## State of California

Staff Report



# Analysis of the South Coast Air Basin PM10 Redesignation Request, Maintenance Plan, and Conformity Budgets

Release Date: February 22, 2010 Scheduled for Consideration: March 25, 2010 California Environmental Protection Agency



# AIR RESOURCES BOARDThis document has been reviewed by the staf f of the California Air Resources Board and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Air Res ources Board, nor does the mention of trade names or commercial products constitute endorsement or recommendation for use.i February 22, 2010 TABLE OF CONTENTS

EXECUTIVE SU MMARY ................................................................................................ 1

I. BACKGRO UND...................................................................................................... 3

II. REDESIGNATION RE QUIREMEN TS .................................................................... 4

III. EVALUATION OF THE SOUTH COAST AIR BAS IN PLAN ................................. 4
A. The South Coast Air Basin Atta ins the 24-Hour PM10 Standar d....................... 4
B. U.S. EPA Approved the South Coast Ai r Basin PM10 SIP and the State Has Met Applicable Act Requirem ents........................................................................... 6 C. Improvement in the South Coast Air Basin PM10 Air Quality is Due to
Permanent and Enforceable Reduct ions in Em issions ........................................... 6
D. Maintenance Plan.............................................................................................. 6

1. Attainment Emissi on Invent ory...................................................................... 6
2. Maintenance Dem onstration.......................................................................... 7
3. PM10 Monitoring Network ............................................................................. 8

4. Verification of C ontinued Atta inment ............................................................. 8

5. Contingenc y Plan .......................................................................................... 8
6. Transportation Confor mity Budgets............................................................... 8

IV. STAFF RECO MMENDATION .............................................................................. 101 February 22, 2010 EXECUTIVE SUMMARY

Background

The South Coast Air Basin (South Coast) is currently designated as a serious
nonattainment area for the 24-hour national ambient air quality standard (NAAQS or standard) for particulate matter of 10 microns in diameter or smalle r (PM10). The South Coast Air Quality Management District (Distric t) adopted the first PM 10 attainment plan for the South Coast in 1991. The plan focuse d on fugitive dust as the primary control strategy for attaining the national 24- hour and the annual PM10 standards. The 1997 plan revision requested extension of the atta inment date to 2006. This revision was approved by the United States Environmental Protection Agen cy (U.S. EPA). In various plan revisions, the District adopted increas ingly stringent dust measures. The 2003 plan revision added control measures to re duce emissions of particulate matter precursors. Adoption of District controls in the South Coast resulted in this area attaining the 24-hour PM10 standard by the 2006 attainment date.

On January 8, 2010, the District adopted the PM10 Redesignation Request and Maintenance Plan for the South Coast (S outh Coast PM10 Maintenance Plan). The plan officially requests this area be redesig nated to attainment for the PM10 standard
and charts the course for conti nued maintenance of the standard.

Shortly before plan adoption, the District developed revised transportation conformity budgets (budgets) for the Main tenance Plan based on U.S. EPA comments that the budgets only include emission reductions from adopted control measures. Because transportation conformity budgets are subjec t to a 30-day public notice requirement, ARB staff has posted the revised budgets to provide for the required public review period. ARB staff proposes adoption of t he updated budgets for the South Coast.

Maintenance Plans Address Act Requirements

The South Coast PM10 Maintenance Plan includes the follo wing components:

• Attainment emission inventories for di rectly emitted PM10 and for particulate matter precursor gases (NOx, SOx, and ROG);

• Demonstration that PM10 attainment concentrations at federal reference monitoring stations will be maintained for ten years after redesignation;

• Commitment to ongoing monitoring network operation for continued verification of attainment; and

• Contingency provisions to address any future violations.

In addition, eight years after the area is redesignated as attainment, the District will
submit a revised South Coast PM10 Main tenance Plan providing for continued attainment for an additional ten years.2 February 22, 2010 Staff Recommendation

Air Resources Board (ARB) staff concur s with the District’s PM10 Redesignation Request and Maintenance Plan fo r the South Coast Air Basin. ARB staff recommends that the Board approve the District’s Sout h Coast PM10 Maintenance Plan, including the updated conformity budgets, as a revision to the California St ate Implementation
Plan for submittal to U.S. EPA. In additi on, ARB staff recomm ends that the Board approve the District’s request that the S outh Coast Air Basin be redesignated from
nonattainment to attainment fo r the national PM10 standard.3 February 22, 2010 I. BACKGROUND

