May 2003 • NREL/SR-540-33795 

R.E. Morris, G.E. Mansell, Y. Jia, and G. Wilson 

ENVIRON International Corporation 

Novato, California 

Impact of Biodiesel Fuels on Air 

Quality and Human Health: 

Task 2 Report 

The Impact of Biodiesel Fuels on Ozone 

Concentrations 

National Renewable Energy Laboratory 

1617 Cole Boulevard 

Golden, Colorado 80401-3393 

NREL is a U.S. Department of Energy Laboratory 

Operated by Midwest Research Institute • Battelle • Bechtel 

Contract No. DE-AC36-99-GO10337 
May 2003 • NREL/SR-540-33795 

Impact of Biodiesel Fuels on Air 

Quality and Human Health: 

Task 2 Report 

The Impact of Biodiesel Fuels on Ozone 

Concentrations 

R.E. Morris, G.E. Mansell, Y. Jia, and G. Wilson 

ENVIRON International Corporation 

Novato, California 

NREL Technical Monitor: K.S. Tyson and R. McCormick

Prepared under Subcontract No. AXE-9-29079-01 

National Renewable Energy Laboratory 

1617 Cole Boulevard 

Golden, Colorado 80401-3393 

NREL is a U.S. Department of Energy Laboratory 

Operated by Midwest Research Institute • Battelle • Bechtel 

Contract No. DE-AC36-99-GO10337 
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ES-1 

EXECUTIVE SUMMARY 

This report evaluates the ozone air quality impacts from the use of biodiesel fuel in the South Coast 

(Los Angeles) Air Basin (SoCAB), lower Lake Michigan, Northeast Corridor, and other cities in the 

Eastern United States (US). The largest impacts on ambient ozone concentrations due to the use of 

biodiesel are expected to be due to changes in NOx emissions from diesel vehicles. Studies, such as 

the Ozone Transport Assessment Group (OTAG), have concluded that regional NOx controls are one 

of the most effective control strategies for reducing regional ozone concentrations in the eastern US. 

However, in some cases, NOx controls result in increased ozone levels, particularly in the urban 

cores of large cities. The assessment of ozone impacts due to biodiesel fuel use must therefore 

include the effects of the fuel on regional ozone and ozone transport as well as the effects within 

urban areas. The ozone air quality modeling conducted as part of this study therefore takes into 

account both urban-scale and regional-scale ozone formation through the use of high-resolution 

urban-scale modeling domains of the cities under study as well as coarser-scale regional-scale 

modeling. 

This report documents Task 2 of the National Renewable Energy Laboratory (NREL) study “Impact 

of Biodiesel Fuels on Air Quality and Human Health”. Under Task 1, engine test data using 

biodiesel and standard diesel fuels were analyzed to estimate the effects biodiesel fuel has on Heavy 

Duty Diesel Vehicle (HDDV) tailpipe NOx, VOC, CO, SO2, and PM emissions and toxicity 

(Lindhjem and Pollack, 2000). The effects of biodiesel fuel use on Carbon Monoxide (CO) and 

Particulate Matter (PM) air quality and Exposure and Human Health Effects are addressed in the 

Task 3, 4, and 5 reports, respectively, of the NREL study. 

The assessment of the impacts of biodiesel fuel use on ozone concentrations is made with respect to 

both 1-hour and 8-hour ozone concentrations. An analysis of daily peak ozone concentrations in 

each urban area is made along with displays of spatial distributions of daily maximum ozone 

concentrations. These results are used to evaluate the effects of biodiesel fuel use on the 1-hour and 

8-hour ozone concentrations and attainment of the National Ambient Air Quality Standard 

(NAAQS). As part of the assessment, ozone exposure metrics are also calculated and evaluated as a 

measure of the impacts on ozone air quality and human health. 

Model and Databases Used 

The selection of the databases and models for the evaluation of biodiesel fuel effects focused on the 

SoCAB, Northeast Corridor cities, and Chicago. Several criteria were considered in the selection of 

the model and databases. These included the following 

• access to the database and models; 

• used recently in generating public policy; 

• preference for a current baseline; 

• databases most acceptable to regulatory agencies; 

• best representation of current conditions; 

• “good” model performance; 

• high heavy-duty diesel vehicle (HDDV) emissions contribution; and 

• both urban and regional representation. 

Based on these selection criteria, database availability, and discussions with the NREL Technical 

Monitor, the following selections were made regarding the models and databases used in this study: 
ES-2 

• The Comprehensive Air Quality Model with Extensions (CAMx) was selected to conduct 

the air quality modeling because it is state-of-science, publicly available, uses two-way 

grid nesting so that both urban- and region-scale issues can be addressed, availability of 

databases, and has been used recently for regulatory decision making (e.g., EPA NOx SIP 

Call Rule and Dallas-Fort Worth and Houston/Galveston SIPs). 

• An enhanced July 1995 OTAG database was used to model the eastern US; – the July 

1995 OTAG 36/12-km database was enhanced by adding two 4-km fine grids, one 

covering the lower Lake Michigan region and the other covering the Northeast Corridor, 

to better simulate urban ozone formation. 

• The EPA 2007 SIP Call emissions inventory was used for the eastern US and the baseline 

(standard diesel) scenario with the MOBILE5 mobile source emissions updated to 

incorporate some of the MOBILE6 emission effects. 

• A new South Coast Air Basin (SoCAB) database for the August 3-7, 1997 Southern 

California Ozone Study (SCOS) episode was used for ozone modeling of Southern 

California. 

• The California Air Resources Board (ARB) latest emissions inventory for 1997 based on 

the EMFAC2000 mobile source emissions model was used for the baseline (standard 

diesel) emissions scenario. 

Effects of Biodiesel Fuel Use 

The incorporation of biodiesel fuel effects in the emission inventory used in this study was 

accomplished with the application of the 1995 version of the Emission Modeling System (EMS95) 

for the eastern US and the ARB’s Gridded Emissions Model (GEM) for the SoCAB. Biodiesel 

effects were accounted for in the Heavy Duty Diesel Vehicle (HDDV) fleet only, and only the effects 

of a 20%/80% biodiesel/diesel fuel blend (B20) were considered. Under Task 1 of the NREL study, 

engine test data were analyzed and the average effects of the use of biodiesel fuel over a standard 

diesel fuel on HDDV tailpipe emissions of ozone precursors were estimated as shown in Table ES-1. 

Table ES-1. Overall average change in mass emission effects due to 

use of biodiesel fuels in HDDVs over using a standard diesel fuel. 

Biodiesel Fuel NOx CO VOC 

B20 +2.4% -13.1% -17.9% 

B100 +13.2% -42.7% -63.2% 

Three emission scenarios were analyzed for 2007 in the eastern US and 1997 for the SoCAB: 

• Standard diesel baseline scenario; 

• 100% penetration in the HDDV fleet of a B20 biodiesel fuel scenario; and 

• 50% penetration in the HDDV fleet of a B20 biodiesel fuel scenario. 
ES-3 

Emission Summary Results 

Table ES-2 summarizes the on-road mobile source NOx, VOC, and CO emission inventory in terms 

of the fractional contribution to the total inventory, the fractional contribution to the anthropogenic 

component, and the fraction of the on-road mobile inventory due to HDDV for the Lake Michigan 

and Northeast Corridor high-resolution (4-km) modeling domains, the 12-km eastern US OTAG 

domain, and the South Coast Air Basin (SoCAB) high-resolution (5-km) domain. While the on-road 

mobile component is a considerable percentage of the overall inventory, the HDDV contribution is 

relatively small, with the exception of the HDDV NOx emissions, which account for approximately 

one third of the on-road mobile inventory. Overall, the HDDV component is a small fraction of the 

entire emission inventory. However, it is also notable that emissions from on-road mobile sources in 

the SoCAB is relatively higher, especially the percentage of HDDV VOC to the total emission 

inventory that is higher in the SoCAB (1.9%) than in the Lake Michigan (0.3%) and North Corridor 

(0.2%) regions. 

The resulting changes in the emission inventory for a representative episode weekday are presented 

in Table ES-3 for the two biodiesel emission scenarios and for the Lake Michigan, Northeast 

Corridor, eastern US, and SoCAB domains. The use of biodiesel fuel with the HDDV fleet is 

estimated to have a very small change (<1%) in all ozone precursor emissions. 

Table ES-2. Summary of on-road mobile and HDDV emission contributions. 

2007 SIP Call Base Case and Eastern US OTAG 12-km Domain 

NOX VOC CO 

Mobile % of Total Inv. 30.20% 2.16% 49.34% 

Mobile % of Anthro. 37.36% 16.73% 49.34% 

HDDV % of Mobile Inv. 35.10% 4.70% 4.50% 

2007 SIP Call Base Case and Lake Michigan 4-km Domain 

NOX VOC CO 

Mobile % of Total Inv. 28.22% 7.36% 47.78% 

Mobile % of Anthro. 40.07% 15.94% 47.78% 

HDDV % of Mobile Inv. 32.60% 4.60% 4.70% 

2007 SIP Call Base Case and Northeast Corridor 4-km Domain 

NOX VOC CO 

Mobile % of Total Inv. 42.03% 2.64% 42.05% 

Mobile % of Anthro. 46.00% 14.12% 42.05% 

HDDV % of Mobile Inv. 35.90% 7.30% 6.30% 

1997 EMFAC2000 Base Case and South Coast Air Basin 5-km Domain 

NOX VOC CO 

Mobile % of Total Inv. 63.34 29.29 86.56 

Mobile % of Anthro. 63.34 33.48 86.56 

HDDV % of Mobile Inv. 41.26 6.50 8.26 
ES-4 

Table ES-3. Summary of emission effects due to B20 biodiesel fuel use. 

 100% B20 Biodiesel 50% B20 Biodiesel 

Emission Component 2007 EUSA OTAG 12-km Domain 2007 EUSA OTAG 12-km Domain 

%Change NOX %Change 

VOC 

%Change 

CO 

%Change NOX %Change 

VOC 

%Change 

CO 

On-Road Mobile 0.841% -0.851% -0.593% 0.421% -0.423% -0.294% 

Total Anthropogenic 0.315% -0.142% -0.293% 0.157% -0.071% -0.145% 

Total 0.254% -0.018% -0.293% 0.127% -0.009% -0.145% 

 2007 Lake Michigan 4-km Domain 2007 Lake Michigan 4-km Domain 

%Change NOX %Change 

VOC 

%Change 

CO 

%Change NOX %Change 

VOC 

%Change 

CO 

On-Road Mobile 0.782% -0.827% -0.599% 0.391% -0.411% -0.297% 

Total Anthropogenic 0.314% -0.132% -0.286% 0.157% -0.066% -0.142% 

Total 0.221% -0.061% -0.286% 0.111% -0.030% -0.142% 

 2007 Northeast Corridor 4-km Domain 2007 Northeast Corridor 4-km Domain 

%Change NOX %Change 

VOC 

%Change 

CO 

%Change NOX %Change 

VOC 

%Change 

CO 

On-Road Mobile 0.863% -1.312% -0.820% 0.431% -0.654% -0.407% 

Total Anthropogenic 0.397% -0.185% -0.345% 0.198% -0.092% -0.171% 

Total 0.363% -0.035% -0.345% 0.181% -0.017% -0.171% 

 1997 SoCAB 5-km Domain 1997 SoCAB 5-km Domain 

%Change NOX %Change 

VOC 

%Change 

CO 

%Change NOX %Change 

VOC 

%Change 

CO 

On-Road Mobile 0.788% -0.274% -0.0749% 0.389% -0.144% -0.037% 

Total Anthropogenic 0.499% -0.092% -0.065% 0.247% -0.048% -0.032% 

Total 0.499% -0.080% -0.065% 0.247% -0.042% -0.032% 

Ozone Modeling Results 

The CAMx, version 3.02, air quality model was exercised for the 7-18 July, 1995 episode on the 

enhanced 36/12/4-km OTAG modeling domain for the 2007 SIP Call Base Case and the 100% and 

50% B20 penetration into the HDDV fleet emission scenarios. Of the 12 episode days modeled, the 

July 11-15, 1995 period was analyzed in detail to evaluate the effects of biodiesel fuel use on urban 

and regional ozone air quality; the July 7-10, 1995 period is used to initialize the model and eliminate 

the influence of the initial concentrations, whereas the July 16-18, 1995 is a clean out period when 

ozone is relatively low so is not regulatory relevant. Modeling results were evaluated separately in 

the Lake Michigan and Northeast Corridor 4-km modeling domains and for selected urban areas in 

the eastern US within the 12-km OTAG modeling domain. The August 3-7, 1997 SCOS episode was 

simulated by CAMx version 3.10 for the three 1997 emissions scenarios in the South Coast Air 

Basin. Results for August 3, 1997 were not analyzed as it was used as an initialization day. 
ES-5 

The use of a 100% or 50% penetration in the HDDV results in very small changes, both 

increases and decreases, in the peak daily maximum 1-hour and 8-hour ozone concentrations in 

the SoCAB and Northeast Corridor, lake Michigan, and other cities in the eastern US. The 

changes in 1-hour and 8-hour ozone peaks due to use of the biodiesel fuel are always < 1 ppb. 

Therefore, the biodiesel fuel use ozone impacts should not be considered significant. 

Tables ES-4 and ES-5 summarizes the maximum increases and decreases in, respectively, daily 

maximum 1-hour and 8-hour ozone concentrations in each of the three regions due to use of 

biodiesel fuel in HDDVs. In the Lake Michigan region, the maximum increase and decrease in 

daily maximum ozone concentrations for the 100% B20 emissions scenario are +0.09 and –0.53 

ppb, respectively. The maximum increases and decreases in daily maximum ozone 

concentrations in the Northeast Corridor are +0.20 and –0.25 ppb, respectively. Similar numbers 

for the SoCAB are +0.22 and –1.20 ppb. Thus, even the maximum changes in daily maximum 

ozone concentrations due to the introduction of biodiesel fuels in the HDDV fleet in the Lake 

Michigan, Northeast Corridor, and SoCAB regions are very small. 

Table ES-4. Maximum increases and decreases in daily maximum 1-hour ozone concentrations 

(ppb) in the Lake Michigan, Northeast Corridor, and South Coast Air Basin regions. 

50% B20 Biodiesel (ppb) 100% B20 Biodiesel (ppb) 

Date Max Increase Max Decrease Max Increase Max Decrease 

2007 Lake Michigan Domain 

July 11, 1995 +0.03 -0.16 +0.05 -0.33 

July 12, 1995 +0.07 -0.10 +0.09 -0.19 

July 13, 1995 +0.05 -0.12 +0.09 -0.24 

July 14, 1995 +0.07 -0.09 +0.09 -0.18 

July 15, 1995 +0.04 -0.26 +0.08 -0.53 

2007 Northeast Corridor Domain 

July 11, 1995 +0.06 -0.08 +0.11 -0.14 

July 12, 1995 +0.07 -0.12 +0.13 -0.25 

July 13, 1995 +0.12 -0.06 +0.15 -0.07 

July 14, 1995 +0.15 -0.04 +0.20 -0.09 

July 15, 1995 +0.10 -0.10 +0.18 -0.20 

1997 South Coast Air Basin Domain 

August 4, 1997 +0.09 -0.48 +0.17 -0.95 

August 5, 1997 +0.10 -0.56 +0.19 -1.11 

August 6, 1995 +0.11 -0.60 +0.22 -1.20 

August 7, 1995 +0.13 -0.49 +0.26 -0.98 
ES-6 

Table ES-5. Maximum increases and decreases in daily maximum 8-hour ozone concentrations 

(ppb) in the Lake Michigan, Northeast Corridor, and South Coast Air Basin regions. 

50% B20 Biodiesel (ppb) 100% B20 Biodiesel (ppb) 

Date Max Increase Max Decrease Max Increase Max Decrease 

2007 Lake Michigan Domain 

July 11, 1995 +0.02 -0.14 +0.04 -0.28 

July 12, 1995 +0.03 -0.09 +0.07 -0.17 

July 13, 1995 +0.04 -0.11 +0.09 -0.21 

July 14, 1995 +0.03 -0.09 +0.07 -0.18 

July 15, 1995 +0.03 -0.20 +0.07 -0.40 

2007 Northeast Corridor Domain 

July 11, 1995 +0.05 -0.07 +0.10 -0.13 

July 12, 1995 +0.05 -0.10 +0.11 -0.20 

July 13, 1995 +0.07 -0.04 +0.12 -0.07 

July 14, 1995 +0.07 -0.04 +0.14 -0.07 

July 15, 1995 +0.06 -0.04 +0.15 -0.08 

1997 South Coast Air Basin Domain 

August 4, 1997 +0.06 -0.34 +0.12 -0.68 

August 5, 1997 +0.07 -0.39 +0.15 -0.77 

August 6, 1995 +0.08 -0.48 +0.15 -0.96 

August 7, 1995 +0.08 -0.42 +0.15 -0.83 

Conclusions 

Measured ozone is typically reported to EPA’s AIRS ozone compliance database to the nearest 1 

ppb. The maximum estimated increase in daily maximum 1-hour or 8-hour ozone concentrations due 

to the use of either a 100% of 50% penetration of a B20 fuel in the HDDV fleet is 0.26 ppb for the 

100% B20 fuel in the SoCAB region on August 7, 1997. As this maximum ozone increase is well 

below 1 ppb, then the use of biodiesel fuel is estimated to have no measurable adverse impact on 1-

hour or 8-hour ozone attainment in Southern California and the Eastern United States. In the Lake 

Michigan and Northeast Corridor regions, the maximum ozone reduction benefit due to the biodiesel 

fuel use is also well below 1 ppb, thus biodiesel use in these two areas is estimated to have no 

measurable beneficial impact on ozone attainment. In the SoCAB, the modeling estimates there will 

be reductions in daily maximum ozone concentrations by as high as approximately 1 ppb, which is a 

small but potentially measurable beneficial impact on ozone attainment. 
TABLE OF CONTENTS 

Page 

EXECUTIVE SUMMARY .................................................................................................... ES-1 

1. INTRODUCTION................................................................................................................ 1-1 

 Background............................................................................................................................ 1-1 

2. DATABASE AND MODEL SELECTION........................................................................ 2-1 

 Model Selection ..................................................................................................................... 2-1 

 Modeling Databases............................................................................................................... 2-2 

 Selection of an Assessment Year......................................................................................... 2-10 

3. BIODIESEL EMISSIONS ASSESSMENT....................................................................... 3-1 

 Emission Scenarios ................................................................................................................ 3-1 

 Emission Summaries.............................................................................................................. 3-2 

4. BIODIESEL OZONE ASSESSMENT............................................................................... 4-1 

 Eastern US Ozone Modeling Results..................................................................................... 4-1 

 South Coast Air Basin Ozone Modeling Results................................................................. 4-38 

5. CONCLUSIONS .................................................................................................................. 5-1 

REFERENCES.......................................................................................................................... R-1 

