CHAPTER 6 

CLEAN AIR ACT REQUIREMENTS 

Introduction 

Federal Clean Air Act Requirements 

California Clean Air Act Requirements 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 1 

INTRODUCTION 

The purpose of the 2003 Revision to the AQMP for the South Coast Air Basin is to set 

forth a comprehensive program that will lead the Basin and those portions of the Salton 

Sea Air Basin under the District’s jurisdiction into compliance with all federal and state 

air quality planning requirements. Specifically, the 2003 AQMP revision is designed to 

satisfy the California CAA triennial update requirements and fulfill the District’s 

commitment to update transportation emission budgets based on the latest approved 

motor vehicle emissions model and planning assumptions. The Plan will be submitted to 

U.S. EPA as SIP revisions once approved by the District’s Governing Board and CARB. 

FEDERAL CLEAN AIR ACT REQUIREMENTS 

In November 1990, Congress enacted a series of amendments to the CAA intended to 

intensify air pollution control efforts across the nation. One of the primary goals of the 

1990 CAA Amendments was an overhaul of the planning provisions for those areas not 

currently meeting NAAQS. The CAA identifies specific emission reduction goals, 

requires both a demonstration of reasonable further progress and an attainment 

demonstration, and incorporates more stringent sanctions for failure to attain or to meet 

interim milestones. There are several sets of general planning requirements, both for 

nonattainment areas [Section 172(c)] and for implementation plans in general [Section 

110(a)(2)]. These requirements are listed and briefly described in Chapter 1 (Tables 1-4 

and 1-5). The general provisions apply to all applicable pollutants unless superseded by 

pollutant-specific requirements. 

The following sections discuss the federal CAA requirements for PM10, ozone, CO, and 

NO2. 

PM10 Planning Requirements 

Results of ambient air quality monitoring data indicate that the Basin exceeds federal 

and state standards for PM10. These microscopically fine particles can originate from 

several industrial processes, including direct emissions and atmospheric chemical 

reactions which convert gases into particles (referred to as “secondary” particulates), and 

from a variety of fugitive dust sources, both natural and man-made. In the western 

portions of the Basin, secondary particulates account for about 45 percent of the annual 

average PM10, while soil and reentrained dust (referred to as “fugitive dust”) accounts 

for about 30 percent. In the eastern portion of the Basin, the contributions from 

secondary particulates and fugitive dust are approximately 40 percent each. Mobile 

sources also contribute directly to ambient PM10 levels through tailpipe emissions and, 

indirectly, through resuspension of road dust. 
Final 2003 AQMP 

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Under the 1990 CAA Amendments, the South Coast Air Basin was originally classified 

as a “moderate” PM10 nonattainment area. In response to SIP submittal requirements of 

the CAA for “moderate” areas, the District submitted applicable portions of the 1991 

AQMP to the U.S. EPA prior to the November 15, 1991 statutory deadline. In 

accordance with the CAA requirements for moderate PM10 nonattainment areas, the 

moderate area PM10 SIP submittal proposed the implementation of “reasonably 

available control measures” (RACM) for fugitive dust sources, and relied upon the 

AQMP for reductions in precursor gaseous emissions as part of the ozone attainment 

plan. In February 1993, EPA reclassified the Basin from a “moderate” to a “serious” 

nonattainment area for PM10. The moderate area SIP further showed that the 

complexity of the problem was of sufficient magnitude that the PM10 standards could 

not be attained by 2001 -- the deadline for serious nonattainment areas. The CAA 

provides a maximum five-year extension to the attainment date for those areas that 

cannot meet the 2001 date after all best available control measures (BACM) have been 

implemented by 1997; thus making 2006 the latest attainment year possible. The 

District had previously shown in the 1997 AQMP and 2002 update that it will need until 

2006 to meet the federal PM10 standards. 

Current PM10 Requirements

For areas such as the Basin that are classified as serious nonattainment for PM10, 

Section 189(b)(3) defines major PM10 sources that would be subject to CAA major 

source requirements. Sections 189(b)(1)(B) and 189(e) of the CAA require the 

implementation of “best available control technology” (BACT) for point sources of 

PM10 and precursor emissions (i.e., precursors of secondary particulates) and BACM 

for area sources of fugitive dust. It should be noted that federal BACT is equivalent to 

California best available retrofit technology (BARCT). U.S. EPA guidance1

 also states 

that, in instances where mobile sources contribute significantly to the area’s exceedance 

of federal PM10 standards, transportation control measures (TCMs) are also to be 

included as part of the PM10 SIP submittal. The CAA requires an attainment 

demonstration for PM10 as well as the establishment of emission reduction milestones 

(CAA Section 189(b)(1), 189(c)(1)). Lastly, contingency measures for PM10, in the 

event of failure to meet emission reduction milestones or achieve attainment, are also 

required as part of the SIP submittal (CAA Section 172(c)(9)).

 

1

 U.S. EPA, State Implementation Plans for Serious PM-10 Nonattainment Areas, and Attainment Date Waivers for 

PM10 Nonattainment Areas Generally; Addendum to the General Preamble for the Implementation of Title I of the 

Clean Air Act Amendments of 1990, Federal Register, pp. 41998-42017, August 16, 1994. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 3 

Major PM10 Source Requirements 

Section 189(b)(3) of the CAA defines a major source of PM10 as any stationary source 

that emits or has a potential to emit at least 70 tons per year of PM10. These major 

sources then would be subject to major source requirements contained in the CAA. 

District Rule 1302(p) defines major PM10 sources in accordance with the CAA, making 

them subject to the major source requirements under New Source Review. 

BACT for Point Sources 

As mentioned in the 1994 and 1997 AQMPs, BACT for point sources of PM10 and 

PM10 precursors is presently addressed through the District’s NSR and RECLAIM 

programs (District Rules 1303 and 2005). 