The South Coast Air Basin (South Coast) is designated as a serious nonattainment area
for the 24-hour PM10 national ambient air quality standard (NAAQS or standard). The area is under the jurisdiction of the S outh Coast Air Qualit y Management District (District). In 1987, the Un ited States Environmental Pr otection Agency (U.S. EPA) adopted the PM10 NAAQS consisting of a 24-hour PM10 standard of 150 micrograms per cubic meter (μg/m 3 ) and an annual standard of 50 μg/m 3 . Effective December 18, 2006, U.S. EPA revoked the annual portion of the PM10 standard.

PM10 is a complex mixture of primary or directly emitted particles (dust and soot), and secondary particles or aerosol droplets form ed in the atmosphere from precursor gases (NOx, SOx, ROG, and ammonia) . PM10 includes the subset s of fine particles with a
diameter of 2.5 microns or less (PM2.5) and of coarse part icles with a diameter between 2.5 and 10 microns. Secondary particles are found mostly in the PM2.5 portion of
PM10.

In the South Coast, currently, the fine fracti on contributes approximately 56 percent and the coarse fraction 44 percent of the average peak PM10 concentrations. Dust is the main component of the coarse fraction in this area.

The District adopted the first PM10 Plan for the South Coast in 1991. This plan focused on a fugitive dust control strategy for attaining the national 24-hour and annual PM10 standards. Control measures were adopted to address fugitive dust emissions from paved and unpaved roads, agricultural activities, construction and demolition activities, and open area wind erosion. The District su bsequently adopted Plan re visions in 1994, 1997, and 2003 providing dust control enha ncements. The 2002 plan revision requested an extension of the PM10 attainment date to 2006. In addition to including control measures for directly emitted PM10, the 2003 Plan revision in cluded controls for gaseous precursors of PM10. The 2007 revisions to the District’s Air Quality Management Plan (AQMP) included an attainm ent demonstration showing continuous
attainment of the standar d through 2020.

On January 8, 2010, the District adopted the PM10 Redesignation Request and Maintenance Plan for the South Coast. The pl an officially requests that the South Coast be redesignated to attainment for the PM10 standard and charts the course for
continued maintenance of the standard through 2030.

Shortly before plan adoption, the District developed revised transportation conformity budgets (budgets) for the Main tenance Plan based on U.S. EPA comments that the budgets only include emission reductions from adopted control measures. Because transportation conformity budgets are subjec t to a 30-day public notice requirement, ARB staff has posted the revised budgets to provide for the required public review period. ARB staff proposes adoption of t he updated budgets for the South Coast.4 February 22, 2010 II. REDESIGNATION REQUIREMENTS

ARB staff reviewed the South Coast PM10 Maintenance Plan within the context of the Clean Air Act (Act), which identifies the fo llowing requirements each area must meet to be redesignated to attainment:

A. The PM10 standard has been attained; B. The District has an approved State Impl ementation Plan (SIP) and the State has met all applicable Act requirements fo r PM10 in the nonattainment area; C. The improvement in PM10 air qualit y is due to permanent and enforceable emission reductions; and D. U.S. EPA has approved a maintenance plan.

The Act also sets the general framework for maintenance plans 1 . Each PM10 maintenance plan must provide for conti nued maintenance of the PM10 standard for ten years after redesignation and in cludes the following components:

1. Attainment emission inventory; 2. Maintenance demonstration;
3. Commitment to continue the monitoring network operation; 4. Commitment for verification of continued attainment; and 5. Contingency plan to promptly correc t any violation of the PM10 NAAQS that occurs after the area has been redesignated.

III. EVALUATION OF THE SOUTH COAST AIR BASIN PLAN

Based on review of the South Coast PM 10 Maintenance Plan and the District’s supporting technical analysis, AR B staff concurs that the Pl an meets the requirements. The following sections describe the major elements of the Plan and the redesignation request.

A. The South Coast Air Basin A ttains the 24-Hour PM10 Standard

In the South Coast, PM10 concentrations ar e measured at nineteen federal reference monitors (FRMs) that collect PM10 sa mples on a 24-hour basis and ten real-time monitors that collect PM10 samples on an hour ly basis (Figure 1). Table 1 lists air quality data for the three-year period of 2005-2007 for the FR Ms demonstrating that the
South Coast attains the 24-hour PM10 standar d. The 24-hour standard is met when the
estimated number of exceedances measured over a three year period averages one or less per year.

