Appendix D 

Reasonable Further Progress and Contingency Reductions 
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May 7, 2007 Appendix D 1 

Introduction

Reasonable further progress (RFP) refers to the annual emission reductions required to 

demonstrate continued and steady progress toward attaining air quality standards. A 

SIP must demonstrate both RFP and attainment to be approvable. It must also include 

contingency emission reductions that must be achieved if a nonattainment area fails to 

meet certain milestones. The RFP requirements for the 8-hour ozone standard are 

described in the “Final Rule to Implement the 8-Hour Ozone National Ambient Air 

Quality Standard,” and build upon the requirements specified in Clean Air Act sections 

172(c)(2), 182(b)(1) and 182(c)(2)(b). 

This appendix will summarize how California meets its RFP and contingency reduction 

requirements. It is important to note that the requirements are met in every 

nonattainment area with already-adopted measures. No new emission reduction 

commitments are required and no reductions from the State Strategy’s proposed new 

measures are needed to meet the requirements. 

RFP Requirements

RFP requirements vary by nonattainment classification. The following is a discussion 

about RFP requirements for California nonattainment areas as initially designated by 

U.S. EPA. 

Areas with a basic classification that can attain the standard within the first five years 

after the designations become effective (2004-2009) do not have to demonstrate RFP. 

Three basic areas, Sutter Buttes, Butte County and San Diego County will meet the 

federal standard by 2009. Areas with a marginal classification – Imperial County and 

San Francisco Bay Area – are not subject to RFP requirements. 

Moderate and basic areas that require more than five years to attain must demonstrate 

RFP. Their RFP demonstrations include an initial 15 percent reduction in ROG and/or 

NOx emissions from the 2002 baseline ROG inventory by 2008. They then must 

achieve additional reductions per year, averaged across each consecutive 3-year period 

or part thereof until their attainment year. Basic areas needing additional time to attain 

include: Eastern Kern, Southern Mountain Counties, Central Mountain Counties, and 

Western Nevada County. Moderate areas include: Ventura, Antelope Valley and 

Western Mojave Desert. 

Areas whose 1-hour ozone rate of progress plans were not approved by the U.S. EPA 

are subject to different RFP requirements. These areas still must meet the initial RFP 

target of 15 percent ROG reductions for the first six years (2002-2008), as set forth in 

Clean Air Act section 182(b)(1). They cannot use NOx emission reductions to satisfy 

the initial target when ROG emissions are not sufficient. The areas subject to this 

restriction are Coachella Valley, Antelope Valley, and Western Mojave Desert, which 

comprise the former Southeast Desert 1-hour ozone nonattainment area. This presents 

a challenge for the former Southeast Desert areas because their nonattainment status 

is due in part to pollution transported from the South Coast. In such situations, 
May 7, 2007 Appendix D 2 

U.S. EPA allows the nonattainment area to account for emissions occurring, and 

emission reductions achieved, in upwind areas to be credited towards rate of progress. 

With transport included in the calculation, the Coachella Valley meets rate of progress 

requirements. 

For RFP, nonattainment areas classified serious and above must demonstrate an 

18 percent reduction in ROG and/or NOx emissions from the 2002 baseline ROG 

inventory by 2008. In the years that follow, they must demonstrate, on average, an 

additional 3 percent per year reduction in ROG and/or NOx emissions until their 

attainment year. Serious areas are: San Joaquin Valley, Coachella Valley and 

Sacramento. Note that for the reasons given above, Coachella Valley is subject to a 

15 percent ROG-only reduction requirement from 2002 to 2008. The South Coast Air 

Basin is classified as severe. 

For moderate and above 8-hour ozone nonattainment areas, a limited amount of NOx 

reductions may also be used, to a point, as a substitution for ROG reductions for RFP. 

NOx emission reductions creditable toward the RFP requirement cannot be greater than 

the cumulative NOx reductions that are necessary to demonstrate attainment. This 

attainment consistency requirement is meant to prevent the substitution of NOx 

reductions for progress purposes that would not lead toward attaining the ozone 

standard. 

U.S. EPA has taken the position in guidance, and not in regulation, that for 

nonattainment areas classified under Subpart 2, reductions needed for progress in the 

attainment year should equate to those needed for attainment. ARB staff disagrees. 

