12

2-Methyl-2-butene 1.92

2,2-Dimethylbutane 1.18

Cyclopentene 0.85

4-Methyl-1-pentene 0.11

Cyclopentane 1.26

2,3-Dimethylbutane 13.63

2-Methylpentane 8.61

3-Methylpentane 5.32

2-Methyl-1-pentene 0.45

1-Hexene 0.37

2-Ethyl-1-butene ND

n-Hexane 6.55

trans-2-Hexene 0.45

cis-2-Hexene 0.28

Methylcyclopentane 3.18

2,4-Dimethylpentane 1.34

Benzene 6.64

Cyclohexane 1.29

2-Methylhexane 3.18

2,3-Dimethylpentane 1.49

3-Methylhexane 3.34

1-Heptene ND

2,2,4-Trimethylpentane 5.30

n-Heptane 3.05

Methylcyclohexane 1.65

2,2,3-Trimethylpentane 1.23

2,3,4-Trimethylpentane 1.93

Toluene 22.26

2-Methylheptane 1.40

3-Methylheptane 1.31

1-Octene 0.08

n-Octane 1.60

Ethylbenzene 3.78

m-Xylene/p-Xylene 12.52

Styrene 2.32

o-Xylene 4.49

1-Nonene 0.21

n-Nonane 1.30

Isopropylbenzene 0.53

a-Pinene 0.47

n-Propylbenzene 1.25

m-Ethyltoluene 3.63

p-Ethyltoluene 2.30

1,3,5-Trimethylbenzene 2.15

o-Ethyltoluene 1.40

b-Pinene 0.75

1,2,4-Trimethylbenzene 5.62

1-Decene ND

n-Decane 1.46

1,2,3-Trimethylbenzene 1.45

m-Diethylbenzene 0.85

p-Diethylbenzene 0.75

1-Undecene 0.12

n-Undecane 1.37

1-Dodecene 0.35

n-Dodecane 0.65

1-Tridecene ND

n-Tridecane 0.16

TNMOC (w/ unknowns) 307.93

TNMOC (speciated) 257.23
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13014 13017 13055 13089 13090 13205

Sampling Date: 6/22/98 6/24/98 6/25/98 6/26/98 6/29/98 6/30/98

Analysis Date: 7/9/98 7/10/98 7/10/98 7/10/98 7/10/98 7/10/98

Compound

Ethylene 1.98 2.19 2.74 4.81 6.08 3.03

Acetylene 1.22 2.09 1.94 12.59 3.31 2.67

Ethane 2.92 4.12 5.21 8.34 6.09 5.91

Propylene 1.03 1.54 1.76 2.48 2.78 2.52

Propane 4.01 4.57 8.55 15.85 9.32 6.56

Propyne 0.10 0.15 0.20 0.37 0.31 0.29

Isobutane 0.99 3.74 1.85 3.62 4.36 1.48

Isobutene/1-Butene 1.81 2.60 2.32 2.87 2.78 2.69

1,3-Butadiene 0.16 0.19 0.32 0.50 0.39 0.42

n-Butane 5.75 20.06 5.07 5.20 7.26 3.79

trans-2-Butene 0.09 1.62 0.18 0.23 0.19 0.22

cis-2-Butene 0.12 1.70 0.18 0.23 0.18 0.22

3-Methyl-1-butene 0.92 1.97 0.25 0.18 1.20 0.28

Isopentane 16.27 55.55 11.35 19.02 18.82 15.09

1-Pentene 0.14 2.51 0.23 0.42 0.34 0.33

2-Methyl-1-butene 0.36 4.16 0.54 0.68 0.49 0.66

n-Pentane 1.90 18.56 3.34 5.19 5.10 3.80

Isoprene 1.51 1.55 1.34 1.40 1.37 1.27

trans-2-Pentene 0.30 4.62 0.52 0.72 0.51 0.68

cis-2-Pentene 0.11 2.39 0.21 0.33 0.23 0.30

2-Methyl-2-butene 0.28 6.57 0.53 0.73 0.52 0.76

2,2-Dimethylbutane 0.17 2.27 0.36 0.97 0.56 0.46

Cyclopentene 0.39 1.20 0.48 0.43 1.11 0.71

4-Methyl-1-pentene 0.03 0.29 0.02 0.07 ND 0.06

Cyclopentane 0.16 2.24 0.31 0.65 0.49 0.35

2,3-Dimethylbutane 2.35 34.90 3.57 6.74 5.15 4.73

2-Methylpentane 1.77 17.42 2.96 6.84 5.61 4.15

3-Methylpentane 0.77 11.47 1.50 3.83 2.10 1.96

2-Methyl-1-pentene 0.06 0.97 0.13 0.18 0.14 0.16

1-Hexene 0.11 0.66 0.17 0.21 0.19 0.21

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.06 12.82 2.05 3.86 2.92 2.45

trans-2-Hexene 0.07 1.01 0.09 0.15 0.15 0.22

cis-2-Hexene 0.03 0.56 0.07 0.09 0.06 0.09

Methylcyclopentane 0.55 5.28 1.11 1.99 1.57 1.30

2,4-Dimethylpentane 0.18 1.56 0.35 0.67 0.48 0.47

Benzene 1.56 5.36 2.52 4.41 3.69 3.15

Cyclohexane 0.25 8.71 0.47 1.18 0.93 0.48

2-Methylhexane 1.11 4.98 1.96 2.62 2.22 1.84

2,3-Dimethylpentane 0.17 1.89 0.61 1.03 0.78 0.68

3-Methylhexane 0.71 4.95 1.16 2.64 1.64 1.52

1-Heptene 0.07 ND ND ND ND ND

2,2,4-Trimethylpentane 1.03 4.96 2.00 3.28 2.48 2.69

n-Heptane 0.60 3.63 0.99 4.36 1.81 1.45

Methylcyclohexane 0.45 1.73 0.82 3.41 1.52 1.02

2,2,3-Trimethylpentane 0.29 1.24 0.48 1.07 0.68 0.64

2,3,4-Trimethylpentane 0.44 1.57 0.74 1.19 0.93 0.99

Toluene 3.53 15.33 6.75 13.68 8.84 8.65

2-Methylheptane 0.17 1.09 0.41 1.03 0.50 0.48

3-Methylheptane 0.15 0.81 0.30 0.66 0.41 0.36

1-Octene 0.14 0.13 0.07 0.08 0.11 0.07

n-Octane 0.34 1.34 0.57 1.20 0.79 0.58

Ethylbenzene 0.63 2.67 1.27 4.13 1.71 1.83

m-Xylene/p-Xylene 1.95 9.52 4.04 15.14 5.38 6.20

Styrene 0.77 1.49 0.74 4.90 1.33 0.65

o-Xylene 0.77 3.45 1.47 4.31 1.95 2.22

1-Nonene 0.11 0.17 0.08 0.22 0.09 0.12

n-Nonane 0.23 0.76 0.35 0.80 0.44 0.40

Isopropylbenzene ND 0.19 0.06 0.16 0.23 0.09

a-Pinene 0.26 0.31 0.35 0.35 0.27 0.31

n-Propylbenzene 0.20 0.86 0.28 0.62 0.43 0.36

m-Ethyltoluene 0.90 2.80 1.15 2.14 1.51 1.48

p-Ethyltoluene 0.39 1.47 0.53 1.08 0.92 0.70

1,3,5-Trimethylbenzene 0.23 1.39 0.53 1.15 0.59 0.70

o-Ethyltoluene 0.22 1.32 0.49 1.08 0.58 0.67

b-Pinene 0.35 0.77 0.38 0.24 0.74 0.28

1,2,4-Trimethylbenzene 0.89 3.96 1.47 3.13 1.80 1.96

1-Decene ND ND ND ND ND ND

n-Decane 0.23 1.28 0.32 1.06 0.66 0.41

1,2,3-Trimethylbenzene 0.16 1.04 0.26 0.70 0.33 0.34

m-Diethylbenzene 0.05 0.78 0.08 0.17 0.13 0.10

p-Diethylbenzene 0.06 0.44 0.09 0.12 0.09 0.12

1-Undecene ND 0.51 ND 0.04 ND ND

n-Undecane 0.23 17.14 0.13 0.32 0.25 0.13

1-Dodecene 2.31 ND ND ND ND ND

n-Dodecane ND 7.34 0.17 3.81 ND ND

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.27 ND ND ND 0.04 ND

TNMOC (w/ unknowns) 112.47 462.29 132.73 238.78 211.31 149.07

TNMOC (speciated) 71.87 352.47 95.92 199.91 138.96 113.94
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13210 13203D1 13203R1 13204D2 13204R2 13214

Sampling Date: 7/1/98 7/2/98 7/2/98 7/2/98 7/2/98 7/3/98

Analysis Date: 7/11/98 7/8/98 7/9/98 7/9/98 7/9/98 7/11/98

Compound

Ethylene 4.10 6.04 5.72 0.99 6.42 4.02

Acetylene 3.84 13.32 12.32 12.28 11.46 6.90

Ethane 4.69 6.20 8.97 7.45 7.87 8.92

Propylene 3.04 3.49 3.25 3.22 3.04 2.80

Propane 12.80 10.07 9.47 9.34 8.75 13.87

Propyne 0.43 0.55 0.49 0.42 0.43 0.42

Isobutane 2.32 2.67 2.39 2.42 2.27 4.77

Isobutene/1-Butene 3.51 4.38 3.90 3.87 3.77 3.06

1,3-Butadiene 0.22 0.26 0.67 0.43 0.55 0.43

n-Butane 4.58 6.07 7.67 5.39 4.98 10.83

trans-2-Butene 0.42 0.41 0.42 0.38 0.35 0.25

cis-2-Butene 0.44 0.39 0.37 0.36 0.35 0.27

3-Methyl-1-butene 0.96 1.05 0.84 0.81 0.86 0.96

Isopentane 26.46 25.49 22.40 21.57 19.78 25.85

1-Pentene 0.65 0.49 0.66 0.67 0.48 0.49

2-Methyl-1-butene 0.96 0.98 0.98 0.99 0.74 0.81

n-Pentane 6.08 8.23 7.15 7.22 6.61 7.62

Isoprene 1.38 2.29 2.12 1.87 1.95 2.14

trans-2-Pentene 1.11 1.23 1.09 1.15 1.05 0.91

cis-2-Pentene 0.50 0.58 0.53 0.52 0.48 0.40

2-Methyl-2-butene 1.15 1.49 1.33 1.20 1.13 0.77

2,2-Dimethylbutane 0.76 0.62 0.74 0.72 0.65 0.87

Cyclopentene 1.47 1.60 1.54 1.27 1.07 2.17

4-Methyl-1-pentene 0.03 0.09 0.04 0.04 0.04 0.05

Cyclopentane 0.71 0.65 0.70 0.69 0.63 0.73

2,3-Dimethylbutane 7.90 9.35 8.59 8.20 7.62 7.89

2-Methylpentane 7.13 6.37 5.87 6.31 5.70 7.18

3-Methylpentane 3.71 3.77 3.35 3.44 3.02 3.87

2-Methyl-1-pentene 0.21 0.32 0.30 0.31 0.26 0.22

1-Hexene 0.29 0.32 0.25 0.25 0.23 0.29

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.88 4.54 4.20 4.14 3.79 5.43

trans-2-Hexene 0.20 0.26 0.32 0.35 0.32 0.26

cis-2-Hexene 0.12 0.17 0.16 0.15 0.13 0.11

Methylcyclopentane 2.49 2.44 2.25 2.21 1.99 2.37

2,4-Dimethylpentane 0.82 0.73 0.81 0.82 0.70 0.71

Benzene 4.41 5.48 5.28 5.23 4.95 5.18

Cyclohexane 1.72 1.00 0.95 0.90 0.84 1.05

2-Methylhexane 3.80 2.60 2.80 2.76 2.54 2.69

2,3-Dimethylpentane 1.42 0.92 1.11 1.13 1.08 1.06

3-Methylhexane 3.58 2.71 2.53 2.47 2.30 2.55

1-Heptene ND ND ND ND ND 0.21

2,2,4-Trimethylpentane 4.05 4.61 4.43 4.39 4.02 3.44

n-Heptane 3.95 2.30 2.29 2.31 2.15 2.24

Methylcyclohexane 2.74 1.61 1.25 1.48 1.50 1.81

2,2,3-Trimethylpentane 1.13 1.24 1.11 1.11 0.99 0.99

2,3,4-Trimethylpentane 1.40 1.85 1.75 1.65 1.50 1.28

Toluene 17.28 20.00 17.44 17.75 16.11 13.90

2-Methylheptane 0.96 1.07 0.99 1.03 0.92 0.98

3-Methylheptane 0.66 0.82 0.71 0.73 0.67 0.67

1-Octene 0.12 0.08 0.11 0.12 0.12 0.14

n-Octane 1.11 1.39 1.32 1.35 1.29 1.32

Ethylbenzene 2.42 6.97 6.19 6.22 5.69 2.39

m-Xylene/p-Xylene 7.74 25.22 22.54 22.57 20.64 7.67

Styrene 1.24 5.23 5.02 4.97 4.55 3.51

o-Xylene 2.86 7.68 6.79 6.91 6.33 2.83

1-Nonene 0.15 0.10 0.17 0.29 0.28 0.20

n-Nonane 0.69 1.06 0.95 0.97 0.88 1.05

Isopropylbenzene 0.15 0.25 0.26 0.23 0.21 0.17

a-Pinene 0.66 0.51 0.66 0.59 0.55 0.54

n-Propylbenzene 0.61 0.80 0.84 0.81 0.78 0.71

m-Ethyltoluene 2.23 3.28 4.28 2.88 2.87 2.47

p-Ethyltoluene 1.09 1.66 1.84 1.43 1.38 1.25

1,3,5-Trimethylbenzene 1.12 1.64 1.53 1.55 1.43 1.35

o-Ethyltoluene 1.00 1.55 1.50 1.50 1.34 1.37

b-Pinene 0.58 0.54 0.66 0.38 0.43 0.42

1,2,4-Trimethylbenzene 3.05 4.64 4.29 4.12 3.83 3.48

1-Decene ND ND ND ND ND ND

n-Decane 0.85 1.70 1.36 1.41 1.42 1.44

1,2,3-Trimethylbenzene 0.99 1.19 0.77 0.97 0.92 0.80

m-Diethylbenzene 0.20 0.25 0.27 0.26 0.23 0.24

p-Diethylbenzene 0.21 0.27 0.22 0.23 0.23 0.21

1-Undecene 0.07 0.14 0.07 0.07 0.10 0.03

n-Undecane 0.53 0.84 0.77 0.89 0.81 0.68

1-Dodecene ND ND ND ND ND ND

n-Dodecane ND ND 0.62 ND 0.89 0.35

1-Tridecene ND ND ND ND ND ND

n-Tridecane ND 0.12 0.21 0.05 0.28 ND

TNMOC (w/ unknowns) 262.76 304.52 296.85 288.50 278.25 250.83

TNMOC (speciated) 187.12 240.23 227.75 215.15 206.51 201.33
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13323 13322 13321 13366 13374 13522

Sampling Date: 7/6/98 7/7/98 7/8/98 7/9/98 7/10/98 7/13/98

Analysis Date: 7/11/98 VOID 7/16/98 7/16/98 7/16/98 8/19/98

Compound

Ethylene 0.45 3.17 2.43 2.41 3.89

Acetylene 5.02 0.96 2.68 1.89 1.77

Ethane 5.20 2.58 3.39 5.47 6.96

Propylene 2.20 0.82 2.30 1.23 1.88

Propane 8.61 3.74 8.93 4.94 7.05

Propyne 0.29 0.09 ND 0.16 ND

Isobutane 1.74 0.97 1.49 3.12 1.90

Isobutene/1-Butene 2.71 4.73 2.31 1.95 2.14

1,3-Butadiene 0.36 0.21 0.39 0.18 0.23

n-Butane 6.11 3.08 4.07 16.84 3.62

trans-2-Butene 0.22 0.19 0.21 1.25 0.44

cis-2-Butene 0.22 0.21 0.24 1.38 0.55

3-Methyl-1-butene 0.76 0.11 0.20 1.45 0.61

Isopentane 17.12 9.51 15.65 45.48 22.25

1-Pentene 0.35 0.37 0.44 2.24 0.62

2-Methyl-1-butene 0.64 0.42 0.72 3.50 0.35

n-Pentane 4.57 3.28 4.01 15.12 3.31

Isoprene 1.04 0.60 1.85 1.31 2.01

trans-2-Pentene 0.65 0.69 0.68 4.27 0.61

cis-2-Pentene 0.28 0.34 0.31 2.12 0.50

2-Methyl-2-butene 0.69 1.27 0.73 5.52 0.50

2,2-Dimethylbutane 0.47 0.31 0.48 1.89 0.69

Cyclopentene 1.13 1.04 1.24 1.59 1.52

4-Methyl-1-pentene 0.03 ND ND 0.31 ND

Cyclopentane 0.41 0.41 0.43 2.39 0.44

2,3-Dimethylbutane 4.77 0.74 4.74 31.50 3.69

2-Methylpentane 4.71 3.78 4.31 17.44 2.65

3-Methylpentane 2.17 2.06 2.17 10.52 1.82

2-Methyl-1-pentene 0.16 0.13 0.21 0.99 0.12

1-Hexene 0.22 0.19 0.14 0.58 0.10

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 2.51 2.90 2.55 12.98 2.19

trans-2-Hexene 0.17 0.20 0.19 1.07 ND

cis-2-Hexene 0.08 0.11 0.09 0.58 ND

Methylcyclopentane 1.29 1.20 1.33 4.97 1.02

2,4-Dimethylpentane 0.51 0.41 0.43 1.58 0.82

Benzene 3.21 2.05 3.13 6.59 2.77

Cyclohexane 0.53 0.55 0.76 1.17 0.81

2-Methylhexane 1.92 1.80 2.41 3.64 1.25

2,3-Dimethylpentane 0.75 0.55 1.06 1.38 0.88

3-Methylhexane 1.41 1.15 2.33 4.34 1.37

1-Heptene 0.11 0.07 0.44 0.70 ND

2,2,4-Trimethylpentane 2.61 1.49 2.09 4.73 2.20

n-Heptane 1.20 0.98 2.49 3.79 1.14

Methylcyclohexane 1.03 0.64 1.75 1.57 0.77

2,2,3-Trimethylpentane 0.70 0.44 0.62 1.41 0.59

2,3,4-Trimethylpentane 0.94 0.59 0.85 1.72 0.98

Toluene 9.70 7.33 8.18 20.52 6.82

2-Methylheptane 0.57 0.40 0.55 1.10 0.54

3-Methylheptane 0.39 0.30 0.42 0.80 0.70

1-Octene 0.09 0.04 0.07 0.15 ND

n-Octane 0.64 0.63 0.75 1.41 0.83

Ethylbenzene 2.04 1.38 1.47 3.58 1.30

m-Xylene/p-Xylene 6.94 5.17 4.74 12.99 3.75

Styrene 1.23 0.30 0.44 1.48 1.63

o-Xylene 2.40 1.66 1.79 4.27 1.47

1-Nonene 0.14 0.10 0.14 0.19 ND

n-Nonane 0.46 0.33 0.42 0.97 0.59

Isopropylbenzene 0.10 ND ND 0.21 0.41

a-Pinene 0.45 ND 0.59 0.35 0.29

n-Propylbenzene 0.42 0.29 0.35 1.01 0.57

m-Ethyltoluene 1.57 1.12 1.38 3.24 1.44

p-Ethyltoluene 0.76 0.55 0.66 1.77 0.88

1,3,5-Trimethylbenzene 0.78 0.48 0.68 1.48 0.74

o-Ethyltoluene 0.84 0.40 0.74 1.45 0.71

b-Pinene 0.57 ND 1.15 1.23 1.33

1,2,4-Trimethylbenzene 2.15 1.39 1.81 4.34 1.86

1-Decene ND ND ND ND ND

n-Decane 0.54 0.21 0.34 1.00 0.67

1,2,3-Trimethylbenzene 0.40 0.21 0.44 0.74 0.58

m-Diethylbenzene 0.14 0.05 0.07 0.24 0.55

p-Diethylbenzene 0.11 0.06 0.10 0.37 0.36

1-Undecene ND ND ND ND ND

n-Undecane 0.31 ND ND 0.54 0.71

1-Dodecene ND ND ND ND 0.14

n-Dodecane 0.29 ND ND 0.19 0.72

1-Tridecene ND ND ND ND ND

n-Tridecane ND ND ND ND 0.27

TNMOC (w/ unknowns) 168.75 108.32 143.06 367.49 160.87

TNMOC (speciated) 126.31 83.54 116.54 306.87 118.87
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13585 13582 13583 13592D1 13592R1 13593D2