BACM for Fugitive Dust Sources 

For fugitive dust sources, the selection of BACM to be implemented must be based on a 

combination of technical feasibility, cost-effectiveness, and energy/environmental 

considerations. The District developed a list of candidate BACM as part of the 1994 

PM10 BACM SIP submittal. These measures were refined and updated for the 1997 

AQMP: 

CM #97BCM-01: Paved Roads 

 1a Minimal Track-Out 

 1b Routine Street Cleaning 

 1c Post Event Street Cleaning 

 1d/1e Curbs and Gutters / Chemical Stabilization of 

Unpaved Road Shoulders 

CM #97BCM-02: Construction/Demolition Activities 

 Wider Application of Dust Control Plans 

CM #97BCM-03: Unpaved Roads 

 Paving/Chemical Treatment/Speed Reductions 

CM #97BCM-04: Agricultural Activities 

 Soil Conservation Plans 

CM #97BCM-05: Miscellaneous Sources 

 Controls on Weed Abatement 

CM #97BCM-06: Further Emission Reductions from Fugitive Dust Sources 

to Meet Best Available Control Measures Requirements 

(RACM to BACM Upgrade) 

The District committed to adopt all identified candidate BACM via rulemaking action by 

December 31, 1996 and implement these BACM by February 8, 1997. Based on the 

revised emissions inventory and other available information, each of the candidate 

BACM were evaluated for cost-effectiveness and control efficiency. The District 
Final 2003 AQMP 

6 - 4 

completed the BACM technological and cost feasibility analysis prior to July 1996. 

BCM-01(a/b/c), BCM03, BCM-04, and BCM-06 met both the technological and cost 

feasibility criteria and were adopted in February 1997 through amendments to Rule 403 

- Fugitive Dust and new Rule 1186 – PM10 Emissions from Paved and Unpaved Roads 

and Livestock Operations. The District identified the candidate BACM not meeting 

either the technological or cost feasibility criteria. Those measures were CTY-12 

(formerly BCM-01d/e), CTY-13 (formerly BCM-02), and CTY-14 (formerly BCM-05). 

Contingency Measures 97CTY-12 and 97CTY-13 were adopted in February 1997 as 

contingency actions in Rules 403 and 1186. CTY-14 remains a contingency measure in 

the 2003 AQMP. 

The 2003 AQMP includes two new BACM: BCM-07 - Further Emission Reductions 

from Fugitive Dust Sources and BCM-08 - Further Emission Reductions from 

Aggregate and Cement Manufacturing Operations. BCM-07 proposes to review existing 

District BACM regulations to consider enhancements that would further reduce PM10 

emissions from fugitive dust sources. Additionally, the BACM review will consider 

regulations for specific geographic areas based on soil type, wind conditions, and source 

extent. As this control measure may address fugitive dust sources in localized areas, it is 

also intended as a means to ensure compliance in those areas that are subject to high 

levels of PM10. BCM-08 proposes to establish prescriptive measures to control fugitive 

dust from area sources within aggregate facilities and cement plants as well as evaluate 

whether additional controls are necessary for the control of PM10 for sources at 

aggregate and cement manufacturing plant operations subject to District Rule 404 - 

Particulate Matter - Concentration, Rule 405 – Solid Particulate Matter - Weight, and 

Rule 1112.1 - Emissions of Particulate Matter From Cement Kilns. 

Transportation Control Measures 

Transportation control measures meeting the CAA requirements have been submitted in 

previous SIPs, including the 1994 and 1997 California Ozone SIP. Updated 

transportation control measures necessary for attainment of the federal PM10 and ozone 

standards are described in Appendix IV-C. 

PM10 Attainment Demonstration 

Section 189(b)(1)(a) of the CAA requires a PM10 attainment demonstration. The results 

of the attainment demonstration are summarized in Chapter 5. The air quality modeling 

used for the PM10 attainment demonstration is described in Appendix V. 

Establishing PM10 Milestone Targets 

Section 189(c) of the CAA requires the establishment of PM10 milestone targets. The 

2003 AQMP establishes targets for 2003 and the attainment year of 2006. The PM10 

milestone targets are shown in Table 6-1. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 5 

TABLE 6-1 

PM10 Attainment Year Targets 

(Annual Average - Tons per Day) 

Pollutant 2003 2006 

PM10 292 292 

NOx 1,048 935 

SOx 58 57 

VOC 804 673 

Contingency Measures for PM10 

The federal CAA requires PM10 contingency measures to be implemented in the event 

of failure to meet milestone emission reduction targets and/or failure to attain the 

standard by the attainment date in 2006 (CAA Section 172(c)(9)). The PM10 

contingency measures are those BACM measures that have failed either the technical 

feasibility or cost-effectiveness criteria or both. As discussed above, Rules 403 and 

1186 contain contingency actions (based on Contingency Measures 97CTY-12 and 

97CTY-13) to be implemented to meet CAA requirements. CTY-14 is the only 

remaining contingency measure for PM10 carried over from the 1997 AQMP. In 

addition to the fugitive dust contingency measures, other contingency measures for 

ozone serve as contingency for PM10 to reduce VOCs and NOx which are precursors to 

particulate organics and nitrates. Further, 2003 AQMP Contingency Measure CTY-01- 

Accelerated Implementation of Control Measures, includes measures that reduce PM10 

and PM10 precursors. The full descriptions of each of the contingency measures are 

contained in Appendix IV-A, Section 2. 

Ozone Planning Requirements 

This section describes how the 2003 AQMP meets the major ozone planning 

requirements of the federal CAA for the South Coast Air Basin. The requirements 

specifically addressed here are: 

1. the post-1996 VOC rate-of-progress requirements, 

2. the ozone attainment demonstration, 

3. the contingency measure requirements, and 

4. the average vehicle occupancy requirement. 
Final 2003 AQMP 

6 - 6 

Post-1996 VOC Rate-of-Progress

The reasonable further progress requirements in the CAA are intended to ensure that 

each ozone nonattainment area provide for sufficient precursor emission reductions to 

attain the ozone national ambient air quality standard. More specifically, Section 

182(c)(2) requires that each serious and above ozone nonattainment area achieve actual 

VOC emission reductions of at least three percent per year averaged over each 

consecutive three-year period beginning six years after enactment of the Act until the 

area’s attainment date (i.e., November 15, 2010 for the South Coast Air Basin). This is 

called the “post-1996 rate-of-progress” requirement of the CAA. 

