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Proposed Rule

Approval and Promulgation of State Implementation Plans and Designation of Areas for Air Quality Planning Purposes; California-Coachella Valley

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Environmental Protection Agency (EPA).


Proposed rule.


EPA is proposing to approve state implementation plan (SIP) revisions submitted by the State of California to provide for attainment of the particulate matter (PM-10) national ambient air quality standard (NAAQS) in the Coachella Valley area and to establish emissions budgets for purposes of transportation conformity. EPA is also proposing to grant the State's request for an extension of the PM-10 attainment deadline to December 31, 2006. EPA is proposing to approve the SIP revisions under provisions of the Clean Air Act (CAA) regarding EPA action on SIP submittals, SIPs for national primary and secondary ambient air quality standards, and plan requirements for nonattainment areas.


Written comments on this proposal must be received by January 16, 2003.


Comments should be mailed to: Eleanor Kaplan, Office of Air Planning (AIR-2), EPA Region 9, 75 Hawthorne Street, San Francisco, CA 94105-3901. The rulemaking docket for this notice is available for public inspection during normal business hours at the EPA Region 9 office. A reasonable fee may be charged for copying parts of the docket.

Copies of the SIP materials are also available for inspection at the following locations:

California Air Resources Board, 1001 I Street, Sacramento, California 95814

South Coast Air Quality Management District, 21865 E. Copley Drive, Diamond Bar, California 91765-0932. The 2002 plan is electronically available at:​aqmp/​.

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Eleanor Kaplan, (415) 947-4147 or

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Throughout this document “we,” “us,” and “our” means EPA. This supplementary information is organized as follows.

Table of Contents

I. Background

A. Summary

B. Description of the Coachella Valley and its PM-10 Problem

C. Particulate Matter and Health Effects

D. Design and Classification

E. CAA Requirements

II. Evaluation of SIP Submittal

A. Separation of Rulemaking Actions on the Annual and 24-hour Standards

B. Emissions Inventory

C. Control Measures

D. Contingency Measure

E. Reasonable Further Progress and Milestones

F. Attainment Demonstration

G. Extension of Attainment Date

H. Review of the Natural Events Action Plan

I. Motor Vehicle Emission Budgets

III. Summary of EPA's Proposed Action

IV. Administrative Requirements

I. Background

A. Summary

We are proposing to approve the SIP revisions submitted by the State of California to provide for the attainment of the particulate matter (PM-10) NAAQS for the Coachella Valley (Valley) and to grant the State's request that the attainment date be extended from December 31, 2001 to December 31, 2006. We are also proposing to approve the motor vehicle emissions budgets contained in the revised SIP as adequate for transportation conformity purposes.

B. Description of the Coachella Valley and its PM-10 Problem

The Coachella Valley PM-10 nonattainment area consists of an approximately 2,500 square mile portion of central Riverside County in California. The Valley, which is part of the Salton Sea Air Basin, extends in a northwest-southeast direction from the Banning Pass to the Salton Sea and is bounded by the San Jacinto Mountains to the west and the Little San Bernardino Mountains to the east. The Valley includes ten local jurisdictions, namely: the County of Riverside and the following cities: Cathedral City, Coachella, Desert Hot Springs, Indian Wells, Indio, La Quinta, Palm Desert, Palm Springs and Rancho Mirage.

The Valley's climate is continental desert-type with hot summers, mild winters and very little annual rainfall. Elevation ranges from approximately 500 feet above sea level in the northern part of the Valley to about 150 feet below sea level near the Salton Sea.

The economy of the Valley is mixed. The upper portion which includes the area north of Indio is used primarily for resort and retirement activities. The Start Printed Page 77205lower portion is also urbanized but is oriented around an agricultural economy that extends south of the Riverside County-Imperial County boundary. Agricultural commodities such as citrus fruit, dates, grapes, etc. are grown almost year round.

One of the major sources of PM-10 in the Valley is locally generated fugitive dust. Fugitive dust usually refers to the dust put into the atmosphere by the wind blowing over plowed fields, dirt roads or desert or sandy areas with little or no vegetation. There are also human caused sources of fugitive dust that include entrained road dust from paved and unpaved roads, agriculture and construction activities and disturbed vacant land.