Sampling Date: 7/14/98 7/15/98 7/16/98 7/17/98 7/17/98 7/17/98

Analysis Date: 8/19/98 8/7/98 8/7/98 8/19/98 8/21/98 8/20/98

Compound

Ethylene 5.67 8.18 19.52 6.28 5.49 5.87

Acetylene 3.92 4.91 12.81 2.88 2.58 2.62

Ethane 15.77 10.69 29.77 22.04 17.89 19.57

Propylene 2.28 3.51 8.60 2.25 2.05 2.08

Propane 16.17 10.60 29.44 23.34 22.09 25.88

Propyne 0.17 0.63 0.83 0.13 0.14 0.13

Isobutane 4.98 2.29 6.70 8.14 7.68 8.35

Isobutene/1-Butene 2.50 3.73 15.72 2.27 1.97 1.99

1,3-Butadiene 0.33 0.63 1.85 0.31 0.38 0.23

n-Butane 8.98 4.68 17.16 12.28 11.67 15.96

trans-2-Butene 0.37 0.55 1.55 0.39 0.43 0.44

cis-2-Butene 0.62 0.64 1.70 0.57 0.54 0.53

3-Methyl-1-butene 0.60 0.43 2.67 0.10 0.08 0.19

Isopentane 23.54 14.63 66.96 30.97 29.41 25.34

1-Pentene 0.51 0.76 2.38 0.60 0.55 0.60

2-Methyl-1-butene 0.61 0.71 2.16 0.47 0.37 0.42

n-Pentane 6.85 10.74 20.62 8.28 7.91 7.35

Isoprene 1.45 1.58 3.17 1.22 1.11 1.56

trans-2-Pentene 0.82 1.07 3.71 0.71 0.72 0.80

cis-2-Pentene 0.46 0.66 4.89 0.60 0.47 0.54

2-Methyl-2-butene 0.60 0.87 6.17 0.54 0.57 0.50

2,2-Dimethylbutane 0.94 0.99 2.71 1.19 1.16 1.16

Cyclopentene 3.00 0.81 2.58 2.73 2.58 3.10

4-Methyl-1-pentene ND ND 0.26 ND ND ND

Cyclopentane 0.83 0.63 2.14 0.86 0.79 0.71

2,3-Dimethylbutane 7.89 7.54 15.82 5.30 5.10 5.15

2-Methylpentane 5.18 4.29 15.44 5.82 5.57 5.62

3-Methylpentane 3.09 3.31 9.75 3.48 3.27 3.24

2-Methyl-1-pentene 0.19 0.26 0.72 0.15 0.17 0.15

1-Hexene 0.14 0.26 0.76 0.14 0.13 0.12

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.95 4.08 11.27 8.70 8.08 7.45

trans-2-Hexene 0.15 0.15 0.67 0.06 0.05 0.06

cis-2-Hexene ND ND 0.60 ND ND ND

Methylcyclopentane 1.95 2.19 5.50 2.29 2.13 2.08

2,4-Dimethylpentane 0.89 1.00 2.50 0.96 0.82 0.94

Benzene 4.76 5.08 12.25 4.54 4.12 4.24

Cyclohexane 1.19 1.00 1.97 7.96 7.64 6.51

2-Methylhexane 1.61 2.15 5.99 2.37 2.15 2.33

2,3-Dimethylpentane 1.05 1.35 2.90 1.28 1.19 1.45

3-Methylhexane 2.26 2.42 6.51 2.44 2.25 2.31

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 2.48 4.07 11.50 2.66 2.67 2.68

n-Heptane 2.35 1.83 5.75 2.68 2.62 2.53

Methylcyclohexane 1.72 1.35 3.32 2.25 2.09 2.12

2,2,3-Trimethylpentane 0.79 0.89 2.81 0.78 0.81 0.59

2,3,4-Trimethylpentane 1.06 1.49 4.24 1.08 0.96 1.11

Toluene 13.06 14.09 42.09 17.44 16.41 15.87

2-Methylheptane 0.95 1.04 2.61 1.28 1.23 1.38

3-Methylheptane 0.96 1.14 2.58 1.24 1.12 1.10

1-Octene 0.11 ND 0.15 0.11 0.05 0.11

n-Octane 1.30 1.50 4.45 1.68 1.60 2.12

Ethylbenzene 3.75 4.06 8.32 2.42 2.34 4.57

m-Xylene/p-Xylene 12.20 13.11 27.48 7.55 7.24 12.95

Styrene 0.95 3.43 3.21 1.98 1.71 2.57

o-Xylene 3.80 4.41 9.95 2.94 2.76 3.89

1-Nonene 0.16 0.18 0.69 0.30 0.27 0.26

n-Nonane 1.01 1.35 2.90 1.64 1.63 1.72

Isopropylbenzene 0.52 0.64 0.99 0.68 0.61 0.59

a-Pinene 0.36 0.38 ND 0.21 0.51 0.85

n-Propylbenzene 0.75 1.10 2.59 0.99 0.98 0.89

m-Ethyltoluene 2.10 3.10 9.38 2.30 2.28 2.18

p-Ethyltoluene 1.43 1.79 4.80 1.56 1.67 1.53

1,3,5-Trimethylbenzene 1.34 1.59 5.30 1.74 1.56 1.35

o-Ethyltoluene 1.04 1.45 3.57 1.08 1.07 0.99

b-Pinene 0.60 2.94 0.57 0.68 0.91 1.31

1,2,4-Trimethylbenzene 3.14 4.43 13.68 3.66 3.53 3.23

1-Decene ND ND ND ND ND ND

n-Decane 1.11 1.55 3.88 2.41 2.18 2.13

1,2,3-Trimethylbenzene 0.73 1.20 3.34 1.10 0.71 0.68

m-Diethylbenzene 0.41 0.88 0.89 0.48 0.67 0.74

p-Diethylbenzene 0.40 0.70 0.97 0.48 0.47 0.65

1-Undecene ND ND 0.43 ND ND 0.03

n-Undecane 0.91 1.58 3.39 1.86 1.78 1.87

1-Dodecene 0.06 0.71 0.36 0.19 0.25 0.34

n-Dodecane 0.32 0.91 1.53 0.54 0.53 0.83

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.12 0.30 0.57 0.11 0.16 0.14

TNMOC (w/ unknowns) 238.11 293.72 656.60 282.34 267.84 328.18

TNMOC (speciated) 199.24 199.17 547.03 242.74 226.64 243.45
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13593R2 13612 13728 13732 13764 13761

Sampling Date: 7/17/98 7/20/98 7/21/98 7/22/98 7/23/98 7/24/98

Analysis Date: 8/21/98 8/8/98 8/20/98 8/20/98 8/20/98 8/20/98

Compound

Ethylene 5.86 6.16 5.14 4.05 3.84 4.37

Acetylene 2.51 3.97 9.54 2.44 1.72 2.49

Ethane 19.36 12.08 6.33 6.07 3.92 5.16

Propylene 2.17 2.79 2.88 2.16 1.87 2.06

Propane 25.86 14.89 9.17 7.32 3.77 5.15

Propyne 0.15 0.22 0.18 0.16 0.10 ND

Isobutane 8.13 3.20 2.24 4.25 1.24 1.47

Isobutene/1-Butene 2.02 3.30 3.14 3.29 2.16 2.31

1,3-Butadiene 0.24 0.53 0.61 0.38 0.42 0.51

n-Butane 15.80 7.23 5.08 5.17 2.52 2.73

trans-2-Butene 0.39 0.70 0.78 0.78 0.46 0.43

cis-2-Butene 0.52 0.62 0.59 0.62 0.65 0.64

3-Methyl-1-butene 0.17 0.10 0.13 2.21 ND 0.15

Isopentane 25.51 20.07 17.79 26.64 13.38 14.47

1-Pentene 0.54 0.63 0.70 0.91 0.57 0.43

2-Methyl-1-butene 0.41 0.59 0.65 0.48 0.45 0.43

n-Pentane 7.30 5.57 5.79 4.76 3.03 3.27

Isoprene 1.58 1.67 1.72 1.62 1.46 1.50

trans-2-Pentene 0.86 1.10 1.49 0.98 0.88 0.71

cis-2-Pentene 0.53 0.69 0.77 0.60 0.59 0.61

2-Methyl-2-butene 0.47 0.93 1.03 0.93 0.81 0.73

2,2-Dimethylbutane 1.28 0.91 0.99 0.64 0.69 0.75

Cyclopentene 2.98 0.85 0.90 0.79 0.72 0.58

4-Methyl-1-pentene ND 0.02 0.08 0.13 0.03 0.06

Cyclopentane 0.74 0.61 0.69 0.82 0.48 0.40

2,3-Dimethylbutane 4.71 6.88 6.20 4.30 3.60 3.68

2-Methylpentane 5.57 4.60 4.31 3.92 2.32 2.56

3-Methylpentane 3.30 2.76 2.58 2.74 1.57 1.78

2-Methyl-1-pentene 0.12 0.23 0.25 0.17 0.15 0.19

1-Hexene 0.09 0.14 0.17 0.10 0.16 0.07

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 7.53 3.22 3.14 4.07 1.87 2.47

trans-2-Hexene 0.05 0.17 0.17 0.16 0.13 0.08

cis-2-Hexene ND 0.14 0.11 0.09 0.04 0.05

Methylcyclopentane 2.15 1.95 1.62 1.71 1.07 1.16

2,4-Dimethylpentane 1.00 0.92 0.93 0.87 0.67 0.67

Benzene 4.32 3.79 3.94 3.44 2.79 2.40

Cyclohexane 6.49 1.08 0.81 84.57 0.74 1.18

2-Methylhexane 2.04 2.04 1.97 1.83 1.61 1.92

2,3-Dimethylpentane 1.32 1.29 1.24 1.15 1.02 1.17

3-Methylhexane 2.20 1.91 1.82 1.47 1.53 2.01

1-Heptene ND 0.05 ND ND ND ND

2,2,4-Trimethylpentane 2.78 2.94 2.88 1.76 1.63 1.91

n-Heptane 2.52 1.52 1.52 1.27 1.47 1.66

Methylcyclohexane 2.02 1.31 1.12 0.93 0.94 0.98

2,2,3-Trimethylpentane 0.84 0.64 0.62 0.52 0.38 0.30

2,3,4-Trimethylpentane 1.11 1.17 1.12 0.89 0.64 0.82

Toluene 15.82 9.99 12.16 17.47 5.73 6.06

2-Methylheptane 1.31 0.96 1.00 0.55 0.65 0.73

3-Methylheptane 1.06 0.74 1.06 0.85 0.57 0.61

1-Octene 0.07 0.28 ND 0.09 0.14 0.08

n-Octane 2.17 1.17 1.26 1.78 0.81 0.91

Ethylbenzene 4.57 2.80 5.91 2.51 1.17 1.43

m-Xylene/p-Xylene 13.00 8.80 20.73 6.37 3.33 3.91

Styrene 2.30 1.39 1.81 2.41 1.21 1.13

o-Xylene 3.89 3.17 6.20 2.47 1.37 1.70

1-Nonene 0.16 0.39 0.20 0.28 ND 0.04

n-Nonane 1.78 0.87 1.09 1.27 0.62 0.84

Isopropylbenzene 0.57 0.59 0.55 0.56 0.48 0.49

a-Pinene 0.97 0.53 0.51 0.59 0.56 0.89

n-Propylbenzene 0.89 0.92 0.97 0.88 0.59 0.75

m-Ethyltoluene 2.22 2.26 2.65 2.00 1.35 1.54

p-Ethyltoluene 1.54 1.35 1.62 1.40 0.93 1.02

1,3,5-Trimethylbenzene 1.43 1.31 1.62 1.43 0.80 0.90

o-Ethyltoluene 1.06 1.16 1.31 0.91 0.74 0.87

b-Pinene 1.82 1.30 0.70 1.17 1.58 1.41

1,2,4-Trimethylbenzene 3.32 3.13 4.15 3.25 2.12 2.35

1-Decene ND ND ND ND ND ND

n-Decane 2.21 0.94 1.48 4.05 0.63 0.71

1,2,3-Trimethylbenzene 1.04 0.85 0.98 0.69 0.65 0.65

m-Diethylbenzene 0.73 0.56 0.44 0.44 0.48 0.56

p-Diethylbenzene 0.52 0.43 0.42 0.36 0.36 0.40

1-Undecene 0.08 0.06 0.05 0.24 ND ND

n-Undecane 1.85 1.01 1.38 7.05 0.60 0.73

1-Dodecene 0.41 0.54 0.11 ND 0.10 0.06

n-Dodecane 0.82 0.44 0.60 2.06 0.24 0.20

1-Tridecene ND 0.02 ND ND ND ND

n-Tridecane 0.17 0.21 0.18 0.27 0.13 0.09

TNMOC (w/ unknowns) 325.92 216.65 226.67 303.57 126.98 136.13

TNMOC (speciated) 243.29 176.37 186.06 257.58 98.04 109.60
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13778 13894D1 13894R1 13895D2 13895R2 13903

Sampling Date: 7/27/98 7/28/98 7/28/98 7/28/98 7/28/98 7/29/98

Analysis Date: 8/21/98 8/18/98 8/19/98 8/18/98 8/19/98 8/18/98

Compound

Ethylene 3.02 4.04 3.97 3.37 3.60 2.91

Acetylene 1.69 1.73 1.32 2.29 1.70 1.30

Ethane 3.06 4.89 5.00 4.12 4.28 2.78

Propylene 1.49 1.77 1.73 1.72 1.77 1.49

Propane 4.89 11.42 11.20 10.43 11.74 4.05

Propyne 0.12 ND ND ND ND ND

Isobutane 1.59 2.08 2.06 2.00 2.19 0.95

Isobutene/1-Butene 1.77 1.94 1.92 1.76 1.95 1.76

1,3-Butadiene 0.29 0.28 0.31 0.21 0.29 0.22

n-Butane 2.21 2.38 2.18 2.21 2.52 1.92

trans-2-Butene 0.38 0.37 0.44 0.51 0.41 0.35

cis-2-Butene 0.57 0.55 0.63 0.51 0.53 0.53

3-Methyl-1-butene 0.16 ND ND ND ND ND

Isopentane 12.05 11.29 12.05 12.74 13.64 14.54

1-Pentene 0.48 0.49 0.45 0.40 0.36 0.45

2-Methyl-1-butene 0.30 0.27 0.32 0.33 0.33 0.36

n-Pentane 2.76 2.69 2.73 2.56 2.93 3.01

Isoprene 1.26 1.19 1.13 1.12 1.21 1.15

trans-2-Pentene 0.80 0.67 0.66 0.68 0.70 0.63

cis-2-Pentene 0.57 0.59 0.59 0.55 0.53 0.51

2-Methyl-2-butene 0.63 0.52 0.46 0.46 0.65 0.51

2,2-Dimethylbutane 0.63 0.67 0.71 0.57 0.68 0.58

Cyclopentene 0.58 0.92 0.67 0.71 0.72 0.42

4-Methyl-1-pentene ND ND ND ND ND ND

Cyclopentane 0.48 0.49 0.54 0.45 0.47 0.41

2,3-Dimethylbutane 3.62 2.98 3.15 2.82 3.10 2.91

2-Methylpentane 2.97 2.18 2.93 2.28 2.76 1.97

3-Methylpentane 1.65 1.69 1.61 1.55 1.75 1.39

2-Methyl-1-pentene 0.15 0.12 0.12 0.13 0.18 0.15

1-Hexene 0.10 0.14 0.10 0.12 0.13 0.07

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.97 1.82 1.86 1.71 2.04 1.49

trans-2-Hexene 0.13 0.10 0.09 0.09 0.08 ND

cis-2-Hexene ND ND ND ND ND ND

Methylcyclopentane 1.05 1.02 1.04 1.01 1.14 1.11

2,4-Dimethylpentane 0.75 0.69 0.72 0.63 0.75 0.64

Benzene 1.91 2.05 2.20 2.04 2.25 1.91

Cyclohexane 1.22 0.74 0.74 1.56 1.68 0.79

2-Methylhexane 2.63 1.26 1.96 1.68 1.84 0.87

2,3-Dimethylpentane 1.22 0.96 1.09 0.96 1.00 0.79

3-Methylhexane 2.27 1.77 1.67 1.58 1.81 1.54

1-Heptene ND 0.03 0.03 0.08 0.05 ND

2,2,4-Trimethylpentane 2.03 1.71 1.56 1.37 1.64 1.34

n-Heptane 2.29 1.76 1.66 1.64 1.75 1.39

Methylcyclohexane 1.37 1.16 1.03 1.03 1.23 0.74

2,2,3-Trimethylpentane 0.52 0.31 0.34 0.34 0.43 0.32

2,3,4-Trimethylpentane 0.78 0.77 0.76 0.68 0.74 0.62

Toluene 6.84 6.34 6.16 5.97 6.61 4.72

2-Methylheptane 0.69 0.68 0.63 0.62 0.64 0.54

3-Methylheptane 0.71 0.65 0.67 0.67 0.68 0.52

1-Octene ND ND ND ND ND ND

n-Octane 0.79 0.97 0.88 0.86 0.89 0.83

Ethylbenzene 1.33 1.56 1.51 1.53 1.63 1.14

m-Xylene/p-Xylene 3.80 4.51 4.15 4.23 4.66 3.00

Styrene 1.05 0.86 0.76 1.01 1.01 1.24

o-Xylene 1.51 1.57 1.61 1.65 1.74 1.26

1-Nonene ND ND ND ND ND ND

n-Nonane 0.60 0.62 0.66 0.62 0.60 0.58

Isopropylbenzene 0.49 0.50 0.45 0.38 0.45 0.44

a-Pinene 0.37 0.47 0.48 0.37 0.50 0.40

n-Propylbenzene 0.62 0.69 0.63 0.70 0.60 0.56

m-Ethyltoluene 1.26 1.47 1.45 1.41 1.47 1.19

p-Ethyltoluene 0.85 1.18 0.93 0.96 0.95 0.83

1,3,5-Trimethylbenzene 0.80 0.97 0.87 0.90 0.87 0.81

o-Ethyltoluene 0.60 0.69 0.60 0.72 0.72 0.75

b-Pinene 1.12 1.10 1.04 1.24 1.19 1.46

1,2,4-Trimethylbenzene 1.76 2.19 2.15 2.14 2.26 1.82

1-Decene ND ND ND ND ND ND

n-Decane 0.66 0.73 0.71 0.65 0.71 0.61

1,2,3-Trimethylbenzene 0.49 0.68 0.84 0.51 0.55 0.48

m-Diethylbenzene 0.55 0.52 0.45 0.50 0.46 0.58

p-Diethylbenzene 0.31 0.46 0.40 0.41 0.42 0.32

1-Undecene 0.69 ND ND ND ND ND

n-Undecane 0.63 0.80 0.71 0.71 0.67 0.68

1-Dodecene 0.10 ND ND ND ND ND

n-Dodecane 0.22 0.32 0.30 0.20 0.20 0.22

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.12 0.13 0.15 0.10 0.10 0.11

TNMOC (w/ unknowns) 130.17 129.21 126.11 127.10 134.08 118.62

TNMOC (speciated) 99.37 105.16 104.85 102.07 110.09 85.95
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13942 13959 14058 13979D1 13979R1 13980D2

Sampling Date: 7/31/98 8/3/98 8/4/98 8/5/98 8/5/98 8/5/98

Analysis Date: 8/18/98 8/19/98 8/28/98 8/19/98 8/20/98 8/19/98

Compound

Ethylene 4.23 6.00 5.70 2.26 9.92 8.95

Acetylene 1.74 17.26 4.40 5.53 5.85 5.67

Ethane 5.43 14.86 14.19 4.11 16.20 13.49

Propylene 1.98 3.06 2.18 4.55 4.16 3.93

Propane 6.19 15.83 14.76 47.83 43.03 41.32

Propyne ND 0.53 0.20 0.62 0.25 0.56

Isobutane 1.56 5.17 4.68 5.41 5.03 4.58

Isobutene/1-Butene 2.45 3.24 2.08 4.56 4.13 3.93

1,3-Butadiene 0.31 0.61 0.34 1.00 0.80 0.83

n-Butane 4.45 8.89 7.80 8.07 7.23 7.12

trans-2-Butene 0.42 0.59 0.40 0.94 0.67 0.88

cis-2-Butene 0.53 0.62 0.52 0.85 0.79 0.82

3-Methyl-1-butene 0.11 ND 0.30 0.16 0.13 0.22

Isopentane 12.41 25.00 24.50 35.93 32.78 32.30

1-Pentene 0.48 0.77 0.66 1.11 0.87 1.10

2-Methyl-1-butene 0.39 0.73 0.53 1.02 0.97 1.03

n-Pentane 3.07 7.79 6.71 10.69 9.56 9.25

Isoprene 1.94 2.52 0.83 1.31 1.18 1.18

trans-2-Pentene 0.76 1.11 0.83 1.49 1.35 1.32

cis-2-Pentene 0.59 0.71 0.61 0.99 0.91 0.87

2-Methyl-2-butene 0.69 0.99 0.70 1.42 1.36 1.23

2,2-Dimethylbutane 0.78 1.22 1.36 1.77 1.12 1.20

Cyclopentene 0.68 2.62 1.69 0.81 0.72 0.75

4-Methyl-1-pentene ND ND 0.08 ND ND ND

Cyclopentane 0.54 0.65 0.92 1.29 0.96 0.77

2,3-Dimethylbutane 3.48 6.70 7.13 11.84 10.67 10.91

2-Methylpentane 2.95 5.84 7.60 8.62 7.56 7.22

3-Methylpentane 1.68 3.66 4.13 5.08 4.50 4.46

2-Methyl-1-pentene 0.12 0.24 0.19 0.30 0.28 0.26

1-Hexene 0.14 0.19 0.16 0.31 0.23 0.32

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.92 4.72 4.38 6.43 6.06 5.57

trans-2-Hexene 0.10 0.44 0.12 0.46 0.22 0.47

cis-2-Hexene ND ND ND 0.18 0.13 0.14

Methylcyclopentane 1.11 2.13 2.00 3.08 2.70 2.69

2,4-Dimethylpentane 0.71 1.06 0.88 1.38 1.29 1.17

Benzene 2.52 5.13 4.44 6.83 6.03 6.04

Cyclohexane 0.89 1.11 1.55 2.19 1.90 1.90

2-Methylhexane 1.39 1.82 2.54 5.78 5.41 5.55

2,3-Dimethylpentane 1.03 1.09 1.26 2.36 2.39 2.07

3-Methylhexane 1.20 2.46 3.02 6.85 6.15 5.90

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 1.85 3.37 2.91 5.59 4.84 4.76

n-Heptane 1.18 2.55 5.87 7.72 6.85 6.42

Methylcyclohexane 0.90 1.80 3.95 3.48 3.04 3.00

2,2,3-Trimethylpentane 0.46 0.91 1.13 1.81 1.62 1.50

2,3,4-Trimethylpentane 0.79 1.30 1.13 2.07 1.77 1.72

Toluene 5.89 15.22 15.02 23.21 20.59 19.86

2-Methylheptane 0.66 1.27 1.44 1.56 1.34 1.32

3-Methylheptane 0.67 1.02 1.24 1.56 1.30 1.44

1-Octene ND ND 0.05 0.09 0.08 0.10

n-Octane 0.93 1.77 1.66 1.96 1.56 1.68

Ethylbenzene 1.41 5.38 2.41 4.21 3.87 3.77

m-Xylene/p-Xylene 3.74 17.87 7.18 12.66 11.42 10.93

Styrene 1.11 2.50 0.94 2.15 1.93 1.98

o-Xylene 1.55 5.71 2.61 4.66 4.21 4.02

1-Nonene ND 0.17 0.11 0.28 0.19 0.08

n-Nonane 0.68 1.28 1.11 1.47 1.25 1.36

Isopropylbenzene 0.57 0.64 0.61 0.75 0.54 0.65

a-Pinene 0.42 0.54 0.16 1.22 0.89 0.86

n-Propylbenzene 0.64 0.91 0.78 1.25 1.15 1.16

m-Ethyltoluene 1.55 2.73 2.00 3.92 3.51 3.46

p-Ethyltoluene 1.00 1.75 1.34 2.25 1.98 2.08

1,3,5-Trimethylbenzene 0.91 1.52 1.27 2.18 2.03 1.98

o-Ethyltoluene 0.71 1.28 1.03 1.63 1.61 1.54

b-Pinene 1.13 0.38 0.47 0.83 0.72 0.74

1,2,4-Trimethylbenzene 2.29 3.84 3.12 5.54 5.10 4.87

1-Decene ND ND ND ND ND ND

n-Decane 0.71 1.46 1.27 1.62 1.50 1.52

1,2,3-Trimethylbenzene 0.65 1.11 1.11 1.83 1.49 1.68

m-Diethylbenzene 0.54 0.58 0.54 0.59 0.68 0.61

p-Diethylbenzene 0.41 0.51 0.45 0.65 0.62 0.58

1-Undecene ND ND 0.05 ND ND ND

n-Undecane 0.75 1.45 1.08 1.52 1.49 1.66

1-Dodecene ND ND 0.07 ND 0.11 0.07

n-Dodecane 0.28 0.59 0.43 0.70 0.59 0.97

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.11 0.17 0.13 0.28 0.25 0.31