According to Section 182(c)(2)(C), actual NOx emission reductions which occur after 

1990 can be used to meet post-1996 VOC emission reduction requirements provided the 

NOx reductions satisfy the following criteria. First, the control strategy used to 

demonstrate attainment must consist of both VOC and NOx control measures. More 

specifically, the mix of VOC and NOx emission reductions used to satisfy the post-1996 

rate-of-progress requirements of the CAA must be consistent with the controlled VOC 

and NOx emission levels used in the modeling demonstration. And lastly, the combined 

annual VOC and NOx reductions must average three percent per year. As discussed 

below, since the baseline VOC emissions are below the overall target levels for the 

milestone years 2005 and 2008 there is no need for NOx substitution in those years; 

NOx substitution is only necessary in 2010. 

The 2003 AQMP post-1996 rate-of-progress demonstration for the Basin is presented in 

Tables 6-2 and 6-3a and 6-3b and Figures 6-1a and 6-1b. These tables and figures 

depict the VOC and NOx emission target levels and the projected baseline for 2005, 

2008, and 2010, respectively. Controlled emission levels are not shown since the VOC 

and NOx emission reductions from existing District and CARB rules, included in the 

projected baseline, are sufficient to meet the CAA rate-of-progress. 

For the milestone years 2005 and 2008, the baseline VOC emission levels are below the 

target levels. In 2010, however, the VOC reductions in the baseline are insufficient and 

NOx substitution is necessary and allowed according to Section 182(c)(2)(C) of the 

CAA. The proposed reduction rates for milestone years are shown in Table 6-2. These 

rates are determined by applying all the creditable VOC reductions at each milestone and 

providing sufficient NOx reductions to satisfy VOC reduction requirements of Section 

182(c)(2). 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 7 

TABLE 6-2 

Percent of VOC and NOx Emission Reductions from the 1990 Baseline 

to Meet the Post-1996 Rate-of-Progress Requirements 

Year VOC NOx CAA* 

2005 42.0 0.0 42.0 

2008 51.0 0.0 51.0 

2010 55.0 2.0 57.0 or attainment 

* The percent VOC and NOx reductions must equal the CAA percent reduction requirements listed here. 

TABLE 6-3A 

Summary of Rate of Progress Calculations - VOC 

ROW CALCULATION STEP a 2005 2008 2010 

1 1990 ROP Base Year b 1869.8 1869.8 1869.8 

2 FMVCP/RVP c Reductions 373.6 386.1 390.5 

3 Adjusted 1990 Base Year d 1496.2 1483.7 1479.3 

4 Required Reduction (%) e 42.0 51.0 55.0 

5 Emission Reductions f 628.4 756.7 813.6 

6 RACT Corrections 0.0 0.0 0.0 

7 I/M Corrections 0.0 0.0 0.0 

8 Target Level g 867.8 727.0 665.7 

9 Projected Baseline h 752.1 687.3 659.4 a

 Units are in tons per day unless otherwise noted; b Contains only anthropogenic emissions; c FMVCP/RVP = Federal Motor Vehicle Control Program/Reid Vapor Pressure; d

 (Row 1) – (Row 2) e

 24% VOC reduction by 1999 and 3% per year (total VOC and NOx reductions) thereafter from the adjusted 1990 

baseline year; f

 [(Row 3) x (Row 4)]/100; g (Row 3) – (Row 5) – (Row 6) – (Row 7); h Projected baseline emissions 

shown in Appendix III taking into account existing rules and projected growth. It includes emission reduction credits. 
Final 2003 AQMP 

6 - 8 

FIGURE 6-1a 

Post-1996 Rate of Progress - VOC 

TABLE 6-3b 

Summary of Rate of Progress Calculations - NOx 

ROW CALCULATION STEP a 2005 2008 2010 

1 1990 ROP Base Year b 1546.4 1546.4 1546.4 

2 FMVCP/RVP c Reductions 0.0 0.0 0.0 

3 Adjusted 1990 Base Year d 1546.4 1546.4 1546.4 

4 Required Reduction (%) e 0.0 0.0 2.0 

5 Emission Reductions f 0.0 0.0 30.9 

6 RACT Corrections 0.0 0.0 0.0 

7 I/M Corrections 0.0 0.0 0.0 

8 Target Level g 1546.4 1546.4 1515.5 

9 Projected Baseline h 951.6 854.2 763.8 a

 Units are in tons per day unless otherwise noted; b Contains only anthropogenic emissions; c FMVCP/RVP = Federal Motor Vehicle Control Program/Reid Vapor Pressure; d

 (Row 1) – (Row 2) e

 24% VOC reduction by 1999 and 3% per year (total VOC and NOx reductions) thereafter from the adjusted 1990 

baseline year; f

 [(Row 3) x (Row 4)]/100; g (Row 3) – (Row 5) – (Row 6) – (Row 7); h Projected baseline emissions 

shown in Appendix III taking into account existing rules and projected growth. It includes emission reduction credits. 

