Early Progress Plans Demonstrating Progress Toward 

Attaining the 8-hour National Air Quality Standard for Ozone 

and 

Setting Transportation Conformity Budgets 

for 

Ventura County 

Antelope Valley - Western Mojave Desert 

Coachella Valley 

Eastern Kern County 

Imperial County 

Revised: February 27, 2008 

Release Date: February 27, 2008 
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Electronic copies of this document can be found on ARB’s website at 

http://www.arb.ca.gov/planning/sip/sip.htm. Alternatively, paper copies may be 

obtained from the Public Information Office, Air Resources Board, 1001 I Street, 

Visitors and Environmental Services Center, 1st Floor, Sacramento, California 

95814, (916) 322-2990. 

For individuals with sensory disabilities, this document is available in Braille, 

large print, audiocassette, or computer disk. Please contact ARB’s Disability 

Coordinator at (916) 323-4916 by voice or through the California Relay Services 

at 711, to place your request for disability services. If you are a person with 

limited English and would like to request interpreter services, please contact 

ARB’s Bilingual Manager at (916) 323-7053. 

This document has been prepared by the staff of the California Air Resources 

Board. Publication does not signify that the contents reflect the views and 

policies of the Air Resources Board, nor does trade names or commercial 

products constitute endorsement or recommendation for use. 

Please send written comments to:

Mr. Ravi Ramalingam, P.E., Manager 

Transportation Strategies Section 

California Air Resources Board 

P.O. Box 2815 

Sacramento, California 95812 

Phone: (916) 322-2085 

Fax: (916) 322-3646 

For general questions, contact:

Mr. Dennis Wade, Air Pollution Specialist 

Motor Vehicle Assessments Section 

Phone: (916) 327-2963 

Email: dwade@arb.ca.gov
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Early Progress Plans Demonstrating Progress 

Toward Attaining the Federal 8-hour National Air Quality 

Standard for Ozone 

TABLE OF CONTENTS 

RECOMMENDATION......................................................................................... 1

BACKGROUND....................................................................................................1

INVENTORIES AND TRANSPORTATION CONFORMITY BUDGETS...............3

• Ventura County 

• Antelope Valley/Western Mojave Desert 

• Coachella Valley 

• Eastern Kern County 

• Imperial County 

APPENDIX.............................................................................Appendix-1 

• Revisions to Appendix A of the State Strategy for California’s 2007 

State Implementation Plan 
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 1 February 27, 2008 

RECOMMENDATION 

Air Resources Board (ARB or the Board) staff recommends that the Board adopt 

the ozone Early Progress Plans in this report as amendments to the State 

Implementation Plan (SIP) in order to establish transportation conformity 

emissions budgets for Ventura County, Antelope Valley - Western Mojave 

Desert, Coachella Valley, Eastern Kern County and Imperial County. Normally, 

these conformity budgets would be with set with reasonable further progress 

(RFP) plans. However, the U.S. Environmental Protection Agency (U.S. EPA) is 

revising its regulations setting out the requirements for RFP plans and will not be 

able to approve RFP plans for these areas until that revision is complete. Setting 

conformity budgets with these early progress plans will allow transportation 

planning to move forward in the interim. 

BACKGROUND 

Transportation conformity is a provision of the federal Clean Air Act that requires 

transportation planning agencies to demonstrate that their transportation plans, 

funding programs, and projects are consistent with (“conform to”) the SIP. One 

part of demonstrating conformity is a comparison, by transportation planning 

agencies, of vehicle emissions from transportation plans to emissions budgets in 

the SIP. An emissions budget is the level of emissions from on-road motor 

vehicles that ensures an area makes progress toward clean air and ultimately 

meets air quality standards by the mandated deadline. 

Normally, emissions budgets would be set with an RFP plan. However, 

U.S. EPA is revising its RFP regulations for areas whose air quality is dominated 

by pollution from upwind regions. Until those revisions are complete, U.S. EPA 

will not approve RFP plans and related conformity budgets for these types of 

areas. 

The transportation planning process still needs conformity budgets, and 

U.S. EPA’s inability to approve RFP plans creates a timing problem. To keep the 

transportation planning process moving, ARB staff has prepared early progress 

plans for the sole purpose of establishing transportation conformity emission 

budgets for the four nonattainment areas caught up by U.S. EPA’s revisions, and 

for Imperial County, whose pending reclassification will generate a need for 

transportation conformity emissions budgets. 

An early progress plan is an optional plan and must simply show some progress 

toward attainment. The inventories for each of the five areas decline in the future 

with already adopted controls, thereby demonstrating progress. The plans are 

simple, containing the inventory demonstrating progress and the associated 

budgets. 
 2 February 27, 2008 

INVENTORIES AND CONFORMITY BUDGETS 

The inventories presented below for stationary, area-wide and other mobile 

sources for all areas are consistent with the emission inventories submitted to 

U.S. EPA as part of the State Strategy for California’s 2007 State Implementation 

Plan adopted by the Board in September 2007. These inventories contain 

reductions from adopted regulations only. Consequently, these early progress 

plans do not create any new regulatory SIP commitments. 