TNMOC (w/ unknowns) 136.51 283.93 250.54 376.53 345.76 335.04

TNMOC (speciated) 105.49 238.97 201.07 306.67 295.56 286.68
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 13980R2 14055 14056 14091 14231

Sampling Date: 8/5/98 8/6/98 8/7/98 8/10/98 8/13/98

Analysis Date: 8/20/98 8/28/98 8/28/98 9/21/98 9/2/98

Compound

Ethylene 11.02 5.67 1.64 3.24 5.06

Acetylene 6.19 4.45 1.59 2.42 4.44

Ethane 17.65 42.52 3.08 3.70 13.24

Propylene 4.60 3.12 0.92 1.65 2.17

Propane 47.02 45.32 3.26 5.97 12.47

Propyne 0.41 0.19 ND ND 0.17

Isobutane 5.20 10.35 1.38 2.60 3.94

Isobutene/1-Butene 4.33 3.99 1.24 1.83 2.57

1,3-Butadiene 0.83 0.58 0.13 0.26 0.43

n-Butane 7.90 23.21 6.09 2.56 7.59

trans-2-Butene 0.68 0.71 0.68 0.51 0.58

cis-2-Butene 0.85 0.89 0.78 0.48 0.67

3-Methyl-1-butene 0.19 ND 0.37 0.12 0.14

Isopentane 35.43 34.04 23.06 11.33 22.74

1-Pentene 1.01 1.39 1.29 0.55 0.62

2-Methyl-1-butene 1.13 0.96 1.72 0.32 0.62

n-Pentane 10.39 14.63 8.58 2.96 6.65

Isoprene 1.30 1.71 0.52 1.16 0.68

trans-2-Pentene 1.54 1.81 2.42 0.67 1.03

cis-2-Pentene 0.97 1.26 1.42 0.53 0.74

2-Methyl-2-butene 1.52 1.76 3.00 0.70 0.84

2,2-Dimethylbutane 1.57 1.32 1.38 0.72 0.99

Cyclopentene 0.94 0.96 0.71 0.53 1.04

4-Methyl-1-pentene ND ND 0.14 ND ND

Cyclopentane 1.02 1.40 1.53 0.53 0.75

2,3-Dimethylbutane 11.80 10.63 17.47 3.70 7.76

2-Methylpentane 8.50 9.05 9.59 2.81 5.12

3-Methylpentane 4.97 5.43 6.14 1.85 3.12

2-Methyl-1-pentene 0.38 0.39 0.58 0.12 0.18

1-Hexene 0.31 0.34 0.36 0.13 0.21

2-Ethyl-1-butene ND ND ND ND ND

n-Hexane 6.79 7.93 7.24 1.84 3.59

trans-2-Hexene 0.37 0.32 0.51 0.09 0.13

cis-2-Hexene 0.17 0.12 0.29 0.08 0.13

Methylcyclopentane 2.96 3.98 2.94 1.22 1.93

2,4-Dimethylpentane 1.42 1.49 1.21 0.72 0.87

Benzene 6.85 6.18 4.09 2.66 4.20

Cyclohexane 2.21 3.02 0.75 1.02 1.21

2-Methylhexane 5.75 3.71 1.82 3.11 2.30

2,3-Dimethylpentane 2.56 1.77 1.06 1.46 1.34

3-Methylhexane 6.88 3.64 2.44 3.40 2.35

1-Heptene ND ND ND ND ND

2,2,4-Trimethylpentane 5.60 4.44 3.09 2.16 2.86

n-Heptane 7.23 3.83 2.00 3.01 1.99

Methylcyclohexane 3.37 3.65 0.92 1.76 1.51

2,2,3-Trimethylpentane 1.79 0.97 0.71 0.51 0.71

2,3,4-Trimethylpentane 1.93 1.76 1.18 0.81 1.15

Toluene 22.70 18.25 10.60 7.56 10.32

2-Methylheptane 1.48 1.73 0.78 0.64 0.88

3-Methylheptane 1.43 1.49 0.73 0.64 0.84

1-Octene 0.07 0.08 ND ND 0.09

n-Octane 1.84 2.47 1.00 0.75 1.12

Ethylbenzene 4.23 3.54 2.04 1.18 1.90

m-Xylene/p-Xylene 12.39 10.70 6.80 3.44 5.50

Styrene 2.09 1.78 0.83 0.82 1.52

o-Xylene 4.55 4.10 2.35 1.38 2.05

1-Nonene 0.20 0.12 0.06 ND 0.10

n-Nonane 1.43 1.61 0.69 0.60 0.73

Isopropylbenzene 0.61 0.81 0.47 0.42 0.43

a-Pinene 1.04 0.90 0.10 0.24 0.48

n-Propylbenzene 1.20 1.40 0.76 0.52 0.67

m-Ethyltoluene 3.87 3.55 1.96 1.16 1.64

p-Ethyltoluene 2.22 2.25 1.20 0.81 1.06

1,3,5-Trimethylbenzene 2.23 2.07 1.03 0.77 0.94

o-Ethyltoluene 1.60 1.63 0.78 0.75 0.78

b-Pinene 0.85 1.09 0.64 0.82 0.86

1,2,4-Trimethylbenzene 5.42 5.38 2.83 1.69 2.42

1-Decene ND ND ND ND ND

n-Decane 1.63 1.61 0.48 0.59 0.79

1,2,3-Trimethylbenzene 1.45 1.37 0.77 0.39 0.64

m-Diethylbenzene 0.58 1.09 0.51 0.37 0.55

p-Diethylbenzene 0.45 0.88 0.43 0.28 0.54

1-Undecene ND 0.14 ND ND 0.04

n-Undecane 1.76 1.75 0.49 0.54 0.69

1-Dodecene 0.24 0.22 0.13 ND 0.17

n-Dodecane 1.29 0.55 0.18 0.21 0.40

1-Tridecene ND ND 0.02 ND ND

n-Tridecane 0.29 0.67 0.08 0.09 0.18

TNMOC (w/ unknowns) 379.30 407.49 211.78 137.65 206.50

TNMOC (speciated) 307.04 348.11 170.07 104.39 171.18
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14246D1 14246R1 14247D2 14247R2 14218 14226

Sampling Date: 8/14/98 8/14/98 8/14/98 8/14/98 8/17/98 8/18/98

Analysis Date: 9/10/98 9/11/98 9/10/98 9/11/98 9/11/98 9/21/98

Compound

Ethylene 5.79 5.83 5.89 5.81 5.01 5.31

Acetylene 4.69 4.85 4.66 4.80 3.74 4.19

Ethane 13.04 13.26 13.09 13.06 6.20 9.50

Propylene 2.72 2.76 2.62 2.67 2.46 2.79

Propane 17.90 18.24 17.99 17.95 6.25 10.18

Propyne 0.15 0.22 0.16 0.14 0.23 0.16

Isobutane 3.98 4.04 3.97 3.95 1.63 2.51

Isobutene/1-Butene 2.60 2.76 2.68 2.65 2.70 2.87

1,3-Butadiene 0.50 0.55 0.54 0.53 0.51 0.52

n-Butane 5.63 5.82 5.79 5.74 5.16 12.16

trans-2-Butene 0.54 0.55 0.50 0.51 0.48 0.50

cis-2-Butene 0.56 0.56 0.60 0.58 0.55 0.66

3-Methyl-1-butene 0.18 0.12 0.20 0.20 0.16 0.19

Isopentane 23.49 23.44 22.09 21.92 16.27 16.49

1-Pentene 0.70 0.63 0.67 0.64 0.52 0.59

2-Methyl-1-butene 0.57 0.65 0.66 0.63 0.58 0.74

n-Pentane 6.15 6.37 6.22 6.25 4.78 6.72

Isoprene 0.83 0.94 0.86 0.87 0.93 1.00

trans-2-Pentene 0.94 0.98 1.00 1.00 0.99 1.06

cis-2-Pentene 0.64 0.64 0.69 0.63 0.69 0.72

2-Methyl-2-butene 0.79 0.76 0.82 0.78 0.90 0.94

2,2-Dimethylbutane 0.98 1.13 1.03 0.94 1.10 1.04

Cyclopentene 0.41 0.52 0.49 0.41 0.47 0.63

4-Methyl-1-pentene ND 0.11 ND ND ND ND

Cyclopentane 0.75 0.76 0.82 0.88 0.71 0.68

2,3-Dimethylbutane 7.32 7.40 7.38 7.35 5.82 6.24

2-Methylpentane 4.92 5.11 4.86 4.76 4.16 4.45

3-Methylpentane 3.32 3.44 3.39 3.36 2.59 2.85

2-Methyl-1-pentene 0.25 0.19 0.19 0.21 0.26 0.22

1-Hexene 0.22 0.27 0.25 0.21 0.15 0.20

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 6.85 6.96 6.74 6.11 2.88 3.42

trans-2-Hexene 0.15 0.15 0.17 0.16 0.15 0.17

cis-2-Hexene 0.12 0.13 0.20 0.12 0.12 0.12

Methylcyclopentane 2.51 2.58 2.54 2.53 1.78 2.10

2,4-Dimethylpentane 0.92 1.07 1.00 0.97 0.86 0.92

Benzene 3.98 3.87 3.92 3.94 3.62 4.06

Cyclohexane 2.17 2.19 2.13 2.26 0.91 1.53

2-Methylhexane 2.94 2.52 2.68 3.10 1.87 2.35

2,3-Dimethylpentane 1.34 1.37 1.29 1.56 1.07 1.28

3-Methylhexane 3.13 3.22 3.18 3.35 1.96 2.19

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 3.32 3.38 3.36 3.40 3.05 2.93

n-Heptane 2.70 2.73 2.63 2.62 1.57 1.74

Methylcyclohexane 1.82 1.84 1.79 1.81 0.99 1.31

2,2,3-Trimethylpentane 0.89 0.93 0.85 0.89 0.66 0.66

2,3,4-Trimethylpentane 1.26 1.31 1.27 1.33 1.30 1.22

Toluene 16.32 16.63 16.40 16.41 9.40 12.40

2-Methylheptane 1.02 1.09 1.08 1.05 0.75 0.90

3-Methylheptane 0.97 1.01 1.00 1.06 0.84 0.74

1-Octene 0.04 0.05 0.06 0.05 0.04 0.07

n-Octane 1.39 1.38 1.34 1.32 0.89 1.03

Ethylbenzene 2.42 2.53 2.44 2.50 2.05 2.84

m-Xylene/p-Xylene 7.29 7.58 7.30 7.37 6.18 9.09

Styrene 1.26 1.09 1.09 0.93 1.23 1.11

o-Xylene 2.71 2.82 2.71 2.76 2.32 3.12

1-Nonene 0.16 0.15 0.13 0.15 0.10 0.07

n-Nonane 1.02 1.03 0.99 0.95 0.64 0.75

Isopropylbenzene 0.44 0.48 0.44 0.53 0.45 0.47

a-Pinene 0.71 0.82 0.64 0.69 0.54 0.58

n-Propylbenzene 0.81 0.87 0.84 0.89 0.74 0.73

m-Ethyltoluene 2.28 2.19 2.30 2.29 1.82 1.88

p-Ethyltoluene 1.35 1.38 1.38 1.41 1.08 1.13

1,3,5-Trimethylbenzene 1.39 1.37 1.35 1.31 1.01 1.07

o-Ethyltoluene 1.05 1.04 1.17 1.24 0.96 0.93

b-Pinene 0.82 0.84 0.52 0.51 0.88 0.44

1,2,4-Trimethylbenzene 3.35 3.36 3.22 3.31 2.59 2.74

1-Decene ND ND ND ND ND ND

n-Decane 1.39 1.35 1.28 1.32 0.78 0.82

1,2,3-Trimethylbenzene 0.65 0.66 0.94 0.80 0.69 0.69

m-Diethylbenzene 0.49 0.53 0.50 0.54 0.51 0.42

p-Diethylbenzene 0.37 0.42 0.46 0.50 0.44 0.31

1-Undecene 0.04 0.06 0.03 0.07 ND ND

n-Undecane 1.14 1.15 1.64 1.68 0.79 0.70

1-Dodecene 0.12 0.08 0.10 0.11 0.11 0.03

n-Dodecane 0.45 0.47 0.82 0.83 0.30 0.22

1-Tridecene ND 0.02 ND ND ND ND

n-Tridecane 0.17 0.14 0.23 0.15 0.13 ND

TNMOC (w/ unknowns) 234.38 238.62 234.68 234.92 178.84 200.50

TNMOC (speciated) 196.29 199.70 196.32 196.32 137.06 167.35
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14241 14240 14351 14519D1 14519R1 14525D2

Sampling Date: 8/19/98 8/20/98 8/21/98 8/27/98 8/27/98 8/27/98

Analysis Date: 9/11/98 9/22/98 9/22/98 10/16/98 10/19/98 10/16/98

Compound

Ethylene 8.24 5.94 3.75 5.01 4.96 4.95

Acetylene 5.76 3.93 3.07 3.43 3.39 3.42

Ethane 9.75 14.97 8.38 8.38 8.31 8.31

Propylene 3.30 2.44 1.74 2.13 2.23 2.13

Propane 18.52 15.30 9.93 15.57 15.81 15.54

Propyne 0.20 0.19 0.13 0.17 0.16 0.14

Isobutane 4.00 4.53 3.02 2.60 2.61 2.55

Isobutene/1-Butene 2.84 2.05 1.77 2.31 2.41 2.29

1,3-Butadiene 0.58 0.31 0.26 0.39 0.38 0.35

n-Butane 5.01 7.60 4.88 4.43 4.65 4.49

trans-2-Butene 0.59 0.44 0.43 0.41 0.42 0.44

cis-2-Butene 0.67 0.58 0.56 0.47 0.56 0.50

3-Methyl-1-butene 1.39 0.15 0.17 0.15 0.13 0.13

Isopentane 22.65 24.97 22.56 23.15 24.37 17.42

1-Pentene 0.70 0.64 0.73 0.52 0.54 0.47

2-Methyl-1-butene 0.83 0.60 0.56 0.59 0.62 0.55

n-Pentane 6.74 6.50 4.94 4.25 4.53 4.32

Isoprene 1.04 0.88 0.87 0.81 0.83 0.84

trans-2-Pentene 1.18 0.86 0.73 0.81 0.91 0.80

cis-2-Pentene 0.75 0.62 0.58 0.54 0.58 0.56

2-Methyl-2-butene 1.19 0.63 0.61 0.97 1.05 0.75

2,2-Dimethylbutane 1.18 1.18 0.97 0.86 0.95 0.77

Cyclopentene 2.46 2.47 2.58 0.78 0.73 0.48

4-Methyl-1-pentene 0.07 ND ND 0.04 0.08 0.05

Cyclopentane 0.93 0.77 0.62 0.62 0.62 0.54

2,3-Dimethylbutane 8.73 8.88 4.83 5.40 5.81 5.33

2-Methylpentane 5.70 5.26 4.04 4.38 4.54 3.68

3-Methylpentane 3.54 3.15 2.52 2.35 2.47 2.42

2-Methyl-1-pentene 0.23 0.22 0.19 0.19 0.21 0.19

1-Hexene 0.20 0.13 0.23 0.15 0.18 0.16

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 6.13 3.71 3.43 2.86 2.83 2.73

trans-2-Hexene 0.22 0.15 0.13 0.17 0.08 0.14

cis-2-Hexene 0.11 0.08 0.06 0.11 0.12 0.07

Methylcyclopentane 2.36 2.01 1.60 1.66 1.69 1.53

2,4-Dimethylpentane 1.16 0.92 0.79 0.82 0.78 0.75

Benzene 5.67 4.51 3.38 3.34 3.44 3.40

Cyclohexane 1.41 1.22 18.05 1.02 0.93 1.01

2-Methylhexane 2.65 2.61 1.76 2.37 2.26 2.62

2,3-Dimethylpentane 1.57 1.30 1.20 1.29 1.24 1.28

3-Methylhexane 2.84 2.35 1.75 2.65 2.71 2.59

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 3.88 2.76 2.04 2.62 2.59 2.55

n-Heptane 3.08 2.64 1.73 2.05 2.11 2.13

Methylcyclohexane 2.37 2.64 1.53 1.52 1.60 1.58

2,2,3-Trimethylpentane 1.03 0.96 0.48 0.66 0.78 0.68

2,3,4-Trimethylpentane 1.62 1.03 0.86 0.92 1.07 1.04

Toluene 28.68 20.56 11.07 15.61 15.84 15.92

2-Methylheptane 1.52 1.54 0.89 0.80 0.99 0.82

3-Methylheptane 1.35 1.30 0.77 0.80 0.83 0.68

1-Octene 0.14 0.08 0.10 0.07 0.07 0.04

n-Octane 1.98 1.85 1.14 1.06 1.05 1.07

Ethylbenzene 4.70 3.68 3.91 1.98 1.96 1.96

m-Xylene/p-Xylene 16.24 12.79 14.78 5.50 5.68 5.67

Styrene 1.22 0.90 1.65 1.13 1.23 0.79

o-Xylene 5.26 3.80 3.88 2.14 2.17 2.17

1-Nonene 0.43 0.23 0.26 0.16 0.13 0.11

n-Nonane 1.76 1.56 1.93 0.74 0.79 0.74

Isopropylbenzene 0.64 0.45 0.50 0.43 0.43 0.42

a-Pinene 0.62 0.24 0.34 0.23 0.20 0.20

n-Propylbenzene 1.22 0.88 1.15 0.64 0.63 0.64

m-Ethyltoluene 3.57 2.03 2.67 1.62 1.58 1.63

p-Ethyltoluene 2.14 1.38 1.80 1.01 0.99 1.02

1,3,5-Trimethylbenzene 2.43 1.53 2.07 0.88 0.92 0.99

o-Ethyltoluene 1.67 0.97 1.09 0.82 0.77 0.72

b-Pinene 0.48 0.39 0.89 0.70 0.70 0.56

1,2,4-Trimethylbenzene 5.64 3.18 4.31 2.33 2.38 2.35

1-Decene ND ND ND ND ND ND

n-Decane 2.88 2.27 3.02 0.80 0.80 0.91

1,2,3-Trimethylbenzene 1.39 0.88 1.15 0.52 0.61 0.69

m-Diethylbenzene 0.76 0.37 0.63 0.41 0.43 0.40

p-Diethylbenzene 0.53 0.46 0.44 0.33 0.36 0.41

1-Undecene 0.10 0.07 0.10 0.07 0.07 0.07

n-Undecane 1.76 1.22 1.83 0.87 0.91 0.86

1-Dodecene 0.09 0.13 0.20 0.24 0.31 0.16

n-Dodecane 0.67 0.33 0.68 0.46 0.47 0.41

1-Tridecene 0.04 ND 0.10 ND ND 0.05

n-Tridecane 0.16 0.12 0.28 0.16 0.16 0.08

TNMOC (w/ unknowns) 307.52 254.57 238.17 192.31 197.10 180.88

TNMOC (speciated) 245.14 210.28 188.06 158.47 162.72 151.20
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14525R2 14524 14552 14581D1 14581R1 14582D2