868

727

666

752

687 659

0

100

200

300

400

500

600

700

800

900

1000

2005 2008 2010

Milestone Year

Emissions (tpd)

Target Level Projected Baseline
Chapter 6 Federal and State Clean Air Act Requirements

6 - 9 

Ozone Attainment Demonstration

Under the federal CAA, air quality modeling is an integral part of the planning process 

to achieve clean air. Specifically, Section 182(b)(1)(A) requires that moderate and 

above ozone nonattainment areas must reduce VOC and NOx emissions sufficiently to 

attain the national ambient air quality standard for ozone. It is not sufficient for extreme 

ozone nonattainment areas to meet the post-1996 rate-of-progress requirements of the 

CAA; extreme ozone nonattainment areas, such as the Basin, must also demonstrate 

attainment by November 15, 2010. This may result in emission reductions in addition to 

those required by the reasonable further progress components of the CAA [i.e., Sections 

182(b)(1) and 182(c)(2)]. A summary of the ozone attainment demonstration is provided 

in Table 5-2 of Chapter 5. The ozone attainment demonstration is fully described in 

Appendix V. 

1546 1546 1515

952

854

764

0

200

400

600

800

1000

1200

1400

1600

1800

2005 2008 2010

Milestone Year

Target Level Projected Baseline

FIGURE 6-1b 

Post-1996 Rate of Progress – NOx
Final 2003 AQMP 

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Contingency Measures

Section 172(c)(9) of the 1990 CAA requires that the plan shall provide for 

implementation of specific measures in the event an area fails to make reasonable further 

progress or to attain the applicable standards by the specified dates. Such measures shall 

be included in the Plan revision as contingency measures to take effect without further 

action by the State or the Administrator. In addition to the contingency provisions 

required under Section 172(c)(9), Section 182(c)(9) requires the plan revision to provide 

for the implementation of specific measures to be undertaken if the area fails to meet any 

applicable milestone for ozone. Such measures must be included in the plan revision as 

contingency measures to take effect without further action by the State or the U.S. EPA 

Administrator upon a failure by the State to meet the applicable milestone. The 

contingency measures included as part of the 2003 AQMP are contained in Appendix 

IV-A, Section 2.

Average Vehicle Occupancy Requirements (AVO)

Section 182 (d)(1)(A) of the CAA requires the District to include transportation control 

strategies and TCMs in the Plan that offset any growth in emissions from growth in 

vehicle trips and vehicle miles traveled and attain reduction of mobile source emissions. 

Such control measures must be developed in accordance with the guidelines listed in 

Section 108(f) of the CAA. The programs listed in Section 108(f) of the CAA include, 

but are not limited to, public transit improvement projects, traffic flow improvement 

projects, the construction of high occupancy vehicle (HOV) facilities and other mobile 

source emission reduction programs. The TCMs included in the 2003 AQMP (see 

Appendix IV-C) have been developed to meet the requirements of Section 182(d)(1)(A) 

and 108(f) of the CAA and include the capital-based and non-capital-based facilities, 

projects and programs contained in the Regional Mobility Element and programmed 

through the RTIP process. As an additional measure of reducing mobile source 

emissions, Section 182(d)(1)(B) of the CAA allows the implementation of employerbased trip reduction programs that are aimed at improving the average vehicle 

occupancy (AVO) rates. As an alternative to trip reduction programs, Section 

182(d)(1)(B) also allows the substitution of these programs with alternative programs 

that achieve equivalent emission reductions. Rule 2202 - On-Road Motor Vehicle 

Mitigation Options, adopted in December 1995, was developed to comply with CAA 

Section 182(d)(1)(B); emission reductions from Rule 2202 are reflected in the baseline 

inventory. 

Carbon Monoxide Attainment Demonstration 

The South Coast Air Basin has historically had a persistent CO problem. However, 

there has been considerable improvement in CO air quality in the Basin from 1976 to 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 11 

2002. In 2001, the Basin met both the federal and state 8-hour CO standards for the first 

time at all monitoring stations. During a particularly stagnant morning in January 2002, 

however, the 8-hour federal standard was exceeded at one location. This was the only 

location and day exceeding the federal standard in 2002. Since the provision specified 

in the federal CAA defining attainment of the federal 8-hour average CO standard allows 

no more than one day and one location to exceed the standard in a two-year period, the 

Basin is currently in compliance with the federal 8-hour standard. 

Based on the above, the 2003 revision to the CO Plan provides a dual purpose: it 

replaces the 1997 attainment demonstration that lapsed at the end of 2000, and it 

provides the basis for a CO maintenance plan in the future. Although the trend of 

reducing CO emissions is expected to continue, the 2003 AQMP does not include a 

request for EPA to consider re-designation of the Basin’s CO attainment status at this 

time. A comprehensive discussion of the CO attainment demonstration is included in 

Chapter 5 and Appendix V. 

Section 187(a)(3) of the 1990 CAA requires that adopted and enforceable contingency 

measures be included in the CO attainment demonstration plan submittal (see Appendix 

IV-A, Section 2). One contingency measure is included for CO attainment planning, to 

be implemented if the area fails to maintain the federal standard. 

A list of the contingency measures developed for these CAA requirements is provided in 

Chapter 9. 

Nitrogen Dioxide Maintenance Plan 

Under the CAA, an area can be redesignated as meeting attainment if, among other 

requirements, the U.S. EPA determines that the NAAQS have been attained. Section 

175A of the CAA states that any district that submits a request under Section 107(d) for 

redesignation of a nonattainment area to attainment must submit a revision of the 

applicable SIP that provides for maintenance for at least 10 years after the redesignation. 

U.S. EPA guidance states that a determination of compliance with the NAAQS must be 

based on three complete, consecutive calendar years of quality-assured air quality 

monitoring data. 

The federal annual NO2 standard was met for the first time in 1992 and the standard has 

been met every year since. The South Coast Air Basin was redesignated as an 

attainment area in 1998. As such, based on the ambient nitrogen dioxide measurements 

and the demonstration shown in Chapter 5 that the Basin will maintain the federal 

nitrogen dioxide air quality standard with the projected baseline future-year emissions, 

this Plan serves as the Nitrogen Dioxide Maintenance Plan for the South Coast Air 

Basin. 
Final 2003 AQMP 

6 - 12 

Transportation Conformity Budgets 

The 2003 AQMP sets forth the strategy for achieving the federal one-hour ozone, PM10, 

and CO standards, and maintaining the federal NO2 standard. For on-road mobile 

sources, Section 176(c) of the CAA requires that transportation plans and programs do 

not cause or contribute to any new violation of a standard, increase the frequency or 

severity of any existing violation, or delay the timely attainment of the air quality 

standards. In other words, on-road mobile sources must "conform" to the attainment 

demonstration contained in the SIP. 

