EXECUTIVE SUMMARY

Introduction

Why Is This Plan Being Prepared?

What Is New in This Plan Revision?

How Was This Plan Revision Prepared?

Is Air Quality Improving?

What Are the Applicable Key Federal and State Requirements that 

This Plan Revision Addresses?

How Has the Emissions Inventory Changed?

Has the Overall Control Strategy Changed Significantly?

What Conditions Have Changed to Reflect Attainment of Both 

Ozone and PM10 Standards?

What Other Requirements Are Addressed in This Plan?

What Happened to the Federal Implementation Plan?

What Considerations Have Been Made for Possible New Federal 

Standards for Particulate Matter and Ozone?

Has the Attainment Projection Changed for Federal or

State Standards?
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INTRODUCTION

Air quality in Southern California continues to improve, with 1995 registering some of 

the lowest levels in decades. Yet Southern California still experiences the worst air 

quality in the nation requiring continued diligence to meet air quality standards. 

Continuing the progress toward clean air is a challenging task, not only to recognize and 

understand complex interactions between emissions and resulting air quality, but also to 

pursue the best possible set of strategies to improve air quality while maintaining a 

healthy economy. This 1997 Air Quality Management Plan (AQMP or Plan) is based on 

the 1994 AQMP, and carries forward most of the innovative strategies crafted in that 

Plan. The current AQMP places a greater focus on particulate matter (PM10), since this 

is the first plan required by federal law to demonstrate attainment of the federal PM10

ambient air quality standards. The Plan also updates the demonstration of attainment for 

ozone and carbon monoxide, and includes a maintenance plan for nitrogen dioxide 

(NO2), as the South Coast Air Basin (Basin) now qualifies for attainment of that federal 

standard.

The 1997 AQMP proposes policies and measures to achieve federal and state standards 

for healthful air quality in the Basin and those portions of the Mojave Desert and Salton 

Sea Air Basins (formerly named the Southeast Desert Air Basin) that are under South 

Coast Air Quality Management District (District) jurisdiction (namely, Antelope Valley 

and Coachella Valley). The Antelope Valley will remain under the District’s jurisdiction 

until June 30, 1997. The Coachella Valley PM10 Plan is being prepared as a separate 

document, however, as that area is now the first PM10 serious nonattainment area to 

qualify for redesignation to attainment of the federal PM10 standards.

This revision to the Plan also addresses several state and federal planning requirements 

and incorporates significant new scientific data, primarily in the form of updated 

emissions inventories, ambient measurements, and new models. This Plan is consistent 

with the approaches taken in the 1994 AQMP for the attainment of the federal ozone air 

quality standard, and shows that with refinements to the 1994 AQMP control strategy, 

sufficient emission reductions are achieved to meet all federal criteria pollutant standards 

within the time frames allowed under the federal Clean Air Act.

Some notable regulatory actions have occurred since the 1994 AQMP, all of which have 

been accounted for in this Plan. These include new or amended rules which have been 

adopted since the release of the 1994 AQMP; the implementation of Phase II 

reformulated fuels (California Cleaner Burning Gasoline) in 1996; the replacement of 

the Regulation XV rideshare program with an equivalent emission reduction program 

under Rule 2202; and new incentive programs for generating emission credits. In 

keeping up with advancing computerized communications, the District has established a 

home page on the Internet (http://www.aqmd.gov) where key information can be 
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browsed and downloaded. For the first time, this Plan is being made available via the 

Internet. In the future, the District plans to expand its services by offering electronic 

permit application processing.

WHY IS THIS PLAN BEING PREPARED?

The 1990 Clean Air Act (CAA) established deadlines for PM10 SIP submittals. In 

February, 1993, the U. S. Environmental Protection Agency (U.S. EPA) reclassified the 

South Coast Air Basin and Coachella Valley as “serious” nonattainment areas for PM10. 