Sampling Date: 8/27/98 8/28/98 8/31/98 9/2/98 9/2/98 9/2/98

Analysis Date: 10/19/98 10/16/98 10/15/98 10/2/98 10/22/98 10/2/98

Compound

Ethylene 4.86 7.27 4.10 11.60 11.28 11.49

Acetylene 3.49 4.82 9.48 12.24 11.61 12.30

Ethane 8.48 7.93 8.27 17.02 16.57 16.83

Propylene 2.09 3.46 2.51 5.36 5.09 5.30

Propane 15.75 15.85 13.75 23.99 23.29 23.81

Propyne 0.14 0.15 0.16 0.41 0.40 0.43

Isobutane 2.59 4.63 4.16 6.07 5.87 6.36

Isobutene/1-Butene 2.31 3.37 3.59 5.24 5.20 5.14

1,3-Butadiene 0.41 0.58 0.40 1.06 0.95 1.05

n-Butane 4.47 5.26 5.88 9.67 9.54 9.93

trans-2-Butene 0.44 0.53 0.38 0.77 0.72 0.81

cis-2-Butene 0.54 0.61 0.50 0.87 0.83 0.89

3-Methyl-1-butene 0.15 0.21 ND 0.84 1.14 0.91

Isopentane 17.52 26.10 39.33 41.12 48.94 41.58

1-Pentene 0.54 0.69 0.51 1.12 1.07 1.03

2-Methyl-1-butene 0.63 0.83 0.67 1.38 1.54 1.48

n-Pentane 4.22 6.05 6.05 10.93 10.78 11.15

Isoprene 0.88 1.31 1.20 1.30 1.47 1.32

trans-2-Pentene 0.85 1.19 0.81 1.84 2.03 1.86

cis-2-Pentene 0.58 0.74 0.56 1.03 1.12 1.02

2-Methyl-2-butene 0.94 1.26 1.00 1.96 2.40 2.06

2,2-Dimethylbutane 0.84 1.10 1.20 1.76 1.76 1.96

Cyclopentene 0.55 0.96 1.07 1.72 2.04 1.80

4-Methyl-1-pentene 0.04 0.08 ND 0.09 0.14 0.06

Cyclopentane 0.59 0.88 0.81 1.38 1.38 1.47

2,3-Dimethylbutane 5.33 7.89 5.36 12.18 16.82 12.38

2-Methylpentane 3.68 5.60 4.78 10.02 11.11 9.95

3-Methylpentane 2.40 3.54 3.33 6.05 6.21 6.13

2-Methyl-1-pentene 0.20 0.27 0.14 0.41 0.49 0.40

1-Hexene 0.15 0.20 0.14 0.31 0.41 0.44

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.70 4.39 3.59 6.99 7.68 7.52

trans-2-Hexene 0.11 0.19 0.14 0.34 0.41 0.35

cis-2-Hexene 0.11 0.10 0.12 0.23 0.28 0.25

Methylcyclopentane 1.63 2.34 2.10 3.90 4.17 4.01

2,4-Dimethylpentane 0.89 0.95 0.85 1.54 1.72 1.54

Benzene 3.39 4.57 4.18 6.51 8.17 6.88

Cyclohexane 1.03 1.23 65.14 3.48 3.58 4.41

2-Methylhexane 2.28 2.35 2.18 3.64 3.97 4.31

2,3-Dimethylpentane 1.15 1.23 1.08 1.98 2.06 2.02

3-Methylhexane 2.54 2.67 2.37 4.10 4.42 4.03

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 2.56 3.57 2.79 6.04 6.95 6.23

n-Heptane 2.20 2.20 1.97 3.02 3.61 2.83

Methylcyclohexane 1.54 1.92 2.05 1.92 2.20 1.98

2,2,3-Trimethylpentane 0.81 1.01 0.73 1.41 1.77 1.48

2,3,4-Trimethylpentane 1.00 1.37 1.18 2.29 2.63 2.31

Toluene 15.90 22.54 20.07 22.61 29.32 24.41

2-Methylheptane 0.81 1.20 0.96 1.41 1.66 1.45

3-Methylheptane 0.80 1.11 0.94 1.35 1.58 1.41

1-Octene 0.04 0.09 0.16 0.11 0.15 0.20

n-Octane 1.05 1.55 1.47 1.71 2.13 1.70

Ethylbenzene 2.00 2.87 3.74 3.41 4.78 3.63

m-Xylene/p-Xylene 5.65 8.51 10.50 10.66 14.59 10.98

Styrene 1.00 1.52 3.02 2.00 2.91 2.01

o-Xylene 2.21 3.20 3.69 4.06 5.40 4.20

1-Nonene 0.19 0.24 0.21 0.28 0.33 0.41

n-Nonane 0.70 1.40 1.08 1.47 1.95 1.54

Isopropylbenzene 0.46 0.58 0.62 0.56 0.62 0.55

a-Pinene 0.34 0.45 1.53 0.85 1.04 0.88

n-Propylbenzene 0.62 0.86 0.97 1.05 1.49 1.16

m-Ethyltoluene 1.64 2.42 2.46 3.19 4.83 3.25

p-Ethyltoluene 1.01 1.57 1.38 1.84 2.66 1.88

1,3,5-Trimethylbenzene 1.03 1.63 1.35 2.07 3.02 2.18

o-Ethyltoluene 0.75 0.98 0.99 1.39 2.08 1.45

b-Pinene 0.63 0.90 1.01 1.21 2.13 1.32

1,2,4-Trimethylbenzene 2.40 3.72 3.43 4.93 7.60 5.31

1-Decene ND ND ND ND ND ND

n-Decane 0.76 2.28 2.21 1.86 2.87 2.01

1,2,3-Trimethylbenzene 0.62 0.75 0.99 1.26 1.92 1.38

m-Diethylbenzene 0.45 0.64 0.37 0.74 1.04 0.60

p-Diethylbenzene 0.37 0.49 0.40 0.60 0.84 0.47

1-Undecene 0.05 0.13 0.11 0.09 0.15 0.18

n-Undecane 0.84 1.50 3.80 1.45 2.30 1.69

1-Dodecene 0.46 0.12 0.27 0.39 0.69 0.28

n-Dodecane 0.38 0.66 9.49 0.64 1.15 0.80

1-Tridecene ND ND 0.06 ND 0.04 0.08

n-Tridecane 0.12 0.18 2.67 0.28 0.43 0.32

TNMOC (w/ unknowns) 183.16 256.47 396.45 380.58 454.38 384.29

TNMOC (speciated) 152.91 207.55 290.53 310.58 357.52 319.23
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14582R2 14688 14771D1 14771R1

Sampling Date: 9/2/98 9/3/98 9/4/98 9/4/98

Analysis Date: 10/22/98 10/2/98 10/4/98 10/22/98

Compound

Ethylene 11.39 11.53 6.98 7.08

Acetylene 11.85 21.87 5.16 5.03

Ethane 16.76 13.30 11.25 11.23

Propylene 5.21 5.44 3.19 3.24

Propane 23.50 15.88 20.91 20.96

Propyne 0.48 0.41 0.19 0.25

Isobutane 6.29 4.11 4.17 4.21

Isobutene/1-Butene 5.40 5.71 3.33 3.31

1,3-Butadiene 1.02 1.00 0.52 0.61

n-Butane 9.80 9.59 6.30 6.33

trans-2-Butene 1.03 0.76 0.54 0.52

cis-2-Butene 0.94 0.86 0.64 0.60

3-Methyl-1-butene 0.90 0.30 0.13 0.24

Isopentane 45.79 36.00 27.12 30.81

1-Pentene 1.17 1.19 0.70 0.78

2-Methyl-1-butene 1.70 1.27 0.76 0.95

n-Pentane 11.01 11.62 7.72 7.76

Isoprene 1.63 1.21 0.93 1.07

trans-2-Pentene 2.14 1.64 1.25 1.46

cis-2-Pentene 1.26 0.96 0.72 0.83

2-Methyl-2-butene 2.62 1.72 1.10 1.37

2,2-Dimethylbutane 1.91 1.68 1.22 1.28

Cyclopentene 2.02 1.72 0.77 0.73

4-Methyl-1-pentene 0.13 0.12 0.07 0.08

Cyclopentane 1.49 1.27 1.07 1.01

2,3-Dimethylbutane 15.85 11.97 8.16 9.78

2-Methylpentane 10.80 8.80 6.41 7.14

3-Methylpentane 6.34 5.52 4.58 4.96

2-Methyl-1-pentene 0.46 0.37 0.20 0.31

1-Hexene 0.48 0.30 0.22 0.24

2-Ethyl-1-butene ND ND ND ND

n-Hexane 7.84 6.55 7.37 8.08

trans-2-Hexene 0.43 0.34 0.23 0.26

cis-2-Hexene 0.25 0.15 0.12 0.19

Methylcyclopentane 4.30 3.43 3.23 3.54

2,4-Dimethylpentane 1.79 1.43 1.05 1.31

Benzene 8.41 6.73 4.04 5.11

Cyclohexane 4.45 2.10 1.95 2.34

2-Methylhexane 4.03 3.88 3.69 3.97

2,3-Dimethylpentane 1.98 1.77 1.58 1.65

3-Methylhexane 4.55 3.83 3.98 4.56

1-Heptene ND ND ND ND

2,2,4-Trimethylpentane 7.35 5.41 3.97 4.66

n-Heptane 3.74 3.20 4.79 5.66

Methylcyclohexane 2.35 1.75 3.17 3.56

2,2,3-Trimethylpentane 1.71 1.47 0.89 1.23

2,3,4-Trimethylpentane 2.77 2.09 1.39 1.68

Toluene 31.27 23.34 16.69 22.25

2-Methylheptane 1.73 1.37 1.08 1.28

3-Methylheptane 1.72 1.39 1.00 1.17

1-Octene 0.27 0.09 0.07 0.10

n-Octane 2.19 1.62 1.21 1.53

Ethylbenzene 4.86 7.40 2.22 3.02

m-Xylene/p-Xylene 14.86 25.44 6.68 9.21

Styrene 2.76 1.65 0.75 1.15

o-Xylene 5.64 7.75 2.59 3.45

1-Nonene 0.54 0.21 0.15 0.18

n-Nonane 2.07 1.36 0.89 1.19

Isopropylbenzene 0.74 0.57 0.49 0.46

a-Pinene 1.05 0.93 0.30 0.31

n-Propylbenzene 1.64 0.98 0.63 0.94

m-Ethyltoluene 4.95 2.99 1.77 2.62

p-Ethyltoluene 2.76 1.61 0.99 1.52

1,3,5-Trimethylbenzene 3.15 1.86 1.14 1.54

o-Ethyltoluene 2.14 1.09 1.01 1.56

b-Pinene 1.87 0.63 0.62 1.09

1,2,4-Trimethylbenzene 7.86 3.73 2.74 3.93

1-Decene ND ND ND ND

n-Decane 3.07 2.73 0.90 1.34

1,2,3-Trimethylbenzene 1.50 0.89 0.60 0.78

m-Diethylbenzene 1.08 0.44 0.32 0.49

p-Diethylbenzene 0.85 0.41 0.29 0.39

1-Undecene 0.27 0.15 0.04 0.10

n-Undecane 2.60 4.38 0.89 1.31

1-Dodecene 0.63 ND 0.15 0.27

n-Dodecane 1.25 0.91 0.48 0.77

1-Tridecene 0.12 ND 0.02 0.06

n-Tridecane 0.55 0.08 0.20 0.35

TNMOC (w/ unknowns) 449.44 386.99 248.33 292.01

TNMOC (speciated) 363.28 318.28 214.63 235.10
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14772D2 14772R2 14765 14766D1 14766R1 14767D2

Sampling Date: 9/4/98 9/4/98 9/8/98 9/9/98 9/9/98 9/9/98

Analysis Date: 10/5/98 10/22/98 10/9/98 10/10/98 10/26/98 10/10/98

Compound

Ethylene 7.08 6.97 7.90 2.46 2.69 3.74

Acetylene 5.30 5.10 6.44 1.98 2.04 2.98

Ethane 11.44 11.19 9.15 6.48 7.05 8.42

Propylene 3.05 3.20 3.88 0.93 1.07 1.59

Propane 20.83 20.91 14.46 6.98 7.37 10.37

Propyne 0.16 0.23 0.31 0.04 0.11 0.11

Isobutane 4.12 4.18 2.77 2.07 2.17 3.14

Isobutene/1-Butene 3.33 3.42 4.26 1.23 1.27 1.81

1,3-Butadiene 0.56 0.59 0.73 0.12 0.12 0.23

n-Butane 6.30 6.34 5.83 3.60 3.80 5.44

trans-2-Butene 0.54 0.52 0.57 0.21 0.28 0.40

cis-2-Butene 0.58 0.64 0.60 0.38 0.38 0.58

3-Methyl-1-butene 0.19 0.32 0.29 0.13 0.14 0.10

Isopentane 27.77 32.22 25.50 12.77 15.44 19.17

1-Pentene 0.63 0.75 0.74 0.31 0.28 0.56

2-Methyl-1-butene 0.76 1.01 0.93 0.19 0.31 0.38

n-Pentane 7.61 7.64 6.46 2.75 2.95 4.13

Isoprene 0.90 1.09 1.27 0.55 0.53 0.78

trans-2-Pentene 1.21 1.47 1.29 0.46 0.42 0.63

cis-2-Pentene 0.70 0.89 0.79 0.35 0.36 0.54

2-Methyl-2-butene 0.99 1.38 1.42 0.22 0.36 0.52

2,2-Dimethylbutane 1.24 1.24 1.21 0.65 0.67 0.93

Cyclopentene 0.72 0.78 1.51 1.23 1.52 2.29

4-Methyl-1-pentene 0.07 0.06 0.08 ND 0.02 ND

Cyclopentane 1.03 1.00 0.89 0.41 0.40 0.56

2,3-Dimethylbutane 7.94 10.14 7.99 1.95 2.28 3.24

2-Methylpentane 6.43 7.01 5.98 2.07 2.37 3.27

3-Methylpentane 4.56 4.97 3.67 1.27 1.33 1.95

2-Methyl-1-pentene 0.18 0.32 0.34 0.06 0.09 0.13

1-Hexene 0.18 0.22 0.24 0.08 0.07 0.16

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 7.24 8.07 4.54 1.65 1.67 2.57

trans-2-Hexene 0.21 0.23 0.29 ND 0.07 ND

cis-2-Hexene 0.13 0.15 0.13 ND 0.04 ND

Methylcyclopentane 3.22 0.33 2.44 0.84 0.79 1.26

2,4-Dimethylpentane 1.06 1.30 1.09 0.48 0.55 0.81

Benzene 4.12 5.11 5.61 1.88 2.31 3.31

Cyclohexane 2.93 3.45 1.22 0.77 0.89 0.94

2-Methylhexane 3.40 4.81 2.58 0.92 1.06 1.52

2,3-Dimethylpentane 1.52 1.99 1.28 0.70 0.74 1.09

3-Methylhexane 4.09 4.70 2.72 0.93 1.07 1.52

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 4.00 4.56 3.95 0.98 1.08 1.60

n-Heptane 4.77 5.52 2.12 1.03 1.23 1.73

Methylcyclohexane 3.11 3.64 1.49 1.07 1.20 1.66

2,2,3-Trimethylpentane 1.08 1.21 0.94 0.30 0.30 0.53

2,3,4-Trimethylpentane 1.37 1.69 1.54 0.43 0.51 0.70

Toluene 16.67 22.23 18.32 7.17 9.31 12.88

2-Methylheptane 1.05 1.25 1.08 0.61 0.75 1.01

3-Methylheptane 1.03 1.27 1.11 0.52 0.70 0.86

1-Octene 0.11 0.09 0.14 0.08 0.05 0.11

n-Octane 1.18 1.54 1.37 0.75 0.92 1.32

Ethylbenzene 2.15 3.08 7.95 0.91 1.22 1.58

m-Xylene/p-Xylene 6.37 9.10 29.42 2.49 3.50 4.57

Styrene 0.61 1.31 1.28 0.46 0.63 0.98

o-Xylene 2.55 3.46 8.12 0.86 1.24 1.61

1-Nonene 0.17 0.19 0.15 0.06 0.08 0.19

n-Nonane 0.87 1.19 0.94 0.59 0.80 1.09

Isopropylbenzene 0.41 0.53 0.44 0.28 0.49 0.48

a-Pinene 0.29 0.43 0.39 0.07 0.07 0.18

n-Propylbenzene 0.68 0.91 0.78 0.35 0.56 0.62

m-Ethyltoluene 1.78 2.68 2.32 0.62 1.00 1.11

p-Ethyltoluene 1.05 1.55 1.26 0.50 0.84 0.86

1,3,5-Trimethylbenzene 1.11 1.62 1.30 0.49 0.75 0.80

o-Ethyltoluene 1.11 1.28 1.06 0.37 0.69 0.63

b-Pinene 0.67 1.14 0.66 0.19 0.38 0.45

1,2,4-Trimethylbenzene 2.67 3.95 3.43 0.99 1.58 1.96

1-Decene ND ND ND ND ND ND

n-Decane 0.93 1.43 1.08 0.68 0.95 1.26

1,2,3-Trimethylbenzene 0.77 1.11 0.84 0.34 0.54 0.60

m-Diethylbenzene 0.35 0.57 0.52 0.27 0.47 0.47

p-Diethylbenzene 0.30 0.45 0.41 0.10 0.42 0.34

1-Undecene 0.05 0.05 0.06 0.04 0.04 0.10

n-Undecane 0.90 1.37 1.08 0.42 0.73 0.94

1-Dodecene 0.09 0.35 0.13 0.02 0.12 0.21

n-Dodecane 0.49 0.85 0.47 0.12 0.21 0.27

1-Tridecene ND 0.09 ND ND ND 0.05

n-Tridecane 0.15 0.34 0.10 0.03 0.08 0.06

TNMOC (w/ unknowns) 249.93 301.10 290.00 100.62 121.48 171.48

TNMOC (speciated) 215.19 247.96 235.63 84.25 93.48 135.00
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14767R2 14788 14799 14824 14968 14987D1

Sampling Date: 9/9/98 9/10/98 9/11/98 9/14/98 9/15/98 9/17/98

Analysis Date: 10/26/98 10/12/98 10/21/98 10/17/98 10/20/98 10/20/98

Compound

Ethylene 2.76 2.99 1.88 4.44 5.42 3.06

Acetylene 2.03 2.32 1.47 13.57 4.29 2.32

Ethane 7.05 4.57 4.15 11.11 8.54 4.10

Propylene 1.10 1.25 0.88 2.14 2.36 1.38

Propane 7.28 4.62 4.46 12.83 10.50 4.87

Propyne 0.05 ND ND 0.16 0.16 0.09

Isobutane 2.20 1.16 1.33 2.74 2.96 1.41

Isobutene/1-Butene 1.31 1.76 1.50 2.88 2.97 1.53

1,3-Butadiene 0.14 0.17 0.14 0.41 0.51 0.22

n-Butane 3.77 2.45 2.32 6.67 5.61 2.53

trans-2-Butene 0.29 0.30 0.23 0.47 0.50 0.32

cis-2-Butene 0.40 0.38 0.35 0.51 0.57 0.44

3-Methyl-1-butene 0.05 0.08 0.06 0.15 0.19 0.08

Isopentane 16.67 15.11 10.11 19.19 17.92 16.63

1-Pentene 0.30 0.33 0.33 0.48 0.59 0.45

2-Methyl-1-butene 0.33 0.34 0.22 0.61 0.74 0.28

n-Pentane 2.90 3.03 2.07 5.38 4.64 2.66

Isoprene 0.57 0.43 0.39 0.78 1.10 0.72

trans-2-Pentene 0.44 0.48 0.45 0.87 1.05 0.65

cis-2-Pentene 0.38 0.39 0.37 0.61 0.66 0.44

2-Methyl-2-butene 0.31 0.31 0.56 0.86 0.99 0.41

2,2-Dimethylbutane 0.69 0.63 0.51 0.77 0.90 0.71

Cyclopentene 1.60 0.16 0.32 0.58 0.62 0.60

4-Methyl-1-pentene 0.04 0.02 ND ND 0.07 ND

Cyclopentane 0.39 0.41 0.35 0.73 0.65 0.46

2,3-Dimethylbutane 2.24 2.70 1.90 4.44 5.69 3.05

2-Methylpentane 2.47 2.21 1.52 3.75 4.12 2.81

3-Methylpentane 1.42 1.57 1.07 2.33 2.50 1.54

2-Methyl-1-pentene 0.11 0.11 0.09 0.19 0.25 0.11

1-Hexene 0.12 0.14 0.08 0.14 0.19 0.10

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.67 2.03 1.30 3.08 2.86 1.79

trans-2-Hexene 0.07 ND 0.03 0.18 0.15 0.07

cis-2-Hexene 0.05 0.07 ND 0.09 0.10 0.05

Methylcyclopentane 0.76 1.12 0.70 1.65 1.66 1.06

2,4-Dimethylpentane 0.54 0.67 0.48 0.74 0.93 0.58

Benzene 2.36 2.65 1.93 3.35 3.90 2.40

Cyclohexane 0.59 2.28 0.67 0.95 1.02 0.97

2-Methylhexane 0.85 0.90 0.88 1.53 1.77 1.43

2,3-Dimethylpentane 0.67 0.69 0.72 0.89 1.06 0.94

3-Methylhexane 1.00 1.01 0.80 1.60 1.81 1.45

1-Heptene ND ND 0.41 ND ND ND

2,2,4-Trimethylpentane 1.09 1.43 1.01 2.22 3.16 1.59

n-Heptane 1.24 0.80 0.68 1.27 1.61 1.19

Methylcyclohexane 1.22 0.69 0.66 1.00 1.12 0.88

2,2,3-Trimethylpentane 0.37 0.26 0.29 0.58 0.71 0.29

2,3,4-Trimethylpentane 0.50 0.61 0.44 1.01 1.29 0.69

Toluene 9.12 7.63 4.77 8.89 11.21 9.92

2-Methylheptane 0.72 0.68 0.41 0.68 0.83 0.74

3-Methylheptane 0.68 0.51 0.41 0.68 0.82 0.69

1-Octene 0.06 0.07 ND 0.04 0.05 0.07

n-Octane 0.89 1.02 0.62 0.85 1.04 1.14

Ethylbenzene 1.20 1.59 1.05 2.94 2.03 2.67

m-Xylene/p-Xylene 3.47 4.26 2.60 9.70 6.01 8.86

Styrene 0.78 1.36 1.07 1.13 1.19 0.89

o-Xylene 1.21 1.74 1.27 3.10 2.36 2.57

1-Nonene 0.11 0.22 0.19 0.09 0.11 0.17

n-Nonane 0.81 2.30 2.03 0.59 0.79 1.48

Isopropylbenzene 0.36 0.49 0.50 0.36 0.41 0.43

a-Pinene 0.12 ND 0.08 0.75 0.48 0.13

n-Propylbenzene 0.50 0.99 1.11 0.64 0.69 0.86

m-Ethyltoluene 0.91 2.09 2.51 1.71 2.01 1.97

p-Ethyltoluene 0.69 1.53 1.72 1.00 1.18 1.36

1,3,5-Trimethylbenzene 0.68 1.88 2.04 0.93 1.17 1.38

o-Ethyltoluene 0.47 0.90 1.08 0.81 1.05 0.93

b-Pinene 0.48 0.98 0.60 0.52 0.69 0.23

1,2,4-Trimethylbenzene 1.46 3.51 4.02 2.36 2.99 3.09

1-Decene ND ND ND ND ND ND

n-Decane 0.98 2.75 2.59 0.69 1.01 1.82

1,2,3-Trimethylbenzene 0.50 0.93 1.19 0.77 0.76 0.65

m-Diethylbenzene 0.42 0.46 0.51 0.46 0.48 0.34

p-Diethylbenzene 0.29 0.46 0.48 0.42 0.43 0.38

1-Undecene 0.05 0.11 0.10 0.03 0.08 0.06

n-Undecane 0.68 1.22 1.46 1.11 0.99 0.99

1-Dodecene 0.16 0.08 0.23 0.15 0.13 ND

n-Dodecane 0.26 0.24 0.27 0.64 0.62 0.29

1-Tridecene 0.06 ND ND ND 0.02 ND

n-Tridecane 0.13 0.06 0.04 0.15 0.19 0.07

TNMOC (w/ unknowns) 125.11 148.18 114.88 207.95 192.15 149.41

TNMOC (speciated) 93.54 98.80 85.07 162.14 152.21 113.53
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14987R1 14988D2 14988R2 14974 14977 14997