APPENDICES 

Appendix A: Impacts on Daily Maximum 1-Hour and 

8-Hour Ozone Concentrations Due to 

50% Penetration of B20 Biodiesel Fuel Use in the 

Lake Michigan 4-km Domain 

Appendix B: Impacts on Daily Maximum 1-Hour and 

8-Hour Ozone Concentrations Due to 

50% Penetration of B20 Biodiesel Fuel Use in the 

Northeast Corridor 4-km Domain 

Appendix C: Spatial Displays of CAMx Modeling Results 

For the OTAG 12-km Domain 
Appendix D: Impacts on Daily Maximum 1-Hour and 

8-Hour Ozone Concentrations Due to 

50% Penetration of B20 Biodiesel Fuel Use in the 

South Coast Air Basin 5-km Domain 

TABLES 

Table ES-1. Overall average change in mass emission effects due to 

 use of biodiesel fuels in HDDVs over using a standard diesel fuel...................ES-2 

Table ES-2. Summary of on-road mobile and HDDV emission contributions ....................ES-3 

Table ES-3. Summary of emission effects due to B20 biodiesel fuel use .............................ES-4 

Table ES-4 Maximum increases and decreases in daily 

 maximum 1-hour ozone concentrations (ppb) in the Lake 

 Michigan, Northeast Corridor, and South Coast Air Basin regions ..................ES-5 

Table ES-5. Maximum increases and decreases in daily maximum 

 8-hour ozone concentrations (ppb) in the Lake Michigan, Northeast 

 Corridor, and South Coast Air Basin regions. ...................................................ES-6 

Table 3-1: Overall average mass emission effects due to biodiesel fuels. ............................ 3-1 

Table 3-2. Future year baseline and biodiesel scenario emission 

 summary for 14 July, 1995 for Lake Michigan and Northeast Corridor. ............ 3-4 

Table 3-3. Summary of on-road mobile and HDDV emission contributions ....................... 3-5 

Table 3-4. Summary of emission effects for B20 biodiesel fuel use .................................... 3-6 

Table 3-5. Baseline and biodiesel scenario emission summary 

 for 3-7 August, 1997 For the South Coast Air Basin domain............................ 3-22 

Table 3-6. Summary of on-road mobile and HDDV emission contributions 

 for the South Coast Air Basin domain. .............................................................. 3-23 

Table 3-7. Summary of emission effects for B20 biodiesel fuel use 

 for the South Coast Air Basin domain. .............................................................. 3-24 

Table 4-1. Summary of daily peak 1-hour and 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain. ........................................... 4-3 

Table 4-2. Summary of daily peak 1-hour and 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain 

 for the 2007 standard diesel (SIP Call) and biodiesel 

 emission scenarios.. ........................................................................................... 4-17 

Table 4-3. Summary of exposure metrics for the Lake Michigan 4-km domain ................ 4-31 

Table 4-4. Summary of exposure metrics for the Northeast Corridor 4-km domain .......... 4-32 

Table 4-5. Counties included in each “City” for exposure assessment............................... 4-32 

Table 4-6. Summary of 1-hour ozone exposure metrics in OTAG 12-km domain............. 4-34 

Table 4-7. Summary of 8-hour ozone exposure metrics in OTAG 12-km domain............. 4-36 

Table 4-8. Summary of daily peak 1-hour and 8-hour ozone 

 concentrations in the South Coast Air Basin. .................................................... 4-39 

Table 4-9. Summary of ozone exposure metrics for the South Coast Air Basin. ............... 4-48 
FIGURES 

Figure 2-1. AQMP modeling domain used in this study’s modeling of 

 the August 1997 SCOS episode and the SCOS modeling 

 domain being used for databases under development.......................................... 2-4 

Figure 2-2. OTAG 36-km (outer) domain covering from Texas to 

 Maine and 12-km (inner) nested-grid modeling domain that 

 stretches from Arkansas/Mississippi to Massachusetts/New Hampshire ............ 2-7 

Figure 2-3. LADCO Grid M modeling domain...................................................................... 2-8 

Figure 2-4. Enhanced OTAG modeling domain that includes two high- 

 resolution 4-km nested-grids covering the Northeast Corridor and 

 Lake Michigan regions within the standard OTAG 36/12-km grid..................... 2-9 

Figure 3-1a. Daily total NOx emissions (tpd) for the 2007 SIP Call 

 in the Lake Michigan domain on 14 July, 1995................................................... 3-8 

Figure 3-1b. Daily on-road mobile source NOx emissions (tpd) for the 

 2007 SIP Call in the Lake Michigan domain on 14 July, 1995 ........................... 3-8 

Figure 3-1c. Increases in daily total NOx emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995...................................................................................... 3-9 

Figure 3-1d. Increases in daily total NOx emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995...................................................................................... 3-9 

Figure 3-2a. Daily total NOx emissions (tpd) for the 2007 SIP Call 

 in the Northeast Corridor domain on 14 July, 1995........................................... 3-10 

Figure 3-2b. Daily on-road mobile source NOx emissions (tpd) for the 

 2007 SIP Call in the Northeast Corridor domain on 14 July, 1995 ................... 3-10 

Figure 3-2c. Increases in daily total NOx emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Northeast Corridor 

 domain on 14 July, 1995.................................................................................... 3-11 

Figure 3-2d. Increases in daily total NOx emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Northeast Corridor 

 domain on 14 July, 1995.................................................................................... 3-11 

Figure 3-3a. Daily total VOC emissions (tpd) for the 2007 SIP Call 

 in the Lake Michigan domain on 14 July, 1995................................................. 3-12 

Figure 3-3b. Daily on-road mobile source VOC emissions (tpd) for the 

 2007 SIP Call in the Lake Michigan domain on 14 July, 1995 ......................... 3-12 

Figure 3-3c. Reductions in daily total VOC emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995.................................................................................... 3-13 
Figure 3-3d. Reductions in daily total VOC emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995.................................................................................... 3-13 

Figure 3-4a. Daily total VOC emissions (tpd) for the 2007 SIP Call in the 

 Northeast Corridor domain on 14 July, 1995..................................................... 3-14 

Figure 3-4b. Daily on-road mobile source VOC emissions (tpd) for the 

 2007 SIP Call in the Northeast Corridor domain on 14 July, 1995 ................... 3-14 

Figure 3-4c. Reductions in daily total VOC emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Northeast 

 Corridor domain on 14 July, 1995 ..................................................................... 3-15 

Figure 3-4d. Reductions in daily total VOC emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Northeast 

 Corridor domain on 14 July, 1995 ..................................................................... 3-15 

Figure 3-5a. Daily total CO emissions (tpd) for the 2007 SIP Call in 

 the Lake Michigan domain on 14 July, 1995..................................................... 3-16 

Figure 3-5b. Daily on-road mobile source CO emissions (tpd) for the 

 2007 SIP Call in the Lake Michigan domain on 14 July, 1995 ......................... 3-16 

Figure 3-5c. Reductions in daily total CO emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995.................................................................................... 3-17 

Figure 3-5d. Reductions in daily total CO emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Lake Michigan 

 domain on 14 July, 1995.................................................................................... 3-17 

Figure 3-6a. Daily total CO emissions (tpd) for the 2007 SIP Call in 

 the Northeast Corridor domain on 14 July, 1995............................................... 3-18 

Figure 3-6b. Daily on-road mobile source CO emissions (tpd) for the 

 2007 SIP Call in the Northeast Corridor domain on 14 July, 1995. .................. 3-18 

Figure 3-6c. Reductions in daily total CO emissions (tpd) for the 

 2007 100% B20 biodiesel fuel scenario in the Northeast 

 Corridor domain on 14 July, 1995 ..................................................................... 3-19 

Figure 3-6d. Reductions in daily total CO emissions (tpd) for the 

 2007 50% B20 biodiesel fuel scenario in the Northeast 

 Corridor domain on 14 July, 1995 ..................................................................... 3-19 

Figure 3-7a. Daily total NOx emissions (tpd) for the 1997 baseline 

 in the South Coast Air Basin on August 4, 1997 ............................................... 3-25 

Figure 3-7b. Daily on-road mobile source NOx emissions (tpd) for the 

 1997 baseline in the South Coast Air Basin on August 4, 1997........................ 3-25 

Figure 3-7c. Increases in daily total NOx emissions (tpd) for the 

 1997 100% B20 biodiesel fuel scenario in the South Coast 

 Air Basin on August 4, 1997.............................................................................. 3-26 

Figure 3-7d. Increases in daily total NOx emissions (tpd) for the 

 1997 50% B20 biodiesel fuel scenario in the South Coast 

 Air Basin on August 4, 1997.............................................................................. 3-26 
Figure 3-8a. Daily total VOC emissions (tpd) for the 1997 baseline 

 in the South Coast Air Basin on August 4, 1997 ............................................... 3-27 

Figure 3-8b. Daily on-road mobile source VOC emissions (tpd) for the 

 1997 baseline in the South Coast Air Basin on August 4, 1997........................ 3-27 

Figure 3-8c. Increases in daily total VOC emissions (tpd) for the 

 1997 100% B20 biodiesel fuel scenario in the South Coast 

 Air Basin on August 4, 1997.............................................................................. 3-28 

Figure 3-8d. Increases in daily total VOC emissions (tpd) for the 

 1997 50% B20 biodiesel fuel scenario in the South Coast 

 Air Basin on August 4, 1997.............................................................................. 3-28 

Figure 3-9a. Daily total CO emissions (tpd) for the 1997 baseline 

 in the South Coast Air Basin on August 4, 1997 ............................................... 3-29 

Figure 3-9b. Daily on-road mobile source CO emissions (tpd) for the 

 1997 baseline in the South Coast Air Basin on August 4, 1997........................ 3-29 

Figure 3-9c. Reductions in daily total CO emissions (tpd) 

 for the 1997 100% B20 biodiesel fuel scenario in the 

 South Coast Air Basin on August 4, 1997 ......................................................... 3-30 

Figure 3-9d. Reductions in daily total CO emissions (tpd) 

 for the 1997 50% B20 biodiesel fuel scenario in the 

 South Coast Air Basin on August 4, 1997 ......................................................... 3-30 

Figure 4-1a. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 11, 1995 for the 2007 SIP Call scenario....................................................... 4-4 

Figure 4-1b. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 12, 1995 for the 2007 SIP Call scenario....................................................... 4-4 

Figure 4-1c. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 13, 1995 for the 2007 SIP Call scenario....................................................... 4-5 

Figure 4-1d. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 14, 1995 for the 2007 SIP Call scenario....................................................... 4-5 

Figure 4-1e. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 15, 1995 for the 2007 SIP Call scenario....................................................... 4-6 

Figure 4-2a. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 11, 1995 for the 2007 SIP Call scenario....................................................... 4-7 

Figure 4-2b. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 12, 1995 for the 2007 SIP Call scenario....................................................... 4-7 

Figure 4-2c. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 13, 1995 for the 2007 SIP Call scenario....................................................... 4-8 
Figure 4-2d. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 14, 1995 for the 2007 SIP Call scenario....................................................... 4-8 

Figure 4-2e. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Lake Michigan 4-km domain on 

 July 15, 1995 for the 2007 SIP Call scenario....................................................... 4-9 

Figure 4-3a. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Lake Michigan domain on July 11, 1995........................................................... 4-10 

Figure 4-3b. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Lake Michigan domain on July 12, 1995........................................................... 4-10 

Figure 4-3c. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Lake Michigan domain on July 13, 1995........................................................... 4-11 

Figure 4-3d. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Lake Michigan domain on July 14, 1995........................................................... 4-11 

Figure 4-3e. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Lake Michigan domain on July 15, 1995........................................................... 4-12 

Figure 4-4a. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Lake Michigan domain on July 11, 1995........................................................... 4-13 

Figure 4-4b. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Lake Michigan domain on July 12, 1995........................................................... 4-13 

Figure 4-4c. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Lake Michigan domain on July 13, 1995........................................................... 4-14 

Figure 4-4d. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Lake Michigan domain on July 14, 1995........................................................... 4-14 

Figure 4-4e. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Lake Michigan domain on July 15, 1995........................................................... 4-15 

Figure 4-5a. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 11, 1995 for the 2007 SIP Call scenario..................................................... 4-18 

Figure 4-5b. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 12, 1995 for the 2007 SIP Call scenario..................................................... 4-18 

Figure 4-5c. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 13, 1995 for the 2007 SIP Call scenario..................................................... 4-19 
Figure 4-5d. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 14, 1995 for the 2007 SIP Call scenario..................................................... 4-19 

Figure 4-5e. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 15, 1995 for the 2007 SIP Call scenario..................................................... 4-20 

Figure 4-6a. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 11, 1995 for the 2007 SIP Call scenario..................................................... 4-21 

Figure 4-6b. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 12, 1995 for the 2007 SIP Call scenario..................................................... 4-21 

Figure 4-6c. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 13, 1995 for the 2007 SIP Call scenario..................................................... 4-22 

Figure 4-6d. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 14, 1995 for the 2007 SIP Call scenario..................................................... 4-22 

Figure 4-6e. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the Northeast Corridor 4-km domain on 

 July 15, 1995 for the 2007 SIP Call scenario..................................................... 4-23 

Figure 4-7a. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Northeast Corridor domain on July 11, 1995..................................................... 4-24 

Figure 4-7b. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Northeast Corridor domain on July 12, 1995..................................................... 4-24 

Figure 4-7c. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Northeast Corridor domain on July 13, 1995..................................................... 4-25 

Figure 4-7d. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Northeast Corridor domain on July 14, 1995..................................................... 4-25 

Figure 4-7e. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 1-hour ozone concentrations in the 

 Northeast Corridor domain on July 15, 1995..................................................... 4-26 

Figure 4-8a. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Northeast Corridor domain on July 11, 1995..................................................... 4-27 

Figure 4-8b. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Northeast Corridor domain on July 12, 1995..................................................... 4-27 

Figure 4-8c. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Northeast Corridor domain on July 13, 1995..................................................... 4-28 
Figure 4-8d. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Northeast Corridor domain on July 14, 1995..................................................... 4-28 

Figure 4-8e. Impacts of 100% penetration of B20 biodiesel fuel on 

 daily maximum 8-hour ozone concentrations in the 

 Northeast Corridor domain on July 15, 1995..................................................... 4-29 

Figure 4-9a. Spatial distribution of daily maximum 

 1-hour ozone concentrations in the South Coast Air 

 Basin on August 4, 1997 for the baseline scenario............................................ 4-40 

Figure 4-9b. Spatial Distribution Of Daily Maximum 1-Hour Ozone 

 Concentrations In The South Coast Air Basin On 

 August 5, 1997 For The Baseline Scenario ....................................................... 4-40 

Figure 4-9c. Spatial distribution of daily maximum 1-hour ozone 

 concentrations in the South Coast Air Basin on 

 August 6, 1997 for the baseline scenario........................................................... 4-41 

Figure 4-9d. Spatial distribution of daily maximum 1-hour 

 ozone concentrations in the South Coast Air Basin 

 on August 7, 1997 for the baseline scenario ...................................................... 4-41 

Figure 4-10a. Spatial distribution of daily maximum 8-hour 

 ozone concentrations in the South Coast Air Basin 

 on August 4, 1997 for the baseline scenario ...................................................... 4-42 

Figure 4-10b. Spatial distribution of daily maximum 8-hour 

 ozone concentrations in the South Coast Air Basin 

 on August 5, 1997 for the baseline scenario ...................................................... 4-42 

Figure 4-10c. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the South Coast Air Basin on 

 August 6, 1997 for the baseline scenario........................................................... 4-43 

Figure 4-10d. Spatial distribution of daily maximum 8-hour ozone 

 concentrations in the South Coast Air Basin on 

 August 7, 1997 for the baseline scenario........................................................... 4-43 

Figure 4-11a. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 1-hour ozone concentrations in 

 the South Coast Air Basin on August 4, 1997 for 

 the baseline scenario .......................................................................................... 4-44 

Figure 4-11b. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 1-hour ozone concentrations in 

 the South Coast Air Basin on August 5, 1997 for 

 the baseline scenario .......................................................................................... 4-44 

Figure 4-11c. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 1-hour ozone concentrations in 

 the South Coast Air Basin on August 6, 1997 for 

 the baseline scenario .......................................................................................... 4-45 

Figure 4-11d. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 1-hour ozone concentrations in 

 the South Coast Air Basin on August 7, 1997 for 

 the baseline scenario .......................................................................................... 4-45 
Figure 4-12a. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 8-hour ozone concentrations in 

 the South Coast Air Basin on August 4, 1997 for the 

 baseline scenario ................................................................................................ 4-46 

Figure 4-12b. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 8-hour ozone concentrations in 

 the South Coast Air Basin on August 5, 1997 for the 

 baseline scenario ................................................................................................ 4-46 

Figure 4-12c. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 8-hour ozone concentrations in 

 the South Coast Air Basin on August 6, 1997 for the 

 baseline scenario ................................................................................................ 4-47 

Figure 4-12d. Impacts of 100% penetration of B20 biodiesel fuel 

 on daily maximum 8-hour ozone concentrations in 

 the South Coast Air Basin on August 7, 1997 for the 

 baseline scenario ................................................................................................ 4-47 
1-1 

1. INTRODUCTION 

BACKGROUND

Biodiesel fuels have been investigated for a number of reasons, such as an extender for 

petroleum-based fuels derived from a domestic renewable energy source. But lately the primary 

interest is the potential for a more environmentally benign fuel. One potential benefit of 

biodiesel is that it can biologically degrade, making spills and leaks less of a concern. However, 

the potential for exhaust emission reductions and reductions in emissions toxicity are of the most 

interest. Several studies have shown that large reductions in hydrocarbon, particulate, and 

carbon monoxide emissions are expected from its use either as a neat fuel or as a blend with 

petroleum-derived fuels. 

There have been several studies regarding the effects of biodiesel fuels on exhaust emissions of 

NOx, VOC, CO, and particulate matter (PM). Almost all of these studies have examined 

emissions from heavy-duty diesel vehicle (HDDV) engines. However, the effects of biodiesel 

use on ambient air quality have not been quantified. Thus, the National Renewable Energy 

Laboratory (NREL) has retained ENVIRON International Corporation to estimate the air quality 

and resultant and health effect toxic impacts from the use of biodiesel fuels in several cities in 

the U.S. 

Ozone is formed in the atmosphere through complex reactions involving Volatile Organic 

Compounds (VOC) and oxides of Nitrogen (NOx) in the presence of sunlight. Reducing VOC 

emissions usually reduces ozone or has no effect. However, reducing NOx emissions may 

reduce or increase ozone concentrations. Currently there is a 1-hour ozone standard that is not to 

exceed 0.12 ppm (124 ppb) more than once per year averaged over 3 years. Thus, a violation of 

the 1-hour ozone standard occurs when the fourth highest values in 3-years at any monitor 

exceeds 0.12 ppm. More recently EPA has promulgated on 8-hour ozone standard that is 

expressed as the 3-year average of the fourth highest value with a threshold of 0.08 ppm (84 

ppb). 

Effects of Biodiesel Fuel on Ozone Concentrations 

The introduction of biodiesel fuels can produce a small increase in NOx emissions from diesel 

vehicles that might, in turn, influence ozone concentrations. The Ozone Transport Assessment 

Group (OTAG) found that for the eastern U.S. regional NOx controls are the most effective 

control strategy for reducing regional ozone concentrations (OTAG, 1997). However, the 

OTAG study also found that, on occasion in some urban areas, NOx controls resulted in ozone 

increases. These NOx disbenefits occur in the very largest metropolitan areas, such as New 

York City and Chicago, or in areas with high NOx emissions, such as cities along the Ohio River 

(e.g., Louisville and Cincinnati). Even in areas where occasional NOx disbenefits do occur due 

to local NOx controls, further downwind benefits (i.e., ozone reductions) will likely be realized. 