U.S. EPA's transportation conformity rule, found in 40 CFR parts 51 and 93, details the 

requirements for establishing motor vehicle emissions budgets in SIPs for the purpose of 

ensuring the conformity of transportation plans and programs with the SIP attainment 

demonstration. The on-road motor vehicle emissions budgets act as a "ceiling" for 

future on-road mobile source emissions. Exceedances of the budget indicate an 

inconsistency with the SIP, and could jeopardize the flow of federal funds for 

transportation improvements in the region. As required by the CAA, a comparison of 

regional on-road mobile source emissions to these budgets will occur during the periodic 

updates of regional transportation plans and programs. 

The on-road motor vehicle emissions estimates for the 2003 AQMP were analyzed using 

the CARB's EMFAC2002 on-road mobile source emission factor model in conjunction 

with the most recent motor vehicle activity data from SCAG. Emissions forecasts were 

generated for the summer, winter, and annual average planning inventory using 

EMFAC2002 for each milestone and attainment or maintenance year. The ozone 

emissions budgets for VOC and NOx are derived from the summer planning inventory 

and the reductions from defined new measures in the 2003 SIP. The PM10 emissions 

budgets for PM10 and the PM10 precursors VOC and NOx, and are derived from the 

annual average planning inventory. The CO and NO2 emissions budgets for CO and 

NOx, respectively, are both derived from the winter planning inventory. These budgets 

reflect existing control programs and new commitments for technology and 

transportation control measures. 

The SIP emissions inventory includes both defined commitments to develop specific 

measures and less defined long-term strategies allowed under Section 182(e)(5) of the 

Clean Air Act, also known as the "black box." The emissions budgets factor in only onroad mobile source reductions from adopted measures and the defined commitments. 

This SIP includes an overall emissions reduction commitment for the long-term Statelocal strategy under Section 182(e)(5) for all sources, including an extensive public 

process to identify specific measures. The plan does not allocate emission reductions by 

source sector. In 2006-2007, the carrying capacity will be reassessed and the black box 

further defined. At that time, the SIP will be revised to identify specific measures that 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 13 

may affect on-road mobile, off-road mobile, stationary, and area-wide sources to fulfill 

the long-term obligation. The combination of emission reductions will depend on which 

new technologies prove feasible. Until these long-term measures are identified, the 

transportation emissions budget can only reflect the anticipated benefits of defined 

measures in this plan. In the next SIP revision, we will adjust the budgets to reflect the 

latest control strategy, including commitments for additional reductions from on-road 

motor vehicles. 

This approach is consistent with U.S. EPA's transportation conformity rule, which 

provides that if emissions budgets rely on new control measures, these measures should 

be specified in the SIP and the emissions reductions from each control measure should 

be quantified and supported by agency commitments for adoption and implementation 

schedules. Moreover, the rule provides that conformity analyses by transportation 

agencies may not take credit for measures which have not been implemented unless the 

measures are "projects, programs, or activities" in the SIP supported by written 

implementation commitments by the responsible agencies (62 FR 43780, 40 CFR 93, 

subpart A). 

The emissions budgets for ozone and PM10 are provided here for up to the respective 

attainment year. However, since transportation analyses are needed beyond the 

attainment dates, the carrying capacities for PM10 and ozone attainment demonstration 

also serve as the budgets for future years (e.g., 2010, 2020 and 2030 for PM10 and 2020 

and 2030 for ozone). Ozone precursor emissions from motor vehicles are projected to 

continue declining through these extended periods. However, there is projected longterm growth in direct PM10 emissions due to increased vehicle travel on paved and 

unpaved roads. 

To address this increase in primary PM10 emissions from travel while continuing to 

provide for attainment after 2006, this plan establishes a mechanism for conformity 

demonstration purposes based on the implementation of the new control measure, 

"Transportation Conformity Budget Backstop Control Measure" in which commitments 

are made to achieve additional primary PM10 reductions from transportation-related 

PM10 source categories in 2020 and 2030 to offset the increased emissions. 

Specifically, the measure is proposed to be adopted in 2019 and 2029 in order to achieve 

9 and 16 tons per day of PM10 reductions in 2020 and 2030, respectively. This measure 

will be revised in future SIP revisions to reflect updated PM10 emission inventories and 

attainment demonstrations. 
Final 2003 AQMP 

6 - 14 

TABLE 6-4 

Motor Vehicle Emissions Budgets: PM10 * 

(Annual Average - Tons Per Day)

 2003 2006 

VOC Baseline EMFAC2002 315.8 263.8 

SCAG TCM Benefits 0.0 -8.5 

Adjusted Baseline EMFAC2002 315.8 255.3 

South Coast AQMD Rule 2202 -3.5 -2.6 

I/M Improvements -1.9 -2.6 

Adjusted Inventory 310.4 250.1 

New Defined State Measures 0.0 0.0 

New Local Measures 0.0 0.0 

Mobile Source Emission Budgets** 311 251 

 

 2003 2006 

NOx Baseline EMFAC2002 641.8 562.9 

SCAG TCM Benefits 0.0 -7.0 

Adjusted Baseline EMFAC2002 641.8 555.9 

South Coast AQMD Rule 2202 -4.1 -2.9 

I/M Improvements -2.8 -4.1 

Adjusted Inventory 634.9 548.9 

New Defined State Measures 0.0 0.0 

New Local Measures 0.0 0.0 

Mobile Source Emission Budgets** 635 549 

2003 2006 

PM10 Baseline EMFAC2002 18.9 19.9 

SCAG TCM Benefits 0.0 -0.6 

Adjusted Baseline EMFAC2002 18.9 19.3 

South Coast AQMD Rule 2202 -0.1 -0.1 

I/M Improvements 0.0 0.0 

Reentrained road dust (paved) 136.8 134.9 

Reentrained road dust (unpaved) 9.7 8.7 

Road Construction dust 2.2 2.2 

Adjusted Inventory 167.6 165.0 

New Defined State Measures 0.0 0.0 

New Local Measures 0.0 0.0 

Mobile Source Emission Budgets** 168 166 

* 2006 budget is applicable to all future years beyond 2006. 