Sampling Date: 9/17/98 9/17/98 9/17/98 9/18/98 9/22/98 9/23/98

Analysis Date: 10/26/98 10/20/98 10/26/98 10/15/98 10/21/98 10/23/98

Compound

Ethylene 3.08 3.10 3.13 14.16 6.18 3.55

Acetylene 2.37 2.24 2.43 10.49 9.02 2.57

Ethane 4.09 4.03 4.14 19.33 13.48 6.82

Propylene 1.34 1.37 1.40 6.47 2.89 1.54

Propane 4.83 4.88 4.90 24.75 11.97 7.27

Propyne 0.10 0.03 0.06 0.48 0.28 ND

Isobutane 1.39 1.41 1.38 6.29 3.55 1.65

Isobutene/1-Butene 1.64 1.68 1.66 6.49 3.49 1.96

1,3-Butadiene 0.21 0.33 0.21 1.42 0.56 0.31

n-Butane 2.57 2.67 2.56 9.57 6.66 3.84

trans-2-Butene 0.29 0.30 0.33 0.97 0.55 0.38

cis-2-Butene 0.40 0.43 0.39 1.04 0.53 0.39

3-Methyl-1-butene 0.06 0.04 0.04 0.36 0.21 0.12

Isopentane 17.16 15.38 16.09 37.01 23.53 13.95

1-Pentene 0.47 0.44 0.42 1.13 0.61 0.44

2-Methyl-1-butene 0.30 0.39 0.36 1.86 0.73 0.50

n-Pentane 2.58 2.62 2.59 11.34 5.63 3.19

Isoprene 0.64 0.77 0.73 1.51 0.69 0.85

trans-2-Pentene 0.52 0.60 0.63 2.77 1.01 0.66

cis-2-Pentene 0.44 0.46 0.48 1.46 0.63 0.47

2-Methyl-2-butene 0.38 0.39 0.45 2.98 0.95 0.55

2,2-Dimethylbutane 0.56 0.64 0.58 1.64 0.93 0.73

Cyclopentene 0.61 0.73 0.73 0.90 0.89 0.46

4-Methyl-1-pentene ND 0.04 0.05 0.12 ND ND

Cyclopentane 0.43 0.40 0.40 1.50 0.78 0.59

2,3-Dimethylbutane 2.99 3.05 3.04 17.01 6.34 3.25

2-Methylpentane 2.82 2.57 2.58 10.48 4.92 2.81

3-Methylpentane 1.53 1.58 1.59 6.71 3.00 1.76

2-Methyl-1-pentene 0.09 0.11 0.11 0.61 0.18 0.15

1-Hexene 0.08 0.09 0.07 0.47 0.18 0.16

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.84 1.81 1.80 7.38 3.55 1.94

trans-2-Hexene 0.08 0.07 0.10 0.54 0.19 0.07

cis-2-Hexene 0.07 0.06 0.06 0.32 0.14 0.07

Methylcyclopentane 0.98 1.00 1.01 4.37 2.08 1.14

2,4-Dimethylpentane 0.59 0.58 0.63 2.05 0.91 0.66

Benzene 2.34 2.53 2.53 9.52 4.82 2.76

Cyclohexane 0.97 1.34 1.37 2.33 1.16 1.17

2-Methylhexane 1.66 1.48 1.65 4.42 2.14 1.45

2,3-Dimethylpentane 0.95 0.96 0.87 2.37 1.20 0.95

3-Methylhexane 1.49 1.48 1.49 4.91 2.26 1.28

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 1.56 1.66 1.67 8.38 3.03 1.93

n-Heptane 1.14 1.21 1.25 4.05 2.22 1.05

Methylcyclohexane 0.86 0.91 0.92 2.79 1.81 1.02

2,2,3-Trimethylpentane 0.25 0.38 0.35 2.00 0.91 0.45

2,3,4-Trimethylpentane 0.68 0.71 0.69 3.34 1.21 0.82

Toluene 9.72 10.11 9.94 37.77 12.97 6.87

2-Methylheptane 0.71 0.79 0.79 1.92 1.00 0.57

3-Methylheptane 0.58 0.56 0.70 1.92 1.10 0.60

1-Octene 0.07 0.07 0.06 0.15 ND 0.09

n-Octane 1.15 1.16 1.14 2.45 1.19 0.80

Ethylbenzene 2.57 2.77 2.58 5.93 3.54 1.38

m-Xylene/p-Xylene 8.53 9.42 9.30 18.58 11.62 3.82

Styrene 0.90 0.69 0.86 1.93 1.74 0.82

o-Xylene 2.49 2.72 2.61 6.95 3.92 1.58

1-Nonene 0.14 0.15 0.24 0.39 0.14 0.10

n-Nonane 1.47 1.53 1.47 1.92 0.89 0.67

Isopropylbenzene 0.33 0.46 0.31 0.74 0.45 0.37

a-Pinene 0.16 0.35 0.50 3.22 0.22 0.09

n-Propylbenzene 0.96 0.92 0.87 1.87 0.82 0.60

m-Ethyltoluene 2.18 2.16 2.22 6.08 2.28 1.47

p-Ethyltoluene 1.60 1.43 1.47 3.20 1.37 0.93

1,3,5-Trimethylbenzene 1.54 1.50 1.62 3.36 1.39 0.88

o-Ethyltoluene 1.32 1.01 1.14 3.11 1.01 0.88

b-Pinene 0.23 0.54 0.35 1.76 0.52 0.35

1,2,4-Trimethylbenzene 3.75 3.56 3.75 9.08 3.55 2.32

1-Decene ND ND ND ND ND ND

n-Decane 1.76 1.88 1.81 3.11 1.06 0.85

1,2,3-Trimethylbenzene 1.28 0.86 1.13 2.77 0.89 0.72

m-Diethylbenzene 1.26 0.56 0.89 1.00 0.46 0.42

p-Diethylbenzene 1.00 0.39 0.70 0.85 0.39 0.25

1-Undecene 0.07 0.07 0.07 0.24 0.06 0.04

n-Undecane 1.22 1.04 1.13 2.21 0.90 0.78

1-Dodecene ND ND ND 0.26 0.05 0.07

n-Dodecane 0.28 0.30 0.27 1.16 0.45 0.32

1-Tridecene 0.03 ND 0.02 0.11 ND ND

n-Tridecane 0.06 0.05 0.05 0.28 0.15 0.19

TNMOC (w/ unknowns) 150.08 148.02 150.01 472.64 233.66 135.64

TNMOC (speciated) 116.85 115.97 117.94 384.43 192.13 106.53
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 14992 15016D1 15016R1 15017D2 15017R2 15036

Sampling Date: 9/24/98 9/25/98 9/25/98 9/25/98 9/25/98 9/28/98

Analysis Date: 10/23/98 10/24/98 10/27/98 10/24/98 10/27/98 10/27/98

Compound

Ethylene 4.34 4.32 4.24 4.49 4.25 20.51

Acetylene 6.62 2.85 2.79 2.90 2.90 19.08

Ethane 12.79 8.32 8.22 8.52 8.25 32.00

Propylene 1.85 1.77 1.80 1.85 1.89 9.43

Propane 12.03 8.39 8.38 8.53 8.29 24.44

Propyne 0.11 0.14 0.06 0.11 0.13 0.75

Isobutane 3.59 2.81 2.80 2.89 2.84 7.68

Isobutene/1-Butene 2.04 1.95 2.01 1.98 2.00 10.03

1,3-Butadiene 0.27 0.33 0.33 0.38 0.33 2.04

n-Butane 6.73 5.34 5.36 5.49 5.38 19.32

trans-2-Butene 0.36 0.36 0.35 0.28 0.31 1.38

cis-2-Butene 0.41 0.44 0.45 0.44 0.42 1.47

3-Methyl-1-butene 0.12 0.12 0.14 0.13 0.10 0.50

Isopentane 22.26 15.75 15.51 16.93 16.74 60.88

1-Pentene 0.47 0.43 0.41 0.42 0.48 1.92

2-Methyl-1-butene 0.37 0.40 0.43 0.51 0.48 3.03

n-Pentane 4.73 3.87 3.85 3.96 3.90 18.87

Isoprene 0.47 0.54 0.53 0.53 0.57 2.06

trans-2-Pentene 0.64 0.62 0.62 0.68 0.66 4.48

cis-2-Pentene 0.45 0.47 0.50 0.44 0.51 2.34

2-Methyl-2-butene 0.49 0.39 0.41 0.40 0.39 4.74

2,2-Dimethylbutane 0.88 0.75 0.72 0.72 0.69 2.62

Cyclopentene 0.88 0.41 0.38 0.34 0.35 2.19

4-Methyl-1-pentene ND ND ND ND ND 0.28

Cyclopentane 0.59 0.49 0.53 0.52 0.58 2.33

2,3-Dimethylbutane 3.61 3.89 3.83 3.90 3.85 27.93

2-Methylpentane 3.73 2.76 2.67 3.00 2.95 17.38

3-Methylpentane 2.17 1.84 1.87 1.93 1.85 10.81

2-Methyl-1-pentene 0.14 0.12 0.12 0.13 0.12 0.95

1-Hexene 0.12 0.22 0.18 0.19 0.20 0.76

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 2.82 2.12 2.18 2.15 2.29 11.87

trans-2-Hexene 0.08 0.08 0.09 0.09 0.14 1.08

cis-2-Hexene 0.11 0.09 0.13 0.11 0.09 0.56

Methylcyclopentane 1.41 1.21 1.26 1.31 1.27 6.65

2,4-Dimethylpentane 0.79 0.64 0.68 0.62 0.61 2.83

Benzene 3.97 3.02 3.07 3.11 3.08 14.75

Cyclohexane 0.97 2.38 2.46 1.12 1.14 2.50

2-Methylhexane 1.61 1.92 1.90 2.02 1.93 6.73

2,3-Dimethylpentane 1.01 0.93 0.99 1.00 0.93 2.95

3-Methylhexane 1.65 1.82 1.85 1.85 1.84 7.56

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 1.90 1.91 1.88 2.00 1.96 11.72

n-Heptane 1.53 1.86 1.91 1.91 1.88 6.20

Methylcyclohexane 1.23 1.30 1.35 1.30 1.30 3.64

2,2,3-Trimethylpentane 0.54 0.51 0.41 0.50 0.49 2.98

2,3,4-Trimethylpentane 0.78 0.79 0.78 0.77 0.79 4.58

Toluene 8.33 7.21 7.42 7.34 7.20 50.54

2-Methylheptane 0.75 0.67 0.70 0.73 0.65 3.20

3-Methylheptane 0.76 0.57 0.70 0.57 0.67 3.19

1-Octene 0.05 ND ND 0.05 0.06 0.24

n-Octane 1.07 1.00 0.99 1.05 0.96 4.35

Ethylbenzene 1.72 1.36 1.41 1.39 1.33 10.08

m-Xylene/p-Xylene 5.07 3.82 3.89 3.90 3.83 33.71

Styrene 0.91 0.64 0.61 0.67 0.68 2.72

o-Xylene 1.92 1.57 1.52 1.57 1.45 11.84

1-Nonene 0.06 0.06 0.03 0.11 0.06 0.46

n-Nonane 0.79 0.69 0.71 0.69 0.73 2.78

Isopropylbenzene 0.44 0.37 0.31 0.38 0.33 1.00

a-Pinene 0.18 0.20 0.12 0.14 0.12 2.44

n-Propylbenzene 0.53 0.53 0.45 0.53 0.43 2.52

m-Ethyltoluene 1.39 1.26 1.21 1.32 1.12 8.72

p-Ethyltoluene 0.92 0.87 0.71 0.86 0.71 4.58

1,3,5-Trimethylbenzene 0.79 0.75 0.68 0.82 0.69 4.97

o-Ethyltoluene 0.81 0.66 0.62 0.72 0.57 3.64

b-Pinene 0.19 0.29 0.25 0.28 0.27 1.72

1,2,4-Trimethylbenzene 1.98 1.89 1.82 1.86 1.82 13.56

1-Decene ND ND ND ND ND ND

n-Decane 0.65 0.52 0.62 0.54 0.65 3.55

1,2,3-Trimethylbenzene 0.52 0.44 0.67 0.51 0.58 3.61

m-Diethylbenzene 0.36 0.38 0.48 0.39 0.46 1.35

p-Diethylbenzene 0.30 0.28 0.39 0.30 0.34 1.08

1-Undecene ND 0.02 0.03 0.03 0.02 0.29

n-Undecane 0.62 0.60 0.56 0.63 0.55 2.58

1-Dodecene 0.03 ND ND ND ND 0.45

n-Dodecane 0.22 0.22 0.25 0.25 0.18 1.61

1-Tridecene ND 0.01 0.03 0.01 0.02 0.09

n-Tridecane 0.05 0.04 0.03 0.04 0.03 0.45

TNMOC (w/ unknowns) 173.36 137.99 145.19 141.68 139.42 705.84

TNMOC (speciated) 145.03 117.61 117.63 120.16 117.68 548.09
SNMOC 1998 REPORT

SITE CODE: DLTX

All concentrations reported in ppbC

Sample No.: 15056 15059

Sampling Date: 9/29/98 9/30/98

Analysis Date: 10/27/98 10/28/98

Compound

Ethylene 19.23 10.24

Acetylene 13.49 10.01

Ethane 23.95 12.06

Propylene 9.01 4.93

Propane 49.47 15.26

Propyne 0.69 0.34

Isobutane 8.81 10.52

Isobutene/1-Butene 10.52 5.40

1,3-Butadiene 1.49 0.93

n-Butane 29.48 11.00

trans-2-Butene 1.76 0.72

cis-2-Butene 2.05 0.79

3-Methyl-1-butene 0.79 0.35

Isopentane 82.67 50.49

1-Pentene 2.48 1.02

2-Methyl-1-butene 3.42 1.33

n-Pentane 23.60 19.13

Isoprene 0.83 1.05

trans-2-Pentene 5.64 1.91

cis-2-Pentene 2.84 1.08

2-Methyl-2-butene 5.63 1.92

2,2-Dimethylbutane 2.59 1.46

Cyclopentene 2.19 0.90

4-Methyl-1-pentene 0.28 0.13

Cyclopentane 2.27 1.57

2,3-Dimethylbutane 30.62 12.34

2-Methylpentane 17.11 9.42

3-Methylpentane 11.69 6.54

2-Methyl-1-pentene 0.97 0.39

1-Hexene 0.78 0.37

2-Ethyl-1-butene ND ND

n-Hexane 15.40 8.90

trans-2-Hexene 0.90 0.34

cis-2-Hexene 0.57 0.22

Methylcyclopentane 7.53 5.12

2,4-Dimethylpentane 2.70 1.60

Benzene 13.04 7.04

Cyclohexane 5.06 5.74

2-Methylhexane 10.65 4.04

2,3-Dimethylpentane 4.23 1.90

3-Methylhexane 11.17 4.97

1-Heptene ND ND

2,2,4-Trimethylpentane 11.30 6.09

n-Heptane 9.91 5.20

Methylcyclohexane 5.99 3.65

2,2,3-Trimethylpentane 3.10 1.68

2,3,4-Trimethylpentane 4.12 2.26

Toluene 54.78 940.16

2-Methylheptane 2.94 1.80

3-Methylheptane 2.90 1.72

1-Octene 0.20 0.16

n-Octane 3.49 3.23

Ethylbenzene 7.69 6.28

m-Xylene/p-Xylene 25.47 20.79

Styrene 3.25 4.14

o-Xylene 9.48 6.86

1-Nonene 0.49 0.37

n-Nonane 3.23 2.31

Isopropylbenzene 1.07 0.84

a-Pinene 3.37 0.89

n-Propylbenzene 2.73 1.37

m-Ethyltoluene 8.51 4.18

p-Ethyltoluene 4.72 2.46

1,3,5-Trimethylbenzene 5.46 2.69

o-Ethyltoluene 3.51 1.65

b-Pinene 1.79 0.77

1,2,4-Trimethylbenzene 13.25 6.22

1-Decene ND ND

n-Decane 5.33 3.33

1,2,3-Trimethylbenzene 3.23 1.51

m-Diethylbenzene 1.34 0.75

p-Diethylbenzene 1.09 0.63

1-Undecene 0.24 0.10

n-Undecane 3.47 3.16

1-Dodecene 0.51 0.30

n-Dodecane 2.09 1.52

1-Tridecene 0.13 0.10

n-Tridecane 0.56 0.24

TNMOC (w/ unknowns) 784.54 1267.42

TNMOC (speciated) 648.32 1145.75
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 14674 14675 14686 14665 14697 14693