In addition to man-made sources, windblown dust from the desert also is a major contributor to PM-10 in the Valley. High winds occur in the area because the low elevation in part of the Valley provides a natural path for the movement of air from the ocean into the desert during the summer and for the passage of storms moving from west to east during the winter. These winds can occasionally exceed 60 miles per hour and can pick up large amounts of natural desert soils which can then be transported over large distances.

C. Particulate Matter and Health Effects

Particulate matter with an aerodynamic diameter of less than 10 micrometers (PM-10) is the pollutant that is the subject of this action. The NAAQS are safety thresholds for certain ambient air pollutants set by EPA to protect public health and welfare. PM-10 is among the ambient air pollutants for which EPA has established a health-based standard. There are two separate NAAQS for PM-10, an annual standard of 50 micrograms per cubic meter (μg/m3) and a 24-hour standard of 150 μg/m3.[1] PM-10 causes adverse health effects by penetrating deep in the lung, aggravating the cardiopulmonary system. Children, the elderly, and people with asthma and heart conditions are the most vulnerable.

D. Design and Classification

When the Clean Air Act Amendments (CAAA) were enacted in 1990, all areas in the United States that were previously designated as federal nonattainment areas for PM-10, including the Valley, were initially designated as “moderate” PM-10 nonattainment. Once an area is designated nonattainment, section 188 of the CAA outlines the process for classification of the area and establishes the area's attainment date.

EPA determined on January 8, 1993, that the Valley could not practicably attain the PM-10 NAAQS by the applicable attainment deadline for moderate areas which was December 31, 1994, per section 188 (c)(1) of the Act, and reclassified the area as serious PM-10 nonattainment. See 58 FR 3334. In accordance with section 189(b)(2) of the Act, the applicable deadline for submittal of SIPs for the Valley addressing the requirements for serious PM-10 nonattainment areas in section 189(b) and (c) of the Act were:

(1) August 8, 1994 (18 months after the effective date of the reclassification), SIP to ensure the implementation of BACM no later than 4 years after reclassification;

(2) February 8, 1997 (4 years after the effective date of the reclassification), SIP to provide for progress and expeditious attainment.

The South Coast Air Quality Management District (SCAQMD), which has jurisdiction over the Valley, adopted the 1994 Best Available Control Measures (BACM) SIP for the Valley on July 8, 1994 and the California Air Resources Board (CARB) submitted the plan to us on August 26, 1994. The 1994 plan, in accordance with the provisions of CAA section 189(b)(1)(B), identified the Best Available Control Measures (BACM) that were required for this serious PM-10 nonattainment area and committed to implementation of these measures by February 8, 1997.

Subsequent air quality monitoring data indicated that there were no violations of the annual or 24-hour PM-10 NAAQS in the Valley for the years 1993-1995. On December 13, 1996 the SCAQMD adopted a Request for Redesignation and a Maintenance Plan (“1996 plan”) and on February 5, 1997 CARB submitted the plan to us. The 1996 plan addressed the remaining plan provisions for serious PM-10 nonattainment areas, as specified in the CAA sections 188 and 189, and requested redesignation to attainment based on three years of clean data. However, before EPA acted on the 1996 plan, the area recorded a violation of the annual PM-10 NAAQS during the period from 1999 through 2001 and was therefore unable to meet its attainment date of December 31, 2001.

On June 21, 2002 and September 13, 2002 the SCAQMD adopted an amendment to the 1996 Valley Plan (“2002 Plan”). The California Air Resources Board (CARB) submitted the 2002 Plan to EPA on November 18, 2002. The amendment contains four revisions: (1) It requests an extension of the attainment date to December 31, 2006; (2) it demonstrates attainment by 2006; (3) it establishes motor vehicle emissions budgets for purposes of transportation conformity and (4) it formally withdraws the maintenance plan provisions and the redesignation request contained in the 1996 plan. On November 20, 2002, we found that the 2002 Plan met the completeness criteria in 40 CFR part 51, appendix V.

For the 1996 and 2002 Plans the SCAQMD and CARB satisfied applicable statutory and regulatory requirements for reasonable public notice and hearing prior to adoption of both the 1996 and 2002 Plans, and the motor vehicle budgets. The SCAQMD conducted public workshops, and properly noticed the public hearings at which the Plans were adopted. The SIP submittal for the 1996 and 2002 Plans includes proof of publication of notices for the public hearings. Therefore, we conclude that the 1996 and 2002 Plans met the public notice and involvement requirements of sections 110(a)(1) of the CAA.