1 Calcagni, John, Memorandum, Procedures for Processing Requests to Redesignate Areas to Attainment, Office of Air Quality Planning and Standards , Research Triangle Park, North Carolina, September 4, 1992. http://www.epa.gov/ttn/oarpg/t5 /memoranda/rede signmem090492.pdf5 February 22, 2010 Figure 1. PM10 Monitori ng Stations in the South Coast Air Basin

Table 1

. South Coast Air Basin FRM PM10 Data from 2005 to 2007

Observed
Maximum 24-hour

Concentration (a)
( μ g/m 3 ) Three-year
Total Number of Days Exceeding
the
Standard Monitoring Station Name

2005 2006 2007 2005-2007 Los Angeles County Los Angeles-North Main 70 59 78 0 Los Angeles-Westchester 44 45 128 0 North Long Beach 66 78 75 0 South Long Beach 131 117 123 0
Burbank 92 71 109 0
Azusa 76 81 82 0
Santa Clarita 55 53 131 0 Orange County
Anaheim 65 104 75 0 Mission Viejo 41 57 74 0 Riverside County
Norco 79 74 93 0
Riverside-Rubidoux 123 109 118 0
Mira Loma -- 124 142 N/A (b)

Perris 80 125 120 0 Banning Airport 76 75 78 0 San Bernardino County
Ontario 74 78 115 0

Fontana 108 142 111 0
San Bernardino 72 92 136 0
Redlands 61 103 97 0
Crestline 49 63 89 0

a. Data do not include PM10 concentrations caused by natural/exceptional events which are excluded from regulatory consideration. b. Monitoring since 2006.6 February 22, 2010 On three days over the 2005 to 2007 period, the 24-hour standard wa s exceeded due to high wind events or fireworks on a national holiday. These exceedances can be excluded under the federal rule for except ional events since they are not reasonably preventable or controllable. Documentation for these thr ee events has been submitted to U.S. EPA for concurrence as exceptional events.

B. U.S. EPA Approved the South Co ast Air Basin PM10 SIP and the State Has Met Applicable Act Requirements

On April 18, 2003, U.S. EPA approved the PM10 elements of t he 1997 South Coast AQMP and the 2002 plan update with a December 31, 2006 attainment deadline for the South Coast. In addition, ARB and the Distr ict have met all of the Act requirements applicable for a serious PM10 nonattainment ar ea to be considered for redesignation.

C. Improvement in the South Coast Ai r Basin PM10 Air Quality is Due to
Permanent and Enforceable Reductions in Emissions

The District has adopted the tighter dust cont rol rules committed to in the Basin’s 2003 PM10 attainment plan revision. In addition, the District has adopted rules controlling emissions of particulate matter precursors (NOx, SOx, and ROG). These measures have provided for continuous a ttainment of the 24-hour PM10 standard (excluding exceptional or nat ural events) in the region since 2004, despite regional growth. Adopted measures are fully enforceable.

Based on analyses of long-term meteorologi cal variables, including rainfall, wind speeds, and stagnation, the District found that meteorological conditions during the 2005-2007 period were not unusually favorable to lower PM10 levels. Therefore, air quality improvements leading to PM10 attain ment in the Basin are due to emission reductions from adopted, fully enforceable control measures.

D. Maintenance Plan

The South Coast PM10 Maintenance Pl an includes the fo llowing components:
attainment emission invent ory; maintenance demonstrati on; commitment to continue monitoring network operation; commitment for verification of continued attainment; and contingency plan. In addition, transportati on conformity budgets have been updated.

1. Attainment Emission Inventory

An emission inventory is a critical tool us ed to support evaluation, control, and mitigation of air pollution which is comprised of a syste matic listing of the sources of air pollutants along with the amount of pollutants emitted fr om each source or category over a given period of time. Emission inventories are estimates of the air pollutant emissions released into the environment – they ar e not direct ambient concentration measurements. To determine the expected emissions in future years, emission inventories incorporate the effects of growth and existi ng regulations (baseline7 February 22, 2010 inventories). An attainment inventory identifies the level of emissions during the period when air quality data show attainment.