Sampling Date: 8/25/98 8/27/98 8/29/98 9/1/98 9/2/98 9/3/98

Analysis Date: 9/23/98 10/16/98 10/15/98 10/2/98 11/12/98 10/3/98

Compound

Ethylene 4.64 1.70 2.96 8.41 3.89 5.58

Acetylene 4.19 1.73 2.53 8.04 3.30 5.22

Ethane 8.45 4.71 11.58 12.35 11.32 6.83

Propylene 2.53 0.97 1.53 4.08 1.89 2.72

Propane 14.01 12.81 28.64 24.91 15.21 12.88

Propyne ND ND ND 0.25 0.12 0.17

Isobutane 5.05 1.05 3.56 11.73 2.55 2.28

Isobutene/1-Butene 3.92 1.88 1.62 3.35 2.23 2.47

1,3-Butadiene 0.37 0.10 0.28 0.80 0.32 0.52

n-Butane 9.65 2.69 10.11 12.77 6.42 4.79

trans-2-Butene 0.54 0.22 0.39 0.81 0.30 0.41

cis-2-Butene 0.63 0.34 0.44 1.04 0.38 0.50

3-Methyl-1-butene 0.27 ND 0.09 1.35 0.07 0.17

Isopentane 51.10 12.31 17.34 47.27 22.63 17.82

1-Pentene 0.88 0.36 0.51 1.10 0.48 0.50

2-Methyl-1-butene 0.88 0.24 0.49 1.56 0.44 0.62

n-Pentane 6.32 1.68 4.65 12.79 4.24 4.59

Isoprene 0.72 0.37 0.49 0.95 0.56 0.48

trans-2-Pentene 1.00 0.42 0.63 1.79 0.63 0.77

cis-2-Pentene 0.74 0.34 0.50 1.07 0.42 0.52

2-Methyl-2-butene 0.84 0.23 0.37 1.64 0.25 0.37

2,2-Dimethylbutane 0.94 0.50 0.71 1.10 0.63 0.77

Cyclopentene 0.58 0.15 0.26 0.42 0.35 0.24

4-Methyl-1-pentene 0.09 ND ND 0.04 ND ND

Cyclopentane 0.83 0.31 0.65 1.29 0.62 0.72

2,3-Dimethylbutane 2.42 0.79 2.05 3.12 1.30 1.75

2-Methylpentane 4.51 1.40 3.12 7.08 3.51 3.52

3-Methylpentane 3.05 1.02 2.03 5.16 2.03 2.53

2-Methyl-1-pentene 0.36 0.12 0.12 0.39 0.14 0.21

1-Hexene 0.36 0.11 0.16 0.28 0.16 0.16

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 4.11 1.16 2.36 11.64 2.35 2.72

trans-2-Hexene 0.20 ND 0.07 0.33 0.11 0.13

cis-2-Hexene 0.10 ND 0.07 0.24 0.09 0.09

Methylcyclopentane 2.28 0.62 1.51 4.70 1.66 1.93

2,4-Dimethylpentane 1.63 0.72 1.17 2.56 1.16 1.40

Benzene 3.78 1.81 2.92 6.93 3.91 4.16

Cyclohexane 2.46 0.72 1.55 110.41 1.21 1.33

2-Methylhexane 2.19 1.10 1.27 2.77 1.41 1.74

2,3-Dimethylpentane 2.49 1.19 1.75 3.80 1.84 2.26

3-Methylhexane 2.66 1.30 1.33 3.31 1.63 1.84

1-Heptene ND 0.68 ND ND ND ND

2,2,4-Trimethylpentane 4.01 1.09 2.66 5.31 2.89 3.33

n-Heptane 1.95 1.13 1.05 2.55 1.28 1.43

Methylcyclohexane 3.18 0.60 0.92 2.84 0.96 1.04

2,2,3-Trimethylpentane 7.28 4.34 2.27 2.20 1.84 1.50

2,3,4-Trimethylpentane 113.85 72.02 32.46 21.59 23.87 17.03

Toluene 188.03 102.54 50.09 50.24 38.18 30.08

2-Methylheptane 1.95 1.32 1.14 1.38 0.94 0.89

3-Methylheptane 2.26 1.64 1.10 1.22 0.97 0.92

1-Octene 0.46 0.41 0.29 0.18 0.25 0.11

n-Octane 1.47 0.90 0.91 1.53 0.92 0.87

Ethylbenzene 3.62 2.18 4.16 4.70 2.54 2.47

m-Xylene/p-Xylene 9.39 5.52 9.80 10.52 6.92 6.68

Styrene 9.50 7.88 5.07 4.23 5.21 2.02

o-Xylene 10.89 7.44 5.86 5.25 4.18 3.62

1-Nonene 11.49 8.66 5.08 3.33 3.51 2.44

n-Nonane 1.29 1.54 0.91 1.84 0.64 0.57

Isopropylbenzene 0.51 0.32 0.36 0.44 0.48 0.31

a-Pinene 0.19 0.31 0.09 0.34 0.09 0.26

n-Propylbenzene 0.86 0.55 0.72 0.95 0.67 0.58

m-Ethyltoluene 1.77 1.07 1.78 2.67 1.67 1.42

p-Ethyltoluene 1.15 0.88 1.11 1.51 0.95 0.78

1,3,5-Trimethylbenzene 1.68 1.57 1.78 2.14 1.06 1.05

o-Ethyltoluene 0.64 0.55 0.76 0.94 0.70 0.59

b-Pinene 0.10 2.33 2.16 1.01 3.32 0.31

1,2,4-Trimethylbenzene 2.62 1.99 3.01 2.79 2.50 2.16

1-Decene ND ND ND ND ND ND

n-Decane 2.57 1.88 1.34 3.56 1.01 0.74

1,2,3-Trimethylbenzene 0.73 0.48 0.50 0.87 0.68 0.48

m-Diethylbenzene 0.52 0.54 0.43 0.41 0.46 0.33

p-Diethylbenzene 0.67 0.48 0.57 0.49 0.66 0.31

1-Undecene 0.19 0.05 0.16 0.22 ND ND

n-Undecane 5.06 1.30 1.11 2.40 0.82 0.47

1-Dodecene 0.37 0.30 0.70 0.43 1.07 0.26

n-Dodecane 9.72 0.37 0.46 4.41 0.32 0.15

1-Tridecene ND ND 0.04 ND ND ND

n-Tridecane 1.17 0.09 0.12 1.42 0.11 0.04

TNMOC (w/ unknowns) 2206.87 944.38 558.42 633.12 399.35 299.86

TNMOC (speciated) 552.87 292.12 252.76 469.57 213.41 183.00
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 14791 14790 14792D1 14792R1 14793D2 14793R2

Sampling Date: 9/4/98 9/5/98 9/8/98 9/8/98 9/8/98 9/8/98

Analysis Date: 10/17/98 10/4/98 10/9/98 10/24/98 10/9/98 10/24/98

Compound

Ethylene 3.78 2.65 10.26 9.16 10.35 9.24

Acetylene 17.42 2.34 9.92 8.47 9.71 8.43

Ethane 12.71 6.75 19.42 17.88 18.00 17.97

Propylene 7.93 1.45 5.51 4.95 5.25 4.87

Propane 104.04 11.61 191.96 169.25 185.32 170.09

Propyne 0.51 ND 0.23 0.25 0.27 0.20

Isobutane 7.62 1.54 6.26 5.54 6.06 5.53

Isobutene/1-Butene 4.37 1.96 3.15 2.74 3.19 2.81

1,3-Butadiene 1.42 0.19 1.03 0.94 1.04 0.99

n-Butane 27.41 3.48 19.44 17.06 19.02 17.09

trans-2-Butene 1.32 0.32 0.84 0.72 0.75 0.65

cis-2-Butene 1.39 0.38 0.82 0.78 0.84 0.75

3-Methyl-1-butene 1.49 ND 0.42 0.20 0.18 0.24

Isopentane 41.41 12.15 19.88 17.87 19.32 19.00

1-Pentene 1.84 0.34 0.94 0.77 0.77 0.81

2-Methyl-1-butene 2.72 0.31 1.37 1.18 1.06 1.21

n-Pentane 16.88 3.11 7.54 6.66 7.40 6.69

Isoprene 1.12 0.39 0.89 0.82 0.79 0.88

trans-2-Pentene 3.18 0.44 1.77 1.52 1.55 1.57

cis-2-Pentene 1.87 0.34 1.07 0.96 0.92 0.98

2-Methyl-2-butene 3.68 0.26 1.88 1.62 1.42 1.70

2,2-Dimethylbutane 1.52 0.50 1.07 0.94 1.05 1.01

Cyclopentene 0.95 0.34 0.69 0.38 0.47 0.45

4-Methyl-1-pentene 0.19 ND 0.19 0.07 0.09 0.09

Cyclopentane 1.89 0.49 0.89 0.96 0.98 0.94

2,3-Dimethylbutane 4.51 1.21 2.33 2.53 2.35 2.51

2-Methylpentane 11.44 2.49 6.24 6.03 5.95 6.09

3-Methylpentane 7.48 1.90 4.64 3.97 4.42 3.99

2-Methyl-1-pentene 0.72 0.07 0.44 0.38 0.34 0.35

1-Hexene 0.49 0.11 0.30 0.24 0.27 0.23

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 9.14 1.79 5.62 4.97 5.12 5.00

trans-2-Hexene 0.78 0.06 0.43 0.43 0.37 0.45

cis-2-Hexene 0.44 0.06 1.17 1.08 1.09 1.06

Methylcyclopentane 5.71 1.01 3.66 3.28 3.46 3.28

2,4-Dimethylpentane 4.61 0.81 2.79 2.62 2.53 2.48

Benzene 12.44 1.93 9.06 8.01 7.31 7.97

Cyclohexane 5.12 1.00 2.11 2.08 2.24 1.90

2-Methylhexane 4.14 1.14 3.08 2.56 2.53 2.71

2,3-Dimethylpentane 7.11 1.28 4.42 3.85 3.89 3.90

3-Methylhexane 4.54 0.94 3.42 2.89 2.93 2.97

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 9.44 1.84 6.54 5.72 5.69 5.74

n-Heptane 3.75 0.82 2.85 2.59 2.52 2.61

Methylcyclohexane 2.48 0.64 2.02 1.72 1.70 1.74

2,2,3-Trimethylpentane 2.67 1.83 1.77 1.60 1.60 1.72

2,3,4-Trimethylpentane 17.62 26.51 11.65 10.20 10.38 10.91

Toluene 53.10 40.98 39.82 35.46 33.48 36.66

2-Methylheptane 1.82 0.83 1.34 1.23 1.22 1.24

3-Methylheptane 1.95 0.94 1.44 1.07 1.06 1.09

1-Octene 0.26 0.17 0.17 0.14 0.12 0.16

n-Octane 1.54 0.62 1.24 1.23 1.16 1.32

Ethylbenzene 7.29 1.64 4.95 4.46 4.08 4.61

m-Xylene/p-Xylene 20.97 4.44 14.18 13.64 11.59 13.93

Styrene 6.33 3.77 2.18 2.34 1.96 2.46

o-Xylene 8.47 3.37 5.55 5.62 4.79 5.82

1-Nonene 2.79 3.34 1.88 1.83 1.59 1.92

n-Nonane 1.27 0.54 0.90 0.89 0.82 0.88

Isopropylbenzene 0.60 0.27 0.35 0.42 0.38 0.41

a-Pinene 0.80 0.22 0.52 0.40 0.41 0.49

n-Propylbenzene 1.48 0.45 0.98 1.09 0.86 1.09

m-Ethyltoluene 4.56 0.85 2.93 3.09 2.45 3.16

p-Ethyltoluene 2.36 0.53 1.49 1.67 1.32 1.68

1,3,5-Trimethylbenzene 2.87 0.74 1.87 1.97 1.67 2.00

o-Ethyltoluene 1.70 0.39 1.15 1.30 1.06 1.27

b-Pinene 1.25 1.74 0.80 0.93 0.77 0.90

1,2,4-Trimethylbenzene 7.27 1.27 4.64 5.00 3.99 5.16

1-Decene ND ND ND ND ND ND

n-Decane 1.88 0.72 1.24 1.18 1.09 1.25

1,2,3-Trimethylbenzene 1.63 0.27 0.90 1.08 0.90 1.14

m-Diethylbenzene 0.57 0.27 0.48 0.49 0.52 0.55

p-Diethylbenzene 0.65 0.30 0.49 0.57 0.48 0.52

1-Undecene 0.22 ND 0.06 0.17 0.10 0.07

n-Undecane 1.71 0.61 1.06 1.13 0.94 1.09

1-Dodecene 0.21 0.45 0.11 0.04 0.08 0.11

n-Dodecane 0.73 0.19 0.54 0.55 0.35 0.42

1-Tridecene ND ND ND ND 0.03 ND

n-Tridecane 0.10 0.08 0.06 0.13 0.06 0.09

TNMOC (w/ unknowns) 687.83 315.69 569.52 513.83 523.44 524.23

TNMOC (speciated) 519.70 168.75 475.27 427.59 441.82 433.30
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 14830 14808 14829 15013 15011 15012

Sampling Date: 9/9/98 9/10/98 9/11/98 9/12/98 9/14/98 9/15/98

Analysis Date: 10/10/98 10/14/98 10/12/98 10/13/98 10/17/98 10/17/98

Compound

Ethylene 9.55 3.56 4.25 6.79 4.89 1.28

Acetylene 8.97 3.45 4.23 6.26 11.65 1.14

Ethane 25.01 10.81 9.19 24.00 10.07 6.61

Propylene 4.80 1.63 2.17 3.22 5.54 0.68

Propane 242.48 18.38 18.32 86.46 48.99 7.34

Propyne 0.29 ND 0.07 0.22 0.28 ND

Isobutane 5.54 2.69 3.49 4.91 5.82 1.41

Isobutene/1-Butene 2.93 1.77 2.07 2.23 3.42 1.30

1,3-Butadiene 0.80 0.26 0.36 0.55 1.05 0.11

n-Butane 22.67 7.36 6.87 17.39 18.85 3.42

trans-2-Butene 0.55 0.39 0.35 0.42 1.16 0.32

cis-2-Butene 0.70 0.49 0.47 0.62 1.33 0.33

3-Methyl-1-butene 1.28 0.10 1.20 0.62 0.92 26.14

Isopentane 13.00 17.62 35.56 25.67 32.59 8.83

1-Pentene 0.99 0.64 0.35 1.02 1.52 0.29

2-Methyl-1-butene 1.22 0.53 0.61 1.12 2.28 0.13

n-Pentane 8.18 5.18 5.07 10.15 13.23 1.83

Isoprene 0.75 0.72 0.78 0.60 0.88 0.34

trans-2-Pentene 1.49 0.74 0.68 1.16 2.58 0.37

cis-2-Pentene 0.92 0.52 0.53 0.74 1.56 0.28

2-Methyl-2-butene 1.26 0.51 0.50 0.50 3.06 0.14

2,2-Dimethylbutane 1.07 0.65 0.72 0.84 1.18 0.47

Cyclopentene 0.41 0.15 0.47 0.35 0.64 0.11

4-Methyl-1-pentene 0.08 ND ND 0.09 0.12 ND

Cyclopentane 1.05 0.63 0.78 0.94 1.44 0.36

2,3-Dimethylbutane 2.60 1.24 1.49 2.55 3.56 0.71

2-Methylpentane 6.44 2.94 3.55 6.92 8.33 1.22

3-Methylpentane 4.35 2.09 2.37 5.01 5.54 0.91

2-Methyl-1-pentene 0.45 0.12 0.18 0.32 0.54 ND

1-Hexene 0.26 0.13 0.12 0.31 0.34 ND

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 5.17 2.68 3.29 6.58 6.59 1.03

trans-2-Hexene 0.34 0.15 0.11 0.24 0.57 0.03

cis-2-Hexene 0.41 0.08 0.53 0.36 0.35 ND

Methylcyclopentane 3.27 1.65 1.98 3.35 4.30 0.69

2,4-Dimethylpentane 2.35 1.16 1.21 2.37 3.60 0.55

Benzene 7.25 3.24 4.29 6.38 9.01 1.39

Cyclohexane 1.72 3.86 16.67 2.16 2.07 0.91

2-Methylhexane 2.81 1.25 2.20 2.38 2.86 0.93

2,3-Dimethylpentane 3.70 1.77 2.16 3.72 4.91 0.80

3-Methylhexane 2.80 1.50 2.69 2.69 3.12 0.64

1-Heptene 0.92 ND 0.94 ND ND ND

2,2,4-Trimethylpentane 5.07 2.49 2.75 4.85 6.51 1.06

n-Heptane 2.28 1.24 2.14 2.09 2.75 0.50

Methylcyclohexane 1.57 1.08 4.21 1.66 1.79 0.58

2,2,3-Trimethylpentane 1.68 1.43 1.38 1.62 2.23 1.29

2,3,4-Trimethylpentane 12.53 18.15 13.68 12.79 20.32 20.76

Toluene 37.72 34.10 37.64 39.26 46.60 30.12

2-Methylheptane 1.13 0.93 1.27 1.03 1.38 0.66

3-Methylheptane 1.30 0.96 1.32 1.17 1.26 0.73

1-Octene 0.18 0.16 0.12 0.18 0.19 ND

n-Octane 1.19 1.04 1.45 1.09 1.22 0.59

Ethylbenzene 4.88 2.88 2.97 6.13 4.91 1.11

m-Xylene/p-Xylene 14.39 6.34 7.99 18.41 13.87 2.98

Styrene 2.34 3.23 4.78 3.17 7.21 3.53

o-Xylene 5.50 3.57 3.86 6.82 6.25 2.67

1-Nonene 1.95 2.68 2.20 1.93 2.80 2.82

n-Nonane 0.89 1.79 2.06 1.24 0.90 0.44

Isopropylbenzene 0.35 0.42 0.56 0.59 0.49 0.37

a-Pinene 0.45 0.37 0.35 0.98 0.42 ND

n-Propylbenzene 0.72 0.69 0.93 1.06 1.04 0.39

m-Ethyltoluene 2.11 1.54 2.17 2.63 3.01 0.71

p-Ethyltoluene 1.18 1.02 1.52 1.56 1.63 0.55

1,3,5-Trimethylbenzene 1.47 1.45 2.23 1.78 1.96 0.63

o-Ethyltoluene 0.86 0.75 0.86 1.06 1.17 0.36

b-Pinene 0.52 1.61 2.84 1.48 1.09 1.80

1,2,4-Trimethylbenzene 3.17 2.40 4.25 3.94 4.81 1.00

1-Decene ND ND ND ND ND ND

n-Decane 1.31 2.22 4.20 1.89 1.47 0.61

1,2,3-Trimethylbenzene 0.76 0.77 1.19 0.78 1.25 0.26

m-Diethylbenzene 0.26 0.41 0.43 0.56 0.57 0.40

p-Diethylbenzene 0.31 0.43 0.54 0.49 0.59 0.41

1-Undecene 0.05 0.16 0.16 0.13 0.11 ND

n-Undecane 1.24 1.46 4.33 1.58 0.98 0.52

1-Dodecene ND 0.53 0.54 0.32 0.18 0.49

n-Dodecane 0.28 0.30 1.84 0.55 0.43 0.16

1-Tridecene ND ND ND ND ND ND

n-Tridecane ND 0.05 0.23 0.19 0.06 0.11

TNMOC (w/ unknowns) 4856.83 920.76 552.09 531.22 532.90 255.78

TNMOC (speciated) 501.50 201.28 261.85 367.19 372.19 151.64
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 15014D1 15014R1 15015D2 15015R2 15028 15094

Sampling Date: 9/18/98 9/18/98 9/18/98 9/18/98 9/22/98 9/23/98

Analysis Date: 10/26/98 12/7/98 10/21/98 10/27/98 10/21/98 10/21/98

Compound

Ethylene 11.00 12.77 11.18 10.93 6.26 8.45

Acetylene 8.98 10.92 8.95 8.92 5.28 6.89

Ethane 24.01 27.55 24.32 23.70 5.64 11.60

Propylene 5.09 6.08 5.17 5.15 2.84 3.87

Propane 54.59 64.54 55.81 55.19 45.03 40.83

Propyne 0.38 0.50 0.31 0.32 0.26 0.27

Isobutane 6.58 7.67 7.63 7.62 1.82 4.07

Isobutene/1-Butene 3.30 3.68 3.33 3.37 2.41 2.72

1,3-Butadiene 1.17 1.36 1.17 1.16 0.65 0.73

n-Butane 18.70 21.94 21.32 21.01 6.23 11.51

trans-2-Butene 0.77 0.97 0.81 0.76 0.43 0.53

cis-2-Butene 0.98 1.05 0.93 1.00 0.51 0.69

3-Methyl-1-butene 2.20 2.43 0.57 0.48 1.01 0.56

Isopentane 0.00 @ 0.00 @ 0.00 @ 0.00 @ 14.37 25.18

1-Pentene 1.17 1.28 1.17 1.17 0.57 0.76

2-Methyl-1-butene 1.72 2.08 1.78 1.72 0.76 0.99

n-Pentane 13.00 15.26 14.62 14.33 5.53 7.43

Isoprene 0.86 0.85 0.91 0.85 0.68 0.73

trans-2-Pentene 2.02 2.31 2.03 2.12 1.00 1.25

cis-2-Pentene 1.19 1.28 1.20 1.26 0.61 0.73

2-Methyl-2-butene 1.71 1.87 1.68 1.57 0.93 1.42

2,2-Dimethylbutane 1.24 1.30 1.27 1.20 0.66 0.79

Cyclopentene 0.75 0.44 0.57 0.63 0.29 0.47

4-Methyl-1-pentene 0.16 0.14 0.06 0.13 ND 0.09

Cyclopentane 1.43 1.71 1.50 1.49 0.69 0.95

2,3-Dimethylbutane 4.58 5.29 4.72 4.53 2.31 2.50

2-Methylpentane 9.94 12.23 9.67 9.32 4.21 5.03

3-Methylpentane 6.50 7.63 6.42 6.42 2.73 3.24

2-Methyl-1-pentene 0.49 0.65 0.54 0.50 0.27 0.26

1-Hexene 0.42 0.48 0.42 0.43 0.21 0.19

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 7.69 9.26 7.98 7.73 3.33 4.09

trans-2-Hexene 0.49 0.80 0.46 0.49 0.22 0.24

cis-2-Hexene 0.33 0.40 0.28 0.31 0.17 0.15

Methylcyclopentane 4.89 5.80 5.00 4.90 2.31 2.70

2,4-Dimethylpentane 3.02 3.57 3.10 3.06 1.32 1.77

Benzene 10.53 12.61 11.01 10.69 4.88 5.66

Cyclohexane 2.89 3.30 5.85 5.81 1.63 57.98

2-Methylhexane 4.20 4.90 3.58 3.45 3.01 2.62

2,3-Dimethylpentane 4.68 5.35 4.45 4.40 2.39 2.95

3-Methylhexane 4.86 5.85 4.61 4.44 3.11 2.57

1-Heptene 1.56 ND ND ND ND ND

2,2,4-Trimethylpentane 6.51 7.64 6.61 6.48 3.02 3.62

n-Heptane 3.72 3.88 3.90 3.89 2.83 2.13

Methylcyclohexane 2.57 3.03 2.74 2.64 1.50 1.72

2,2,3-Trimethylpentane 1.75 2.11 1.80 1.79 1.56 1.51

2,3,4-Trimethylpentane 7.92 9.26 8.22 8.06 16.34 13.72

Toluene 34.04 40.81 36.72 35.96 30.06 33.66

2-Methylheptane 1.55 1.79 1.62 1.58 1.05 0.97

3-Methylheptane 1.65 1.47 1.39 1.71 1.08 0.95

1-Octene 0.42 0.51 0.39 0.32 0.09 0.13

n-Octane 2.15 2.44 2.22 2.23 1.01 1.04

Ethylbenzene 4.91 5.85 4.92 4.57 3.28 3.87

m-Xylene/p-Xylene 13.66 16.48 14.29 13.55 8.50 10.58

Styrene 1.76 2.00 1.48 1.27 2.60 3.56

o-Xylene 5.22 6.00 5.20 4.90 4.21 4.74

1-Nonene 1.67 1.86 1.44 1.46 2.22 2.05

n-Nonane 1.23 1.40 1.21 1.20 0.68 0.81

Isopropylbenzene 0.42 0.34 0.32 0.40 0.41 0.40

a-Pinene 0.53 0.62 0.78 0.60 2.12 1.11

n-Propylbenzene 0.84 1.08 0.95 0.80 0.87 0.82

m-Ethyltoluene 2.54 2.97 2.83 2.38 2.62 2.41

p-Ethyltoluene 1.46 1.73 1.61 1.38 1.35 1.29

1,3,5-Trimethylbenzene 1.70 1.96 1.85 1.61 1.65 1.67

o-Ethyltoluene 0.97 1.50 1.05 0.97 1.05 1.04

b-Pinene 0.79 0.69 0.51 0.37 1.02 1.33

1,2,4-Trimethylbenzene 4.20 4.58 4.48 3.81 3.81 4.38

1-Decene ND ND ND ND ND ND

n-Decane 1.26 1.55 1.30 1.26 0.83 1.46

1,2,3-Trimethylbenzene 0.95 1.13 0.96 0.93 0.70 0.88

m-Diethylbenzene 0.46 0.38 0.32 0.34 0.49 0.57

p-Diethylbenzene 0.51 0.42 0.45 0.36 0.57 0.45

1-Undecene 0.07 0.14 0.09 0.11 ND 0.07

n-Undecane 0.89 1.05 0.96 0.82 0.79 1.60

1-Dodecene 0.09 0.12 0.04 ND 0.37 0.60

n-Dodecane 0.36 0.45 0.38 0.34 0.34 1.43

1-Tridecene ND 0.08 ND ND ND 0.07

n-Tridecane 0.05 0.05 0.05 0.03 0.16 0.50

TNMOC (w/ unknowns) 19201.33 23241.52 19026.46 19799.96 1814.45 684.61

TNMOC (speciated) 338.87 395.50 349.46 340.70 235.73 332.57

@ A large non-target peak prevents quantitation of this compound.
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 15088D1 15088R1 15089D2 15089R2 15093D1 15093R1