OTAG concluded that the benefits of NOx control for reducing ozone transport into an urban 

area outweighed any potential disbenefits due to local controls in an urban area. Thus, any 

credible ozone assessment of the ozone benefits of biodiesel needs to include both the effects of 

the fuel on regional ozone and ozone transport as well as the effects within the urban area itself. 

This means that the ozone air quality modeling impact of biodiesel fuel use needs to account for 
1-2 

both urban-scale and regional-scale ozone formation regimes. Thus, the air quality modeling 

needs to incorporate high-resolution (e.g., 4-5-km) urban-scale modeling as well as coarser (e.g., 

10-20-km) regional-scale modeling. 

Purpose 

This document is the Task 2 Report for the NREL “Impacts of Biodiesel Fuels on Air Quality 

and Human Health study. The objective of Task 2 is to estimate the effects of the use of 

biodiesel fuels on elevated ozone concentrations in three cities that represent the range of ozone 

nonattainment areas in the U.S. The ozone air quality impacts of biodiesel fuel use are estimated 

using air quality modeling. The impacts of biodiesel fuel use on ozone concentrations are 

estimated for the South Coast (Los Angeles) Air Basin (SoCAB) region of Southern California, 

the Lake Michigan region (e.g. Chicago, Milwaukee, Gary, and Southwestern Michigan), and the 

Northeast Corridor region (e.g., New York City, Philadelphia, Baltimore, and Washington DC). 

Results also presented for other eastern US cities and for regional-scale ozone across the eastern 

US. Under Task 1 of the study, biodiesel test data were analyzed and recommendations for 

incorporating biodiesel effects on pollutant mass emissions for use in air quality modeling made 

(Lindhjem and Pollack, 2000). Other tasks of the study address the effects of biodiesel fuel use 

on Carbon Monoxide (CO, Task 3) and Particulate Matter (PM, Task 4) air quality, and on 

human health effects due to air toxics (risk and exposure, Task 5). 
2-1 

2. DATABASE AND MODEL SELECTION 

The selection of the model and databases for evaluation of the effects of biodiesel fuel use on 

ozone concentrations focused on the following three “cities”: Los Angeles, the Northeast 

Corridor, and Chicago. An accurate evaluation of the effects of biodiesel use needs to 

adequately simulate urban photochemistry. Thus, a fine grid (4-5-km) was used in each city to 

properly simulate urban-scale ozone formation. The following criteria were considered in the 

selection of the model and database for use in this study: 

• Access to database and models 

• Used recently to generate public policy (e.g. SIP) 

• Current baseline preferable to future-year baseline 

• Database most acceptable to regulatory agencies 

• Best representation of current conditions 

• “Good” model performance 

• High HDDV contribution 

• Urban and regional representation 

MODEL SELECTION 

Currently there are several photochemical grid models available (e.g., UAM-IV, UAM-V, 

CAMx, CMAQ, etc.) that would likely be acceptable to the EPA and other regulatory agencies 

for use in ozone modeling. During the 1990’s, the UAM-IV was the preferred model in EPA’s 

Guidelines for Air Quality Modeling. However, more recently it has been removed from the list 

as EPA’s recommended model and currently EPA has no specific recommended air quality 

model for ozone. As the UAM-IV model does not support nested grids, it is an urban only model 

that can not treat regional issues so is not considered for this study. The UAM-V model does 

support nested grid applications and has also been used recently for generating public policy 

(OTAG, 1997; EPA, 1998a). However, the UAM-V is proprietary and not publicly available 

thus eliminating it from consideration. 

EPA has recently released (June 1999) its models-3 Community Multi-Scale Air Quality 

(CMAQ) modeling system. CMAQ is designed to be a one-atmosphere model that treats all air 

pollution issues. It is designed to run using just output from the MM5 meteorological model. 

CMAQ does not support two-way grid nesting so the impacts of urban controls on regional air 

quality can not be assessed. Because it is fairly new, there are very few CMAQ databases 

available and it has not yet been used for any regulatory decisions. 

The Comprehensive Air-quality Model with extensions (CAMx) is a three-dimensional two-way 

nested-grid photochemical grid model capable of treating both urban-scale and regional-scale 

ozone issues. CAMx was used by EPA in the recent NOx SIP Call technical analysis to evaluate 

the benefits and estimate the contributions of emissions from different States on downwind 

nonattainment (EPA, 1998a,b). CAMx is a nested-grid photochemical grid model with Plume in 

Grid (PiG) capability that is based on the latest (> 1995) science and coding practices. CAMx is 

also publicly available (available from www.camx.com) with no restrictions on its use. CAMx 

was used in the Dallas-Fort Worth and Houston/Galveston SIP modeling and is being used for 

public policy and potential SIP modeling for other Texas cities (e.g., Beaumont/Port Arthur, San 
2-2 

Antonio/Austin, and East Texas). In addition to Texas applications, the Lake Michigan States 

(LADCO, IL, IN, MI, and WI), Northeast States, and Midwest states are also using CAMx for 

their ozone air quality public policy decisions. CAMx is also one of the models being 

considered for use by the South Coast Air Quality Management District (SCAQMD) and the 

California Air Resources Board (ARB) for the 2002 AQMP/SIP for the South Coast Air Basin 

(SoCAB). Based on its public availability, technical attributes to treat both urban- as well as 

regional-scale ozone, and extensive use by EPA, States, and Stakeholders to generate public 

policy and SIP ozone control plans, CAMx was selected to evaluate the impacts of biodiesel 

fuels on ozone concentrations for this study. 

MODELING DATABASES 

High resolution (4 to 5-km) photochemical modeling databases are needed to simulate the effects 

of biodiesel fuel use. However, because transport is potentially an important component of 

ozone formation in the eastern US, the Northeast Corridor and Lake Michigan modeling 

databases should also be regional in nature so the effects of biodiesel fuel use can be assessed in 

both the urban and regional environments. 

Southern California Databases 

The 1997 Air Quality Management Plan (AQMP) and State Implementation Plan (SIP) and 1998 

AQMP/SIP Revision for the South Coast Air Basin (SoCAB) used the UAM-IV photochemical 

grid model (Morris and Myers, 1990) and databases based on episodes from the 1987 Southern 

California Air Quality Study (SCAQS) (SCAQMD, 1997). Of these, the August 1987 SCAQS 

UAM-IV database is the best quality and most limiting (i.e., has the highest ozone). However, 

the 1987 SCAQS episodes and databases are now rather dated. 

In 1997, the Southern California Ozone Study (SCOS) was conducted to collect ambient data for 

the development of new photochemical modeling databases for the SoCAB. The California Air 

Resources Board (ARB) and South Coast Air Quality Management District (SCAQMD) are 

using the SCOS data to develop new modeling databases to support the 2002 AQMP/SIP. The 

highest ozone during the SCOS field study occurred during the August 3-7, 1997 episode. A new 

modeling database has been developed for the SoCAB and the August 3-7, 1997 SCOS episode 

using the latest meteorological (MM5) and photochemical (CAMx) modeling technology 

(Yarwood et al., 2002; Morris et al., 2001; 2002). This database has been used by the National 

Academia of Sciences (NAS) to assess the effects new ozone standards may have on 

transportation planning (ENVIRON, 2002), to assess the causes of higher observed ozone on 

weekend days versus weekdays (Yarwood et al., 2002), and to assess the ozone impacts of 

advanced technology vehicles (Morris et al., 2001; 2002). The use of the more recent 1997 

SCOS database is preferable and more acceptable to the regulatory agencies than the older 1987 

SCAQS database. Thus the August 3-7, 1997 SCOS CAMx/MM5 database was selected in this 

study to assess the effects biodiesel fuel use would have on ozone formation in the SoCAB. 

Figure 2-1 displays the southern California modeling domain used in the 1997/1999 Air Quality 

Management Plan (AQMP) for the new SCOS modeling domain that will be used for the 1997 

SCOS episode databases under development. The ARB is developing new emissions for the 

enlarged SCOS domain. However, at the time this study was initiated, emissions were only 
2-3 

available for the smaller AQMP domain, thus the August 3-7, 1997 CAMx/MM5 database only 

addresses the AQMP domain. As ozone formation in the SoCAB is completely contained within 

the AQMP domain, then use of the smaller AQMP domain will have no effect on the biodiesel 

fuel ozone assessment in the SoCAB. However, results for San Diego, Santa Barbara, Mojave 

Dessert, and Imperial County will not be available. 

The August 3-7, 1997 CAMx/MM5 database was run using 1997 emissions for the AQMP 

domain and the model estimated ozone concentrations compared with the observed values in a 

model performance evaluation. The CAMx/MM5 modeling system reproduced the observed 

ozone concentrations in the SoCAB during August 4-7, 1997 quite well (Yarwood et al., 2002; 

Morris et al., 2001; 2002) meeting all of EPA’s ozone modeling performance goals for SIP 

modeling (EPA, 1991). This is in contrast to the performance of the UAM-IV for the 1987 

SCAQS episodes that was poor and exceeded EPA’s performance goals (SCAQMD, 1997). 

A new 1997 baseline emission inventory was developed by the California Air Resources Board 

(ARB) based on the EMFAC2000 mobile source emissions model. The EMFAC2000 produces 

more VOC, CO, and NOx emissions than its predecessor (EMFAC7G) that was used in the 

1997/1999 SIP/AQMP modeling. For photochemical modeling, EMFAC2000 uses link-based 

vehicle miles traveled (VMT), speed, and starts data from the Direct Transportation Impact 

Model (DTIM4) travel demand model. The ARB EMFAC2000/DTIM4 mobile emissions model 

was used in this study.
2-4 

CAMx Modeling Domains 

Figure 2-1. AQMP modeling domain used in this study’s modeling of the August 1997 SCOS episode and the Sdomain being used for databases under development.

San Bernardino

Kern San Luis Obispo

Santa Barbara

Ventura

Los Angeles

Riverside

Orange

San Diego Imperial

150 200 250 300 350 400 450 500 550 600 650 

36003650370037503800385039003950

AQMP

UTM Easting (km)

UTM Northing (km)
2-5 

Northeast Corridor Region Database 

Since the 1994 SIP modeling of the Northeast Corridor urban cities, photochemical modeling of 

the Northeast Ozone Transport Region (OTR) has been performed mainly as part of OTAG and 

the EPA NOx SIP Call and related analysis. OTAG developed four regional-scale modeling 

databases for periods from July 1988, July 1991, July 1993, and July 1995. Of these, the July 

1995 episode is the most recent and most appropriate for use in evaluating biodiesel fuel use in 

the Northeast Corridor region. The OTAG domain consists of a 36-km grid covering the entire 

eastern US and a 12-km nested grid covering the central portion of the domain, including the 

northeast corridor (see Figure 2-2). The EPA used the four OTAG databases and the UAM-V 

and CAMx photochemical models to provide the technical basis for the NOx SIP Call. 

However, numerous questions have been raised concerning the adequacy of 12-km grid 

resolution for simulating ozone concentrations, especially in the urban areas such as the 

Northeast Corridor and Lake Michigan areas (e.g., Tesche et al., 1998; Morris et al., 1998a,b). 

The Northeast States are in the process of developing new higher-resolution photochemical 

modeling databases that are not yet available 

Chicago Area Databases 

The OTAG/SIP Call databases discussed above also cover the Chicago and Lake Michigan area, 

albeit at fairly coarse (12-km) resolution. Thus, the same database and simulation could possibly 

be used to address both the Northeast Corridor and Chicago ozone issues. However, the 

adequacy of the 12-km grid resolution for simulating urban ozone formation is questionable. 

The Lake Michigan Air Directors Consortium (LADCO) and four Lake Michigan States (IL, IN, 

MI, and WI) have developed more refined databases for the 4-km “Grid M” region displayed in 

Figure 2-3. Grid M databases have been developed for the June and July 1991 LMOS episodes 

and two 1995 databases. These databases were used by LADCO and the Lake Michigan States 

to develop comments on the EPA NOx SIP Call for local public ozone policy discussions and 

were also used for the St. Louis SIP modeling. All information generated by LADCO is publicly 

available and they have indicted that the revised updated emissions inventory would also be 

publicly available. LADCO is currently developing new databases for the region using MM5 

and the CAMx models. Although the Grid M databases have been developed using 4-km 

resolution, almost all of the Grid M modeling analysis has been conducted at a 12-km resolution. 

Selection of Ozone Modeling Databases for the 

Northeast Corridor and Lake Michigan Regions 

The July 1995 OTAG database is an attractive photochemical modeling database for assessing 

the impacts of biodiesel fuel use on ozone formation because: 

• It has been used in OTAG and EPA’s NOx SIP Call and Tier 2/Low Sulfur 

Rulemakings so therefor has regulatory stature; 

• Can address both the Northeast Corridor and Lake Michigan urban areas; and 

• Would also provide a regional assessment of the impacts of biodiesel use on ozone 

concentrations in other cities across the eastern US. 
2-6 

However, the July 1995 OTAG database 36/12-km resolution is inadequate for properly 

simulating urban-scale ozone formation processes that may be important for the biodiesel fuel 

ozone impact assessment. Although the LADCO Grid M databases are routinely run at 12-km 

resolution, 4-km resolution versions of the database do exist. However, the Grid M databases 

cover just the Midwest so could not be used to assess ozone impacts in the Northeast Corridor. 

Thus, to perform ozone modeling of the Northeast Corridor and Lake Michigan areas it was 

decided to enhance the July 7-15, 1995 OTAG episode database adding two high-resolution 4-

km nested-grids as follows: 

1. One for the Northeast Corridor stretching from Washington D.C. to Connecticut and 

including the urban cities of Washington DC, Baltimore, Philadelphia, and New York 

City; and 

2. Another covering the Lower Lake Michigan region and including Chicago, 

Milwaukee, Gary, and Southwest Michigan. 

Figure 2-4 displays the enhanced 36/12/4-km nested-grid domain for the July 1995 OTAG 

episode that includes high-resolution (4-km) grids for the Northeast Corridor and Lake Michigan 

regions. Although the focus on the biodiesel ozone impact assessment will be on ozone within 

the 4-km high-resolution Northeast Corridor and Lake Michigan areas, modeling results will also 

be obtained for other eastern US cities such as Atlanta, Birmingham, St. Louis, Memphis, 

Cincinnati, Pittsburgh, Detroit, etc., albeit using a lower grid resolution (12-km). 
2-7 

Figure 2-2. OTAG 36-km (outer) domain covering from Texas to Maine and 12-km (inner) nested-grid modelinstretches from Arkansas/Mississippi to Massachusetts/New Hampshire. 

-94 -89 -84 -79 -74 

29323538414447

Longitude

Latitude
2-8 

Figure 2-3. LADCO Grid M modeling domain used for the June 1991 and July 1995 episodes, 

both 4-km and 12-km versions of the databases are available. 

-92 -91 -90 -89 -88 -87 -86 -85 -84 -83

35

36

37

38

39

40

41

42

43

44

45
2-9 

Figure 2-4. Enhanced OTAG modeling domain that includes two high-resolution 4-km nestedgrids covering the Northeast Corridor and Lake Michigan regions within the standard OTAG 

36/12-km grid. 
2-10 

SELECTION OF AN ASSESSMENT YEAR 

Originally NREL preferred that the assessment of biodiesel fuel use on ozone formation use a 

current baseline year (e.g., 1995-2000) rather than a projected future-year baseline to reduce 

uncertainties associated with projecting emissions to future-years. It is recognized that there are 

numerous uncertainties associated with emissions, including projecting emissions to a futureyear, so that use of a future-year projected inventory (e.g., 2005, 2007, or 2010) adds another 

potentially unnecessary layer of uncertainty to the modeling analysis. However, biodiesel fuel 

use will occur in a future, not historical year. As emissions have changed and will continue to 

change over the years, it makes more sense to make the biodiesel ozone impact assessment for a 

more current or future-year. 

For the eastern US (including the Northeast Corridor and Lake Michigan) biodiesel fuel use 

ozone impact assessment, a future-year of 2007 was selected. This future-year was also used by 

OTAG and EPA in their various recent rulemakings. The growth and control projections for 

2007 have been extensively reviewed and updated. 

For the assessment of biodiesel fuel use in the SoCAB, it was originally intended to use the 2010 

1-hour ozone attainment year. However, because the ARB/SCAQMD are in the process of 

developing a new SIP/AQMP, the latest 2010 emissions inventory is not available yet. Thus, the 

choice was to go back to the old 1997/1999 AQMP/SIP 2010 emission projections based on 

EMFAC7G or use the latest ARB 1997 emission inventories that are based on EMFAC2000. It 

was decided to proceed with the study using a 1997 assessment year for the following reasons: 

• The 1997 year is based on the EMFAC2000, whereas the current 2010 inventory is 

based on EMFAC7G; 

• There are numerous other emission updates in the current 1997 inventory not present 

in the currently available 2010 inventory (e.g., non-road, stationary sources, area 

sources, etc.); 

• The 2010 emission projections for the SoCAB are even more uncertain than usual due 

to the inclusion of 182(e)(5) emission control measures in the 1-hour ozone SIP 

control plan that are based on no known control technology. 
3-1 

3. BIODIESEL EMISSIONS ASSESSMENT 

Under Task 1 of the NREL Biodiesel Air Quality Impacts Study, engine dynamometer test data 

were reviewed and analyzed for a variety of engine types and model years for both a 20%/80% 

biodiesel/diesel fuel blend (B20) and a 100% biodiesel fuel (B100), as well as a standard diesel 

fuel. Table 3-1 summarizes the results of these analyses with respect to biodiesel fuel effects on 

heavy-duty diesel vehicle (HDDV) mass emissions for ozone precursors. A detailed discussion 

of the emission effects due to biodiesel fuels can be found in the Task 1 report (Lindhjem and 

Pollack, 2000). For the assessment of impacts of biodiesel fuel use on ozone concentrations for 

the future year scenarios, the effects of biodiesel fuels were accounted for only in the HDDV 

fleet. As it is unlikely to expect there will be sufficient biodiesel fuel produced to allow a 

significant penetration of B100 fuel in either the Lake Michigan, the Northeast Corridor, or the 

South Coast Air Basin (SoCAB), regions the assessment was made for just the B20 fuel only. A 

B20 fuel also has better biological stability and less water issues than a B100 fuel. 

Table 3-1. Overall average change in mass emission effects due to biodiesel fuels in 

HDDVs over using a standard diesel fuel. 

Biodiesel Fuel NOx CO VOC 

B20 +2.4% -13.1% -17.9% 

B100 +13.2% -42.7% -63.2% 

EMISSION SCENARIOS 

The biodiesel fuel effects on ambient ozone concentrations are assessed in the Northeast 

Corridor and Lake Michigan areas and the eastern U.S. for the following scenarios and the future 

year 2007: 

• Future-year baseline diesel fuel (ARB standard diesel) 

• 100% penetration of B20 fuel 

• 50% penetration of B20 fuel 

The gridded model-ready emission inventories for the Lake Michigan and Northeast Corridor 

modeling domains were prepared using the 1995 version of the Emission Modeling System 

(EMS95) and an enhanced version of the MOBILE5 emission factor model. The MOBILE5 

model was modified to account for currently known changes to be implemented in MOBILE6. 