Beyond meeting the CAA public notice and involvement requirements, the SCAQMD and the Coachella Valley Association of Governments (CVAG) conducted an exemplary program involving the public in the SIP development process. A Valley Task Force (Task Force) was formed with a wide diversity of members including mayors and city council members of all Valley cities, tribal chairs or co-chairs from all local Indian tribes, city managers, representatives from the local farm bureau, building industry association, developers, CALTRANS, and staff from the SCAQMD, CARB and EPA. The Task Force operated through sub-committees to review and comment on SIP development and implementation issues. The Task Force intends to assist adoption and implementation of the control measures that it helped develop. Start Printed Page 77206

E. CAA Requirements

Title I of the CAA was substantially amended in 1990 to establish new planning requirements and attainment deadlines for the NAAQS. The most fundamental of these nonattainment area provisions applicable to the Valley is the requirement that the State submit a SIP demonstrating attainment of the PM-10 NAAQS. This demonstration must be based upon enforceable measures to achieve emission reductions leading to emissions at or below the level predicted to result in attainment of the NAAQS throughout the nonattainment area. The measures must meet the standard for Reasonably Available Control Measures (RACM) and BACM and the measures must be implemented expeditiously and ensure attainment no later than the applicable CAA deadline.

EPA has issued a “General Preamble” describing the Agency's preliminary views on how EPA intends to act on SIPs submitted under Title I of the Act. See 57 FR 13498 (April 16, 1992), 57 FR 18070 (April 28, 1992). EPA later issued an Addendum to the General Preamble providing guidance on SIP requirements for serious PM-10 areas. 59 FR 41998 (August 16, 1994). The reader should refer to these documents for a more detailed discussion of EPA's preliminary interpretations of Title I requirements. In this proposed rulemaking action, EPA applies these policies to the Valley PM-10 SIP submittal, taking into consideration the specific factual issues presented.

Since the 2002 Plan requests an extension of the attainment date beyond the applicable deadline of December 31, 2001, it is also subject to the provisions of CAA section 188(e) which deal with the requirements for extension of attainment dates for serious PM-10 nonattainment areas.

II. Evaluation of the SIP Submittals

A. Separation of Rulemaking Actions on the Annual and 24-hour Standards

Although, as discussed above, the Act contains two PM-10 NAAQS (an annual and a 24-hour standard) in this proposed action we are evaluating the Valley 2002 Plan only for its compliance with the requirements for attaining the annual PM-10 standard.[2] We need not, at this time, evaluate the plan for its compliance with the Act's requirements for the 24-hour PM-10 standard because the data indicate that there were no violations of the 24-hour standard during the period 1993-2001.[3] We find therefore that the area is currently in attainment for the 24-hour PM standard.

Although the Valley had attained both the annual and 24-hour PM-10 NAAQS during the years 1993-1995, increased construction activities in the Valley during the period 1999-2001 caused a violation of the annual standard at the area's two monitoring sites as shown in Table 1.

Table 1.—Annual Arithmetic Mean for PM-10 in the Valley, 1999-2001

199920002001Expected AAM
Palm Springs28.924.426.726.7
Note: samples collected on high wind days are excluded.

B. Emissions Inventory

CAA section 172(c)(3) requires that nonattainment area plans include a comprehensive, accurate, and current inventory of actual emissions from all sources in the nonattainment area.

The inventory in the 2002 Plan supersedes the 1996 Plan inventory and includes a 2000 base year inventory that utilizes the 1995 inventory representing annual average and 24-hour emissions. Information on the methodology that was employed in developing estimates for emissions sources for the 1995 inventory is contained in Chapter 3 of the 1996 Plan.

In addition to the 2000 base year inventory, the 2002 Plan provides future year inventories for 2003 and 2006. The emission reductions assumed from control measure implementation by December 2003 are included in the 2003 inventory.