The CAA specified that four years from that reclassification date, a PM10 SIP must be 

submitted to U.S. EPA, and that submittal must demonstrate attainment of both the 24-

hour and annual average PM10 ambient air quality standards by 2006 -- the latest date 

allowed under the act. This Plan is being prepared to meet that submittal deadline. 

In addition, under state law, a comprehensive AQMP must also be prepared every three 

years, the next being due in 1997. Because there are key linkages between two criteria 

pollutants -- ozone and PM10 -- this AQMP integrates the technical and policy issues of 

both pollutants. The 1997 AQMP therefore satisfies both state and federal requirements 

for plan submittals.

WHAT IS NEW IN THIS PLAN REVISION?

Each revision of the AQMP represents a snapshot in time, based on best available 

information. The 1997 AQMP generally is very similar to the structure of the 1994 Plan 

but like all new editions includes significant enhancements. Key new elements are: 

 Use of the most current air quality information (1995), including special 

particulate matter data from the PM10 Technical Enhancement Program (PTEP);

 Improved emissions inventories; especially for motor vehicles, fugitive dust, and 

ammonia sources;

 A similar, but fine-tuned overall control strategy with continuing emphasis on 

flexible, alternative approaches including intercredit trading;

 A determination that certain control measures contained in the 1994 AQMP, are 

infeasible, most notably the future indirect source measures;

 Enhanced modeling for particulates;
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 Separate analyses for the desert portions within the District’s jurisdiction: the 

Coachella Valley within the Salton Sea Air Basin; and the Antelope Valley 

within the Mojave Desert Air Basin. (Note: these desert areas were formerly 

referred to as the Southeast Desert Air Basin);

 Amendments to the federal Post-1996 Rate-of-Progress Plan and the Federal 

Attainment Plans for ozone and carbon monoxide; 

 A Maintenance Plan for nitrogen dioxide; and

 An attainment demonstration and State Implementation Plan Revision for PM10.

HOW WAS THIS PLAN REVISION PREPARED?

This AQMP Revision was developed based on input and participation of numerous 

individuals and groups since the adoption of the 1994 AQMP. In particular, as part of its 

actions on the 1994 Plan, the District Governing Board formed a PM10 Task Force to 

“oversee the expeditious development of a PM10 Attainment Plan consistent with 

requirements established in state and federal law.” That Task Force, with a membership 

of 56 individuals representing business, industry, government, academia, and 

environmental groups, has convened at least once a month since its inception in June 

1995.

To help provide important technical and scientific data to support the development of the 

PM10 Plan, the Governing Board in December 1994 established the PM10 Technical 

Enhancement Program (PTEP), a cooperative study designed to provide new ambient 

data for particulates, improved emissions inventories, and improved models to predict 

future levels of particulates. That program, jointly funded by the District, U.S. EPA, City 

of Los Angeles, County Sanitation Districts of Los Angeles, Western States Petroleum 

Association, Southern California Gas Company, CalMat, and Southern California Rock 

Products Association, successfully delivered critical new information which was directly 

input to this Plan.

The District and the Southern California Association of Governments (SCAG) sponsored 

several other plan-related task forces and working groups. In addition, public comments 

were received in response to public workshops and consultation meetings held in January 

1996 (control measures), May 1996 (modeling), and June 1996 (emissions inventories). 

Regional public workshops were conducted in September 1996 and regional public 

hearings are being held in October 1996 to seek inputs on the draft AQMP.

In preparing this Plan, the District coordinated closely with both SCAG, The Southern 

California Economic Partnership (The Partnership) and the California Air Resources 
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Board (ARB), as well as the U.S. EPA. SCAG has the primary responsibility for 

providing future growth projections and the development of transportation control 

measures; The Partnership has the responsibility for the coordination of market based 

Advanced Transportation Technology (ATT) implementation strategies and market 

growth indicators; ARB has the primary responsibility for the development of mobile 

source emissions inventories as well as mobile source and consumer product control 

measures. Their inputs are included in this Plan. Also, the U.S. EPA provided 

information on the status of the control efforts for federally regulated sources, and has 

initiated a public consultation process to further that effort.