The EMS95 was configured for the OTAG 36-km and 12-km domains and for the two 4-km 

nested grids, as shown in Figure 2-4, and exercised for the July 7-18, 1995 episode. The baseline 

emissions scenario was developed for the year 2007 assuming implementation of both the 

Regional Ozone Transport (i.e., the NOx SIP Call) Rule (ROTR) and the Tier 2/Low Sulfur Rule. 

The effects of B20 biodiesel fuels on NOx, VOC and CO were accounted for only in HDDV 

portion of the inventory through modification of the on-road mobile emission factors in the 

EMS95 input data files using the adjustment factors in Table 3-1. EMS95 was then re-run for 

the 100% penetration level of B20 fuel and for the 50% penetration level (assumed adjustments 

of +1.2%, -8.95% and –6.55% for NOx, VOC and CO, respectively) in order to provide the 

model-ready gridded emission inventories for the two future-year biodiesel emission scenarios. 
3-2 

The biodiesel fuel effects on ambient ozone concentrations are assessed in the South Coast Air 

Basin for the following scenarios and the base year 1997: 

• 1997 baseline diesel fuel (CARB standard diesel) 

• 100% penetration of B20 fuel 

• 50% penetration of B20 fuel 

The gridded model-ready emission inventories for the South Coast Air Basin (SoCAB) were 

prepared using EMFAC2000/DTIM4 on-road mobile source emissions models and the California 

Air Resources Board (ARB) Gridded Emissions Model (GEM) for the August 1997 Southern 

California Ozone Study (SCOS) episode. Currently only base year (1997) emissions are 

available using EMFAC2000/DTIM4. Therefore, the baseline diesel emissions scenario was 

developed for the year 1997. The effects of 100% and 50% penetration levels of B20 biodiesel 

fuels on NOx, VOC and CO were accounted for only in HDDV portion of the inventory through 

source control modification in the GEM model. 

EMISSION SUMMARIES 

Emissions modeling was performed for the eastern US on a 36/12/4-km grid with 4-km domains 

covering the Northeast Corridor and Lake Michigan regions using EMS95 and for the SoCAB at 

5-km resolution using GEM. 

Lake Michigan and Northeast Corridor Emission Summaries 

Table 3-2 summarizes the NOx, VOC and CO emissions for the Lake Michigan and Northeast 

Corridor 4-km domains as well as the OTAG 12-km modeling domain by major emission source 

categories for July 14, 1995, a representative episode weekday. Table 3-3 provides a summary 

of the effects of biodiesel fuel on HDDV NOx, VOC and CO emissions in terms fraction of onroad mobile emissions to the total inventory (anthropogenic plus biogenic), the fraction of onroad mobile emission to the total anthropogenic inventory, and the fraction of HDDV emissions 

to the total on-road mobile inventory. The resulting overall changes in emission inventories by 

major source category for each domain and for the two emissions scenarios are summarized in 

Table 3-4. 

As a percentage of the total on-road mobile inventory (in the baseline scenario), the HDDV 

fraction of NOx emissions varies from approximately 32% to 36%, depending on the domain, 

while the percentage of on-road mobile emissions in the total anthropogenic inventory is 

somewhat higher, varying from approximately 37% to 46%. As a percentage of the total 

inventory (anthropogenic plus biogenic), the on-road mobile NOx emissions vary from 

approximately 28% to 42%. The variation seen across the domains is a result of the difference in 

fleet mix and amount of biogenic NOx emissions, with the Northeast Corridor domain exhibiting 

a higher percentage of HDDV within the entire vehicle fleet as compared to the Lake Michigan 

domain. Note that in these summary tables, the OTAG 12-km domain also includes the 

contributions from both the Lake Michigan and the Northeast Corridor domains. The resulting 

overall impacts on the total NOx emission inventory due to use of a B20 fuel is much less than 

1%, as seen in Table 3-4, varying from only 0.22% to 0.36% for the 100% penetration level, and 

0.11% to 0.18% for the 50% penetration level of B20 biodiesel fuel. 
3-3 

Similar results are seen for VOC and CO emission effects. The fraction of on-road mobile VOC 

emissions due to the HDDV contribution varies from 4.7% to 7.3%, with the largest percentage 

occurring in the Northeast Corridor domain. As a percentage of the anthropogenic emissions, 

on-road mobile VOC accounts for approximately 14% to 17% of the inventory, while the onroad mobile contribution ranges from approximately 2% to 7% of the total (anthropogenic plus 

biogenic) VOC emission inventory. For CO, the fraction of HDDV emissions vary from 4.5% to 

6.3% of the on-road mobile component, while the on-road mobile CO emissions range from 

approximately 42% to 50% of the total emission inventory. As with the NOx emission effects, 

the overall VOC and CO emission reductions due to biodiesel fuel use are very small. For the 

100% penetration scenario, total VOC emission inventory reductions range from 0.018% to 

0.06%, while the impacts due to the 50% penetration level are approximately 0.01% to 0.02%. 

For CO, reductions in the total emissions inventory range from 0.28% to 0.35% for the 100% 

B20 biodiesel scenario, and only 0.14% to 0.17% for the 50% penetration scenario. 
3-4 

Table 3-2. Future year baseline and biodiesel scenario emission summary for 14 July, 1995 for Lake Michigan aCorridor. 

 2007 SIP CALL 2007 100% B20 Biodiesel 2007 50% Emission Component OTAG 12km Domain NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) Area 8113.01 15464.90 50618.14 8113.01 15464.90 50618.14 8113.01 Low Points 918.29 2874.23 3487.71 918.29 2874.23 3487.71 918.29 Elevated Points 1738.49 160.63 1661.42 1738.49 160.63 1661.42 1738.49 On-Road Mobile 6435.27 3714.19 54237.05 6489.41 3682.57 53915.25 6462.34 Total Anthropogenic 17205.06 22213.94 110004.32 17259.20 22182.32 109682.52 17232.13 Biogenic 4081.86 149670.95 0.00 4081.86 149670.95 0.00 4081.86 Total 21286.92 171884.89 110004.32 21341.06 171853.27 109682.52 21313.99 

Lake Michigan 4km DomainNOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) 

Area 929.95 1701.96 5771.70 929.95 1701.96 5771.70 929.95 Low Points 82.80 418.82 422.85 82.80 418.82 422.85 82.80 Elevated Points 7.28 1.18 12.57 7.28 1.18 12.57 7.28 On-Road Mobile 684.15 402.41 5681.24 689.50 399.09 5647.19 686.82 Total Anthropogenic 1704.18 2524.38 11888.36 1709.53 2521.05 11854.32 1706.86 Biogenic 714.96 2942.20 0.00 714.96 2942.20 0.00 714.96 Total 2419.14 5466.58 11888.36 2424.49 5463.25 11854.32 2421.82 

Northeast Corridor 4km Domain 

NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) 

Area 1137.85 2641.74 11450.81 1137.85 2641.74 11450.81 1137.85 Low Points 182.54 554.27 279.02 182.54 554.27 279.02 182.54 Elevated Points 227.11 25.07 224.18 227.11 25.07 224.18 227.11 On-Road Mobile 1318.08 529.18 8667.11 1329.45 522.24 8596.02 1323.77 Total Anthropogenic 2865.58 3750.26 20621.12 2876.95 3743.32 20550.03 2871.27 Biogenic 270.77 16282.81 0.00 270.77 16282.81 0.00 270.77 Total 3136.35 20033.07 20621.12 3147.72 20026.13 20550.03 3142.04 
3-5 

Table 3-3. Summary of on-road mobile and HDDV emission contributions.

On-Road Mobile Emission Summary for 2007 SIP Call 

 OTAG 12km Domain 

NOX VOC CO 

Mobile % of Total Inv. 30.20% 2.16% 49.34% 

Mobile % of Anthro. 37.36% 16.73% 49.34% 

HDDV % of Mobile Inv. 35.10% 4.70% 4.50% 

 Lake Michigan 4km Domain 

NOX VOC CO 

Mobile % of Total Inv. 28.22% 7.36% 47.78% 

Mobile % of Anthro. 40.07% 15.94% 47.78% 

HDDV % of Mobile Inv. 32.60% 4.60% 4.70% 

 Northeast Corridor 4km Domain 

NOX VOC CO 

Mobile % of Total Inv. 42.03% 2.64% 42.05% 

Mobile % of Anthro. 46.00% 14.12% 42.05% 

HDDV % of Mobile Inv. 35.90% 7.30% 6.30% 
3-6 

Table 3-4. Summary of emission effects for B20 biodiesel fuel use. 

 2007 100% B20 Biodiesel 2007 50% B20 Biodiesel Emission Component OTAG 12km Domain OTAG 12km Domain 

%Change NOX %Change VOC %Change CO %Change NOX %Change V

Area 0.000% 0.000% 0.000% 0.000% 0.000% Low Points 0.000% 0.000% 0.000% 0.000% 0.000% Elevated Points 0.000% 0.000% 0.000% 0.000% 0.000% On-Road Mobile 0.841% -0.851% -0.593% 0.421% -0.423% Total Anthropogenic 0.315% -0.142% -0.293% 0.157% -0.071% Biogenic 0.000% 0.000% 0.000% 0.000% 0.000% Total 0.254% -0.018% -0.293% 0.127% -0.009%  Lake Michigan 4km Domain Lake Michigan 4km Domain 

%Change NOX %Change VOC %Change CO %Change NOX %Change V

Area 0.000% 0.000% 0.000% 0.000% 0.000% Low Points 0.000% 0.000% 0.000% 0.000% 0.000% Elevated Points 0.000% 0.000% 0.000% 0.000% 0.000% On-Road Mobile 0.782% -0.827% -0.599% 0.391% -0.411% Total Anthropogenic 0.314% -0.132% -0.286% 0.157% -0.066% Biogenic 0.000% 0.000% 0.000% 0.000% 0.000% Total 0.221% -0.061% -0.286% 0.111% -0.030%  Northeast Corridor 4km Domain Northeast Corridor 4km Domain 

%Change NOX %Change VOC %Change CO %Change NOX %Change V

Area 0.000% 0.000% 0.000% 0.000% 0.000% Low Points 0.000% 0.000% 0.000% 0.000% 0.000% Elevated Points 0.000% 0.000% 0.000% 0.000% 0.000% On-Road Mobile 0.863% -1.312% -0.820% 0.431% -0.654% Total Anthropogenic 0.397% -0.185% -0.345% 0.198% -0.092% Biogenic 0.000% 0.000% 0.000% 0.000% 0.000% Total 0.363% -0.035% -0.345% 0.181% -0.017% 
3-7 

The spatial distributions of the daily total NOx, VOC and CO emissions and the impacts due to 

B20 biodiesel fuel use for a representative episode day (14 July, 1995) are displayed in Figures 

3-1 through 3-6 for the two 4-km nested grid domains and for the 100% and 50% B20 

penetration levels. Figures 3-1a and 3-1b display the spatial distributions of total surface NOx 

emissions and on-road mobile source NOx emissions in the Lake Michigan 4-km domain, 

respectively. The on-road mobile component accounts for approximately 28% of the total NOx

emissions and are primarily located within the major urban centers of Chicago and Milwaukee. 

The increases in total daily NOx due to the introduction of B20 biodiesel fuel in the HDDV fleet 

are displayed in Figures 3-1c and 3-1d for the 100% and 50% penetration levels, respectively. 

As expected, the largest increases are seen within the urban areas of the domain with small 

differences distributed along the major transportation routes. In both biodiesel emission 

scenarios however, the increases are very small. 

In Figures 3-2a and 3-2b the corresponding spatial distributions of NOx emissions are displayed 

for the Northeast Corridor domain in terms of the daily total and on-road mobile source 

component, respectively. In the Northeast Corridor the mobile source component accounts for 

almost 45% of the daily total and, although the highest emissions on-road are generally confined 

to the urban centers, the emissions are seen to be more widely distributed across the domain due 

to the denser traffic networks linking Washington, DC, Baltimore, Philadelphia and New York 

City. While relatively small, the resulting increases in NOx emissions under the 100% and 50% 

B20 biodiesel scenarios are correspondingly spread across the domain with the largest 

differences occurring within the major urban centers as shown in Figures 3-2c and 3-2d. 

The daily total and on-road mobile VOC emissions and the corresponding reductions due to the 

B20 biodiesel emission scenarios are displayed in Figures 3-3 and 3-4 for the Lake Michigan and 

Northeast Corridor domains, respectively. As with the NOx emissions, the spatial distribution of 

on-road mobile source VOC emissions are generally confined within the major urban centers. 

The percentage of total VOC emissions due to on-road mobile sources is approximately 7% in 

the Lake Michigan domain while within the Northeast Corridor domain, the on-road mobile 

component accounts for only approximately 2.5%, due to the higher percentage of biogenic 

VOCs within the domain. The spatial distribution of VOC emission reductions realized due to 

biodiesel fuel use are similar to those of NOx, with the largest differences generally within the 

urban areas of the domains and smaller emission reductions distributed along the major 

highways and transportation networks. 

The spatial distribution of daily total and on-road mobile CO emissions, as well as the reductions 

resulting from the use of B20 biodiesel fuel, are presented in Figures 3-5 and 3-6 for the Lake 

Michigan and Northeast Corridor domains, respectively. For CO emissions the mobile source 

component accounts for approximately 42% to 48% of the total CO emissions in the Lake 

Michigan and Northeast Corridor domains. As such, the spatial distributions of the daily total 

and on-road mobile CO emissions are very similar, confined mainly to the urban centers and the 

transportation corridors of the domains. The reductions in CO emissions for the Lake Michigan 

and Northeast Corridor domains for each of the biodiesel emission scenarios are displayed in 

Figures 3-5c, 3-5d, 3-6c and 3-6d. As with the NOx and VOC emissions, overall CO emission 

reductions for the 50% and 100% penetration level of a B20 fuel are small, ranging from 

approximately 0.14% to 0.35%, and are generally throughout the traffic networks and urban 

centers of the Lake Michigan and Northeast Corridor domains. 
3-8 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 21 tpd

Total = 2352 tpd

Daily Total NOx Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-1a. Daily total NOx emissions (tpd) for the 2007 SIP Call in the Lake Michigan 

domain on 14 July, 1995. 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 4 tpd

Total = 646 tpd

Daily On-road Mobile NOx Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-1b. Daily on-road mobile source NOx emissions (tpd) for the 2007 SIP Call in the 

Lake Michigan domain on 14 July, 1995. 
3-9 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Increases in Daily Total NOx Emissions (tpd)

100% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-1c. Increases in daily total NOx emissions (tpd) for the 2007 100% B20 biodiesel fuel 

scenario in the Lake Michigan domain on 14 July, 1995. 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Increases in Daily Total NOx Emissions (tpd)

50% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-1.d. Increases in daily total NOx emissions (tpd) for the 2007 50% B20 biodiesel fuel 

scenario in the Lake Michigan domain on 14 July, 1995. 
3-10 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 20 tpd

Total = 2875 tpd

Daily Total NOx Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-2a. Daily total NOx emissions (tpd) for the 2007 SIP Call in the Northeast Corridor 

domain on 14 July, 1995. 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 6 tpd

Total = 1291 tpd

Daily On-road Mobile NOx Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-2b. Daily on-road mobile source NOx emissions (tpd) for the 2007 SIP Call in the 

Northeast Corridor domain on 14 July, 1995. 
3-11 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Increases in Daily Total NOx Emissions (tpd)

100% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-2c. Increases in daily total NOx emissions (tpd) for the 2007 100% B20 biodiesel fuel 

scenario in the Northeast Corridor domain on 14 July, 1995. 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Increases in Daily Total NOx Emissions (tpd)

50% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-2d. Increases in daily total NOx emissions (tpd) for the 2007 50% B20 biodiesel fuel 

scenario in the Northeast Corridor domain on 14 July, 1995. 
3-12 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 42 tpd

Total = 5401 tpd

Daily Total VOC Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-3a. Daily total VOC emissions (tpd) for the 2007 SIP Call in the Lake Michigan 

domain on 14 July, 1995. 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 2 tpd

Total = 374 tpd

Daily On-road Mobile VOC Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-3b. Daily on-road mobile source VOC emissions (tpd) for the 2007 SIP Call in the 

Lake Michigan domain on 14 July, 1995. 
3-13 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Reductions in Daily Total VOC Emissions (tpd)

100% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-3c. Reductions in daily total VOC emissions (tpd) for the 2007 100% B20 biodiesel 

fuel scenario in the Lake Michigan domain on 14 July, 1995.

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Reductions in Daily Total VOC Emissions (tpd)

50% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-3d. Reductions in daily total VOC emissions (tpd) for the 2007 50% B20 biodiesel 

fuel scenario in the Lake Michigan domain on 14 July, 1995.
3-14 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 46 tpd

Total = 19965 tpd

Daily Total VOC Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-4a. Daily total VOC emissions (tpd) for the 2007 SIP Call in the Northeast Corridor 

domain on 14 July, 1995.

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 2 tpd

Total = 516 tpd

Daily On-road Mobile VOC Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-4b. Daily on-road mobile source VOC emissions (tpd) for the 2007 SIP Call in the 

Northeast Corridor domain on 14 July, 1995. 
3-15 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Reductions in Daily Total VOC Emissions (tpd)

100% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-4c. Reductions in daily total VOC emissions (tpd) for the 2007 100% B20 biodiesel 

fuel scenario in the Northeast Corridor domain on 14 July, 1995. 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Reductions in Daily Total VOC Emissions (tpd)

50% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-4d. Reductions in daily total VOC emissions (tpd) for the 2007 50% B20 biodiesel 

fuel scenario in the Northeast Corridor domain on 14 July, 1995. 
3-16 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 289 tpd

Total = 11413 tpd

Daily Total CO Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-5a. Daily total CO emissions (tpd) for the 2007 SIP Call in the Lake Michigan domain 

on 14 July, 1995. 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Max = 40 tpd

Total = 5302 tpd

Daily On-road Mobile CO Emissions (tpd)

07sipcall -- LakeMI_4km

July 14, 1995

Figure 3-5b. Daily on-road mobile source CO emissions (tpd) for the 2007 SIP Call in the Lake 

Michigan domain on 14 July, 1995. 
3-17 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Reductions in Daily Total CO Emissions (tpd)

100% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-5c. Reductions in daily total CO emissions (tpd) for the 2007 100% B20 biodiesel fuel 

scenario in the Lake Michigan domain on 14 July, 1995. 