CARB uses a California-specific model known as EMFAC for the mobile source component of the emissions inventories, including the model used to calculate exhaust and evaporative emissions from motor vehicles and the contribution of mobile emissions to the PM-10 inventory. The version of the model that was and remains currently available for use in the 1996 and 2002 Plans is known as EMFAC 7G, adopted by CARB in 1996. (CARB, Methodology for Estimating Emissions from On-Road Motor Vehicles, 1996). EPA has approved EMFAC 7G for use in transportation plan and program conformity analyses (letter from David Howekamp, EPA to Michael P. Kenny, CARB, dated April 16, 1998).

CARB has recently prepared draft revisions to EMFAC 7G, which CARB has committed to finalize and submit in the near future. However, because EMFAC 7G represented the best available emissions model at the time the plan was developed and submitted, our approval of the 2002 Plan's emissions inventory and the motor vehicle emissions budgets derived from EMFAC 7G is warranted at this time.

Both SCAQMD and CARB have committed to submit within a very short period of time a revised plan with updated and refined emission inventories and budgets. The agencies will base the new plan and budgets on use of the most current and accurate emissions data, including the revised version of the EMFAC model for motor vehicle emissions incorporating the latest planning assumptions on vehicle fleet and age distribution, and incorporating the latest activity levels.

In proposing to approve the 2002 Plan based on EMFAC 7G, we also find it significant that the motor vehicle exhaust and brake and tire wear emissions in both the 1996 and 2002 Start Printed Page 77207Plan inventories constitute only about 3% of the total emissions, demonstrating that PM-10 from motor vehicles (exclusive of reentrained dust from paved and unpaved roads) is not a significant contributor to the air quality problem in the Valley. In summary, we are proposing to approve the 2002 Plan based on EMFAC 7G because it is the only currently approved model, CARB and SCAQMD have committed to revise the PM-10 Plan based on the updated version of EMFAC in 2003, and the overall contribution of PM-10 from motor vehicles is only about 3%.

The transportation conformity implications of our proposed approval are discussed later in this document in Section II under Motor Vehicle Emissions Budgets.

C. Control Measures

1. Applicable Requirements

Because the Valley is classified as serious nonattainment for PM-10, the nonattainment plan for the area must include control measures that reflect a BACM level of control for each source category that contributes significantly to a violation of the annual NAAQS. CAA section 189(b)(1)(B).[4]

By analogy to Title I Part C of the Clean Air Act relating to Prevention of Significant Deterioration (PSD), EPA interprets BACM for serious PM-10 areas as generally similar to the definition of Best Available Control Technology (BACT) for the PSD program. PM-10 BACM is therefore defined as “the maximum degree of emissions reduction of PM-10 and PM-10 precursors from a source * * * which is determined on a case by case basis, taking into account energy, environmental, and economic impacts and other costs, to be achievable for such source through application of production processes and available methods, systems, and techniques for control of each such pollutant.” General Preamble Addendum, 59 FR 42010 (August 16, 1994).

Finally, the control measures in the serious area plan must be sufficient to achieve expeditious attainment by the applicable date.

2. Identification of Significant Source Categories

The 1996 Plan (Tables 4-1 and 4-2) used receptor modeling to identify the emission sources that contribute to the PM-10 air quality at specific receptor sites. The receptor model used is the Chemical Mass Balance (CMB) Model. This method matches the measured chemical components of the PM-10 samples with known chemical profiles of individual sources of PM-10 particles. The results of this model are shown in Table 4-1 of the 1996 Plan “Annual Average Source Contributions for the Coachella Valley.”

Future year PM-10 concentrations were estimated using a linear rollback approach for each primary source. In the linear rollback approach, it is presumed that future year PM-10 contributions from each source category are a linear function of emission rates for each source category. Table 4-3 in the 1996 Plan provides base year and future ambient PM-10 concentrations.

From these evaluations, the 1996 Plan identified significant sources and a determination of which categories have “significant” impacts on PM-10 concentrations. The significant sources identified include background, transport, mobile, fugitive dust (including construction, paved roads, unpaved roads, agriculture, windblown), and vegetative burning.

We propose to find that the 2002 Plan has not excluded any source categories that should be considered significant from its list of significant source categories. The 2002 Plan presents acceptable modeling to evaluate the impact of various PM-10 sources and source categories on PM-10 levels.