The on-road mobile inventories and the transportation conformity budgets are 

estimated using California’s EMFAC2007 on-road mobile emissions model. 

EMFAC2007 was approved by U.S. EPA on January 18, 2008. Transportation 

conformity budgets are estimated the year before an area’s attainment year. 

This is consistent with U.S. EPA guidance, which states that attainment should 

be demonstrated for the last full ozone season before an area’s attainment year. 

Motor vehicle activity data used for all areas except Eastern Kern County was 

updated by the Southern California Association of Governments (SCAG) in 

December, 2007 from SCAG’s Draft 2008 Regional Transportation Plan 

transportation model runs. Transportation activity data for Eastern Kern County 

is from the Kern Council of Governments provided in January 2008. 

REVISIONS TO THE JANUARY 29, 2008 VERSION 

After these plans were posted on January 29, 2008, ARB staff discovered that 

some of the input data used by the on-road emissions estimation model, EMFAC, 

had been corrupted. This resulted in errors in emissions calculations affecting 

the inventories and transportation conformity budgets for Antelope Valley – 

Western Mojave Desert and Eastern Kern County. The table entries for these 

areas on the following pages reflect the corrected numbers. 

For Antelope Valley – Western Mojave Desert, the changes result in a new ROG 

budget in 2009 of 22 tons per day from the original 21 tons per day, and a new 

NOx budget of 77 tons per day from the original 74 tons. In the case of Eastern 

Kern County, the ROG budget in 2008 goes from 4 to 5 tons per day, and the 

NOx budget from 16 to 18 tons per day. 

ARB staff consider these changes minor and do not impact the overall progress 

in these two areas.
 3 February 27, 2008 

Ventura County

Ventura County 

Summer Planning Emissions Inventory*

Adjusted for Rules and Programs through December 31, 2006

Tons per Day

Reductions, 

2002-2009

 2002 2009 

Tons 

per Day Percent 

ROG 

 Stationary 10.7 10.0

 

 Area-wide 14.1 14.1

 

 On-road Mobile 20.2 12.0

 

 Other Mobile 15.2 14.0

 

 Total ROG 60.3 50.0 10.3 17% 

NOx 

 Stationary 6.5 6.3

 

 Area-wide 1.3 1.3

 

 On-road Mobile 30.1 18.5

 

 Other Mobile 37.5 36.3

 

 Total NOx 75.3 62.4 12.9 17% 

* Summer Planning Inventory v.1.06 

As shown above, the emissions inventory from all sources shows a 17 percent 

reduction in both ROG and NOx in 2009 compared to the 2002 base year. This 

demonstrates significant progress toward attainment of the federal 8-hour 

standard. 
 4 February 27, 2008 

Ventura County 

Transportation Conformity Budgets 

Summer Planning Emissions in Tons per Day 

2009 

ROG NOx 

On-Road Emissions from EMFAC2007 12.0 19.0 

 

Off Model Reductions* 0.0 -0.5 

Net On-Road Emissions 12.0 18.5 

Conformity Budget** 13 19 

* Reductions from adopted rules not reflected in EMFAC2007 

** Budget obtained by rounding up to the nearest ton 

Presented above are the transportation conformity budgets for Ventura County in 

2009. EMFAC2007 emission factors were used with motor vehicle activity 

provided by the Southern California Association of Governments in 

January 2008. 
 5 February 27, 2008 

Antelope Valley – Western Mojave Desert

Antelope Valley – Western Mojave Desert 

Summer Planning Emissions Inventory*

Adjusted for Rules and Programs through December 31, 2006

Tons per Day

Reductions, 

2002-2009

 2002 2009 

Tons 

per Day Percent 

ROG 

 Stationary 12.0 13.2

 

 Area-wide 10.9 11.0

 

 On-road Mobile 28.2 21.9

 

 Other Mobile 20.1 24.4

 

 Total ROG 71.2 70.6 0.6 1% 

NOx 

 Stationary 44.2 50.4

 

 Area-wide 1.0 1.0

 

 On-road Mobile 89.3 76.0

 

 Other Mobile 50.4 40.0

 

 Total NOx 184.9 167.5 17.4 9% 

* Summer Planning Inventory v.1.06 

As shown above, the emissions inventory from all sources shows a combined 

percent reduction of ozone precursors of 10 percent in 2009 compared to the 

2002 base year. This demonstrates significant progress toward attainment of the 

federal 8-hour standard. 
 6 February 27, 2008 

Antelope Valley - Western Mojave Desert 

Transportation Conformity Budgets 

Summer Planning Emissions in Tons per Day 

2009 

ROG NOx 

On-Road Emissions from EMFAC2007 22.0 80.6 

 

Off Model Reductions* 0.0 -4.6 

Net On-Road Emissions 21.9 76.0 

Conformity Budget** 22 77 

* Reductions from adopted rules not reflected in EMFAC2007 

** Budget obtained by rounding up to the nearest ton 

Presented above are the transportation conformity budgets for the Antelope 

Valley – Western Mojave Desert in 2009. EMFAC2007 emission factors were 

used with motor vehicle activity provided by the Southern California Association 

of Governments in January 2008. 
 7 February 27, 2008 

Coachella Valley

Coachella Valley 

Summer Planning Emissions Inventory*

Adjusted for Rules and Programs through December 31, 2006

Tons per Day

Reductions, 

2002-2012

 2002 2012 

Tons 

per Day Percent 

ROG 

 Stationary 1.7 2.7

 