-89.5 -89.0 -88.5 -88.0 -87.5 -87.0 -86.5 -86.0 -85.5 -85.0

Longitude (degrees)

40.0

40.5

41.0

41.5

42.0

42.5

43.0

Latitude (degrees)

Reductions in Daily Total CO Emissions (tpd)

50% B20 Biodiesel -- LakeMI_4km

July 14, 1995

Figure 3-5d. Reductions in daily total CO emissions (tpd) for the 2007 50% B20 biodiesel fuel 

scenario in the Lake Michigan domain on 14 July, 1995. 
3-18 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 143 tpd

Total = 20160 tpd

Daily Total CO Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-6a. Daily total CO emissions (tpd) for the 2007 SIP Call in the Northeast Corridor 

domain on 14 July, 1995. 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Max = 55 tpd

Total = 8493 tpd

Daily On-road Mobile CO Emissions (tpd)

07sipcall -- NE_4km

July 14, 1995

Figure 3-6b. Daily on-road mobile source CO emissions (tpd) for the 2007 SIP Call in the 

Northeast Corridor domain on 14 July, 1995. 
3-19 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Reductions in Daily Total CO Emissions (tpd)

100% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-6c. Reductions in daily total CO emissions (tpd) for the 2007 100% B20 biodiesel fuel 

scenario in the Northeast Corridor domain on 14 July, 1995. 

 

-78 -77 -76 -75 -74 -73 -72

Longitude (degrees)

38.5

39.0

39.5

40.0

40.5

41.0

41.5

42.0

42.5

Latitude (degrees)

Reductions in Daily Total CO Emissions (tpd)

50% B20 Biodiesel -- NE_4km

July 14, 1995

Figure 3-6d. Reductions in daily total CO emissions (tpd) for the 2007 50% B20 biodiesel fuel 

scenario in the Northeast Corridor domain on 14 July, 1995. 
3-20 

South Coast Air Basin Emission Summary 

Table 3-5 summarizes the effects of biodiesel fuel on HDDV NOx, VOC and CO emissions for 

the South Coast Air Basin 5-km AQMP modeling domain by major emissions source category 

and the August 3-7, 1997 episode days. Table 3-6 provides a summary of on-road mobile and 

HDDV emission contributions. The resulting overall changes in emission inventories by major 

source category and the two emission scenarios are summarized in Table 3-7. 

As a percentage of the on-road mobile inventory (in the baseline scenario), the HDDV fraction of 

NOx emissions vary from approximately 26% to 42%, depending on which day, while the 

percentage of on-road mobile emissions in the total anthropogenic inventory is somewhat higher, 

varying from approximately 59% to 65%. The resulting overall impacts on the total NOx 

emission inventory due to use of a B20 fuel is much less than 1%, as seen in Table 3-7, varying 

from only 0.277% to 0.510% for the 100% penetration level, and 0.135% to 0.255% for the 50% 

penetration level of B20 biodiesel fuel. 

Similar results are seen for VOC and CO emission effects. The fraction of on-road mobile VOC 

emissions due to the HDDV contribution varies from 4.6% to 6.8%, with the largest percentage 

occurring on August 7, 1997 (a Thursday). As a percentage of the anthropogenic emissions, onroad mobile VOC accounts for approximately 29.7% to 34.5% of the inventory, while the onroad mobile contribution ranges from approximately 26.2% to 29.4% of the total (anthropogenic 

plus biogenic) VOC emission inventory. For CO, the fraction of HDDV emissions vary from 

4.3% to 8.6% of the on-road mobile component, while the on-road mobile CO emissions range 

from approximately 71.0% to 86.6% of the total emission inventory. It is noticed that there are 

no NOx and CO emission reported from biogenic sources in the ARB’s emissions database. 

As with the NOx emission effects, the overall VOC and CO emission reductions due to biodiesel 

fuel use are extremely small. For the 100% penetration B20 scenario, total VOC emission 

inventory reductions range from 0.031% to 0.082%, while the impacts due to the 50% 

penetration level are approximately 0.015% to 0.042%. For CO, reductions in the total 

emissions inventory range from 0.026% to 0.067% for the 100% B20 biodiesel scenario, and 

only 0.013% to 0.034% for the 50% penetration scenario. 

Spatial distributions of the daily total NOx, VOC and CO emissions and the impacts due to 

100% and 50% penetration of B20 biodiesel fuel for a representative episode day (August 4, 

1997) are displayed in Figure 3-7 through Figure 3-9 for the 5-km nested grid domains. 

Figures 3-7a and 3-7b display the spatial distributions of total surface NOx emissions and onroad mobile source NOx emissions in the South Coast Air Basin 5-km domain, respectively. 

The on-road mobile component are accounted for about 59% of the total NOx emissions and are 

primarily located within the major urban centers of the SoCAB. The increases in total daily NOx 

due to the introduction of B20 biodiesel fuel in the HDDV fleet are displayed in Figures 3-7c and 

3-7d for the 100% and 50% penetration levels, respectively. As expected, the largest increases 

are seen within the urban areas of the domain with the largest differences distributed along the 

major transportation routes. In both biodiesel emission scenarios however, the increases are very 

small. 

The daily total and on-road mobile VOC emissions and the corresponding reductions due to the 

B20 biodiesel emission scenarios are displayed in Figure 3-8 for the SoCAB 5-km modeling 

domain. As with the NOx emissions, the spatial distribution of on-road mobile source VOC 
3-21 

emissions are generally confined within the major urban centers and major highways. The 

percentage of total VOC emissions due to on-road mobile sources is approximately 29%. The 

spatial distribution of VOC emission reductions realized due to biodiesel fuel use shows that the 

largest differences generally within the urban areas of the domains (e.g., downtown Los Angeles 

and Anaheim) and relatively smaller emission reductions distributed along the major highways 

and transportation networks. Different from the spatial distribution of NOx emission reductions, 

the VOC emission reductions along the major transportation networks is less obvious due to the 

lower percentage (only 6.5%) of HDDV source to the mobile inventory. 

The spatial distributions of daily total and on-road mobile CO emissions, as well as the 

reductions resulting from the use of B20 biodiesel fuel, are presented in Figures 3-9 for the 

SoCAB 5-km modeling domain. For CO emissions, the mobile source component accounts for 

approximately 87% of the total CO emissions. As such, the spatial distributions of the daily total 

and on-road mobile CO emissions are very similar, confined mainly to the urban centers and the 

transportation corridors of the domains. The reductions in CO emissions for each of the 

biodiesel emission scenarios are displayed in Figures 3-9c and 3-9d. As with the NOx and VOC, 

overall CO emission reductions for the 50% and 100% penetration level of B20 fuel are small 

and generally throughout the traffic networks and urban centers of the SoCAB domain. 
3-22 

Table 3-5. Baseline and biodiesel scenario emissions summary for 3-7 August, 1997 for SoCAB domain 

Emission Component 1997 BASELINE 1997 100% B20 Biodiesel 1997 50% B20 August 3 NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) VOC (tpd) CO (tpd) NOX (tpd) Area 400.48 1591.14 2596.75 400.48 1591.14 2596.75 400.48 Points 120.69 35.85 49.73 120.69 35.85 49.73 120.69 On-Road Mobile 743.2 688.1 6487.4 746.7 687.3 6485 744.9 Total Anthropogenic 1264.37 2315.09 9133.88 1267.87 2314.29 9131.48 1266.07 Biogenic 0 309.9 0 0 309.9 0 0 Total 1264.37 2624.99 9133.88 1267.87 2624.19 9131.48 1266.07 August 4 Area 470.13 1487.22 1157.59 470.13 1487.22 1157.59 470.13 Points 124.71 35.83 46.49 124.71 35.83 46.49 124.71 On-Road Mobile 1027.4 766.4 7744.2 1035.5 764.3 7738.4 1031.4 Total Anthropogenic 1622.24 2289.45 8948.28 1630.34 2287.35 8942.48 1626.24 Biogenic 0 327.6 0 0 327.6 0 0 Total 1622.24 2617.05 8948.28 1630.34 2614.95 8942.48 1626.24 August 5 Area 471.08 1486.72 1156.91 471.08 1486.72 1156.91 471.08 Points 118.33 103.79 338.21 118.33 103.79 338.21 118.33 On-Road Mobile 1110.1 837.9 8361.9 1118.6 835.8 8355.9 1114.3 Total Anthropogenic 1699.51 2428.41 9857.02 1708.01 2426.31 9851.02 1703.71 Biogenic 0 424.4 0 0 424.4 0 0 Total 1699.51 2852.81 9857.02 1708.01 2850.71 9851.02 1703.71 August 6 Area 470.98 1486.81 1157.12 470.98 1486.81 1157.12 470.98 Points 124.35 122.78 419.93 124.35 122.78 419.93 124.35 On-Road Mobile 1069.4 794.7 8196.8 1077.8 792.5 8190.8 1073.6 Total Anthropogenic 1664.73 2404.29 9773.85 1673.13 2402.09 9767.85 1668.93 Biogenic 0 360.5 0 0 360.5 0 0 Total 1664.73 2764.79 9773.85 1673.13 2762.59 9767.85 1668.93 August 7 Area 470.98 1486.81 1157.12 470.98 1486.81 1157.12 470.98 Points 126.32 74.54 213.44 126.32 74.54 213.44 126.32 On-Road Mobile 1050.6 746.9 7744 1059 744.8 7737.9 1054.8 Total Anthropogenic 1647.9 2308.25 9114.56 1656.3 2306.15 9108.46 1652.1 Biogenic 0 269.4 0 0 269.4 0 0 Total 1647.9 2577.65 9114.56 1656.3 2575.55 9108.46 1652.1 
3-23 

Table 3-6. Summary of on-road mobile and HDDV emission contributions for SoCAB

On-Road Mobile Emission Summary for 1997 Baseline 

 South Coast Air Basin 5-km Domain 

NOX VOC CO 

3-Aug 

Mobile % of Total Inv. 58.77 26.20 71.02 

Mobile % of Anthro. 58.77 29.71 71.02 

HDDV % of Mobile Inv. 25.75 4.55 4.26 

4-Aug 

Mobile % of Total Inv. 63.34 29.29 86.56 

Mobile % of Anthro. 63.34 33.48 86.56 

HDDV % of Mobile Inv. 41.26 6.50 8.26 

5-Aug 

Mobile % of Total Inv. 65.33 29.37 84.85 

Mobile % of Anthro. 65.33 34.51 84.85 

HDDV % of Mobile Inv. 40.90 6.18 8.18 

6-Aug 

Mobile % of Total Inv. 64.25 28.75 83.88 

Mobile % of Anthro. 64.25 33.06 83.88 

HDDV % of Mobile Inv. 41.67 6.46 8.25 

7-Aug 

Mobile % of Total Inv. 63.77 28.98 84.98 

Mobile % of Anthro. 63.77 32.36 84.98 

HDDV % of Mobile Inv. 42.25 6.75 8.58 
3-24 

Table 3-7. Summary of emission effects for B20 biodiesel fuel use in the SoCAB. 

Emission Component 1997 100% Biodiesel 1997 50% Biodiesel 3-Aug % Change NOX % Change VOC %Change CO % Change NOX % Change VOC Area 0.0000 0.0000 0.0000 0.0000 0.0000 Points 0.0000 0.0000 0.0000 0.0000 0.0000 On-Road Mobile 0.4709 -0.1163 -0.0370 0.2287 -0.0581 Total Anthropogenic 0.2768 -0.0346 -0.0263 0.1345 -0.0173 Biogenic 0.0000 0.0000 0.0000 0.0000 0.0000 Total 0.2768 -0.0305 -0.0263 0.1345 -0.0152 4-Aug Area 0.0000 0.0000 0.0000 0.0000 0.0000 Points 0.0000 0.0000 0.0000 0.0000 0.0000 On-Road Mobile 0.7884 -0.2740 -0.0749 0.3893 -0.1435 Total Anthropogenic 0.4993 -0.0917 -0.0648 0.2466 -0.0480 Biogenic 0.0000 0.0000 0.0000 0.0000 0.0000 Total 0.4993 -0.0802 -0.0648 0.2466 -0.0420 5-Aug Area 0.0000 0.0000 0.0000 0.0000 0.0000 Points 0.0000 0.0000 0.0000 0.0000 0.0000 On-Road Mobile 0.7657 -0.2506 -0.0718 0.3783 -0.1313 Total Anthropogenic 0.5001 -0.0865 -0.0609 0.2471 -0.0453 Biogenic 0.0000 0.0000 0.0000 0.0000 0.0000 Total 0.5001 -0.0736 -0.0609 0.2471 -0.0386 6-Aug Area 0.0000 0.0000 0.0000 0.0000 0.0000 Points 0.0000 0.0000 0.0000 0.0000 0.0000 On-Road Mobile 0.7855 -0.2768 -0.0732 0.3927 -0.1384 Total Anthropogenic 0.5046 -0.0915 -0.0614 0.2523 -0.0458 Biogenic 0.0000 0.0000 0.0000 0.0000 0.0000 Total 0.5046 -0.0796 -0.0614 0.2523 -0.0398 7-Aug Area 0.0000 0.0000 0.0000 0.0000 0.0000 Points 0.0000 0.0000 0.0000 0.0000 0.0000 On-Road Mobile 0.7995 -0.2812 -0.0788 0.3998 -0.1339 Total Anthropogenic 0.5097 -0.0910 -0.0669 0.2549 -0.0433 Biogenic 0.0000 0.0000 0.0000 0.0000 0.0000 Total 0.5097 -0.0815 -0.0669 0.2549 -0.0388 
3-25 

Figure 3-7a. Daily total NOx emissions (tpd) for the 1997 baseline in the South Coast Air Basin 

on August 4, 1997. 

Figure 3-7b. Daily on-road mobile source NOx emissions (tpd) for the 1997 baseline in the 

South Coast Air Basin on August 4, 1997 

300 350 400 450 500 550 600

3700

3750

3800

3850

0

2

4

6

8

10

12

14

16

18

20

max = 17 TPD

total = 1456 TPD

Daily Total NOX Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin

300 350 400 450 500 550 600

3700

3750

3800

3850

0

2

4

6

8

10

12

14

16

18

20

max = 13 TPD

total = 1001 TPD

Daily On-road Mobile NOX Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin
3-26 

Figure 3-7c. Increases in daily total NOx emissions (tpd) for the 1997 100% B20 biodiesel fuel 

scenario in the South Coast Air Basin on August 4, 1997. 

Figure 3-7d. Increases in daily total NOx emissions (tpd) for the 1997 50% B20 biodiesel fuel 

scenario in the South Coast Air Basin on August 4, 1997 

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.1072 TPD 

Increases in Daily Total NOX Emissions (tpd)

August 04, 1997

100% Penetration B20 Biodiesel

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.0536 TPD 

Increases in Daily Total NOX Emissions (tpd)

August 04, 1997

50% Penetration B20 Biodiesel
3-27 

Figure 3-8a. Daily total VOC emissions (tpd) for the 1997 baseline in the South Coast Air 

Basin on August 4, 1997 

Figure 3-8b. Daily on-road mobile source VOC emissions (tpd) for the 1997 baseline in the 

South Coast Air Basin on August 4, 1997.

300 350 400 450 500 550 600

3700

3750

3800

3850

0

2

4

6

8

10

12

14

16

18

20

max = 21 TPD

total = 1878 TPD

Daily Total VOC Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin

300 350 400 450 500 550 600

3700

3750

3800

3850

0

2

4

6

8

10

12

14

16

18

20

max = 10 TPD

total = 764 TPD

Daily On-road Mobile VOC Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin
3-28 

 

Figure 3-8c. Increases in daily total VOC emissions (tpd) for the 1997 100% B20 biodiesel fuel 

scenario in the South Coast Air Basin on August 4, 1997. 

 

Figure 3-8d. Increases in daily total VOC emissions (tpd) for the 1997 50% B20 biodiesel fuel 

scenario in the South Coast Air Basin on August 4, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.032 TPD 

Reductions in Daily Total VOC Emissions (tpd)

August 04, 1997

100% Penetration B20 Biodiesel

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.016 TPD 

Reductions in Daily Total VOC Emissions (tpd)

August 04, 1997

50% Penetration B20 Biodiesel
3-29 

Figure 3-9a. Daily total CO emissions (tpd) for the 1997 baseline in the South Coast Air Basin 

on August 4, 1997. 

Figure 3-9b. Daily on-road mobile source CO emissions (tpd) for the 1997 baseline in the 

South Coast Air Basin on August 4, 1997.

300 350 400 450 500 550 600

3700

3750

3800

3850

0

10

20

30

40

50

60

70

80

90

100

max = 108 TPD

total = 8861 TPD

Daily Total CO Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin

300 350 400 450 500 550 600

3700

3750

3800

3850

0

10

20

30

40

50

60

70

80

90

100

max = 97 TPD

total = 7721 TPD

Daily On-road Mobile CO Emissions (tpd)

August 04, 1997

1997 Baseline in the South Coast Air Basin
3-30 

 

Figure 3-9c. Reductions in daily total CO emissions (tpd) for the 1997 100% B20 biodiesel 

fuel scenario in the South Coast Air Basin on August 4, 1997. 

 

Figure 3-9d. Reductions in daily total CO emissions (tpd) for the 1997 50% B20 biodiesel fuel 

scenario in the South Coast Air Basin on August 4, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.0994 TPD 

Reductions in Daily Total CO Emissions (tpd)

August 04, 1997

100% Penetration B20 Biodiesel

300 350 400 450 500 550 600

3700

3750

3800

3850

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.05

0.075

0.1

max = 0.0497 TPD 

Reductions in Daily Total CO Emissions (tpd)

August 04, 1997

50% Penetration B20 Biodiesel
4-1 

4. BIODIESEL OZONE ASSESSMENT 

In this section, the impacts of biodiesel fuel use on ambient ozone concentrations are presented 

and discussed. The results of the CAMx high-resolution (4-km) modeling of the Lake Michigan 

and Northeast Corridor regions are presented first, followed by the lower resolution (12-km) 

modeling results for other eastern US cities. The section concludes with discussing the highresolution (5-km) modeling results for the South Coast Air Basin (SoCAB). The impacts of 

biodiesel fuel use on air quality and human health are related through the evaluation of: 

• Estimated peak 1-hour and 8-hour daily maximum ozone concentrations in each 

urban area are used to assess the effects biodiesel fuel would have on attainment; 

• Effects of biodiesel fuel use are also assessed by examining the spatial distribution of 

daily maximum 1-hour and 8-hour ozone concentrations and their differences with 

the standard diesel base case; and 

• Various air quality exposure metrics are used to assess the impacts of biodiesel fuel 

on population exposure to elevated ozone concentrations. 

EASTERN US OZONE MODELING RESULTS 

The Comprehensive Air Quality Model with Extensions (CAMx), version 3.02 

(www.camx.com) was exercised for the 7-18 July, 1995 episode on the enhanced 36/12/4-km 

OTAG modeling domain shown in Figure 2-4. Meteorological input data files developed from 

the RAMS meteorological model for the 36-km and 12-km domains and the July 1995 OTAG 

modeling episode were used for each of the emission scenarios investigated. Note that separate 

high-resolution (4-km) meteorological data input files for the 4-km Northeast Corridor and Lake 

Michigan domains were not developed, instead CAMx interpolated the 4-km inputs from the 12-

km resolution meteorological data. However, the emission inputs were developed separately for 

the two fine-grid domains at the 4-km high-resolution using the EMS95 emissions model. While 

the model was exercised for the entire July 7-18, 1995 period, only the results for 11-15, July 

1995 are discussed here as the July 7-10 period is used for initialization and July 16-18 period 

are low ozone clean out days. 