IS AIR QUALITY IMPROVING?

Yes. Air quality levels continue to show improvement. In 1995, for example, ozone 

levels peaked at 0.26 parts per million -- the lowest such level since the District was 

established. There were only 14 Stage I ozone episodes, also the lowest number since 

the episode program was initiated by the ARB in the 1970s. Nitrogen dioxide met the 

federal standards for the third year in a row, thereby qualifying the Basin for 

redesignation to attainment for that pollutant. (A maintenance plan for nitrogen dioxide 

is included in this Plan to satisfy one of the federal requirements needed for 

redesignation to attainment.) Annual average PM10 levels are nearly 25 percent lower 

than a decade ago at the highest PM10 site in the Metropolitan Riverside County Area.

In 1995, the federal air quality standard for ozone was exceeded at one or more locations 

in the Basin on 98 days. While this is the lowest number of days since recordkeeping 

began, it still is more frequent than any other area of the nation. Federal 24-hour 

standards for PM10 were exceeded on 7 percent of the days sampled, while carbon 

monoxide exceeded federal standards on only 4 percent of the days. Figure ES-1 shows 

the 1995 maximum air pollutant concentrations in the South Coast Air Basin as a 

percentage of air quality standards.

WHAT ARE THE APPLICABLE KEY FEDERAL AND STATE 

REQUIREMENTS THAT THIS PLAN REVISION ADDRESSES?

Federal

In November 1990, Congress enacted a series of amendments to the Clean Air Act 

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

goals of the 1990 amendments to the Clean Air Act (CAA) was an overhaul of the 

planning provisions for those areas not currently meeting National Ambient Air Quality 

Standards (NAAQS). The CAA identifies specific emission reduction goals, requires 
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both a demonstration of reasonable further progress and attainment, and incorporates 

more stringent sanctions for failure to attain or to meet interim milestones. 

0

50

100

150

200

250

300

Ozone

(1-Hour)

Carbon

Monoxide

(8-Hour)

Nitrogen

Dioxide

 (1-Hour/

Annual)

Sulfur

Dioxide

 (1-Hour/

Annual)

PM10

(Annual)

Sulfate*

 (24-Hour)

Lead**

(Month/

Quarter)

State Standard

Federal Standard

Percent of Standard

Standard

* There is no federal standard for sulfate.

FIGURE ES-1

1995 Maximum Pollutant Concentrations in the South Coast Air Basin

The CAA requires the District to develop: (1) a Federal Attainment Plan for PM10 as 

required by Section 189(b)(2), and (2) a post-1996 Rate-of-Progress Plan as required in 

Section 182(c)(2)(B). In addition, any revisions to previous demonstrations of 

attainment must be resubmitted to U.S. EPA. For the Plan, this includes the ozone and 

carbon monoxide demonstrations for the Basin, and ozone demonstrations for the Los 

Angeles county portion of the Mojave Desert Air Basin (Antelope Valley), and for the 

Riverside nonattainment area of the Salton Sea Air Basin (Coachella - San Jacinto 

Planning Area).

State

The California Clean Air Act (CCAA) was signed into law on September 30, 1988. 

Through its many requirements, the CCAA serves as an important consideration in the 

Basin’s attainment planning efforts.
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Key CCAA requirements that the District must address in the 1997 AQMP are to: apply 

Best Available Retrofit Control Technology; reduce nonattainment pollutants and their 

precursors at a rate of five percent per year, or, if this cannot be done, include all feasible 

measures and an expeditious implementation schedule; reduce population exposure to 

severe nonattainment pollutants (i.e., ozone, carbon monoxide, and nitrogen dioxide for 

the Basin) according to a prescribed schedule; and, rank control measures by costeffectiveness and implementation priority. Additionally, state law requires market-based 

programs proposed as part of the attainment strategy to meet specific design 

requirements. As a result of recent legislation (SB 772, chaptered in 1995), the District 

is now prohibited from enforcing rules requiring employee trip reduction plans. 