The South Coast PM10 Maintenance Plan presents the updated 20 07 AQMP baseline emission inventories for PM10, NOx, ROG, and SOx for 2002, 2006, and 2008, plus projected emissions for 2010 through 2012 (provi ding a bracket for the start of the maintenance period depending upon plan appr oval by U.S. EPA), 2014, 2020, and 2023 (bracketing the expected 10-year main tenance period), and 2030. 2007 AQMP inventory updates include the latest point and area source emission information; ARB
EMFAC 2007 mobile source emission out puts; and planning assumptions in the
Southern California Association of Gove rnment’s (SCAG) In terim 2007 Regional Transportation Plan (2007 RTP).

2. Maintenance Demonstration

The 2003 PM10 attainment plan used linear ro llback to demonstrate attainment of the
24-hour PM10 standard. Linear rollback assu mes that future PM10 levels above background concentrations will dec rease in proportion to projec ted emission reductions. The linear rollback technique was based on PM 10 chemical components. For the five sites where PM10 component species were sa mpled, the components were matched to the appropriate emission inventory categories in the rollback analysis

.

The South Coast PM10 Maintenance Plan de monstrates maintenanc e of the 24-hour PM10 standard by estimating the PM2.5 and the coarse portions of PM10 concentrations using two separate methodologies : 1) the PM2.5 portion using regional photochemical modeling, 2) the coarse portion using linear rollback simulations. This analysis employed baseline emission invent ories for 2005 and 2010 through 2030. The projected PM2.5 and coarse fractions were added to estimate future-year maximum
24-hour PM10 concentrations. Table 2 lis ts the 2010 through 2012, 2014, 2020, 2023, and 2030 projected maximum 24-hour PM10 val ues per county, which demonstrate
continued attainment of the 24-hour NAAQS throughout the Basin.

Table 2. Projected Maintena nce of 24-hour PM10 NAAQS in the
South Coast Air Basin

Year Predicted County Maximum 24-hour PM10 Concentration ( μ g/m 3 ) Los Angeles Orange Riverside San
Bernardino

2010 102 79 120 126
2011 101 79 119 125

2012 101 78 118 125
2014 102 79 117 126
2020 102 80 117 126

2023 103 81 118 128
2030 109 86 125 1368 February 22, 2010 The South Coast is projected to maintain attainment with the PM10 standard due to ARB, District, and other local control measures already in place. In addition, future emissions in PM10 precursors are projected to decrease even further as a result of the implementation of controls in the 2007 AQMP for PM2.5 and ozone in the Basin.

3. PM10 Monitoring Network

The District commits to continue PM10 monitori ng to verify sustained attainment of the
PM10 standard in the South Coast. The exis ting PM10 monitoring network in the South
Coast includes nineteen FRM and ten real-t ime PM10 monitors (Figure 1). Federal regulations require daily sampling at the site reporting peak PM10 concentrations. The
real-time PM10 monitors will be used to me et the daily monitoring requirement.

4. Verification of Continued Attainment

To verify continued attainment of t he PM10 standards, the District commits to
reevaluate the South Coast PM10 Maintenance Plan as pa rt of the AQMP revision currently scheduled for 2011. Eight years afte r the South Coast has been redesignated to attainment, the District will submit to U. S. EPA the required revi sion to the Plan demonstrating maintenance of the standard for the following ten year period. On a regular basis, the District will continue to analyze PM10 data from FRM and continuous monitors and compare daily PM10 values to the level of the 24-hour standard.

5. Contingency Plan

The Act requires the maintenance plan to include contingency provisions for prompt correction of any PM10 standard violation t hat might occur after the area has been redesignated to attainment. The maintenance plan is not required to contain fully adopted contingency measures that will go into e ffect without further state action as is required in attainment SIPs. Instead, for maintenance plans, the area must have a plan to ensure that contingency measures are adopted once they are triggered.

Implementation of the 2007 AQMP serves as an on-going contingency measure for maintaining the PM10 standard in the South Coast, since emission reductions from control measures designed to attain t he PM2.5 and ozone standards will effectively
reduce PM10 concentrations. If nonetheless the 24-hour PM10 standard is exceeded,
and data evaluation shows the violation is not due to a natural or ex ceptional event, the
District will evaluate further enhancements to ke y existing PM10 measures to achieve necessary emission reductions as expeditiously as possible.