** Rounded up to the nearest ton. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 15 

TABLE 6-5 

Motor Vehicle Emissions Budgets: Ozone 

(Summer Planning - Tons Per Day) 

2005 2008 2010 

VOC Baseline EMFAC2002 267.5 233.6 208.6 

SCAG TCM Benefits 0.0 -13.7 -15.7 

Adjusted Baseline EMFAC2002 267.5 219.9 192.8 

South Coast AQMD Rule 2202 -2.7 -2.1 -1.7 

I/M Improvements -2.7 -2.2 -1.9 

Adjusted Inventory 262.1 215.6 189.2 

New Defined State Measures 0.0 0.0 -34.2 

New Local Measures 0.0 0.0 0.0 

Mobile Source Emissions Budgets** 263 216 156 

 

2005 2008 2010 

NOx Baseline EMFAC2002 552.9 474.9 413.9 

SCAG TCM Benefits 0.0 -5.5 -7.8 

Adjusted Baseline EMFAC2002 552.9 469.4 406.0 

South Coast AQMD Rule 2202 -2.9 -2.3 -1.8 

I/M Improvements -4.2 -3.7 -3.4 

Adjusted Inventory 545.8 463.4 400.9 

New Defined State Measures 0.0 0.0 -37.4 

New Local Measures 0.0 0.0 0.0 

Mobile Source Emissions Budgets** 546 464 364 

 

** Rounded up to the nearest ton. 
Final 2003 AQMP 

6 - 16 

TABLE 6-6 

Motor Vehicle Emissions Budgets: Carbon Monoxide 

(Winter Planning - Tons Per Day) 

 2002 

CO Baseline EMFAC2002 3402.4 

SCAG TCM Benefits 0.0 

Adjusted Baseline EMFAC2002 3402.4 

South Coast AQMD Rule 2202 -41.9 

I/M Improvements 0.0 

Adjusted Inventory 3360.5 

New Defined State Measures 0.0 

New Local Measures 0.0 

 Mobile Source Emission Budgets** 3361 

** Rounded up to the nearest ton. 

TABLE 6-7 

Motor Vehicle Emissions Budgets: Nitrogen Dioxide * 

(Winter Planning - Tons Per Day) 

 2003 

NOx Baseline EMFAC2002 692.3 

SCAG TCM Benefits 0.0 

Adjusted Baseline EMFAC2002 692.3 

South Coast AQMD Rule 2202 -4.4 

I/M Improvements -2.8 

Adjusted Inventory 685.0 

New Defined State Measures 0.0 

New Local Measures 0.0 

 Mobile Source Emission Budgets** 686 

* 2003 budget applicable to future years, including the last year of 

maintenance plan (i.e., 2010). 

** Rounded up to the nearest ton. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 17 

CALIFORNIA CLEAN AIR ACT REQUIREMENTS 

The California Clean Air Act established a number of legal mandates to facilitate 

achieving health-based state air quality standards at the earliest practicable date. The 

following CCAA requirements are addressed in the remainder of this chapter: 

(1) Demonstrate the overall effectiveness of the air quality program; 

(2) Reduce nonattainment pollutants at a rate of five percent per year, or include 

all feasible measures and an expeditious adoption schedule; 

(3) Ensure no net increase in emissions from new or modified stationary sources; 

(4) Reduce population exposure to severe nonattainment pollutants according to 

a prescribed schedule; 

(5) Include any other feasible controls that can be implemented, or for which 

implementation can begin, within 10 years of adoption of the most recent air 

quality plan; and 

(6) Rank control measures by cost-effectiveness. 

Plan Effectiveness 

The CCAA requires, beginning on December 31, 1994 and every three years thereafter, 

that the District demonstrate the overall effectiveness of its air quality program [H&SC 

40924(b)]. Trends in the following air quality indicators are used to demonstrate the 

recent (i.e., for the three preceding years) effectiveness of the District’s program: 

(1) VOC, NOx, and carbon monoxide (CO) emissions; 

(2) ozone and CO exceedance days; and 

(3) ozone and CO population exposure. 

Trends in the Basin-wide annual average rate of reduction of VOC, NOx, and CO 

emissions since 1997 are shown in Chapter 3. Since 1997, emissions of VOC, NOx, and 

CO have decreased on an annual basis by five percent, three percent, and six percent, 

respectively. 

The number of days exceeding state standards in 1990 through 2001 for ozone, CO, and 

PM10 air quality is illustrated in Figure 6-2. Even over this relatively short time period, 

it is evident that air quality has improved in the Basin. Trends in NO2 air quality are not 

shown in Figure 6-3; however, improvement in air quality relative to that pollutant is 

also evident and the region has been redesignated to attainment for the state NO2 air 
Final 2003 AQMP 

6 - 18 

quality standard in 1996. The reader is referred to Appendix II for a more 

comprehensive discussion of local air quality trends. 

FIGURE 6-2 

Days Exceeding State Standards 

Trends in population exposure are shown in Table 6-8. Population exposure is a 

particularly good indicator of air quality trends since it takes into account spatial and 

temporal changes in air quality. For example, per-capita population exposure reflects 

the length of time the Basin population is exposed to unhealthful air quality. Table 6-8 

shows the per-capita exposure to ozone and CO for the historical period 1986-88 and for 

the years 1993, 1995, 1997, and 2000. The per-capita levels shown in the table represent 

average exposure above the state 1-hour standard levels for each pollutant. 