We believe a plain reading of the Act indicates that a 3 percent reduction per year is 

needed between the next-to-last milestone year and the attainment year. For example, 

in a severe-15 area, the next-to-last milestone year is 2017 and the attainment year is 

2018. A 45 percent reduction is needed in 2017 for RFP. Therefore, the RFP 

requirement for the next year (2018) is three percent more, or 48 percent – and not the 

reductions needed for attainment. 

Upwind Emissions in RFP Demonstrations

Ozone levels are influenced by ROG and NOx emitted both within a nonattainment area 

and transported from upwind locations. U.S. EPA acknowledges this relationship by 

allowing emission reductions from upwind locations outside the nonattainment area to 

be included for RFP, up to 100 kilometers for ROG and 200 kilometers for NOx. 

The inclusion of transport contributions of ROG and NOx provides key emission 

reductions in RFP analyses for the following nonattainment areas: Antelope Valley and 

Western Mojave Desert, Central Mountain Counties, Coachella Valley, Eastern Kern, 

Southern Mountain Counties and Western Nevada. Their emission inventories for RFP 

purposes include ROG and NOx emissions from counties that are (1) entirely within the 

designated 100km and 200km distances, and (2) part of the area’s established 

federally-approved transport couples. 

Federal Motor Vehicle Control Program Adjustments 
May 7, 2007 Appendix D 3 

Section 182(b)(1)(D) of the Clean Air Act stipulates that emission reductions stemming 

from the federal on-road motor vehicle control program as it existed in 1990 may not be 

used to help meet minimum emission reduction requirements for RFP purposes. This 

precludes states from securing the emission reductions required to demonstrate 

satisfactory progress for ozone simply on the merit of the federal motor vehicle control 

program as it existed in 1990. The Clean Air Act also prohibits states from taking credit 

for emission reductions resulting from using gasoline with a Reid vapor pressure limit 

specified by 1990. States are required to adjust for the benefits of these federal 

programs in RFP calculations. ARB staff has considered the combined benefits of the 

federal motor vehicle and fuel volatility programs for purposes of this discussion, and 

will reference them below as the “federal program” and “federal program adjustments”. 

California’s pioneering efforts to set emission standards from motor vehicles resulted in 

nationwide emission standards adopted by U.S EPA. In general, California’s auto 

emission standards have been, and are, more stringent than federal standards, 

particularly for passenger vehicles. 

In analyzing what federal program adjustments should be made to California 

nonattainment area RFP reductions, ARB staff analysis concluded that the federal 

program did not provide any additional benefits beyond California’s program and that 

the federal program adjustment in all nonattainment areas should be zero. This is a bit 

different than the rate of progress reductions for the last 1-hour ozone SIP, where some 

federal program adjustments were made. ARB staff’s methodology for calculating the 

federal program benefits remains unchanged, except to reflect a change in the baseline 

year from 1990 (for 1-hour ozone plans) to 2002. 

California’s on-road control program has continued to advance since 1990, so 

emissions from motor vehicles in 2002 are much lower than they were in 1990. 

Additionally, large increases in vehicle miles traveled from 1990 to 2002 result in a 

higher-emitting federal fleet for 8-hour ozone RFP than for the 1-hour ozone rate of 

progress. Combined, these factors lead to the conclusion that the pre-1990 federal 

program provides no benefits to California in 8-hour ozone RFP plans. 

Contingency Requirements

Contingency reductions are to take effect without further ARB or air district action if the 

nonattainment area does not achieve an RFP milestone, or if the area does not attain 

the federal 8-hour ozone or PM2.5 standard at the end of their identified attainment 

year. This requirement does not apply to marginal nonattainment areas, only to basic, 

moderate, serious, severe and extreme areas (for RFP only). Since these contingency 

reductions must be achieved without further action, U.S. EPA has interpreted this to 

mean that the contingency reductions must be from measures that have already been 

adopted when the submittal is made (or possibly prior to U.S. EPA taking action). 

The bulk of emission reductions needed to attain the federal standards in this submittal 

are achieved through regulations that make up California’s mobile source emission 

control program, which has been very successful in reducing emissions within California 
May 7, 2007 Appendix D 4 

and represents the foundation supporting attainment of both federal and State ambient 

air quality standards. ARB has a well established history of adopting and implementing 

mobile source control regulations on time or earlier than it has committed to do so. As a 

result, we expect to achieve, and even exceed, our RFP goals without the need for 

contingency reductions. 