6. Transportation Conformity Budgets

Under section 176(c) of the Act, transportation plans, pr ograms, and projects that receive federal funding or require federal approval must be found to be fully consistent9 February 22, 2010 with the SIP. The federal trans portation conformity regulation 2 found in 40 CFR parts 51 and 93 requires SIPs to specify on-road motor vehicle emission budgets (budgets)
that are consistent with attainment and maintenance of NAAQS. The conformity regulation requires metropolitan planning org anizations to demonstrate that emissions from regional transportation plans and pr ograms do not exceed these “emission budgets.”

The District updated the South Coast transpo rtation conformity budgets using ARB’s
latest on-road mobile source emission fa ctor model EMFAC200 7 and transportation activity data from the 2008 RTP, Amendmen t 1 as adopted by SCAG in December 2008. The budgets U.S. EPA previously appr oved as part the 2003 PM10 Attainment
Plan were based on EMFAC 2002 and SCAG’s 2001 RTP.

The District conducted an attainment modeli ng sensitivity analysis to evaluate the impact of increased motor vehicle emissions from potential growth on ambient PM10
concentrations. Even if PM10 baseline emissions from motor vehicles were to increase by up to 20 tons per day (tpd), the South Coast would continue to show attainment through 2030 (Table 3).

Table 3. Projected 24-hour PM10 Concentrations Assu ming a 20 tpd Increase in
the South Coast Air Basin Baseline PM10 Emissions

Year Predicted County Maximum 24-hour PM10 Concentration ( μ g/m 3 ) Los Angeles Orange Riverside San
Bernardino

2010 105 81 124 131

2011 105 82 123 131
2012 105 81 122 130
2014 105 82 121 131
2020 106 83 121 132

2023 107 84 123 133
2030 113 89 129 141

Prior to the District’s Board hearing, the Dis trict revised the transportation conformity budgets in the South Coast PM10 Maintenanc e Plan, to reflect U.S. EPA‘s comment that the budgets only include emission reduc tions from already adopted control
measures. Table 4 lists the revised on-road motor vehicle emission budgets for transportation conformity established fo r the years 2010, 2020, and 2030. After consultation with the District and SCAG, 5 t pd of PM10 were added to the conformity budget for 2030 and 7 tpd, 4 t pd, and 3 tpd of ROG to the budgets for 2010, 2020, and 2030, respectively. Appendix C of the AR B Staff Report for the 2007 South Coast

2 U.S. EPA maintains online inform ation on its transportation conformity program, including access to relevant rulemakings, policy guidance, and reports at: http://www.epa.gov/otaq/stateresources/transconf/index.htm10 February 22, 2010 PM2.5 SIP presented the relati ve emissions contribution to the South Coast PM2.5 formation from precursor gases, including R OG. Based on the established ratios, the
additional ROG emissions tr anslate to adding 1 tpd of PM10 emissions (rounding to whole tpd) for 2010, 2020, and 2030, respecti vely. Total additions for the 2030 budget are therefore the equivalent of 6 tpd of PM10. The additiona l 6 tpd of PM10 represents only 30 percent of the 20 t pd PM10 included in the District’s attainment modeling sensitivity analysis. The 6 t pd of PM10 facilitates antici pated growth while setting an emissions budget that ensures continued ma intenance of the sta ndard. ARB staff posted the revised budgets on ARB’s website to provide for the required 30-day public review. The revised emission budgets fulfill the requirements of the Act and U.S. EPA regulations to ensure that transportation acti vities support continued maintenance of the
PM10 standard.

Table 4. Transportation Conformity Emissions Budgets for PM10 in the
South Coast Air Basin (Annual average)

Emission Budget (tons per day) 2010 2020 2030

PM10 159 164 175
NOx 372 180 116
ROG 182 110 81

IV. STAFF RECOMMENDATION

ARB staff has reviewed the PM10 Redesig nation Request and Maintenance Plan for the
South Coast Air Basin and consulted with the Dis trict staff during this review. ARB staff
finds that the South Coast Air Basin PM 10 Maintenance Plan meets all applicable Act requirements. ARB staff belie ves that implementation of this plan will continue to
maintain PM10 levels below the national air quality standard in the South Coast. Therefore, we recommend t hat the Board adopt the South Coast PM10 Maintenance Plans and the updated transpor tation conformity budgets for the South Coast, as a
revision to the California SIP for submi ttal to U.S. EPA. In addition, ARB staff recommends that the Board approve the Distr ict’s request that the South Coast Air Basin be redesignated from nonattainment to attainment for the national PM10
standard.