The table clearly shows that the per-capita exposure to ozone and CO has decreased 

dramatically since the 1986-88 period. The Basin is below the state 1-hour CO standard; 

therefore, the per-capita exposure to CO is zero. 

0

50

100

150

200

250

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Days Exceeding

Ozone CO PM10*

*PM10 is normally measured every sixth day so actual number of days could be six times higher for the entire period

2001
Chapter 6 Federal and State Clean Air Act Requirements

6 - 19 

TABLE 6-8 

Trends in Annual Average Per-Capita Exposure to Ozone and CO 

Based on 1-Hour Averages 

 Annual Average Per-Capita Exposure 

Period 

or Year 

Ozone 

(pphm-hrs) 

CO 

(ppm-hrs) 

1986-88 198.5 8.4 

1993 71.8 0.1 

1995 46.6 0.0 

1997 8.0 0.0 

2000 4.6 0.0 

In summary, the trends of all the indicators show improved air quality in the South Coast 

Air Basin; the population is being exposed to unhealthful air quality less and less each 

year. These air quality improvements are the direct result of AQMP implementation. 

Emission Reductions 

“Planning” inventories are developed to characterize emissions during periods when air 

quality standards are exceeded and to serve as the basis for emissions reduction 

accounting (see Chapter 3). The planning inventories are higher than the comparable 

annual average emission inventories; this difference is primarily due to seasonal 

temperature changes and the corresponding effects on pollutant emissions rates (e.g., 

higher solvent and gasoline evaporative emissions on hot summer days; more fuel 

combustion on cold days). 

The planning inventory 1990 baseline emissions and estimated emission reductions for 

the reporting years 1997, 2000, and 2003 is presented in Table 6-9. These estimates are 

based on the controlled emissions and the adoption and implementation schedules 

contained in Chapter 7. As seen in the table, the proposed control strategy falls short of 

the CCAA emission reduction goals (i.e., five percent per year for all nonattainment 

pollutants) even with the implementation of maximum feasible controls and an 

expeditious adoption schedule. Nonetheless, the strategy represents “all feasible control 

measures” and an “expeditious adoption schedule” as permitted under H&S Code 40914. 
Final 2003 AQMP 

6 - 20 

TABLE 6-9 

Summary of 2003 AQMP Emissions Based on Planning Inventory Emissions (tons/day)* 

 Summer Ozone Inventory Winter CO 

Inventory 

Year VOC NOx CO 

1990 Baseline 1,870 1,546 10,329 

Emission Reductions 

 1997 648 (35%) 381 (25%) 3,869 (37%) 

CCAA 

Requirement 

 (35%) (35%) (35%) 

 2000 823 (44%) 393 (25%) 4,729 (46%) 

CCAA 

Requirement 

 (50%) (50%) (50%) 

2003 1,024 (55%) 517 (33%) 5,802 (56%) 

CCAA 

Requirement 

 (65%) (65%) (65%)

*Emission reductions are estimated as the 1990 equivalent. Percent reductions from 1990 

baseline are shown in parenthesis. 

Population Exposure 

The CCAA also requires a reduction in overall population exposure to criteria pollutants. 

Specifically, exposure to severe nonattainment pollutants above standards must be 

reduced by at least: 

(1) 25 percent by December 31, 1994; 

(2) 40 percent by December 31, 1997; and 

(3) 50 percent by December 31, 2000. 

Reductions are to be calculated based on per-capita exposure and the severity of 

exceedances. This provision is applicable to ozone, CO and NO2 in the Basin [H&S 

Code 40920(c)]. The definition of exposure is the number of persons exposed to a 

specific pollutant concentration level above the state standard times the number of hours 

exposed. The per-capita exposure is the population exposure (units of pphm-personshours) divided by the total population. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 21 

The Regional Human Exposure (REHEX) model is used to estimate per-capita exposure 

reduction. It considers population mobility; time spent indoors, outdoors and in transit; 

exposure by age classification; and activity pattern by season and weekday/weekend. 

Ozone

An analysis using the REHEX model indicates that the CCA Amendments exposure 

reduction targets have been achieved for ozone with a margin of safety. Figure 6-3 

summarizes the results and compares exposure reductions to the targets. 

The REHEX model also allows more detailed exposure reduction estimates 

disaggregated by age group and county. These results are summarized in Figures 6-4 

and 6-5, respectively. As shown, the greatest exposure reduction for an individual age 

class is for children, who have longer exposure to outdoor concentrations; the 

geographic location with the most improvement for all age groups is that comprised of 

the two inland counties. 

FIGURE 6-3 

Percent Reductions in Annual Average Per-Capita Exposure to Ozone 

0

10

20

30

40

50

60

70

80

90

100

Year

Percent Reduction

0

10

20

30

40

50

60

70

80

90

100

1997 2000

CAA Requirements REHEX
Final 2003 AQMP 

6 - 22 

FIGURE 6-4 

Per-Capita Ozone Exposure Above the State Standard by Age Group 

FIGURE 6-5 

Per-Capita Ozone Exposure Above the State Standard by County 

0

1

2

3

4

5

6

7

8

9

10

All Ages Children Adolescents Adults

Hours

1997 2000

0

5

10

15

20

25

30

Basin Los Angeles Orange Riverside San Bernardino

Hours

1997 2000
Chapter 6 Federal and State Clean Air Act Requirements

6 - 23 

Carbon Monoxide

As discussed in Chapter 5 and in Appendix V, the 1-hour and 8-hour CO standards have 

been met. Therefore, the Basin population will not be exposed to unhealthful CO levels 

and thus per capita exposure is reduced 100 percent from the 1986-88 base levels. 