Sampling Date: 9/24/98 9/24/98 9/24/98 9/24/98 9/28/98 9/28/98

Analysis Date: 10/22/98 10/27/98 10/22/98 10/27/98 10/27/98 10/28/98

Compound

Ethylene 2.16 2.29 2.21 2.18 13.71 14.02

Acetylene 1.77 1.78 1.80 1.78 11.02 11.53

Ethane 3.38 3.43 3.45 3.47 31.30 32.23

Propylene 1.11 1.04 1.10 1.16 8.67 8.86

Propane 8.95 8.80 9.15 8.80 51.02 52.50

Propyne ND ND 0.06 0.06 0.49 0.49

Isobutane 0.86 0.93 0.93 0.94 7.10 7.22

Isobutene/1-Butene 1.25 1.06 1.26 1.14 4.26 4.28

1,3-Butadiene 0.18 0.16 0.22 0.19 1.45 1.46

n-Butane 2.18 2.22 2.27 2.33 23.74 24.32

trans-2-Butene 0.32 0.33 0.30 0.32 1.15 1.17

cis-2-Butene 0.36 0.39 0.36 0.42 1.25 1.29

3-Methyl-1-butene 0.05 ND ND ND 1.94 1.90

Isopentane 10.89 10.83 9.54 8.45 42.92 44.75

1-Pentene 0.33 0.38 0.34 0.32 1.58 1.63

2-Methyl-1-butene 0.29 0.26 0.35 0.25 2.64 2.73

n-Pentane 1.83 1.81 1.89 1.87 21.30 21.93

Isoprene 0.41 0.43 0.43 0.43 1.16 1.25

trans-2-Pentene 0.46 0.50 0.47 0.47 3.67 3.77

cis-2-Pentene 0.34 0.34 0.39 0.41 1.94 2.01

2-Methyl-2-butene 0.18 0.15 0.24 0.24 4.21 4.33

2,2-Dimethylbutane 0.41 0.38 0.48 0.46 1.55 1.67

Cyclopentene 0.17 0.11 0.10 0.16 1.11 1.08

4-Methyl-1-pentene ND ND ND ND 0.22 0.22

Cyclopentane 0.33 0.33 0.33 0.41 2.31 2.37

2,3-Dimethylbutane 1.03 1.09 1.06 1.11 8.87 9.20

2-Methylpentane 1.87 1.80 1.82 1.79 14.46 14.96

3-Methylpentane 1.08 1.07 1.14 1.14 9.16 9.46

2-Methyl-1-pentene 0.06 0.09 0.09 0.10 0.89 0.92

1-Hexene 0.08 0.07 0.09 0.10 0.57 0.61

2-Ethyl-1-butene ND ND ND ND ND ND

n-Hexane 1.27 1.28 1.28 1.30 11.87 12.25

trans-2-Hexene 0.05 0.06 0.08 0.08 0.94 0.96

cis-2-Hexene 0.07 0.05 0.06 0.06 0.59 0.64

Methylcyclopentane 0.96 0.99 0.97 0.99 7.90 8.14

2,4-Dimethylpentane 0.70 0.67 0.65 0.70 4.21 4.37

Benzene 1.80 1.70 1.81 1.74 14.18 14.47

Cyclohexane 1.07 1.07 1.81 1.63 4.67 4.80

2-Methylhexane 1.07 1.03 1.33 0.96 5.25 5.30

2,3-Dimethylpentane 1.04 0.98 1.12 0.97 5.93 6.11

3-Methylhexane 1.02 1.01 1.09 0.99 6.02 6.17

1-Heptene ND ND ND ND ND ND

2,2,4-Trimethylpentane 1.14 1.16 1.13 1.11 8.85 9.15

n-Heptane 0.83 0.87 0.92 0.84 5.62 5.87

Methylcyclohexane 0.62 0.64 0.68 0.59 3.91 4.00

2,2,3-Trimethylpentane 0.58 0.53 0.60 0.55 2.38 2.45

2,3,4-Trimethylpentane 6.15 6.10 6.16 5.72 9.85 10.17

Toluene 11.48 11.42 11.56 10.76 47.04 48.59

2-Methylheptane 0.43 0.48 0.47 0.45 1.97 2.07

3-Methylheptane 0.48 0.47 0.48 0.51 2.17 2.21

1-Octene 0.04 ND 0.05 0.06 0.22 0.26

n-Octane 0.48 0.45 0.51 0.46 2.21 2.33

Ethylbenzene 1.20 1.14 1.25 1.15 7.26 7.63

m-Xylene/p-Xylene 2.86 2.77 2.98 2.70 22.31 23.14

Styrene 1.61 1.47 1.55 1.29 2.63 2.73

o-Xylene 1.46 1.51 1.63 1.47 8.29 8.58

1-Nonene 0.87 0.86 0.93 0.81 1.61 1.67

n-Nonane 0.40 0.40 0.45 0.36 1.63 1.68

Isopropylbenzene 0.32 0.27 0.36 0.28 0.68 0.63

a-Pinene 0.21 0.22 0.20 0.35 1.73 1.79

n-Propylbenzene 0.44 0.36 0.46 0.35 1.73 1.78

m-Ethyltoluene 0.86 0.72 0.92 0.74 5.03 5.27

p-Ethyltoluene 0.57 0.47 0.65 0.42 2.74 2.81

1,3,5-Trimethylbenzene 0.60 0.53 0.66 0.50 3.21 3.31

o-Ethyltoluene 0.39 0.37 0.52 0.34 1.88 1.97

b-Pinene 0.94 0.67 0.83 0.65 1.30 1.23

1,2,4-Trimethylbenzene 1.31 1.23 1.41 1.26 8.23 8.71

1-Decene ND ND ND ND ND ND

n-Decane 0.46 0.42 0.50 0.47 2.42 2.51

1,2,3-Trimethylbenzene 0.30 0.44 0.32 0.33 1.99 2.03

m-Diethylbenzene 0.30 0.39 0.40 0.35 0.81 0.89

p-Diethylbenzene 0.30 0.36 0.40 0.25 0.74 0.94

1-Undecene ND ND ND 0.08 0.25 0.34

n-Undecane 0.46 0.37 0.73 0.58 1.69 1.96

1-Dodecene 0.40 0.07 0.48 0.15 0.20 0.25

n-Dodecane 0.13 0.08 0.43 0.31 0.74 0.75

1-Tridecene ND ND ND ND ND ND

n-Tridecane 0.05 0.03 0.12 0.06 0.28 0.20

TNMOC (w/ unknowns) 174.98 170.44 181.39 164.87 682.56 710.03

TNMOC (speciated) 90.06 84.78 92.82 82.73 500.81 517.28
SNMOC 1998 REPORT

SITE CODE: JUMX

All concentrations reported in ppbC

Sample No.: 15095D2 15095R2 15091

Sampling Date: 9/28/98 9/28/98 9/29/98

Analysis Date: 10/27/98 10/28/98 10/27/98

Compound

Ethylene 13.64 14.11 11.01

Acetylene 10.96 11.38 9.29

Ethane 31.22 32.46 18.40

Propylene 8.61 8.88 4.89

Propane 50.69 52.35 43.64

Propyne 0.44 0.53 0.40

Isobutane 7.05 7.25 4.86

Isobutene/1-Butene 4.19 4.37 3.73

1,3-Butadiene 1.45 1.51 1.12

n-Butane 23.51 24.42 15.20

trans-2-Butene 1.09 1.15 0.91

cis-2-Butene 1.28 1.33 0.90

3-Methyl-1-butene 2.33 2.70 2.73

Isopentane 41.04 42.81 16.80

1-Pentene 1.73 1.62 1.13

2-Methyl-1-butene 2.60 2.76 1.84

n-Pentane 21.18 21.90 13.61

Isoprene 1.18 1.24 0.95

trans-2-Pentene 3.71 3.78 2.07

cis-2-Pentene 1.99 2.00 1.21

2-Methyl-2-butene 4.29 4.45 2.26

2,2-Dimethylbutane 1.59 1.67 1.14

Cyclopentene 1.00 0.99 0.63

4-Methyl-1-pentene 0.20 0.20 0.12

Cyclopentane 2.30 2.35 1.40

2,3-Dimethylbutane 8.86 9.09 4.75

2-Methylpentane 14.37 14.78 8.96

3-Methylpentane 9.16 9.40 5.88

2-Methyl-1-pentene 0.95 0.97 0.51

1-Hexene 0.53 0.53 0.35

2-Ethyl-1-butene ND ND ND

n-Hexane 12.17 12.52 7.55

trans-2-Hexene 1.05 1.11 0.51

cis-2-Hexene 0.61 0.60 0.30

Methylcyclopentane 7.76 7.96 4.67

2,4-Dimethylpentane 4.12 4.21 2.67

Benzene 14.17 14.54 9.26

Cyclohexane 4.67 4.41 3.03

2-Methylhexane 5.43 5.31 3.27

2,3-Dimethylpentane 6.40 6.13 3.92

3-Methylhexane 5.98 6.13 3.78

1-Heptene ND ND ND

2,2,4-Trimethylpentane 8.78 9.10 5.68

n-Heptane 5.62 5.81 3.59

Methylcyclohexane 3.97 4.03 2.42

2,2,3-Trimethylpentane 2.51 2.39 2.09

2,3,4-Trimethylpentane 8.60 8.86 14.19

Toluene 45.18 46.56 43.80

2-Methylheptane 2.06 2.02 1.47

3-Methylheptane 2.14 2.12 1.56

1-Octene 0.25 0.22 0.20

n-Octane 2.22 2.30 1.64

Ethylbenzene 7.22 7.25 5.16

m-Xylene/p-Xylene 22.25 23.12 15.09

Styrene 2.25 2.44 2.64

o-Xylene 8.21 8.54 6.13

1-Nonene 1.30 1.31 2.00

n-Nonane 1.69 1.68 1.37

Isopropylbenzene 0.57 0.71 0.39

a-Pinene 1.70 1.77 0.75

n-Propylbenzene 1.73 1.80 1.17

m-Ethyltoluene 5.13 5.37 3.31

p-Ethyltoluene 2.66 2.89 1.82

1,3,5-Trimethylbenzene 3.25 3.40 2.26

o-Ethyltoluene 1.99 2.05 1.31

b-Pinene 1.16 1.24 0.94

1,2,4-Trimethylbenzene 8.35 8.81 5.34

1-Decene ND ND ND

n-Decane 2.45 2.45 1.72

1,2,3-Trimethylbenzene 2.00 2.06 1.10

m-Diethylbenzene 0.87 0.87 0.51

p-Diethylbenzene 0.88 0.83 0.50

1-Undecene 0.25 0.30 0.21

n-Undecane 1.77 1.76 1.40

1-Dodecene 0.20 0.23 0.15

n-Dodecane 0.76 0.82 0.47

1-Tridecene ND 0.04 ND

n-Tridecane 0.17 0.20 0.12

TNMOC (w/ unknowns) 645.66 665.22 5375.30

TNMOC (speciated) 495.61 511.25 352.16
 1998 SNMOC - NWNJ

Toxics Option Report ( June 1998 - September 1998 )

SAMPLE SITE # NWNJ 13179 NWNJ 13899 NWNJ 14059 NWNJ 14468

SAMPLE DATE 6/29/98 7/29/98 8/6/98 8/24/98

ANALYSIS DATE 7/23/98 8/13/98 9/21/98 9/23/98

FILE NAME L8GW005 L8HK027 L8IS2001 L8IV023

UNITS ppbv ppbv ppbv ppbv

ACETYLENE 1.76 4.92 5.02 3.71

PROPYLENE 1.92 2.68 7.04 3.66

CHLOROMETHANE 0.52 0.57 0.79 0.57

VINYL CHLORIDE ND 0.00 ND ND

1,3-BUTADIENE 0.09 0.24 ND ND

BROMOMETHANE ND 0.01 U ND ND

CHLOROETHANE ND 0.00 ND ND

ACETONITRILE ND 0.00 ND ND

ACRYLONITRILE ND 0.00 ND ND

METHYLENE CHLORIDE 0.50 0.42 1.00 ND

trans - 1,2 - DICHLOROETHYLENE ND 0.00 ND ND

1,1 - DICHLOROETHANE ND 0.00 ND ND

METHYL TERT-BUTYL ETHER 1.28 2.31 3.81 2.73

METHYL ETHYL KETONE 0.79 1.06 1.88 1.09

CHLOROPRENE ND 0.00 ND ND

BROMOCHLOROMETHANE ND 0.00 ND ND

CHLOROFORM 0.03 U 0.04 0.10 ND

ETHYL TERT BUTYL ETHER ND 0.00 ND ND

1,2 - DICHLOROETHANE ND 0.00 ND ND

1,1,1 - TRICHLOROETHANE 1.01 0.68 0.62 0.62

BENZENE 0.50 1.07 0.69 0.68

CARBON TETRACHLORIDE 0.08 IU 0.11 0.08 U 0.06 U

TERT-AMLY METHYL ETHER ND 0.10 ND ND

1,2 - DICHLOROPROPANE ND 0.00 ND ND

ETHYL ACRYLATE ND 0.00 ND ND

BROMODICHLOROMETHANE ND 0.00 ND ND

TRICHLOROETHYLENE ND 0.06 U 0.37 ND

METHYL METHACRYLATE ND ND ND ND

cis - 1,3 - DICHLOROPROPENE ND 0.00 ND ND

METHYL ISOBUTYL KETONE ND 0.18 0.31 ND

trans - 1,3 - DICHLOROPROPENE ND 0.00 ND ND

1,1,2 - TRICHLOROETHANE ND 0.00 ND ND

TOLUENE 1.87 2.95 4.32 2.00

DIBROMOCHLOROMETHANE ND 0.00 ND ND

N-OCTANE 0.17 0.23 ND ND

TETRACHLOROETHYLENE 0.04 U 0.10 U 0.28 ND

CHLOROBENZENE ND 0.00 ND ND

ETHYLBENZENE 0.35 0.50 0.64 0.31

m,p - XYLENE 0.88 1.41 1.87 0.85

BROMOFORM ND 0.00 ND ND

STYRENE 0.17 0.18 ND ND

1,1,2,2 - TETRACHLOROETHANE ND 0.00 ND ND

o - XYLENE 0.47 0.72 0.87 0.53

m - DICHLOROBENZENE ND 0.00 ND ND

p - DICHLOROBENZENE 0.04 U 0.07 U 0.11 ND

o - DICHLOROBENZENE ND 0.02 U ND ND

U = Under Detection Limit

ND = Not Detected

1 of 3 Nwnj_98.xls
 1998 SNMOC - NWNJ

Toxics Option Report ( June 1998 - September 1998 )

SAMPLE SITE #

SAMPLE DATE

ANALYSIS DATE

FILE NAME

UNITS

ACETYLENE

PROPYLENE

CHLOROMETHANE

VINYL CHLORIDE

1,3-BUTADIENE

BROMOMETHANE

CHLOROETHANE

ACETONITRILE

ACRYLONITRILE

METHYLENE CHLORIDE

trans - 1,2 - DICHLOROETHYLENE

1,1 - DICHLOROETHANE

METHYL TERT-BUTYL ETHER

METHYL ETHYL KETONE

CHLOROPRENE

BROMOCHLOROMETHANE

CHLOROFORM

ETHYL TERT BUTYL ETHER

1,2 - DICHLOROETHANE

1,1,1 - TRICHLOROETHANE

BENZENE

CARBON TETRACHLORIDE

TERT-AMLY METHYL ETHER

1,2 - DICHLOROPROPANE

ETHYL ACRYLATE

BROMODICHLOROMETHANE

TRICHLOROETHYLENE

METHYL METHACRYLATE

cis - 1,3 - DICHLOROPROPENE

METHYL ISOBUTYL KETONE

trans - 1,3 - DICHLOROPROPENE

1,1,2 - TRICHLOROETHANE

TOLUENE

DIBROMOCHLOROMETHANE

N-OCTANE

TETRACHLOROETHYLENE

CHLOROBENZENE

ETHYLBENZENE

m,p - XYLENE

BROMOFORM

STYRENE

1,1,2,2 - TETRACHLOROETHANE

o - XYLENE

m - DICHLOROBENZENE

p - DICHLOROBENZENE

o - DICHLOROBENZENE

NWNJ 14487D1 NWNJ 14487R1 NWNJ 14488D2 NWNJ 14488R2

8/25/98 8/25/98 8/25/98 8/25/98

10/15/98 12/1/98 10/15/98 12/1/98

L8JM019 L8LA009 L8JM019 L8JM010

ppbv ppbv ppbv ppbv

3.66 3.82 3.74 3.75

3.88 3.66 3.92 3.63

0.58 0.59 0.63 0.58

ND ND ND ND

0.18 0.21 0.17 0.16

ND ND ND ND

ND ND ND ND

ND ND ND ND

ND ND ND ND

0.27 0.26 0.27 0.25

ND ND ND ND

ND ND ND ND

2.11 1.94 2.19 1.92

1.15 1.49 1.02 1.19

ND ND ND ND

ND ND ND ND

ND ND 0.04 U ND

ND ND ND ND

ND ND ND ND

0.42 0.39 0.44 0.42

1.04 0.99 1.03 0.94

0.11 0.11 0.11 0.11

ND ND ND ND

ND ND ND ND

ND ND ND ND

ND ND ND ND

ND ND ND ND

ND ND ND ND

ND ND ND ND

0.14 0.14 0.12 0.13

ND ND ND ND

ND ND ND ND

3.02 2.90 3.71 3.70

ND ND ND ND

0.12 0.16 0.15 0.12

0.43 0.42 0.41 0.40

ND ND ND ND

0.45 0.45 0.46 0.42

1.34 1.30 1.37 1.26

ND ND ND ND

0.16 0.17 0.16 0.16

ND ND ND ND

0.63 0.63 0.66 0.61

ND ND ND ND

0.12 0.11 0.13 0.11

ND ND ND ND

U = Under Detection Limit

ND = Not Detected

2 of 3 Nwnj_98.xls
 1998 SNMOC - NWNJ

Toxics Option Report ( June 1998 - September 1998 )

SAMPLE SITE #

SAMPLE DATE

ANALYSIS DATE

FILE NAME

UNITS

ACETYLENE

PROPYLENE

CHLOROMETHANE

VINYL CHLORIDE

1,3-BUTADIENE

BROMOMETHANE

CHLOROETHANE

ACETONITRILE

ACRYLONITRILE

METHYLENE CHLORIDE

trans - 1,2 - DICHLOROETHYLENE

1,1 - DICHLOROETHANE

METHYL TERT-BUTYL ETHER

METHYL ETHYL KETONE

CHLOROPRENE

BROMOCHLOROMETHANE

CHLOROFORM

ETHYL TERT BUTYL ETHER

1,2 - DICHLOROETHANE

1,1,1 - TRICHLOROETHANE

BENZENE

CARBON TETRACHLORIDE

TERT-AMLY METHYL ETHER

1,2 - DICHLOROPROPANE

ETHYL ACRYLATE

BROMODICHLOROMETHANE

TRICHLOROETHYLENE

METHYL METHACRYLATE

cis - 1,3 - DICHLOROPROPENE

METHYL ISOBUTYL KETONE

trans - 1,3 - DICHLOROPROPENE

1,1,2 - TRICHLOROETHANE

TOLUENE

DIBROMOCHLOROMETHANE

N-OCTANE

TETRACHLOROETHYLENE

CHLOROBENZENE

ETHYLBENZENE

m,p - XYLENE

BROMOFORM

STYRENE

1,1,2,2 - TETRACHLOROETHANE

o - XYLENE

m - DICHLOROBENZENE

p - DICHLOROBENZENE

o - DICHLOROBENZENE

NWNJ 14984 NWNJ 15058

9/18/98 9/30/98

11/3/98 10/24/02

L8KC011 L8J!015

ppbv ppbv

3.66 7.15

4.67 8.04

0.89 0.39

ND ND

0.09 0.46

ND ND

ND ND

ND ND

ND ND

1.25 0.68

ND ND

ND ND

1.59 6.21

1.07 1.18

ND ND

ND ND

ND 0.06

ND ND

ND ND

0.48 0.60

0.69 2.23

0.11 0.11

ND 0.16

ND ND

ND ND

ND ND

0.08 ND

ND ND

ND ND

ND 0.12

ND ND

ND ND

2.19 6.92

ND ND

0.15 0.35

0.20 0.20

ND ND

0.35 0.96

0.92 2.88

ND ND

0.12 0.24

ND ND

0.46 1.43

ND ND

0.04 U 0.26

ND ND

U = Under Detection Limit

ND = Not Detected

3 of 3 Nwnj_98.xls
.
1998 SNMOC CARBONYLS

Sample Site: Newark, New Jersey NWNJ

Underivatized Concentration (ppbv)