Biodiesel Ozone Impact Assessment for the Lake Michigan Region

The spatial distribution of estimated daily maximum 1-hour ozone concentrations are displayed 

in Figure 4-1 for the 2007 SIP Call Base Case in the Lake Michigan 4-km domain. Ozone 

concentration levels in the region for the first two days (July 11-12) are relatively low with daily 

peaks estimated to be below the 1-hour ozone standard (124 ppb) occurring northeast of the 

Chicago urban area. On July 13, the region of high ozone in excess of 124 ppb is estimated to 

occur along the western side of lower Lake Michigan with a peak of 166.6 ppb that occurs over 

Lake Michigan just off the shoreline from Racine, Wisconsin. The following day (July 14) the 

urban plume emanating from the Chicago area has shifted northeast and extends across the lower 

portion of the lake with exceedances of the 1-hour standard reaching southwestern Michigan. 

The daily peak ozone of 177.9 ppb occurs over the center of lower Lake Michigan. On July 15, 

the region of elevated ozone concentrations is considerably smaller and located just offshore 

from downtown Chicago with a daily peak value of 163.5 ppb. Small regions of ozone 
4-2 

concentrations in excess of 124 ppb are estimated to occur along the lakeshore in Illinois and 

Indiana. 

Predicted daily maximum 8-hour ozone concentrations for the 2007 SIP Call base case standard 

diesel scenario in the Lake Michigan 4-km domain are displayed in Figure 4-2 for the period of 

July 11-15, 1995. The spatial distribution of 8-hour ozone concentrations is similar to the 1-hour 

ozone distributions, although the extent of elevated ozone levels above the 8-hour ozone standard 

(84 ppb) is larger than the extent of 1-hour exceedances since the 8-hour standard is more 

stringent. As for the daily maximum 1-hour ozone concentrations, the predicted 8-hour ozone 

levels for the first two days (July 11-12) are relatively low, however on July 12 a small region of 

8-hour ozone concentrations that exceed the standard are estimated to occur over the western 

portion of the lake northeast of Chicago with a peak of 87.7 ppb. On July 13 a broad region of 8-

hour ozone in excess of 110 ppb is estimated to occur over the entire portion of lower Lake 

Michigan with exceedances of the standard predicted just west of Chicago as well as along the 

eastern shore of the lake in southwestern Michigan. By July 14, the estimated 8-hour peak of 

157.9 ppb has shifted east occurring over the center of lower Lake Michigan with the region of 

8-hour ozone exceedances spreading northeastward into Michigan. The spatial distribution of 

daily maximum 8-hour ozone concentrations on July 15 are similar to the 1-hour concentrations, 

although the area of estimated ozone concentrations that exceed the 8-hour ozone standard is 

considerably larger than the area of 1-hour ozone exceedances with ozone levels in excess of 84 

ppb predicted to occur in northeastern Illinois as well as southeastern Wisconsin on the July 15. 

Figures 4-3 and 4-4 display the impacts due to 100% penetration of B20 biodiesel fuel use on the 

daily maximum 1-hour and 8-hour ozone concentrations in the Lake Michigan 4-km domain, 

respectively. Since the 100% penetration level results in higher impacts compared to the 50% 

penetration scenario, only the results of the 100% penetration scenario are presented and 

discussed here. Although significantly smaller, the spatial distribution of impacts for the 50% 

penetration scenario is very similar to the 100% penetration scenario. Spatial displays of the 50% 

penetration of B20 biodiesel fuel emission scenarios are presented in Appendix A. In order that 

the impacts on reducing the exceedances of the 1-hour and 8-hour NAAQS can be assessed, the 

displays include hachured contours representing the regions of daily peak ozone concentrations 

(in the 2007 SIP Call baseline) above the 124 ppb and 84 ppb ozone standard thresholds for the 

1-hour and 8-hour daily peaks, respectively. This allows us to assess whether any ozone 

increases or decreases due to biodiesel fuel use occurs in areas that are estimated to exceed the 

ozone standard. 

An examination of Figure 4-3 reveals that for all episode days the impacts on the daily maximum 

1-hour ozone concentrations are small and, except for July 11-12, are generally confined to a 

small region within and downwind of the Chicago urban area. Note that both benefits (ozone 

reductions) and disbenefits (ozone increases) are predicted. The disbenefits are highly localized 

having little or no impact on areas that exceed the 1-hour standard. The ozone reductions, while 

small (ranging from approximately 0.17-0.53 ppb) are seen in most cases to occur in areas of 

high ozone so would aide in reducing the ozone concentrations levels above the NAAQS in the 

2007 SIP Call baseline simulation. 

Figure 4-4 displays the impacts on the daily maximum 8-hour ozone concentration in the Lake 

Michigan domain due to the introduction of B20 biodiesel fuel at the 100% penetration level. 

The spatial distribution of impacts are very similar to those of the 1-hour concentrations. 

However in this case, the benefits due to biodiesel fuel use on reducing ozone occur in areas of 

NAAQS exceedances since the region exceeding the standard in the baseline are far more 

widespread than in the case of the daily maximum 1-hour ozone concentrations. 
4-3 

Table 4-1 summarizes the impacts due to B20 biodiesel fuel use on the daily 1-hour and 8-hour 

peak ozone concentrations in the Lake Michigan 4-km domain for both the 50% and 100% B20 

penetration emission scenarios. Note that the differences in peak concentrations may not 

correspond to the maximum reductions seen in Figures 4-3 and 4-4 since these maximum ozone 

reductions do not necessarily occur at the same location as the ozone peaks. 

Table 4-1. Summary of daily peak 1-hour and 8-hour ozone concentrations in the Lake 

Michigan 4-km domain for the 2007 standard diesel (SIP Call) and biodiesel emission scenarios. 

Lake Michigan 1-Hour Ozone 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

(ppb) (ppb) (% Difference) (ppb) (% Difference)

July 11, 1995 88.60 88.51 -0.102% 88.42 -0.205% 

July 12, 1995 103.41 103.36 -0.051% 103.31 -0.103% 

July 13, 1995 166.80 166.77 -0.020% 166.74 -0.040% 

July 14, 1995 177.98 177.98 0.002% 177.99 0.005% 

July 15, 1995 163.54 163.48 -0.040% 163.41 -0.080% 

Lake Michigan 8-Hour Ozone 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

(ppb) (ppb) (% Difference) (ppb) (% Difference)

July 11, 1995 80.46 80.43 -0.035% 80.40 -0.070% 

July 12, 1995 87.80 87.80 0.000% 87.80 0.000% 

July 13, 1995 148.24 148.21 -0.020% 148.18 -0.041% 

July 14, 1995 157.93 157.93 -0.005% 157.92 -0.011% 

July 15, 1995 146.78 146.75 -0.026% 146.71 -0.052% 
4-4 

Figure 4-1a. Spatial distribution of daily maximum 1-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure 4-1b. Spatial distribution of daily maximum 1-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 12, 1995 for the 2007 SIP Call scenario. 
4-5 

Figure 4-1c. Spatial distribution of daily maximum 1-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure 4-1d. Spatial distribution of daily maximum 1-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 14, 1995 for the 2007 SIP Call scenario. 
4-6 

Figure 4-1e. Spatial distribution of daily maximum 1-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 15, 1995 for the 2007 SIP Call scenario. 
4-7 

Figure 4-2a. Spatial distribution of daily maximum 8-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure 4-2b. Spatial distribution of daily maximum 8-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 12, 1995 for the 2007 SIP Call scenario. 
4-8 

Figure 4-2c. Spatial distribution of daily maximum 8-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure 4-2d. Spatial distribution of daily maximum 8-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 14, 1995 for the 2007 SIP Call scenario. 
4-9 

Figure 4-2e. Spatial distribution of daily maximum 8-hour ozone concentrations in the Lake 

Michigan 4-km domain on July 15, 1995 for the 2007 SIP Call scenario. 
4-10 

Figure 4-3a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Lake Michigan domain on July 11, 1995. 

Figure 4-3b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Lake Michigan domain on July 12, 1995. 
4-11 

Figure 4-3c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Lake Michigan domain on July 13, 1995. 

Figure 4-3d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Lake Michigan domain on July 14, 1995. 
4-12 

Figure 4-3e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Lake Michigan domain on July 15, 1995. 
4-13 

Figure 4-4a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Lake Michigan domain on July 11, 1995. 

Figure 4-4b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Lake Michigan domain on July 12, 1995. 
4-14 

Figure 4-4c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Lake Michigan domain on July 13, 1995. 

Figure 4-4d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Lake Michigan domain on July 14, 1995. 
4-15 

Figure 4-4e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Lake Michigan domain on July 15, 1995. 
4-16 

Biodiesel Ozone Impact Assessment for the Northeast Corridor Region

The spatial distribution of the predicted daily maximum 1-hour ozone concentrations for the 

2007 SIP Call baseline simulation in the Northeast Corridor 4-km domain are displayed in Figure 

4-5. On the first day of the analysis period (July 11), predicted 1-hour ozone concentrations are 

relatively low with a peak of 109 ppb occurring just downwind of Washington D.C. High ozone 

levels are predicted on July 12 with a peak (145.6 ppb) again occurring downwind of 

Washington D.C. Small regions of 1-hour ozone exceedances are estimated for the Washington 

and Baltimore urban areas as well as in New Jersey east of Philadelphia. By July 13, the plume 

of elevated ozone concentrations extends the length of the Corridor from the 

Washington/Baltimore urban area through New Jersey and New York and into southern 

Connecticut, although no exceedances of the 1-hour NAAQS are predicted in the domain. The 

spatial distribution of estimated ozone concentrations on July 14 are similar to the previous day 

only with a large region of exceedances evident downwind of New York City over Long Island 

and Long Island Sound with a peak of 156.8 ppb predicted just north of Long Island over the 

sound. On July 15, the urban plume of elevated ozone concentrations moves east offshore from 

Long Island with a daily peak of 177 ppb and a broad region of ozone in excess of the standard 

east of New York City and confined mainly south of Long Island. In addition, a small region of 

ozone exceedances is predicted to occur near Washington D.C. and Baltimore spreading across 

the northern portion of Chesapeake Bay. 

The spatial distributions of daily maximum 8-hour ozone concentrations in the Northeast 

Corridor domain, displayed in Figure 4-6, are quite similar to those of the daily peak 1-hour 

concentrations. However, as in the case of the Lake Michigan 4-km domain, the regions of 

exceedances of the 8-hour ozone standard are considerably larger than the regions exceeding the 

1-hour ozone standard. The daily maximum 8-hour ozone concentrations are predicted to exceed 

the proposed standard of 84 ppb on all days during July 11-15 within Northern Corridor domain 

for the 2007 SIP Call baseline simulation. 

The impacts on the daily maximum 1-hour and 8-hour ozone concentrations due to B20 biodiesel 

fuel use at a 100% penetration level in the Northeast Corridor domain are presented in Figures 4-

7 and 4-8, respectively. The corresponding displays for the 50% penetration scenario are 

presented in Appendix B. While both benefits and disbenefits due to biodiesel fuel use are 

estimated throughout the domain, unlike in the Lake Michigan domain, the disbenefits in the 

Northeast Corridor domain tend to be equal to or out-weigh the benefits in terms of the 

magnitude of the peaks and are more widespread in terms of spatial extent. 

On the first two days of the evaluation period, 1-hour ozone benefits are predicted for the New 

York City and Philadelphia urban areas, whereas slight disbenefits are estimated to occur in the 

region between Washington D.C. and Baltimore. On July 13, a localized reduction in 1-hour 

ozone is predicted in New York City with regions of ozone increases occurring downwind of 

Washington D.C. extending northeast. Impacts on July 14 are mainly disbenefits covering a 

broad region throughout the Corridor with a slight ozone reduction occurring downwind of New 

York City over Long Island. On July 15, the region of increases in 1-hour ozone concentrations 

has shifted east extending across Chesapeake Bay and Delaware and offshore south of Long 

Island. While this broad region of ozone increases adversely impacts the areas of ozone 

exceedances in the baseline simulation, a small region of benefits are also seen just south of 

Long Island. 
4-17 

In Figure 4-8 the impacts on the daily maximum 8-hour ozone concentrations are displayed and 

are seen to be very similar to the 1-hour impacts with respect to the spatial distribution. The 

impacts on the exceedances of the proposed 8-hour standard are more widespread since the 

regions of exceedances in the 2007 SIP Call baseline are likewise more broadly distributed 

throughout the Northeast Corridor domain. 

The impacts due to B20 biodiesel fuel use on the daily 1-hour and 8-hour peak ozone 

concentrations in the Northeast Corridor 4-km domain for both the 50% and 100% penetration 

emission scenarios are summarized in Table 4-2. Except for July 14, slight increases in the daily 

peak 1-hour and 8-hour ozone concentrations are seen in the Northeast corridor due to use of 

biodiesel fuels. However, these increases in the ozone peaks are very small with maximum 

increases in 1-hour and 8-hour ozone peaks due to the biodiesel use of 0.09 ppb (0.051%) and 

0.10 ppb (0.066%), respectively, occurring on July 15, 1995. 

Table 4-2. Summary of daily peak 1-hour and 8-hour ozone concentrations in the Northeast 

Corridor 4-km domain for the 2007 standard diesel (SIP Call) and biodiesel emission scenarios. 

Northeast Corridor 1-Hour Ozone 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

(ppb) (ppb) (% Difference) (ppb) (% Difference)

July 11, 1995 109.06 109.08 0.024% 109.11 0.049% 

July 12, 1995 145.70 145.72 0.015% 145.74 0.028% 

July 13, 1995 119.80 119.81 0.006% 119.82 0.017% 

July 14, 1995 156.89 156.89 -0.003% 156.88 -0.007% 

July 15, 1995 177.02 177.06 0.025% 177.11 0.051% 

Northeast Corridor 8-Hour Ozone 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

(ppb) (ppb) (% Difference) (ppb) (% Difference)

July 11, 1995 102.40 102.42 0.021% 102.44 0.046% 

July 12, 1995 123.95 123.98 0.023% 124.01 0.045% 

July 13, 1995 108.44 108.48 0.035% 108.52 0.071% 

July 14, 1995 142.03 142.05 0.018% 142.08 0.035% 

July 15, 1995 155.26 155.31 0.033% 155.36 0.066% 
4-18 

Figure 4-5a. Spatial distribution of daily maximum 1-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure 4-5b. Spatial distribution of daily maximum 1-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 12, 1995 for the 2007 SIP Call scenario. 
4-19 

Figure 4-5c. Spatial distribution of daily maximum 1-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure 4-5d. Spatial distribution of daily maximum 1-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 14, 1995 for the 2007 SIP Call scenario. 
4-20 

Figure 4-5e. Spatial distribution of daily maximum 1-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 15, 1995 for the 2007 SIP Call scenario. 
4-21 

Figure 4-6a. Spatial distribution of daily maximum 8-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure 4-6b. Spatial distribution of daily maximum 8-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 12, 1995 for the 2007 SIP Call scenario. 
4-22 

Figure 4-6c. Spatial distribution of daily maximum 8-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure 4-6d. Spatial distribution of daily maximum 8-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 14, 1995 for the 2007 SIP Call scenario. 
4-23 

Figure 4-6e. Spatial distribution of daily maximum 8-hour ozone concentrations in the 

Northeast Corridor 4-km domain on July 15, 1995 for the 2007 SIP Call scenario. 
4-24 

Figure 4-7a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Northeast Corridor domain on July 11, 1995. 

Figure 4-7b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Northeast Corridor domain on July 12, 1995. 
4-25 

Figure 4-7c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Northeast Corridor domain on July 13, 1995. 

Figure 4-7d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Northeast Corridor domain on July 14, 1995. 
4-26 

Figure 4-7e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the Northeast Corridor domain on July 15, 1995. 
4-27 

Figure 4-8a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Northeast Corridor domain on July 11, 1995. 

Figure 4-8b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Northeast Corridor domain on July 12, 1995. 
4-28 

Figure 4-8c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Northeast Corridor domain on July 13, 1995. 

Figure 4-8d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Northeast Corridor domain on July 14, 1995. 
4-29 

Figure 4-8e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the Northeast Corridor domain on July 15, 1995. 
4-30 

Biodiesel Ozone Impact Assessment for Other Cities in the Eastern US

The CAMx ozone estimates on the OTAG 12-km eastern US domain are presented in Appendix 

C. An examination of Figures C-1 reveals that the highest daily maximum peak 1-hour ozone 

concentrations occur within the Lake Michigan and Northeast Corridor 4-km domains. Small 

regions of 1-hour NAAQS exceedances are estimated to occur in the Atlanta, Birmingham and 

Memphis urban areas as well as in eastern Virginia during July 11-15, 1995 period under the 

2007 SIP Call baseline simulation. Spatial displays of the distribution of daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain for the 2007 SIP Call baseline simulation are 

presented in Figures C-2. In addition to the estimated exceedances of the proposed 8-hour 

standard occurring within the Lake Michigan and Northeast Corridor 4-km domains discussed 

previously, elevated 8-hour ozone concentrations are predicted in the urban areas of the Ohio 

River valley for most days. In addition, exceedances of the standard are predicted to occur for 

the Atlanta and Birmingham urban centers as well as for Detroit and the Lake Erie region and in 

southwestern Pennsylvania. 

Similar to the results within the 4-km modeling domains, the impacts due to B20 biodiesel fuel 

use on both the daily maximum 1-hour and 8-hour ozone concentrations within the OTAG 12-

km domain are relative minor. Displays of the impacts on the daily maximum 1-hour ozone for 

the 100% B20 emission scenario are presented in Figures C-3. For all days within the analysis 

period of July 11-15, 1995, the maximum impact on the 1-hour daily maximum ozone 

concentrations for the 100% penetration scenario occurs in Atlanta where the model predicts an 

ozone increase of approximately 0.2-0.25 ppb. The only reductions in 1-hour ozone are seen to 

occur within the regions of the two 4-km modeling domains. A broad region of small ozone 

increases are estimated to occur within the regions of northern Alabama and Georgia, stretching 

northeast from Atlanta along the Appalachian Mountain range. As expected, the impacts 

resulting from the 50% penetration scenario (displayed in Figures C-4) are similar although 

considerably smaller.

The impacts on the predicted daily maximum 8-hour ozone concentrations for both biodiesel 

emission scenarios, presented in Figures C-5 and Figures C-6 of Appendix C, are qualitatively 

similar to those of the 1-hour ozone impacts. 

Ozone Exposure Estimates in the Eastern US 

As an additional measure of the impacts of biodiesel fuel use on ozone air quality and human 

health, various exposure metrics are evaluated for each of the emission scenarios considered. 

Spatial coverage (exposure) of the hourly 1-hour and 8-hour ozone concentrations above 

thresholds of 124 ppb and 84 ppb, respectively, are calculated for each scenario in terms of the 

number of grid cell-hours above the standard. Also evaluated are the changes in the integrated 

concentrations of 1-hour and 8-hour ozone concentrations (dosage) above ozone thresholds of 

124 ppb and 84 ppb, respectively. The dosage metric is expressed in terms of ppb-grid cellhours above the ozone standard. 