For all nonattainment areas, already-adopted measures provide more emission 

reductions than are needed to meet RFP requirements in every milestone year. 

Therefore, the emission reductions from adopted measures that go beyond the RFP 

requirements will constitute the contingency reductions in the unlikely event that the 

State does not meet the RFP goals. 

Failure to meet federal air quality standards is determined by monitored air quality 

values in the attainment year, and is therefore determined after the end of the 

attainment year. California's motor vehicle emission control program allows ARB to 

provide additional emission reductions each year, based on the increasing benefits of 

measures that are already being implemented. Therefore, ARB proposes to include the 

benefits of one additional year of its ongoing motor vehicle program, including vehicle 

fleet turnover, and light-duty vehicle inspection and maintenance in the year following 

each area’s attainment year. 

Contingencies for new technologies 

In terms of contingency for attainment, additional provisions apply to extreme areas that 

include new technologies in their attainment plans. These attainment demonstration 

plans can rely on future advances in emission reduction technologies (referred to as 

new technologies) if the State, among other things, submits enforceable commitments 

to develop and adopt contingency measures if the anticipated technologies do not 

achieve the planned reductions, and if the State demonstrates that the contingency 

reductions shall be adequate to achieve attainment and reasonable further progress. 

These contingency reductions to back-up the new technology provisions are not due 

until three years before implementation of these new technology provisions. The need 

for technology development and long-term measures, as well the process for identifying 

long-term emission reductions is discussed in Chapter 3. 

Reasonable Further Progress and Contingency Demonstrations

The following descriptions for each nonattainment area outline California’s RFP and 

related contingency reductions demonstrations. Since already-adopted measures 

provide all contingency reductions needed for RFP and attainment, the requirement that 

reductions will occur without any further action by ARB or local air districts is fully met. 

ARB staff reports for each nonattainment area will include demonstration of RFP and 

contingency reductions. Detailed charts providing the background for RFP and 

contingency reductions for South Coast, San Joaquin Valley, and Coachella Valley, can 

be found on pages 6-8 of this appendix. All three of these areas are expected to 

request a change in their nonattainment classifications – extreme for both South Coast 
May 7, 2007 Appendix D 5 

and San Joaquin Valley and severe-15 for Coachella Valley. The charts reflect the 

anticipated nonattainment classifications. 

South Coast 

The South Coast meets its RFP targets through 2014 purely on the basis of ROG 

reductions from the existing control program. From 2017 forward, the South Coast will 

need to use both ROG and NOx reductions from the existing control program. 

Reductions from proposed new measures are not needed to achieve the progress 

targets. 

Adopted measures in the South Coast Air Basin are expected to yield enough 

reductions to meet the RFP goals and will also yield a surplus that will meet the 

contingency reduction requirements for the area. 

San Joaquin Valley 

The San Joaquin Valley meets its RFP targets through both ROG and NOx reductions 

from the existing control program. Reductions from proposed new measures are not 

needed to achieve the progress targets. 

Adopted measures in the San Joaquin Valley are expected to yield enough reductions 

to meet the RFP goals and will also yield a surplus that will meet the contingency 

reduction requirements for the area. 

Coachella Valley 

Because the Southeast Desert 1-hour ozone nonattainment area did not have a 

federally-approved progress plan, the Coachella Valley’s 8-hour RFP plan must 

demonstrate a 15 percent emission reduction from 2002 to 2008 by relying only on 

ROG reductions. The area meets this requirement. Expecting the South Coast District 

to request a bump up to the severe -15 classification for the Coachella Valley, progress 

is calculated through 2018. Upwind emissions of ROG have been used from Orange 

County, the portion of San Bernardino County within the South Coast Air Basin, and the 

portion of Riverside County within South Coast Air Basin. Upwind emissions of NOx 

from these counties and Los Angeles County have also been included. 