However, the District is pursuing equivalent emissions reductions with Rule 2202, 

adopted in 1995, and through the efforts of the REACH (Reduce Emissions And 

Congestion on Highways) Task Force, which has developed several approaches for 

further analysis. Finally, state law requires the plan to provide for attainment of the 

federal and state ambient air quality standards at the earliest practicable date (Health & 

Safety Code Section 40462).

HOW HAS THE EMISSIONS INVENTORY CHANGED?

For this Plan Revision, a 1993 emissions inventory is relied upon to establish baseline 

and future year projections. The inventories were developed according to procedures 

stemming from the Federal Clean Air Act. To meet state and federal law requirements, 

updated 1987 and 1990 emissions inventories are also provided. 

The 1993 emissions inventory now represents the most comprehensive emissions 

inventory ever established for the South Coast Air Basin. Key area source emissions 

were revised for solvent usage categories, fugitive dust, and ammonia sources. On-road 

mobile sources are estimated with the latest approved emissions factors supplied by the 

ARB using EMFAC7G. An updated marine vessels inventory was prepared as part of 

this plan development.

Using the 1993 emissions inventory, future emission forecasts are also developed. These 

forecasts reflect demographic and economic growth forecasts by SCAG. In addition, 

emission reductions resulting from ARB and District regulations adopted by September 

1996 are included in the forecasts.

HAS THE OVERALL CONTROL STRATEGY CHANGED

SIGNIFICANTLY?

No. The basic control strategy remains essentially the same as that adopted in the 1994 

AQMP. However, there are some refinements proposed with this revision. At the time 
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of adoption of the 1994 Plan, two aspects of the AQMP were considered: (1) the control 

measures needed to meet federal CAA requirements for the attainment of the ozone 

standards (referred to as “1994 CA-SIP measures”), and (2) additional control measures 

needed to meet the federal PM10 standards (referred to as “1994 AQMP measures.”) 

Because there was no federal requirement at that time to demonstrate PM10 attainment in 

the 1994 Plan (although it is a federal requirement for the 1997 Plan), those additional 

measures over and above the 1994 CA-SIP measures were not submitted to U.S. EPA as 

a revision to the State Implementation Plan.

With a few exceptions, it has now been determined that the basic strategy contained 

within the 1994 CA-SIP measures are sufficient to demonstrate attainment of both the 

ozone and PM10 federal standards. The notable changes to the control strategy include: 

(1) removal of the future indirect source measures (ISRs); (2) less reliance on 

Transportation Control Measures (TCMs) and on long-term future technologies as 

allowed under Section 182(e)(5) of the CAA; and (3) removal of some otherwise 

infeasible control measures.

WHAT CONDITIONS HAVE CHANGED TO REFLECT ATTAINMENT OF 

BOTH OZONE AND PM10 STANDARDS?

Since the adoption of the 1994 Plan, the District has embarked on a cooperative study to 

gain new information on particulates. Described earlier, the PTEP study has provided 

the District with a wealth of important information which has significantly improved the 

ability to predict future levels of PM10. In particular, these studies have shown that: (1) 

fugitive dust emissions are considerably lower (e.g., less than half) of the previous 

estimates; (2) ammonia emissions from dairy farms in the Chino area, which play a key 

role in the formation of ammonium nitrate PM10, are about one-fourth as high as 

previously estimated; (3) ambient levels of PM10 in the Basin are now approximately 20 

percent lower than those used in the 1994 AQMP (new 1995 data versus previously used 

1986 data); and (4) new modeling tools are able to simulate future year particulate levels 

more reliably than in the past.

With the new data and tools, it can now be determined that fewer additional reductions in 

emissions are needed to meet the federal ambient air quality standards by the statutory 

deadline of 2006, and that there is greater confidence than in the past on these results. 