Table 4-3 summarizes the 1-hour and 8-hour exposure metrics for the Lake Michigan 4-km 

domain for each of the analysis days (July 11-15, 1995) for each scenario considered. Except for 

the July 15 episode day and dosage on July 13, the 1-hour exposure and dosage metrics remain 

the same or increase for both biodiesel emission scenarios. On July 15, a slight decrease is 

predicted for these exposure metrics. In all cases the impacts are seen to be minimal (much less 
4-31 

than 1 percent). Similar results are predicted for the 8-hour exposure metrics. For the 8-hour 

metrics, the magnitude of the exposure and dosage are considerably larger than the 

corresponding 1-hour metrics, since the regions of exceedances of the 8-hour ozone standard are 

more widespread. 

Table 4-3. Summary of exposure metrics for the Lake Michigan 4-km domain. 

Lake Michigan 1-Hour Exposure Metrics 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

July 11, 1995 0 0.00 0 0.00 0 0.00 

July 12, 1995 0 0.00 0 0.00 0 0.00 

July 13, 1995 3557 53683.71 3557 53679.96 3558 53675.61 

July 14, 1995 4603 85841.88 4605 85895.56 4606 85949.85 

July 15, 1995 1225 14279.90 1225 14253.83 1224 14227.32 

Lake Michigan 8-Hour Exposure Metrics 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

July 11, 1995 0 0.00 0 0.00 0 0.00 

July 12, 1995 226 275.63 228 275.27 226 274.84 

July 13, 1995 13196 277238.84 13205 277244.34 13211 277250.59 

July 14, 1995 15526 360967.72 15535 361107.22 15542 361249.53 

July 15, 1995 10572 157262.58 10573 157287.34 10578 157311.08 

Table 4-4 summarizes the corresponding exposure results for the Northeast Corridor 4-km 

domain. Unlike the results for the Lake Michigan domain, all analysis days show an increase in 

both exposure and dosage for the Northeast Corridor for both the 1-hour and 8-hour metrics. 

While the impacts due to the use of biodiesel fuel are such to increase both ozone exposure and 

dosage, the changes are extremely small, less than 1%. 
4-32 

Table 4-4. Summary of exposure metrics for the Northeast Corridor 4-km domain. 

Northeast Corridor 1-Hour Exposure Metrics 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Exposure 

(grid cell-hrs) 

Dosage 

 (ppb-grid cell-hrs) 

July 11, 1995 0 0.00 0 0.00 0 0.00 

July 12, 1995 186 1307.59 187 1311.54 188 1315.56 

July 13, 1995 0 0.00 0 0.00 0 0.00 

July 14, 1995 1582 17513.87 1583 17556.69 1587 17599.14 

July 15, 1995 2932 35904.80 2943 36069.84 2949 36234.43 

Northeast Corridor 8-Hour Exposure Metrics 

 2007 SIP Call 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

July 11, 1995 2659 15252.60 2665 15337.75 2672 15422.56 

July 12, 1995 5786 54222.26 5803 54374.32 5812 54526.00 

July 13, 1995 8351 61252.63 8382 61517.29 8412 61781.13 

July 14, 1995 14312 187447.50 14356 187993.91 14407 188541.19 

July 15, 1995 41985 495718.72 42120 497721.72 42263 499731.53 

The exposure assessment for cities within the OTAG 12-km domain was conducted based on the 

attainment status of the surrounding counties. Each “city” was defined by the 12-km modeling 

grid cells within each of the surrounding counties. Table 4-5 displays the definition of the 

counties used for each urban center. The exposure metrics (exposure and dosage) were 

evaluated for the following cities: Atlanta, GA; Birmingham, AL; Cincinnati, OH; Detroit, MI, 

Louisville, KY; Memphis, TN; Pittsburgh, PA; and St. Louis, MO. 

Table 4-5. Counties included in each “City” for exposure assessment. 

City Counties 

Atlanta Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, 

Fulton, Gwinett, Henry, Paulding, Rockdale 

Birmingham Jefferson, Shelby 

Cincinnati Butler, Clermont, Hamilton (OH) 

Boone, Campbell, Kenton (KY) 

Detroit Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, Wayne 

Louisville Jefferson, Oldham, Bullitt (KY) 

Clark, Floyd (IN) 

Memphis Shelby 

Pittsburgh Allegheny, Armstrong, Beaver, Butler, Fayette, Washington, 

Westmoreland 

St. Louis Franklin, Jefferson, St. Charles, St. Louis (MO) 

Madison, Monroe, St. Clair (IL) 
4-33 

Tables 4–6 and 4-7 summarize the 1-hour and 8-hour exposure metrics for the cities within the 

OTAG 12-km domain, respectively. For the 1-hour metrics, only Atlanta and Birmingham show 

any impacts due to the use of biodiesel fuels, as these are the only areas that were predicted to 

exceed the standard in any of the scenarios considered. As expected, the changes in both the 

exposure and dosage metrics are minimal. The impacts on the 8-hour metrics, presented in Table 

4-7, show that although all urban centers considered are affected with respect to the ozone 

exposure metrics, the impacts are relatively minor. 
4-34 

Table 4-6. Summary of 1-hour ozone exposure metrics in OTAG 12-km domain.

1-Hour Exposure Metrics 

 2007 SIP Call 2007 50% B20 Biodiesel 2007 1

 Peak 

(ppb) 

Exposure (grid 

cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Peak 

(ppb) 

Exposure 

(grid cell-hrs)

Dosage 

(ppb-grid cell-hrs) 

Peak 

(ppb) 

Exp

(grid 

Atlanta 

July 11, 1995 165.07 128 1629.37 165.19 128 1641.93 165.31 July 12, 1995 136.16 20 110.79 136.27 20 112.65 136.38 July 13, 1995 118.43 0 0 118.52 0 0 118.62 July 14, 1995 137.31 26 136.83 137.4 26 139.07 137.49 July 15, 1995 171.55 71 1289.31 171.64 71 1296.16 171.74 

Birmingham 

July 11, 1995 118.07 0 0 118.14 0 0 118.21 July 12, 1995 139.38 14 119.07 139.47 14 120.16 139.55 July 13, 1995 107.21 0 0 107.26 0 0 107.31 July 14, 1995 128.24 4 9.39 128.3 4 9.64 128.37 July 15, 1995 142.57 15 166.88 142.6 15 167.69 142.62 

Cincinnati 

July 11, 1995 77.66 0 0 77.65 0 0 77.64 July 12, 1995 101.23 0 0 101.23 0 0 101.23 July 13, 1995 87.85 0 0 87.88 0 0 87.9 July 14, 1995 103.65 0 0 103.68 0 0 103.71 July 15, 1995 103.63 0 0 103.66 0 0 103.68 

Detroit 

July 11, 1995 66.78 0 0 66.78 0 0 66.78 July 12, 1995 78.79 0 0 78.78 0 0 78.77 July 13, 1995 92.99 0 0 92.99 0 0 92.98 July 14, 1995 111.09 0 0 111.11 0 0 111.13 July 15, 1995 113.7 0 0 113.74 0 0 113.77 

Louisville 

July 11, 1995 98.77 0 0 98.76 0 0 98.75 July 12, 1995 109.94 0 0 109.93 0 0 109.92 July 13, 1995 98.36 0 0 98.39 0 0 98.41 July 14, 1995 119.12 0 0 119.14 0 0 119.16 July 15, 1995 114.9 0 0 114.93 0 0 114.96 
4-35 

1-Hour Exposure Metrics 

 2007 SIP Call 2007 50% B20 Biodiesel 2007 1

 Peak 

(ppb) 

Exposure (grid 

cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Peak 

(ppb) 

Exposure 

(grid cell-hrs)

Dosage 

(ppb-grid cell-hrs) 

Peak 

(ppb) 

Exp

(grid 

Memphis 

July 11, 1995 104.49 0 0 104.5 0 0 104.51 July 12, 1995 113.69 0 0 113.69 0 0 113.68 July 13, 1995 101.46 0 0 101.47 0 0 101.48 July 14, 1995 108.16 0 0 108.19 0 0 108.22 July 15, 1995 110.67 0 0 110.68 0 0 110.69 

Pittsburgh 

July 11, 1995 76.96 0 0 76.97 0 0 76.99 July 12, 1995 99.5 0 0 99.47 0 0 99.44 July 13, 1995 90.23 0 0 90.25 0 0 90.27 July 14, 1995 99.88 0 0 99.9 0 0 99.93 July 15, 1995 108.92 0 0 108.95 0 0 108.99 

St. Louis 

July 11, 1995 102.74 0 0 102.78 0 0 102.82 July 12, 1995 98.14 0 0 98.2 0 0 98.27 July 13, 1995 93.86 0 0 93.92 0 0 93.98 July 14, 1995 100.41 0 0 100.46 0 0 100.51 July 15, 1995 94.23 0 0 94.28 0 0 94.34 
4-36 

Table 4-7. Summary of 8-hour ozone exposure metrics in OTAG 12-km domain. 

8-Hour Exposure Metrics 

 2007 SIP Call 2007 50% B20 Biodiesel 2007 100

 Peak 

(ppb) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Peak 

(ppb) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Peak 

(ppb) 

Expo

(grid ce

Atlanta 

July 11, 1995 152 459 10285.71 152.11 461 10322.01 152.22 July 12, 1995 121.26 221 3116.92 121.35 221 3132.87 121.43 July 13, 1995 110.54 155 1766.58 110.63 155 1776.77 110.71 July 14, 1995 122.77 204 2987.95 122.85 205 3001.82 122.93 July 15, 1995 153.45 262 5280.56 153.53 262 5299.63 153.62 

Birmingham 

July 11, 1995 112.2 169 1662.16 112.26 170 1669.54 112.32 July 12, 1995 127.21 264 3048.26 127.29 265 3064.16 127.36 July 13, 1995 104.18 64 546.9 104.23 64 550.04 104.28 July 14, 1995 118.98 112 1550.98 119.04 112 1555.47 119.1 July 15, 1995 137.78 84 1574.92 137.84 84 1578.58 137.91 

Cincinnati 

July 11, 1995 71.98 0 0 71.97 0 0 71.95 July 12, 1995 91.94 32 119.09 91.93 32 118.91 91.92 July 13, 1995 84.27 2 0.33 84.3 2 0.37 84.32 July 14, 1995 98.4 79 358.58 98.42 79 360.33 98.45 July 15, 1995 99.11 57 297.27 99.13 57 298.34 99.15 

Detroit 

July 11, 1995 62.24 0 0 62.24 0 0 62.23 July 12, 1995 68.11 0 0 68.09 0 0 68.07 July 13, 1995 86.46 8 7.51 86.44 8 7.44 86.43 July 14, 1995 105.78 108 680.81 105.8 108 682.19 105.81 July 15, 1995 107.26 107 939.95 107.29 108 941.7 107.32 

Louisville 

July 11, 1995 90.64 10 31.92 90.63 10 31.89 90.61 July 12, 1995 99.35 34 253.38 99.34 34 253.06 99.33 July 13, 1995 90.43 13 36.46 90.45 13 36.66 90.47 July 14, 1995 111.07 70 631.63 111.09 70 632.88 111.11 
4-37 

8-Hour Exposure Metrics 

 2007 SIP Call 2007 50% B20 Biodiesel 2007 100

 Peak 

(ppb) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Peak 

(ppb) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Peak 

(ppb) 

Expo

(grid ce

July 15, 1995 107.28 84 727.13 107.3 84 728.58 107.33 

Memphis 

July 11, 1995 95.75 22 125.27 95.75 22 125.29 95.76 July 12, 1995 101.56 6 66.3 101.56 6 66.29 101.56 July 13, 1995 91.25 6 22.48 91.26 6 22.61 91.27 July 14, 1995 100.48 20 183.94 100.53 20 184.62 100.57 July 15, 1995 99.6 6 56.86 99.6 6 56.88 99.61 

Pittsburgh 

July 11, 1995 72.79 0 0 72.81 0 0 72.82 July 12, 1995 92.25 24 69.05 92.22 24 68.63 92.19 July 13, 1995 84.48 5 1.59 84.5 5 1.67 84.51 July 14, 1995 95.66 120 440.9 95.68 120 443.77 95.71 July 15, 1995 103.35 174 1123.27 103.38 174 1128.18 103.41 

St. Louis 

July 11, 1995 94.99 19 106.35 95.02 19 106.97 95.06 July 12, 1995 90.97 9 36.16 91.03 9 36.61 91.09 July 13, 1995 89.15 10 26.04 89.2 10 26.53 89.25 July 14, 1995 93.75 24 97.6 93.79 24 98.55 93.84 July 15, 1995 90.76 17 47.41 90.81 17 48.27 90.86 
4-38 

SOUTH COAST AIR BASIN OZONE MODELING RESULTS 

The spatial distribution of the predicted daily maximum 1-hour ozone concentrations for the 

1997 baseline simulation in the South Coast Air Basin (SoCAB) 5-km domain are displayed in 

Figure 4-9. On the first day of the analysis period (August 4), predicted 1-hour ozone 

concentrations are relatively high with a peak of 163 ppb occurring just east of San Bernardino 

along the county line of Riverside and San Bernardino. A broad area of high ozone levels (>124 

ppb) are predicted north and northeast of Los Angeles. Compared to the observations, the model 

overpredicts the ozone concentration a little bit but catches the overall distribution pattern very 

well, especially the observed maximum areas. Two estimated high ozone areas predicted on 

August 5 with one peak (167 ppb) occurring north of Los Angles and another peak occurring east 

of Riverside. Several exceedances with a maximum of 187 ppb are observed in Riverside and its 

downwind area where the ozone concentrations are underestimated by the model. The ozone 

levels are slightly overpredicted by the model in another maximum area north of Los Angeles 

where the observed 1-hour ozone levels are below the standard. The model performs very well 

on August 6. Two ozone exceedance areas occur, again one in the east of Riverside along the 

county boundary and another north and northwest of Los Angeles, are observed and predicted 

well by the model. The spatial distribution of estimated ozone concentrations on August 7 is 

similar to the previous day, but the ozone levels are lower in most of the region with only two 

observed exceedance sites. 

The spatial distributions of daily maximum 8-hour ozone concentrations in the South Coast Air 

Basin, displayed in Figure 4-10, are quite similar to those of the daily peak 1-hour 

concentrations. The predicted high 8-hour ozone level area is quite consistent with observations. 

However, the peak 8-hour ozone concentrations are overestimated during the whole episode 

compared to the observations. And as in the case of the Lake Michigan and Northeast Corridor, 

the regions of exceedances of the proposed 8-hour ozone standard are relatively larger than the 

region exceeding the 1-hour ozone standard. 

The impacts on the daily maximum 1-hour and 8-hour ozone concentrations due to B20 biodiesel 

fuel use at a 100% penetration level in the South Coast Air Basin domain are presented in 

Figures 4-11 and 4-12, respectively. The corresponding displays for the 50% penetration 

scenario are presented in Appendix D. Though increases of ozone concentrations (disbenefits) 

due to the B20 fuel are predicted in the SoCAB domain, however, unlike in the Lake Michigan 

and Northeast Corridor domains, the ozone benefits (reductions) are obvious and out-weigh the 

disbenefits in terms of the magnitude of the peaks and are far more widespread in terms of 

spatial extent. The maximum benefits occur coincidentally in the regions of predicted 

exceedances (of both the 1-hour and 8-hour standards) in the baseline scenario during most days 

of the episode. The benefits due to 100% penetration of B20 biodiesel fuel use range from 0.95 

ppb to 1.2 ppb for daily maximum 1-hour ozone concentrations and 0.68 ppb to 0.96 ppb for 

daily maximum 8-hour ozone concentrations. The increases of ozone concentration due to 100% 

penetration of B20 biodiesel fuel use are overall small, ranging from 0.17 ppb to 0.26 ppb for 

daily maximum 1-hour ozone concentrations and 0.12 ppb to 0.15 ppb for daily maximum 8-

hour ozone concentrations. 

On August 4 (Figure 4-11a), a broad area of 1-hour ozone benefits is predicted from the Los 

Angeles metropolitan area all the way east to the San Bernardino National Forest while trivial 

magnitudes (<0.17ppb) of disbenefits are estimated to occur in the rest of the domain. The 

maximum benefits occur around the city of San Bernardino with a peak ozone reduction value of 

0.95 ppb. On the rest of the episode days, the distribution patterns of the benefits and disbenefits 
4-39 

are similar to that of August 4, except that the maximum benefits center shifts westward to the 

southeast of Los Angeles on August 5, where relative lower ozone levels are predicted. It is also 

noticeable that some benefits areas agree well with the highway system (e.g., highway 10 on 

August 4 and highway 15 on August 7). 

In Figure 4-12 the impacts on the daily maximum 8-hour ozone concentrations are displayed and 

are seen to be very similar to the 1-hour impacts with respect to the spatial distribution. The 

disbenefits are even more trivial (less than 0.15 ppb during the whole episode) than seen for 1-

hour ozone. 

The impacts due to B20 biodiesel fuel use on the daily 1-hour and 8-hour peak ozone 

concentrations in the South Coast Air Basin 5-km domain for both the 50% and 100% 

penetration emission scenarios are summarized in Table 4-8. On all episode days and for both 1-

hour and 8-hour ozone concentrations, the use of biodiesel fuel in the SoCAB is estimated to 

reduce the peak estimated ozone concentrations. However, these reductions in peak ozone 

concentrations are small with the maximum reduction being approximately 1 ppb. 

Table 4-8. Summary of daily peak 1-hour and 8-hour ozone concentrations in the South Coast 

Air Basin 5-km domain for the 1997 standard diesel (Baseline) and biodiesel emission scenarios. 