Adopted measures in the Coachella Valley are expected to yield enough reductions to 

meet the RFP goals and will also yield a surplus that will meet the contingency 

reduction requirements for the area. 
May 7, 2007 Appendix D 6 

Detailed Analysis of South Coast 

Reasonable Further Progress and Contingency 

(summer planning, tons per day) 

2002 2008 2011 2014 2017 2020 2023

Baseline ROG 897.2 651.0 599.2 566.4 546.4 536.4 533.6

FMVCP/RVP Adjustment 0 0 0 0 0 0 0

RACT Corrections 0 0 0 0 0 0 0

Adjusted Baseline ROG 897.2 651.0 599.2 566.4 546.4 536.4 533.6

RFP commitment for ROG reductions 

 from new measures 0 0 0 0 0 0

Required % change since previous 

 milestone year (ROG or NOx) 

 compared to 2002 

18% 9% 9% 9% 9% 9%

Required % change since 2002 

(ROG or NOx) 18% 27% 36% 45% 54% 63%

Target ROG levels 735.7 655.0 574.2 493.5 412.7 332.0

Apparent shortfall in ROG -84.7 -55.8 -7.8 53.0 123.6 201.7

Apparent shortfall in ROG, % -9.4% -6.2% -0.9% 5.9% 13.8% 22.5%

ROG shortfall previously provided by 

 NOx substitution, % 0 0.0% 0.0% 0.0% 5.9% 13.8%

Actual ROG shortfall, % -9.4% -6.2% -0.9% 5.9% 7.9% 8.7%

 

Baseline NOx 1078.4 849.6 737.1 649.7 578.0 530.2 505.1 

FMVCP Adjustment 0 0 0 0 0 0 0 

Adjusted Baseline NOx 1078.4 849.6 737.1 649.7 578.0 530.2 505.1 

RFP commitment for NOx reductions 

 from new measures 0 0 0 0 0 0 0 

Change in NOx since 2002 228.9 341.3 428.7 500.5 548.2 573.3 

Change in NOx since 2002, % 21.2% 31.7% 39.8% 46.4% 50.8% 53.2%

NOx reductions since 2002 already 

 used for RFP substitution and 

 contingency through last milestone 

 year, % 

0.0% 3.0% 6.0% 9.0% 17.9% 28.7%

NOx reductions since 2002 available 

 for RFP substitution and contingency 

 in this milestone year, % 

21.2% 28.7% 33.8% 37.4% 33.0% 24.4%

Change in NOx since 2002 used for 

 ROG substitution in this milestone 

 year, % 

0.0% 0.0% 0.0% 5.9% 7.9% 8.7% 

Change in NOx since 2002 used for 

 contingency in this milestone year, % 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 

Change in NOx since 2002 surplus 

 after meeting substitution and 

 contingency needs in this milestone 

 year, % 

18.2% 25.7% 30.8% 28.5% 22.1% 12.7%

Are RFP Requirements Met? yes yes yes yes yes yes 

Are Contingency Reduction 

Requirements Met? yes yes yes yes yes yes 
May 7, 2007 Appendix D 7 

Detailed Analysis of San Joaquin Valley 

Reasonable Further Progress and Contingency 

(summer planning, tons per day) 

2002 2008 2011 2014 2017 2020 2023

Baseline ROG 468.0 426.5 405.8 403.7 400.3 402.3 408.8

FMVCP/RVP Adjustment 0 0 0 0 0 0 0

RACT Corrections 0 0 0 0 0 0 0

Adjusted Baseline ROG 468.0 426.5 405.8 403.7 400.3 402.3 408.8

RFP commitment for ROG reductions 

 from new measures 0 0 0 0 0 0

Required % change since previous 

 milestone year (ROG or NOx) 

 compared to 2002 

18% 9% 9% 9% 9% 9%

Required % change since 2002 

 (ROG or NOx) 18% 27% 36% 45% 54% 63%

Target ROG levels 383.8 341.6 299.5 257.4 215.3 173.2

Apparent shortfall in ROG 42.8 64.2 104.2 142.9 187.0 235.6

Apparent shortfall in ROG, % 9.1% 13.7% 22.3% 30.5% 40.0% 50.3%

ROG shortfall previously provided by 

 NOx substitution, % 0 9.1% 13.7% 22.3% 30.5% 40.0%

Actual ROG shortfall, % 9.1% 4.6% 8.5% 8.3% 9.4% 10.4%

 