For ozone, based on discussions with ARB and following the recommendations from the 

U.S. EPA and ARB modeling guidelines, of the five modeling episodes, the June 1985 

meteorological episode was dropped from the 1997 AQMP analysis. The 1985 episode 

is the oldest episode used for modeling and represented extreme meteorological 

conditions. Federal air quality standards allow for the exclusion of the highest measured 
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ozone day by allowing on average one exceedance each year or three exceedances over 

three years without causing a violation of the ozone air quality standard.

WHAT OTHER REQUIREMENTS ARE ADDRESSED IN THIS PLAN?

The 1990 Federal Clean Air Act Amendments require the development of near-term and 

long-term transportation control measures (TCMs) as well as contingency measures. The 

federal Clean Air Act requires that both “near-term” and “long-term” TCMs be 

developed for the Basin. Near-term measures must be implemented before the year 

2000, and are primarily defined as transportation improvements as contained in the 

Regional Mobility Element (RME) as provided by SCAG. Long-term measures are to be 

implemented post 2000, and are included in the Advanced Transportation Technology 

Incentive Measures.

Under federal conformity regulations, all federal or federally funded projects must 

conform to the SIP, and must not be a cause of impeding progress toward attainment of 

the federal standards. To establish conformity, emissions from future projects must be 

accounted for in the future baseline emissions inventories, such that the attainment 

demonstrations include these future emissions. For transportation projects, planning is 

now underway out to the year 2020. To establish conformity for those outyear projects, 

the 2010 emissions budget provided in this Plan serves as the emissions budget beyond 

2010. For information purposes only, the Plan also includes an analysis for the year 

2020. The analysis indicates that continued reductions in emissions due to such factors 

as continuing fleet turnovers to low and zero emitting vehicles will counteract growthrelated emissions increases, such that attainment of the standard is maintained from 2010 

to 2020.

WHAT HAPPENED TO THE FEDERAL IMPLEMENTATION PLAN?

In 1995, the U.S. EPA Administrator signed the Federal Implementation Plan (FIP) for 

the South Coast, Ventura, and Sacramento regions. The FIP was prepared under court 

order in response to legal challenges to an earlier AQMP.

Subsequent to the 1994 AQMP, the U.S. Congress rescinded the California FIP. 

However, in approving the CA-SIP measures and the local measures contained in the 

1994 AQMP, the U.S. EPA established a consultative process to evaluate the assignment 

of emission reductions to federal transportation sources. That consultative process 

would be completed in 1997. In the event that the expected emission reductions from 

federal sources are not realized, then a revised ozone attainment demonstration would be 

developed by the end of 1997.
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WHAT CONSIDERATIONS HAVE BEEN MADE FOR POSSIBLE NEW 

FEDERAL STANDARDS FOR PARTICULATE MATTER AND OZONE?

In light of new epidemiological and other health data, the U.S. EPA is currently 

reevaluating the federal standards for particulate matter and ozone. At this time it is 

highly probable that new standards will be promulgated in 1997. For ozone, it is likely 

that the current 1-hour standard will be replaced by an 8-hour standard. For particulate 

matter, it is likely that a new fine particulate standard (PM2.5) will be established for both 

a short-term (24-hour) and long-term (annual) averaging period. It is also probable that a 

form of the current PM10 standards will be retained.

This Plan does not have to address these possible future standards. Forthcoming U.S. 

EPA policies will establish the timelines, as required under the CAA, to meet any new 

standards. However, the District is cognizant of these developments, and, as part of the 

air quality modeling, is providing comparative information regarding the current 

attainment strategies relative to the potential new standards. Generally, this assessment 

shows that the new standards, if promulgated, will be more restrictive than the current 

standards.

HAS THE ATTAINMENT PROJECTION CHANGED FOR FEDERAL OR 

STATE STANDARDS?

No. The 1997 AQMP proposes to attain the state and federal standards in the same time 

frame as proposed in the 1994 AQMP. (See Figure ES-2.)
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FIGURE ES-2

Attainment Target Dates

NO2

CO

PM10

Ozone

Federal

Met

2000

2006

2010

Met

2000

post-2010

post-2010

State
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