 Area-wide 4.7 4.7

 

 On-road Mobile 10.5 6.4

 

 Other Mobile 5.3 4.8

 

 Total ROG 22.3 18.6 3.7 17% 

NOx 

 Stationary 0.9 0.9

 

 Area-wide 0.5 0.4

 

 On-road Mobile 41.0 25.5

 

 Other Mobile 9.3 8.3

 

 Total NOx 51.8 35.1 14.7 32% 

* Summer Planning Inventory v.1.06 

As shown above, the emissions inventory from all sources shows a 17 percent 

reduction in ROG and a 32 percent reduction in NOx in 2012 compared to the 

2002 base year. This demonstrates significant progress toward attainment of the 

federal 8-hour standard. 
 8 February 27, 2008 

Coachella Valley 

Transportation Conformity Budgets 

Summer Planning Emissions in Tons per Day 

2012 

ROG NOx 

On-Road Emissions from EMFAC2007 6.5 27.5 

 

Off Model Reductions* 0.0 -2.0 

Net On-Road Emissions 6.4 25.5 

Conformity Budget** 7 26 

* Reductions from adopted rules not reflected in EMFAC2007 

** Budget obtained by rounding up to the nearest ton 

Presented above are the transportation conformity budgets for the Coachella 

Valley for 2012. EMFAC2007 emission factors were used with motor vehicle 

activity provided by the Southern California Association of Governments. 
 9 February 27, 2008 

Eastern Kern County

Eastern Kern County 

Summer Planning Emissions Inventory*

Adjusted for Rules and Programs through December 31, 2006

Tons per Day

Reductions, 

2002-2008

 2002 2008 

Tons 

per Day Percent 

ROG 

 Stationary 1.0 1.0

 

 Area-wide 1.5 1.4

 

 On-road Mobile 5.6 4.2

 

 Other Mobile 4.7 4.5

 

 Total ROG 12.8 11.1 1.7 13% 

NOx 

 Stationary 18.2 20.6

 

 Area-wide 0.1 0.1

 

 On-road Mobile 21.1 17.2

 

 Other Mobile 14.1 11.5

 

 Total NOx 53.5 49.5 4.1 8% 

* Summer Planning Inventory v.1.06 

As shown above, the emissions inventory from all sources shows a combined 

percent reduction of ozone precursors of 21 percent in 2008 compared to the 

2002 base year. This demonstrates significant progress toward attainment of the 

federal 8-hour standard. 
 10 February 27, 2008 

Eastern Kern County 

Transportation Conformity Budgets 

Summer Planning Emissions in Tons per Day 

2008 

ROG NOx 

On-Road Emissions from EMFAC2007 4.3 20.4 

 

Off Model Reductions* -0.1 -3.2 

Net On-Road Emissions 4.2 17.2 

Conformity Budget** 5 18 

* Reductions from adopted rules not reflected in EMFAC2007 

** Budget obtained by rounding up to the nearest ton 

Presented above are the transportation conformity budgets for Eastern Kern 

County for 2008. EMFAC2007 emission factors were used with motor vehicle 

activity provided by the Kern County Council of Governments in January 2008. 
 11 February 27, 2008 

Imperial County

Imperial County 

Summer Planning Emissions Inventory*

Adjusted for Rules and Programs through December 31, 2006

Tons per Day

Reductions, 

2002-2009

 2002 2009 

Tons 

per Day Percent 

ROG 

 Stationary 1.3 1.4

 

 Area-wide 20.8 20.6

 

 On-road Mobile 8.8 6.9

 

 Other Mobile 6.4 7.4

 

 Total ROG 37.4 36.3 1.1 3% 

NOx 

 Stationary 8.5 8.9

 

 Area-wide 0.9 0.9

 

 On-road Mobile 20.9 16.7

 

 Other Mobile 12.6 10.1

 

 Total NOx 42.9 36.6 6.3 15% 

* Summer Planning Inventory v.1.06 

As shown above, the emissions inventory from all sources shows a 3 percent 

reduction in ROG and a 15 percent reduction in NOx in 2009 compared to the 

2002 base year. This demonstrates significant progress toward attainment of the 

federal 8-hour standard. 
 12 February 27, 2008 

Imperial County 

Transportation Conformity Budgets 

Summer Planning Emissions in Tons per Day 

2009 

ROG NOx 

On-Road Emissions from EMFAC2007 6.9 17.6 

 

Off Model Reductions* 0.0 -0.9 

Net On-Road Emissions 6.9 16.7 

Conformity Budget** 7 17 

* Reductions from adopted rules not reflected in EMFAC2007 

** Budget obtained by rounding up to the nearest ton 

Presented above are the transportation conformity budgets for Imperial County 

for 2009. EMFAC2007 emission factors were used with motor vehicle activity 

provided by the Southern California Association of Governments in 

January 2008.