Baseline NOx 642.30 567.67 493.11 419.55 362.24 321.68 295.14

FMVCP Adjustment 0 0 0 0 0 0 0

Adjusted Baseline NOx 642.30 567.7 493.1 419.5 362.2 321.7 295.1

RFP commitment for NOx reductions 

 from new measures 0 0 0 0 0 0 0

Change in NOx since 2002 74.6 149.2 222.8 280.1 320.6 347.2

Change in NOx since 2002, % 11.6% 23.2% 34.7% 43.6% 49.9% 54.0%

NOx reductions since 2002 already 

 used for RFP substitution and 

 contingency through last milestone 

 year, % 

0.0% 11.6% 16.7% 25.3% 33.5% 43.0%

NOx reductions since 2002 available 

 for RFP substitution and 

 contingency in this milestone year, % 

11.6% 11.6% 18.0% 18.3% 16.4% 11.1%

Change in NOx since 2002 used for 

 ROG substitution in this milestone 

 year, % 

9.1% 4.6% 8.5% 8.3% 9.4% 10.4%

Change in NOx since 2002 used for 

 contingency in this milestone year, % 2.5% 3.0% 3.0% 3.0% 3.0% 3.0%*

Change in NOx since 2002 surplus 

 after meeting substitution and 

 contingency needs in this milestone 

 year, % 

0.0% 6.5% 9.4% 10.1% 7.0% 0.7%

Are RFP Requirements Met? yes yes yes yes yes yes 

Are Contingency Reduction 

Requirements Met? yes yes yes yes yes yes** 

* 2024 mobile source program reductions are relied upon to meet 2023 contingency requirements. 

** Contingency requirements met in 2023 through reductions from already-adopted mobile source 

measures. 
May 7, 2007 Appendix D 8 

Detailed Analysis of Coachella Valley 

Reasonable Further Progress and Contingency 

(summer planning, tons per day) 

2002 2008 2011 2014 2017 2018

Baseline ROG 379.3 299.9 282.0 271.4 265.9 265.0

FMVCP/RVP Adjustment 0 0 0 0 0 0

RACT Corrections 0 0 0 0 0 0

Adjusted Baseline ROG 379.3 299.9 282.0 271.4 265.9 265.0

RFP commitment for ROG reductions from 

 new measures 

0 0 0 0 0

Required % change since previous milestone 

year (ROG or NOx) compared to 2002 15% 9% 9% 9% 3%

Required % change since 2002 

(ROG or NOx) 15% 24% 33% 42% 45%

Target ROG levels 322.4 288.3 254.1 220.0 208.6

Apparent shortfall in ROG -22.50 -6.29 17.32 45.92 56.39

Apparent shortfall in ROG, % -5.9% -1.7% 4.6% 12.1% 14.9%

ROG shortfall previously provided by NOx 

 substitution, % 0.0% 0.0% 0.0% 4.6% 12.1%

Actual ROG shortfall, % -5.9% -1.7% 4.6% 7.5% 2.8%

 

Baseline NOx 1159.3 917.2 794.6 697.2 618.1 597.4 

FMVCP Adjustment 0 0 0 0 0 0 

Adjusted Baseline NOx 1159.3 917.2 794.6 697.2 618.1 597.4 

RFP commitment for NOx reductions 

 from new measures 0 0 0 0 0 0 

Change in NOx since 2002 242.1 364.7 462.0 541.2 561.9 

Change in NOx since 2002, % 20.9% 31.5% 39.9% 46.7% 48.5% 

NOx reductions since 2002 already used 

 for RFP substitution and contingency 

 through last milestone year, % 

 0.0% 3.0% 6.0% 13.3% 23.8% 

NOx reductions since 2002 available for 

 RFP substitution and contingency in 

 this milestone year, % 

 20.9% 28.5% 33.9% 33.4% 24.6% 

Change in NOx since 2002 used for 

 ROG substitution in this milestone 

 year, % 

 0.0% 0.0% 4.3% 7.5% 2.8% 

Change in NOx since 2002 used for 

 contingency in this milestone year, % 3.0% 3.0% 3.0% 3.0% 3.0% 

Change in NOx since 2002 surplus after 

 meeting substitution and contingency 

 needs in this milestone year, % 

 17.9% 25.5% 26.5% 22.9% 18.9% 

Are RFP Requirements Met? yes yes yes yes yes 

Are Contingency Reduction 

Requirements Met? yes yes yes yes yes