Cost Effectiveness Ranking 

The CCAA requires the District Governing Board to determine that the AQMP is a costeffective strategy that will achieve attainment of the state standards by the earliest 

practicable date [H&SC 40913(b)]. In addition, the Plan must include an assessment of 

the cost-effectiveness of available and proposed measures and a list of the measures 

ranked from the least cost-effective to the most cost-effective [H&SC 40922]. 

Table 6-10 and Table 6-11 provide a listing of the control measures that have available 

cost information for stationary and mobile source measures, respectively. The costeffectiveness for stationary source measures ranges from $2,000 to as high as $20,100 

per ton of pollutant reduced. Two methods are used to calculate the cost-effectiveness of 

the mobile source measures. The CARB transmitted the cost-effectiveness values for the 

mobile source measures based on incremental cost analyses, published reports and other 

internal methods. However, the District uses the Discount Cash Flow method in its 

calculations, as it has since the 1987 AQMP. The Discount Cash Flow method is more 

versatile in analyzing complex financial cash flows and is the most widely used cost 

methodology by major businesses. The proposed implementation schedule for these 

measures is provided in Chapter 7 and is based on this information and other relevant 

factors. 
Final 2003 AQMP 

6 - 24 

TABLE 6-10 

Cost-Effectiveness Ranking of District’s Stationary Source Control Measures a

Measure 

Number 

Description Dollars/Ton Ranking by 

Cost 

Effectiveness 

BCM-08 Further Emission Reductions from Aggregate 

and Cement Manufacturing Operations 

$700 1 

WST-01 Emission Reductions from Livestock Waste 

(PR1127) 

$2,000 - $7,000 2 

CMB-09 Emission Reductions from Petroleum Fluid 

Catalytic Cracking Units (PR1105.1) 

$3,500 - $11,500 3 

MSC-05 Truck Stop Electrification $5,000 4 

CMB-10 Additional Reductions for NOx RECALIM $7,000 5 

WST-02 Emission Reductions from Compositing (R1133, 

1133.1, 1133.2) b $10,000 c 6 

CTS-10 Miscellaneous Industrial Coatings and Solvents < $13,500 7 

FUG-05 Emission Reductions from Fugitive Sources < $13,500 7 

PRC-07 Industrial Process Operations < $13,500 7 

PRC-03 Emission Reductions from Restaurant Operations $14,500 8 

CTS-07 Further Emission Reductions from Architectural 

Coatings (R1113) 

< $20,000 9 

a

 The cost-effectiveness values of these measures are based on the Discount Cash Flow methodology and four percent real interest

rate. 

b

 Control Measure WST-02 was adopted January 10, 2003 as Rule 1133 - Composting and Related Operations – General 

Administrative Requirements, Rule 1133.1 Chipping and Grinding Activities, and Rule 1133.2 - Emission Reduction From CoComposting Operations. 

c

 Cost-effectiveness based on VOC and NH3 reductions combined. 
Chapter 6 Federal and State Clean Air Act Requirements

6 - 25 

TABLE 6-11 

Cost-Effectiveness Ranking of State Control Measures* 

Measure Number Current Title Old Measure 

Number 

CE Ratio $/ton 

HC+NOx 

Ranking 

by CE 

SMALL OFF-RD-2 Set Lower Emission Standards for New NonHandheld Lawn and Garden Equipment – Like 

Lawnmowers [Spark-Ignition Engines Under 

25 hp]. 

 1,100 1 

SMALL OFF-RD-1 Set Lower Emission Standards for New 

Handheld Lawn and Garden Equipment – Like 

Weed Trimmers, Leaf Blowers, and Chain 

Saws [Spark-Ignition Engines Under 25 hp]. 

 1,600 2 

OFF-RD LSI-1 Set Lower Emission Standards for New OffRoad Gas Engines [Spark-Ignition Engines 25 

hp and Greater]. 

 2,100 3 

ON-RD HVYDUTY-3 Pursue Approaches to Clean Up the Existing 

and New Truck/Bus Fleet. 

 2,200 4 

MARINE-1 Pursue Approaches to Clean Up the Existing 

Harbor Craft Fleet – Cleaner Engines and 

Fuels. 

MARINE-2 2,600 5 

ON-RD HVYDUTY-1 Augment Truck and Bus Highway Inspections 

with Community-Based Inspections. 

 3,000 6 

OFF-RD LSI-2 Clean Up Existing Off-Road Gas Equipment 

Through Retrofit Controls [Spark-Ignition 

Engines 25 hp and Greater] 

 3,000 6 

LT/MED-DUTY-2 Improve Smog Check to Reduce Emissions 

from Existing Passenger and Cargo Vehicles. 

 3,200 7 

ON-RD HVYDUTY-2 Capture and Control Vapors from Gasoline 

Cargo Tankers. 

 4,000 8 

FVR-1 Increase Recovery of Fuel Vapors from 

Aboveground Storage Tanks. 

 4,000 8 

FVR-3 Reduce Fuel Permeation Through Gasoline 

Dispenser Hoses. 

 4,000 8 

CONS-1 Set New Consumer Products Limits for 2006. 4,480 9 

CONS-2 Set New Consumer Products Limits for 2008-

2010. 

 4,480 9 

OFF-RD LSI-3 Require Zero Emission Forklifts Where 

Feasible – Lift Capacity <8,000lbs]. 

 7,500 10 

FVR-2 Recover Fuel Vapors from Gasoline 

Dispensing at Marinas. 

 8,000 11 

OFF-RD CI-1 Pursue Approaches to Clean Up the Existing 

Off-Road Equipment Fleet [Compression 

Ignition Engines]. 

OFF-RD CI-2 21,000 12 

LT/MED-DUTY-1 Replace or Upgrade Emission Control Systems 

on Existing Passenger Vehicles – Pilot 

Program. 

 22,000 13 

* Cost-effectiveness provided by CARB.