The 2000 inventory in the 2002 Plan indicates that emissions from industrial point sources were insignificant—0.29 tons per day out of a total of 54.44 tons per day from all sources. Therefore, based on their negligible impact on ambient PM-10 levels, we propose to determine that major sources of PM-10 precursors do not contribute significantly to PM-10 levels which exceed the annual standard in the Valley.

3. Description of Control Measures

(a) BACM: Existing Controls

In the 1994 plan (Chapter 4) and the 1996 plan (Chapter 1), the SCAQMD has provided extensive documentation on both the control measures included in the plan and those rejected. The documentation quantifies the costs of implementation, discusses the technological feasibility of control options, explains the schedule for expeditious implementation and examines other factors as part of a comprehensive justification of the measures as reflecting BACM. Implementation of BACM in the Valley has been carried out through dust control ordinances of the local jurisdictions in Valley, and with AQMD Rules 403 and 403.1 serving as backstop regulations for the Valley's construction activity emissions.

The local ordinances developed by Riverside County, Cathedral City, Coachella, Desert Hot Springs, Indian Wells, Indio, La Quinta, Palm Desert, Palm Springs and Rancho Mirage are based on a model fugitive dust control ordinance developed by CVAG, local governments, and the SCAQMD. The ordinances typically require: (1) Dust control plans for each construction project needing a grading permit; (2) plans to pave or chemically treat unpaved surfaces if daily vehicle trips exceed 150; (3) imposition of 15 mph speed limits for unpaved surfaces if daily vehicle trips do not exceed 150; (4) paving or chemical treatment of unpaved parking lots; and (5) actions to discourage use of unimproved property by off-highway vehicles.

SCAQMD Rule 403, Fugitive Dust, helps to establish performance criteria for the local dust ordinances and also serves as a backstop rule for the Valley. The Rule establishes reasonably available and best available fugitive dust control measures to reduce fugitive dust emissions associated with agricultural operations, construction/demolition activities (including grading, excavation, loading, crushing, cutting, planing, shaping or ground breaking), earth-moving activities, track out of bulk material onto public paved roadways, and open storage piles or disturbed surface areas.

The Rule 403 Handbook allows producers to be exempted from Rule 403 requirements if they implement a specified number of conservation practices listed for the particular operation. The handbook includes conservation practices for active operations, inactive operations, farm yard areas, track-out, unpaved roads, and storage piles. EPA approved the handbook into the SIP because implementation of the conservation practices should achieve the emission reductions that would otherwise be accomplished through compliance with the general provisions of Rule 403. (65 FR 8057, February 17, 2000).

SCAQMD Rule 403.1, Wind Entrainment of Fugitive Dust, establishes dust control requirements under high wind conditions in the Valley. The Rule consists of additional Start Printed Page 77208fugitive dust measures for agriculture, abandoned disturbed surface areas, and bulk material deposits entrained by high winds within the Valley. EPA also approved the sections of Rule 403.1 Implementation Handbook including the chapters on “Wind Monitoring” and “Storage Piles”.[5]

Clean Streets Management Program: In order to assure implementation of the control measures that had been enacted for entrained road dust, which is one of the larger source categories in the Valley, CVAG has worked to secure funding for a Clean Streets Management Program through the allocation of Congestion Mitigation and Air Quality (CMAQ) funds which now falls under the Transportation Efficiency Act for the 21st Century (TEA-21). Under the Clean Streets Management Program, local jurisdictions submit proposals to CVAG requesting funding for implementation of clean streets management practices, i.e., stabilization of unpaved shoulders, installation of wind breaks, etc. CVAG has provided technical assistance to the local jurisdictions to identify cost effective eligible projects for CMAQ funding.

(b) Most Stringent Measures (MSM)

One of the requirements for an extension of attainment date, which the Valley has requested (see section II G) is that “the State demonstrates to the satisfaction of the Administrator that the plan for that area includes the most stringent measures that are included in the implementation plan of any State or are achieved in practice in any State, and can feasibly be implemented in the area.” (CAA section 188(e)).