South Coast Air Basin 1-Hour Ozone 

 1997 Baseline 50% B20 Biodiesel 100% B20 Biodiesel 

 (ppb) (ppb) (% Difference) (ppb) (% Difference)

4-Aug-97 163.236 162.871 -0.224 162.501 -0.450 

5-Aug-97 167.000 166.772 -0.137 166.564 -0.261 

6-Aug-97 176.423 175.943 -0.272 175.458 -0.547 

7-Aug-97 160.567 160.442 -0.078 160.383 -0.115 

South Coast Air Basin 8-Hour Ozone 

 1997 Baseline 50% B20 Biodiesel 100% B20 Biodiesel 

 (ppb) (ppb) (% Difference) (ppb) (% Difference)

4-Aug-97 144.482 144.233 -0.172 143.983 -0.345 

5-Aug-97 126.084 125.852 -0.184 125.618 -0.370 

6-Aug-97 140.309 140.037 -0.194 139.762 -0.390 

7-Aug-97 143.504 143.376 -0.089 143.244 -0.181 
4-40 

Figure 4-9a. Spatial distribution of daily maximum 1-hour ozone concentrations in the South 

Coast Air Basin on August 4, 1997 for the baseline scenario 

Figure 4-9b. Spatial distribution of daily maximum 1-hour ozone concentrations in the South 

Coast Air Basin on August 5, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

72

95

120

94

42

37

101

35

98 100

35

94

64

82 124

102

119

42 93

132

50

81

114

89

86

86

88

68

119

78

115

108

99

86

94

72

64

0

50

65

80

95

110

124

140

150

160

170

max = 163.2364 PPB

min = 44.3743 PPB

Daily Max 1-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel - Base Case

300 350 400 450 500 550 600

3700

3750

3800

3850

52

122

84

114

54

66

110

41

130 95

41

74

68

89 82

112

130

40 67

119

61

68

88

107

72

90

122

76

170

121

187

150

93

112

93

76

85 79

120

100

57

113

74 72

88

0

50

65

80

95

110

124

140

150

160

170

max = 167 PPB

min = 43.6005 PPB

Daily Max 1-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel - Base Case
4-41 

Figure 4-9c. Spatial distribution of daily maximum 1-hour ozone concentrations in the South 

Coast Air Basin on August 6, 1997 for the baseline scenario 

Figure 4-9d. Spatial distribution of daily maximum 1-hour ozone concentrations in the South 

Coast Air Basin on August 7, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

28

94

58

89

27

57

59

38

119

43

131

51

59 81

90

154

31 41

115

28

106

57

77

109

51

94

106

151

86

134

141

132

129

134

79

48 126

100

90

111

113

6245

65

0

50

65

80

95

110

124

140

150

160

170

max = 176.4277 PPB

min = 44.4389 PPB

Daily Max 1-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel - Base Case

300 350 400 450 500 550 600

3700

3750

3800

3850

22

76

109

68

22

53

53

54

91 88

32

113

66

51 120

150

135

29 35

122

26

93

87

69

141

48

62

77

122

63

105

115

118

84

116

73

40 105

50

90

120

86

4139

43

0

50

65

80

95

110

124

140

150

160

170

max = 160.5672 PPB

min = 46.7021 PPB

Daily Max 1-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel - Base Case
4-42 

Figure 4-10a. Spatial distribution of daily maximum 8-hour ozone concentrations in the South 

Coast Air Basin on August 4, 1997 for the baseline scenario 

Figure 4-10b. Spatial distribution of daily maximum 8-hour ozone concentrations in the South 

Coast Air Basin on August 5, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

46

69

85

48

32

32

69

32

70 76

26

69

61

50 104

79

92

29 51

104

38

62

82

66

78

63

56

58

90

59

92

80

69

65

77

60

45 11

38

13

45

11

3540

35

0

55

65

75

84

95

105

115

125

135

max = 144.4823 PPB

min = 43.4042 PPB

Daily Max 8-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel - Base Case

300 350 400 450 500 550 600

3700

3750

3800

3850

40

85

67

77

41

56

77

36

99 59

32

68

64

56 68

92

86

28 53

98

49

56

69

88

64

69

65

64

110

67

118

104

64

92

77

70

61 73

98

84

53

85

64 56

68

0

55

65

75

84

95

105

115

125

135

max = 126.084 PPB

min = 42.7495 PPB

Daily Max 8-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel - Base Case
4-43 

Figure 4-10c. Spatial distribution of daily maximum 8-hour ozone concentrations in the South 

Coast Air Basin on August 6, 1997 for the baseline scenario 

Figure 4-10d. Spatial distribution of daily maximum 8-hour ozone concentrations in the South 

Coast Air Basin on August 7, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

19

60

45

63

21

44

44

34

85

33

107

48

35 80

75

118

23 31

96

22

97

52

59

87

40

58

87

106

66

92

94

109

85

115

71

38 97

71

79

76

92

5341

62

0

55

65

75

84

95

105

115

125

135

max = 140.3092 PPB

min = 43.8298 PPB

Daily Max 8-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel - Base Case

300 350 400 450 500 550 600

3700

3750

3800

3850

13

47

74

50

20

50

37

49

60 58

29

103

59

30 101

103

114

21 26

111

18

88

74

41

113

32

39

59

87

49

81

78

83

59

82

58

30 92

44

83

97

69

3437

38

0

55

65

75

84

95

105

115

125

135

max = 143.5037 PPB

min = 45.6672 PPB

Daily Max 8-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel - Base Case
4-44 

Figure 4-11a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the South Coast Air Basin on August 4, 1997 for the baseline scenario 

Figure 4-11b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the South Coast Air Basin on August 5, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

-0.15

0

0.15

0.3

0.6

0.9

1.2

1.5

max = 0.17 PPB 

min = -0.95 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

-0.15

0

0.15

0.3

0.6

0.9

1.2

1.5

max = 0.19 PPB 

min = -1.11 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base
4-45 

Figure 4-11c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the South Coast Air Basin on August 6, 1997 for the baseline scenario 

Figure 4-11d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the South Coast Air Basin on August 7, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

-0.15

0

0.15

0.3

0.6

0.9

1.2

1.5

max = 0.22 PPB 

min = -1.2 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

-0.15

0

0.15

0.3

0.6

0.9

1.2

1.5

max = 0.26 PPB 

min = -0.98 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base
4-46 

Figure 4-12a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the South Coast Air Basin on August 4, 1997 for the baseline scenario 

Figure 4-12b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the South Coast Air Basin on August 5, 1997 for the baseline scenario 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.12 PPB 

min = -0.68 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.15 PPB 

min = -0.77 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base
4-47 

Figure 4-12c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the South Coast Air Basin on August 6, 1997 for the baseline scenario. 

Figure 4-12d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the South Coast Air Basin on August 7, 1997 for the baseline scenario. 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.15 PPB 

min = -0.96 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.15 PPB 

min = -0.83 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel -- 100% Penetration B20 Biodiesel minus Base
4-48 

Ozone Exposure Estimates in the South Coast Air Basin 

The effects of biodiesel fuel use in the South Coast Air Basin (SoCAB) on exposure to 1-hour 

and 8-hour ozone concentrations was estimated using the same exposure and dosage metrics as 

used for the Lake Michigan and Northeast Corridor regions discussed earlier and are shown in 

Table 4-9. The effects of biodiesel fuel use in the SoCAB is to have small reductions in both the 

area exposed to elevated 1-hour and 8-hour ozone concentrations above the standard as well as 

the dosage of the exposure. On most days the ozone exposure/dosage reduction due to the 

biodiesel fuel use is less than 1 percent. However, on August 5, 1997 the 1-hour ozone exposure 

reduction in the 100% B20 scenario approaches 5 percent. 

Table 4-9. Summary of ozone exposure metrics for the South Coast Air Basin. 

South Coast Air Basin 1-Hour Exposure Metrics 

Date 1997 Baseline 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs) 

Exposure 

(grid cell-hrs) 

Dosage 

(ppb-grid cell-hrs)

August 3, 1997 6 4.24 6 4.26 7 4.29 

August 4, 1997 1392 18684.12 1387 18489.31 1381 18294.22 

August 5, 1997 847 7087.28 834 6941.57 826 6798.25 

August 6, 1997 963 14133.96 960 13942.56 958 13752.77 

August 7, 1997 1396 16953.88 1395 16804.77 1388 16655.23 

 

South Coast Air Basin 8-Hour Exposure Metrics 

Date 1997 Baseline 50% B20 Biodiesel 100% B20 Biodiesel 

 Exposure 

(grid cell-hrs) 

Dosage (ppb-grid 

cell-hrs) 

Exposure (grid 

cell-hrs) 

Dosage (ppb-grid 

cell-hrs) 

Exposure (grid 

cell-hrs) 

Dosage (ppb-grid 

cell-hrs) 

August 3, 1997 1254 9335.72 1255 9343.89 1256 9352.00 

August 4, 1997 5763 98219.91 5761 97898.80 5753 97575.40 

August 5, 1997 4378 68444.44 4370 68089.29 4362 67733.53 

August 6, 1997 4233 60373.43 4223 60035.98 4216 59702.98 

August 7, 1997 4987 86027.52 4988 85781.70 4985 85532.16 
5-1 

5. CONCLUSIONS 

The 100% and 50% penetration of a B20 biodiesel fuel is estimated to have very small effects 

(increases and decreases) in ozone concentrations in the Northeast Corridor, Lake Michigan, and 

Southern California regions. For the most part the changes in ozone due to the biodiesel fuel use 

are so small that they would not be measurable. Therefore, the main conclusion of the analysis is 

that the use of a B20 biodiesel in the HDDV fleet would have no significant ozone impact. 
R-1 

REFERENCES 

Emery, C., G. Yarwood, J. Heiken and C. Tran. 1998. “Air Quality Modeling Evaluation of the 

“Cool Communities: Ozone Control Strategy.” Prepared for South Coast Air Quality 

Management District. March. 

ENVIRON. 2002. “User’s Guide Comprehensive Air Quality Model with Extensions (CAMx) 

Version 3.10. Novato, CA. April. 

ENVIRON. 1998a. User's Guide Comprehensive Air Quality Model with Extensions (CAMx) 

Version 2.00. November. 

EPA. 1998b. “Air Quality Modeling Technical Support Document for the NOx SIP Call.” U.S. 

Environmental Protection Agency, Office of Air and Radiation, Research Triangle Park, 

N.C. September 23. 

EPA. 1998a. “Finding of Significant Contribution and Rulemaking for Certain States in the 

Ozone Transport Assessment Group Region for Purposes of Reducing Regional 

Transport of Ozone.” U.S. Environmental Protection Agency, Research Triangle Park, 

N.C. 

Lindhjem, C. and A. Pollack. 2000. “Impact of Biodiesel Fuels on Air Quality – Task 1 Report: 

Incorporate Biodiesel Data Into Vehicle Emission Databases for Modeling” Prepared for 

National Renewal Energy Laboratory, Golden, CO. June. 

Morris, R.E., G.M. Wilson, G. Yarwood. T.Darlington, J. Heiken, J.Heuss, G. Wolff, A. Dunker, 

S. Yamazaki and S. Chatani. 2002. “Evaluation of the Air Quality Impacts of Zero 

Emission Vehicles (ZEVs) and a No ZEV Alternative in the South Coast Air Basin of 

CA”. Presented at the 95th Annual Air and Waste Management Association Meeting and 

Exhibition. Baltimore MD. June 24-26. 

Morris, R.E., G.M. Wilson, G. Yarwood, T. Darlington, J. Heiken, and J. Heuss. 2001. 

“Evaluation of the Air Quality Impacts of Zero Emission Vehicles (ZEVs) and a No ZEV 

Alternative in the South Coast Air Basin of California”. Prepared for C.A.T. Committee. 

November 26. 

Morris, R.E., G.M. Wilson, and E. Tai. 1998b. “State-Specific Ozone and Utility costEffectiveness Assessment on Ozone Exceedances in the Eastern U.S.” Prepared for 

Southeast Michigan Council of Governments and Michigan Department of 

Environmental Quality, ENVIRON International Corporation, Novato, CA. June 24. 

Morris, R.E., G.M. Wilson, and E. Tai. 1998a. “Assessment of the State-Specific Ozone 

Contributions to Ozone Exceedances in the Eastern U.S. and Evaluation of the CostEffectiveness of Alternative Utility Control Measures.” Prepared for The Alliance for a 

Constructive Air Policy (ACAP), ENVIRON International Corporation, Novato, CA. 

June 24. 
R-2 

Morris R.E. and T.C. Myers. 1990. “User's Guide for the Urban Airshed Model. Volume I 

User's Manual for UAM (CB-IV)” prepared for the U.S. Environmental Protection 

Agency (EPA-450/4-90-007a), Systems Applications International, San Rafael, CA. 

 OTAG. 1997. “Ozone Transport Assessment Group - Executive Report. 

 SCAQMD. 1997. "1997 Air Quality Management Plan for the South Coast Air Quality 

Management District." South Coast Air Quality Management District. Diamond Bar, 

CA. 

 Sistla, G. 1999. “Draft Modeling Plan for the Ozone Transport Region 8-Hour Ozone 

Modeling” New York State Department of Environmental Conservation, Albany, N.Y. 

 Tesche, T.W., and R.E. Morris. 1998. “Review of the EPA Ozone Transport SIP Call and 

Recent Post-OTAG Modeling and Analysis Studies.” Prepared for Ohio Environmental 

Protection Agency. April. 

Yarwood, G., T.Stoeckenius, and Heiken. 2002. “Proximate Modeling of Weekday/Weekend 

Ozone Differences for Los Angeles”. Prepared for Coordinating Research Council, Inc., 

CRC Project No. A-36-A1. July 23. 
Appendix A 

Impacts on Daily Maximum 

1-Hour and 8-Hour Ozone Concentrations 

Due to 50% Penetration of B20 Biodiesel Fuel Use 

in the Lake Michigan 4-km Domain

A-1
Figure A-1a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 11, 1995. 

Figure A-1b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 12, 1995. 

A-2
Figure A-1c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 13, 1995. 

Figure A-1d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 14, 1995. 

A-3
Figure A-1e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 15, 1995. 

Figure A-1f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 16, 1995. 

A-4
Figure A-2a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 11, 1995. 

Figure A-2b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 12, 1995. 

A-5
Figure A-2c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 13, 1995. 

Figure A-2d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 14, 1995. 

A-6
Figure A-2e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 15, 1995. 

Figure A-2f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Lake Michigan 4-km domain on July 16, 1995. 

A-7
Appendix B 

Impacts on Daily Maximum 

1-Hour and 8-Hour Ozone Concentrations 

Due to 50% Penetration of B20 Biodiesel Fuel Use 

in the Northeast Corridor 4-km Domain 

B-1
Figure B-1a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 11, 1995. 

Figure B-1b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 12, 1995. 

B-2
Figure B-1c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 13, 1995. 

Figure B-1d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 14, 1995. 

B-3
Figure B-1e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 15, 1995. 

Figure B-1f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 16, 1995. 

B-4
Figure B-2a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 11, 1995. 

Figure B-2b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 12, 1995. 

B-5
Figure B-2c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 13, 1995. 

Figure B-2d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 14, 1995. 

B-6
Figure B-2e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 15, 1995. 

Figure B-2f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the Northeast Corridor 4-km domain on July 16, 1995. 

B-7
Appendix C 

Spatial Displays of CAMx Modeling Results 

For the OTAG 12-km Domain 

C-1
Figure C-1a. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure C-1b. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 12, 1995 for the 2007 SIP Call scenario. 

C-2
Figure C-1c. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure C-1d. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 14, 1995 for the 2007 SIP Call scenario. 

C-3
Figure C-1e. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 15, 1995 for the 2007 SIP Call scenario. 

Figure C-1f. Spatial distribution of daily maximum 1-hour ozone concentrations in the OTAG 

12-km domain on July 16, 1995 for the 2007 SIP Call scenario. 

C-4
Figure C-2a. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 11, 1995 for the 2007 SIP Call scenario. 

Figure C-2b. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 12, 1995 for the 2007 SIP Call scenario. 

C-5
Figure C-2c. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 13, 1995 for the 2007 SIP Call scenario. 

Figure C-2d. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 14, 1995 for the 2007 SIP Call scenario. 

C-6
Figure C-2e. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 15, 1995 for the 2007 SIP Call scenario. 

Figure C-2f. Spatial distribution of daily maximum 8-hour ozone concentrations in the OTAG 

12-km domain on July 16, 1995 for the 2007 SIP Call scenario. 

C-7
Figure C-3a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 11, 1995. 

Figure C-3b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 12, 1995. 

C-8
Figure C-3c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 13, 1995. 

Figure C-3d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 14, 1995. 

C-9
Figure C-3e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 15, 1995. 

Figure C-3f. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 1-hour 

ozone concentrations in the OTAG 12-km domain on July 16, 1995. 

C-10
Figure C-4a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 11, 1995. 

Figure C-4b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 12, 1995. 

C-11
Figure C-4c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 13, 1995. 

Figure C-4d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 14, 1995. 

C-12
Figure C-4e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 15, 1995. 

Figure C-4f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the OTAG 12-km domain on July 16, 1995. 

C-13
Figure C-5a. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 11, 1995. 

Figure C-5b. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 12, 1995. 

C-14
Figure C-5c. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 13, 1995. 

Figure C-5d. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 14, 1995. 

C-15
Figure C-5e. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 15, 1995. 

Figure C-5f. Impacts of 100% penetration of B20 biodiesel fuel on daily maximum 8-hour 

ozone concentrations in the OTAG 12-km domain on July 16, 1995. 

C-16
Figure C-6a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 11, 1995. 

Figure C-6b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 12, 1995. 

C-17
Figure C-6c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 13, 1995. 

Figure C-6d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 14, 1995. 

C-18
Figure C-6e. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 15, 1995. 

Figure C-6f. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the OTAG 12-km domain on July 16, 1995. 

C-19
Appendix D 

Impacts on Daily Maximum 1-Hour and 

8-Hour Ozone Concentrations Due to 

50% Penetration of B20 Biodiesel Fuel Use 

in the South Coast Air Basin 5-km Domain 

D-1
Figure D-1a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 4, 1997. 

 

Figure D-1b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 5, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.09 PPB 

min = -0.48 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.1 PPB 

min = -0.56 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

D-2
Figure D-1c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 6, 1997. 

Figure D-1d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 1-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 7, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.11 PPB 

min = -0.6 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.13 PPB 

min = -0.49 PPB 

Difference in Daily Max 1-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

D-3
Figure D-2a. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 4, 1997. 

Figure D-2b. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 5, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.06 PPB 

min = -0.34 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 04, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.07 PPB 

min = -0.39 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 05, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

D-4
Figure D-2c. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 6, 1997. 

Figure D-2d. Impacts of 50% penetration of B20 biodiesel fuel on daily maximum 8-hour ozone 

concentrations in the South Coast Air Basin 5-km domain on August 7, 1997. 

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.08 PPB 

min = -0.48 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 06, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

300 350 400 450 500 550 600

3700

3750

3800

3850

-1.5

-1.2

-0.9

-0.6

-0.3

0

0.3

0.6

0.9

1.2

1.5

max = 0.08 PPB 

min = -0.42 PPB 

Difference in Daily Max 8-Hour Ozone (ppb)

August 07, 1997

NREL Biodiesel -- 50% Penetration B20 Biodiesel minus Base

D-5
REPORT DOCUMENTATION PAGE Form Approved 

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE

May 2003 

3. REPORT TYPE AND DATES COVERED 

Subcontract Report 

September 1999–January 2003 

4. TITLE AND SUBTITLE

Impact of Biodiesel Fuels on Air Quality and Human Health: Task 2 Report, The Impact of 

Biodiesel Fuels on Ozone Concentrations

6. AUTHOR(S) 

R.E. Morris, G.E. Mansell, Y. Jia, G. Wilson 

5. FUNDING NUMBERS

AXE-9-29079-01 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

ENVIRON International Corporation 

101 Rowland Way 

Novato, CA 94945 

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REPORT NUMBER 

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National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393

10. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

NREL/SR-540-33795 

11. SUPPLEMENTARY NOTES

NREL Technical Monitor: K.S. Tyson and R. McCormick 

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12b. DISTRIBUTION CODE

 

13. ABSTRACT (Maximum 200 words)

This report documents Task 2 of the NREL study “Impact of Biodiesel Fuels on Air Quality and Hyman Health”. Under Task 

1, engine test data using biodiesel and standard diesel fuels were analyzed to estimate the effects biodiesel fuel has on heavy

duty diesel vehicle tailpipe emissions.

15. NUMBER OF PAGES

14. SUBJECT TERMS 

biodiesel; air quality, modeling, emissions 16. PRICE CODE

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