SAMPLE # 13180 13597 13900 14096 14251 14669 14778

SAMPLE DATE 6/29/98 7/20/98 7/29/98 8/7/98 8/18/98 9/2/98 9/10/98

EXTRACTION DATE 8/3/98 8/3/98 8/3/98 8/18/98 9/25/98 10/22/98 10/28/98

ANALYSIS DATE 8/12/98 8/12/98 8/12/98 8/22/98 10/2/98 10/28/98 10/29/98

FILE NAME Q8HK024 Q8HK025 Q8HK026 Q8HU027 Q8JB022 Q8J~019 Q8J#018 

UNITS ppbv ppbv ppbv ppbv ppbv ppbv ppbv

Formaldehyde 3.79 6.04 5.96 19.81 25.34 20.78 18.62

Acetaldehyde 1.92 2.90 2.61 3.96 3.58 5.43 2.26

Acrolein 0.13 0.43 0.25 0.45 1.26 0.54 0.51

Acetone 4.89 6.07 4.96 7.51 6.55 8.83 3.80

Propionaldehyde 0.13 0.36 0.21 0.46 0.22 0.36 0.17

Crotonaldehyde ND ND ND ND ND ND ND

Butyr/Isobutyraldehyde 0.34 0.35 0.28 1.21 1.84 3.54 2.75

Benzaldehyde ND ND ND 0.35 0.46 0.34 0.26

Isovaleraldehyde ND 0.09 ND 0.28 0.23 0.30 0.16

Valeraldehyde ND 0.08 ND 0.17 0.22 0.20 0.11

Tolualdehydes ND ND ND ND ND ND ND

Hexaldehyde 0.13 0.15 0.11 0.37 0.38 0.43 0.26

2,5-Dimethylbenzaldehyde ND ND ND ND ND ND ND

u - Concentration is below the detection limit
1998 SNMOC CARBONYLS

Sample Site: Newark, New Jersey

Underivatized Concentration (ppbv)

SAMPLE #

SAMPLE DATE

EXTRACTION DATE

ANALYSIS DATE

FILE NAME

UNITS

Formaldehyde

Acetaldehyde

Acrolein

Acetone

Propionaldehyde

Crotonaldehyde

Butyr/Isobutyraldehyde

Benzaldehyde

Isovaleraldehyde

Valeraldehyde

Tolualdehydes

Hexaldehyde

2,5-Dimethylbenzaldehyde

u - Concentration is below the detection limit

14810 14985 D1 14985 R1 14986 D2 14986 R2

9/15/98 9/21/98 9/21/98 9/21/98 9/21/98

10/28/98 11/9/98 11/9/98 11/9/98 11/9/98

10/30/98 11/13/98 11/13/98 11/13/98 11/13/98

Q8J#026 Q8KK057 Q8KK058 Q8KK059 Q8KK060 

ppbv ppbv ppbv ppbv ppbv

VOID 22.13 21.62 22.03 21.87

VOID 4.30 4.42 4.38 4.44

VOID 0.79 0.87 0.83 0.70

VOID 6.82 6.85 6.89 6.61

VOID 0.38 0.41 0.43 0.38

VOID ND ND ND ND

VOID 3.22 3.22 2.31 2.50

VOID 0.46 0.41 0.47 0.35

VOID 0.32 0.32 0.27 0.31

VOID 0.24 0.27 0.24 0.22

VOID ND ND ND ND

VOID 0.51 0.34 0.57 0.53

VOID ND ND ND ND
FIELD BLANK DATA

Sample Site: Newark, NJ NWNJ

RAW AMOUNT

Derivatized Conc. (ug/ml)

Sample Date 8/25/98

Data File ID Q8JB019 

FB ID 14502 FB

Date Analyzed 10/2/98

Formaldehyde 0.02

Acetaldehyde 0.05

Acrolein 0.00

Acetone 0.36

Propionaldehyde 0.00

Crotonaldehyde 0.00

Butyr/Isobutyraldehyde 0.39

Benzaldehyde 0.00

Isovaleraldehyde 0.00

Valeraldehyde 0.00

Tolualdehydes 0.00

Hexaldehyde 0.00

2,5-Dimethylbenzaldehyde 0.00

FIELD BLANK

Underivatized Conc.(total ug)

Data File ID Q8JB019 

FB ID 14502 FB

Date Analyzed 10/2/98

Formaldehyde 0.01

Acetaldehyde 0.04

Acrolein ND

Acetone 0.35

Propionaldehyde ND

Crotonaldehyde ND

Butyr/Isobutyraldehyde 0.45

Benzaldehyde ND

Isovaleraldehyde ND

Valeraldehyde ND

Tolualdehydes ND

Hexaldehyde ND

2,5-Dimethylbenzaldehyde ND
1998 SNMOC CARBONYLS

Sample Site: Fort Worth, Texas CAMS13

Underivatized Concentration (ppbv)

SAMPLE # 13605 13906 14175 14667 14787 14899 14981

SAMPLE DATE 7/20/98 7/29/98 8/11/98 9/2/98 9/10/98 9/18/98 9/23/98

EXTRACTION DATE 8/3/98 8/3/98 8/18/98 10/22/98 10/28/98 10/28/98 11/9/98

ANALYSIS DATE 8/12/98 8/12/98 8/22/98 10/28/98 10/29/98 10/30/98 11/12/98

FILE NAME Q8HK021 Q8HK022 Q8HU025 Q8J~016 Q8J#016 Q8J#029 Q8KK029 

UNITS ppbv ppbv ppbv ppbv ppbv ppbv ppbv

Formaldehyde 4.73 2.68 3.77 4.45 3.20 1.58 1.46

Acetaldehyde 2.01 1.16 1.60 2.28 1.58 0.73 0.72

Acrolein 0.09 ND ND 0.21 ND 0.04 ND

Acetone 3.86 2.77 3.93 6.35 3.57 0.59 1.83

Propionaldehyde 0.14 ND 0.20 0.31 0.22 0.10 0.14

Crotonaldehyde ND ND ND ND ND ND ND

Butyr/Isobutyraldehyde 0.44 ND 0.46 0.56 2.03 0.14 0.32

Benzaldehyde ND ND ND 0.28 0.11 ND 0.09

Isovaleraldehyde ND ND ND ND ND ND 0.07

Valeraldehyde ND 0.11 0.05 0.05 ND ND ND

Tolualdehydes ND ND ND ND ND ND ND

Hexaldehyde ND ND 0.15 0.09 0.06 ND ND

2,5-Dimethylbenzaldehyde ND ND ND ND ND 0.09 0.18

u - Concentration is below the detection limit
1998 SNMOC CARBONYLS

Sample Site: Fort Worth, Texas

Underivatized Concentration (ppbv)

SAMPLE #

SAMPLE DATE

EXTRACTION DATE

ANALYSIS DATE

FILE NAME

UNITS

Formaldehyde

Acetaldehyde

Acrolein

Acetone

Propionaldehyde

Crotonaldehyde

Butyr/Isobutyraldehyde

Benzaldehyde

Isovaleraldehyde

Valeraldehyde

Tolualdehydes

Hexaldehyde

2,5-Dimethylbenzaldehyde

u - Concentration is below the detection limit

14996 15020 15033 D1 15033 R1 15034 D2 15034 R2 15051

9/24/98 9/25/98 9/28/98 9/28/98 9/28/98 9/28/98 9/30/98

11/9/98 11/9/98 11/9/98 11/9/98 11/9/98 11/9/98 11/9/98

11/12/98 11/12/98 11/12/98 11/12/98 11/13/98 11/13/98 11/12/98

Q8KK030 Q8KK031 Q8KK048 Q8KK049 Q8KK051 Q8KK052 Q8KK032 

ppbv ppbv ppbv ppbv ppbv ppbv ppbv

2.43 1.97 2.92 3.15 1.59 1.60 4.64

0.86 0.93 1.42 1.40 0.85 0.83 2.55

ND ND 0.13 0.11 0.05 0.08 0.34

0.66 0.67 0.56 0.85 0.52 0.32 6.07

0.12 0.18 0.23 0.34 0.20 0.13 0.36

ND ND ND ND ND ND ND

0.25 0.33 0.59 0.64 0.26 0.33 0.53

0.10 0.14 0.26 0.21 0.21 0.19 0.26

0.07 ND ND ND 0.07 ND 0.14

ND ND ND ND ND ND 0.11

ND ND ND ND ND ND ND

0.14 0.12 0.26 0.33 0.17 0.17 0.12

0.18 0.30 0.36 0.34 0.24 0.20 ND
FIELD BLANK DATA

Sample Site: Fort Worth, TX CAMS13

RAW AMOUNT

Derivatized Conc. (ug/ml)

Sample Date 9/29/98

Data File ID Q8KK016 

FB ID 15031 FB

Date Analyzed 11/12/98

Formaldehyde 0.09

Acetaldehyde 0.11

Acrolein 0.00

Acetone 0.39

Propionaldehyde 0.00

Crotonaldehyde 0.00

Butyr/Isobutyraldehyde 0.71

Benzaldehyde 0.00

Isovaleraldehyde 0.00

Valeraldehyde 0.00

Tolualdehydes 0.00

Hexaldehyde 0.00

2,5-Dimethylbenzaldehyde 0.00

FIELD BLANK

Underivatized Conc.(total ug)

Data File ID Q8KK016 

FB ID 15031 FB

Date Analyzed 11/12/98

Formaldehyde 0.05

Acetaldehyde 0.08

Acrolein ND

Acetone 0.38

Propionaldehyde ND

Crotonaldehyde ND

Butyr/Isobutyraldehyde 0.82

Benzaldehyde ND

Isovaleraldehyde ND

Valeraldehyde ND

Tolualdehydes ND

Hexaldehyde ND

2,5-Dimethylbenzaldehyde ND
1998 SNMOC CARBONYLS

Sample Site: Dallas, Texas CAMS5

Underivatized Concentration (ppbv)

SAMPLE # 13213 13616 13902 14177 14256 14671 14783

SAMPLE DATE 7/3/98 7/20/98 7/29/98 8/11/98 8/19/98 9/2/98 9/10/98

EXTRACTION DATE 8/3/98 8/3/98 8/3/98 8/18/98 9/25/98 10/22/98 9/10/98

ANALYSIS DATE 8/11/98 8/12/98 8/12/98 8/22/98 10/3/98 10/28/98 10/29/98

FILE NAME Q8HK015 Q8HK018 Q8HK019 Q8HU024 Q8JB023 Q8J~015 Q8J#015 

UNITS ppbv ppbv ppbv ppbv ppbv ppbv ppbv

Formaldehyde 7.54 5.31 2.95 4.78 4.50 7.71 14.95

Acetaldehyde 2.89 2.27 1.00 1.67 ND 2.79 13.94

Acrolein 0.12 0.05 ND 0.07 0.13 0.22 0.17

Acetone 5.03 3.41 2.42 4.13 6.79 7.11 13.93

Propionaldehyde 0.25 ND ND 0.25 0.16 0.36 3.13

Crotonaldehyde ND 0.33 0.12 ND ND ND ND

Butyr/Isobutyraldehyde 0.31 0.07 0.14 0.55 0.63 1.18 2.73

Benzaldehyde ND ND ND ND 0.12 0.42 0.45

Isovaleraldehyde ND 0.04 ND ND 0.17 ND 0.24

Valeraldehyde ND ND ND ND ND 0.07 0.43

Tolualdehydes ND 0.39 ND ND 0.22 ND 0.24

Hexaldehyde 0.13 0.10 ND 0.12 0.11 0.16 0.46

2,5-Dimethylbenzaldehyde ND ND ND ND ND ND ND

u - Concentration is below the detection limit
1998 SNMOC CARBONYLS

Sample Site: Dallas, Texas

Underivatized Concentration (ppbv)

SAMPLE #

SAMPLE DATE

EXTRACTION DATE

ANALYSIS DATE

FILE NAME

UNITS

Formaldehyde

Acetaldehyde

Acrolein

Acetone

Propionaldehyde

Crotonaldehyde

Butyr/Isobutyraldehyde

Benzaldehyde

Isovaleraldehyde

Valeraldehyde

Tolualdehydes

Hexaldehyde

2,5-Dimethylbenzaldehyde

u - Concentration is below the detection limit

14999 15024 D1 15024 R1 15025 D2 15025 R2 15043

9/24/98 9/25/98 9/25/98 9/25/98 9/25/98 9/28/98

11/9/98 11/9/98 11/9/98 11/9/98 11/9/98 11/9/98

11/12/98 11/12/98 11/12/98 11/12/98 11/12/98 11/12/98

Q8KK027 Q8KK044 Q8KK045 Q8KK046 Q8KK047 Q8KK028 

ppbv ppbv ppbv ppbv ppbv ppbv

VOID VOID VOID 2.99 2.97 3.39

VOID VOID VOID 1.26 1.37 1.76

VOID VOID VOID 0.13 0.14 0.20

VOID VOID VOID 1.23 1.25 1.97

VOID VOID VOID 0.23 0.23 0.25

VOID VOID VOID ND ND ND

VOID VOID VOID 0.46 0.59 0.61

VOID VOID VOID 0.14 0.15 0.22

VOID VOID VOID 0.10 0.10 ND

VOID VOID VOID ND 0.09 0.10

VOID VOID VOID ND ND ND

VOID VOID VOID 0.15 ND 0.24

VOID VOID VOID 0.18 0.14 0.33
FIELD BLANK DATA

Sample Site: Dallas, TX CAMS5

RAW AMOUNT

Derivatized Conc. (ug/ml)

Sample Date 9/29/98

Data File ID Q8KK017 

FB ID 15082 FB

Date Analyzed 11/12/98

Formaldehyde 0.03

Acetaldehyde 0.08

Acrolein 0.00

Acetone 0.35

Propionaldehyde 0.00

Crotonaldehyde 0.00

Butyr/Isobutyraldehyde 0.41

Benzaldehyde 0.04

Isovaleraldehyde 0.02

Valeraldehyde 0.00

Tolualdehydes 0.00

Hexaldehyde 0.00

2,5-Dimethylbenzaldehyde 0.00

FIELD BLANK

Underivatized Conc.(total ug)

Data File ID Q8KK017 

FB ID 15082 FB

Date Analyzed 11/12/98

Formaldehyde 0.02

Acetaldehyde 0.06

Acrolein ND

Acetone 0.35

Propionaldehyde ND

Crotonaldehyde ND

Butyr/Isobutyraldehyde 0.46

Benzaldehyde 0.06

Isovaleraldehyde 0.03

Valeraldehyde ND

Tolualdehydes ND

Hexaldehyde ND

2,5-Dimethylbenzaldehyde ND
1998 SNMOC CARBONYLS

Sample Site: Dallas, Texas DLTX

Underivatized Concentration (ppbv)

SAMPLE # 13215 13613 13904 14257 14258 14583 14789

SAMPLE DATE 7/3/98 7/20/98 7/29/98 8/11/98 8/20/98 9/2/98 9/10/98

EXTRACTION DATE 8/3/98 8/3/98 8/3/98 9/25/98 9/25/98 10/22/98 10/28/98

ANALYSIS DATE 8/11/98 8/11/98 8/12/98 10/2/98 10/3/98 10/28/98 10/29/98

FILE NAME Q8HK016 Q8HK017 Q8HK020 Q8JB021 Q8JB024 Q8J~017 Q8J#017 

UNITS ppbv ppbv ppbv ppbv ppbv ppbv ppbv

Formaldehyde 3.29 4.37 2.75 3.40 3.15 5.93 4.69

Acetaldehyde 1.12 1.45 0.86 1.66 1.61 2.45 1.42

Acrolein 0.19 0.29 0.12 0.07 0.21 0.23 ND

Acetone 3.15 3.47 2.68 3.28 2.91 2.40 3.46

Propionaldehyde 0.16 0.19 ND 0.21 0.19 0.29 0.15

Crotonaldehyde ND ND ND 0.08 ND ND ND

Butyr/Isobutyraldehyde 0.15 0.31 ND 0.36 0.69 0.43 1.38

Benzaldehyde 0.09 0.11 ND 0.13 0.14 0.20 0.12

Isovaleraldehyde ND ND ND 0.10 0.10 0.15 ND

Valeraldehyde ND ND ND ND 0.13 ND ND

Tolualdehydes ND ND ND 0.15 ND 0.14 ND

Hexaldehyde 0.25 0.13 0.09 0.14 0.13 0.17 0.05

2,5-Dimethylbenzaldehyde ND ND ND 0.09 ND 0.19 ND

u - Concentration is below the detection limit
1998 SNMOC CARBONYLS

Sample Site: Dallas, Texas

Underivatized Concentration (ppbv)

SAMPLE #

SAMPLE DATE

EXTRACTION DATE

ANALYSIS DATE

FILE NAME

UNITS

Formaldehyde

Acetaldehyde

Acrolein

Acetone

Propionaldehyde

Crotonaldehyde

Butyr/Isobutyraldehyde

Benzaldehyde

Isovaleraldehyde

Valeraldehyde

Tolualdehydes

Hexaldehyde

2,5-Dimethylbenzaldehyde

u - Concentration is below the detection limit

14975 14993 D1 14993 R1 14994 D2 14994 R2

9/18/98 9/24/98 9/24/98 9/24/98 9/24/98

10/28/98 11/9/98 11/9/98 11/9/98 11/9/98

10/30/98 11/13/98 11/13/98 11/13/98 11/13/98

Q8J#030 Q8KK053 Q8KK054 Q8KK055 Q8KK056 

ppbv ppbv ppbv ppbv ppbv

2.44 2.15 1.91 1.78 1.95

1.30 0.68 0.70 0.62 0.59

0.08 0.09 0.08 0.06 0.07

3.06 3.81 3.88 3.30 3.20

0.11 0.11 0.11 0.11 0.08

ND ND ND ND ND

0.40 0.53 0.46 0.36 0.21

0.10 0.11 0.11 0.10 0.10

0.08 0.17 0.12 0.09 0.11

ND ND ND ND ND

ND ND ND ND ND

0.15 0.13 ND ND 0.11

ND 0.10 0.14 0.08 0.09
FIELD BLANK DATA

Sample Site: Dallas, TX DLTX

RAW AMOUNT

Derivatized Conc. (ug/ml)

Sample Date 8/27/98

Data File ID Q8JB020 

FB ID 14526 FB

Date Analyzed 10/2/98

Formaldehyde 0.23

Acetaldehyde 0.09

Acrolein 0.00

Acetone 0.44

Propionaldehyde 0.00

Crotonaldehyde 0.00

Butyr/Isobutyraldehyde 0.82

Benzaldehyde 0.00

Isovaleraldehyde 0.00

Valeraldehyde 0.00

Tolualdehydes 0.00

Hexaldehyde 0.00

2,5-Dimethylbenzaldehyde 0.00

FIELD BLANK

Underivatized Conc.(total ug)

Data File ID Q8JB020 

FB ID 14526 FB

Date Analyzed 10/2/98

Formaldehyde 0.13

Acetaldehyde 0.07

Acrolein ND

Acetone 0.43

Propionaldehyde ND

Crotonaldehyde ND

Butyr/Isobutyraldehyde 0.94

Benzaldehyde ND

Isovaleraldehyde ND

Valeraldehyde ND

Tolualdehydes ND

Hexaldehyde ND

2,5-Dimethylbenzaldehyde ND
1998 SNMOC CARBONYLS

Sample Site: Juarez, Mexico JUMX

Underivatized Concentration (ppbv)

SAMPLE # 14831 15029 15090 15092

SAMPLE DATE 9/9/98 9/22/98 9/25/98 9/29/98

EXTRACTION DATE 10/22/98 11/9/98 11/9/98 11/9/98

ANALYSIS DATE 10/28/98 11/12/98 11/12/98 11/12/98

FILE NAME Q8J~028 Q8KK037 Q8KK038 Q8KK040

UNITS ppbv ppbv ppbv ppbv

Formaldehyde 3.24 2.66 2.09 2.18

Acetaldehyde 2.18 1.39 1.07 1.40

Acrolein 0.20 0.06 0.11 0.08

Acetone 5.01 1.62 3.10 2.93

Propionaldehyde 0.29 0.24 0.21 0.22

Crotonaldehyde ND ND ND ND

Butyr/Isobutyraldehyde 0.57 0.31 0.44 0.48

Benzaldehyde 0.10 0.16 0.16 0.17

Isovaleraldehyde ND 0.09 0.11 0.09

Valeraldehyde 0.06 0.27 0.30 0.30

Tolualdehydes ND ND ND ND

Hexaldehyde 0.07 0.05 ND 0.06

2,5-Dimethylbenzaldehyde ND 0.19 0.22 0.23

u - Concentration is below the detection limit

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