Chapter 4 of the 2002 Plan contains a description of the SCAQMD's MSM analysis. That analysis compares the provisions in the Valley's local dust control ordinances and applicable SCAQMD Rules 403 and 403.1 to regulations from Maricopa County (Arizona), Clark County (Nevada) the San Joaquin Valley (California) and the South Coast Air Basin (California). These areas were selected because of similar geographic conditions (arid climates) as the Valley and because of recent planning/rule development efforts in these regions. MSM analyses were provided for each fugitive dust category, including construction activities, disturbed vacant lands, unpaved roads/parking lots, paved road dust and agricultural activities. (See sections 4.1, 4.2, 4.3, 4.4 and 4.5 of the 2002 Plan.)

The upgraded control measures that resulted from the Valley MSM analysis are categorized as Construction (CV BCM 1), Disturbed Lands (CV BCM 2), Unpaved Roads and Unpaved Parking Lots (CV BACM 3), Paved Roads (CV BACM 4), and Agriculture (CV BCM 5). The implementing agencies are either the local jurisdictions or the SCAQMD or, in the instances of Construction and Paved Roads, both parties.

Chapter 5 of the 2002 Plan provides the control strategy that has been developed by the SCAQMD based on their MSM analysis. Table 2 below summarizes Tables 5-1 and 5-2 contained in the 2002 Plan which provide information on the adoption and implementation schedules for the MSMs, the implementing agencies and the estimated tonnage per day reduction for each of these control measures.

Table 2.—MSM Adoption and Implementation Schedules, and Projected Emission Reductions for the Valley

Control measureSource categoryImplementing agencyAdoption scheduleImplementation scheduleEstimated emission reductions 2006
CV BACM 1ConstructionLocal JurisdictionsPrior to 10/1/03Begin no later than 10/1/032.0 tons/day.
AQMDPrior to 1/1/04Begin no later than  1/04
CV BACM 2Disturbed LandsLocal Jurisdictions10/03Begin no later than 10/03TBD After Survey.
CV BACM 3Unpaved Roads and lotsLocal Jurisdictions10/03Begin no later than 10/1/03, phased implementation0.71 tons/day.
CV BACM 4Paved RoadsLocal Jurisdictions10/03Begin no later than 10/1/030.57 tons/day.
AQMD01/04Begin no later than  1/04
CV BCM 5AgricultureAQMD01/04Begin no later than  1/040.02 tons/day.
Total Projected Emission Reductions3.3 tons/day.

3. Implementation of Control Measures

The SCAQMD commits to meet the adoption dates, implementation dates, and emission reduction targets, unless a measure, in whole or in part, is determined to be infeasible. Should that be the case, the SCAQMD commits to achieve equivalent reductions on the same schedule through substitute controls. If the SCAQMD determines that a control measure is infeasible, SCAQMD staff would document the infeasibility of the control measure provision and propose a replacement provision or contingency measure (if necessary) to achieve equivalent emissions reductions. Significant changes to a control measure would need to be documented in a SIP revision and would be subject to EPA review and approval. The plan cites the feasibility criteria as: (1) Cost feasibility, namely that a control measure is considered cost feasible if the cost-effectiveness is less than $5,300 per ton of PM-10 reduced on an annual basis, and (2) Start Printed Page 77209technological feasibility, namely that a control measure is considered technically feasible if the following conditions are satisfied: the control technology is currently available and the control efficiency is at least 10%.

4. Proposed Action on Control Measures

We conclude that the 2002 Plan demonstrates that the control measures for each significant source category are consistent with the BACM requirement in terms of the timing, degree, and extent of the control program and reflect current MSM.

We therefore propose to approve the control measures under CAA section 110(k)(3), as meeting the requirements of CAA sections 110(a), 188(e) and 189(b)(1)(B). We are proposing to approve each of the control measure commitments to adopt and implement rules and ordinances by specified dates and to achieve particular emission reductions by milestone years. We are also proposing to approve the commitment made by the SCAQMD Board directing the Executive Officer to update the 2002 Plan, including emissions budgets in 2003, using the latest approved motor vehicle emissions model and planning assumptions.

D. Contingency Measure

The CAA (section 172(c)(9)) requires that the SIP include contingency measures to be implemented if the area fails to meet progress requirements or to attain the NAAQS by the applicable deadline. Implementation of these contingency measures is automatic, and requires no further action by the SCAQMD or any other agency.

The contingency measure identified in the 2002 Plan, CVCTY 3, is the requirement to reduce emissions from turf overseeding activities on Golf Courses/Turf Areas. Turf overseeding generates fugitive dust through the raking process and thatch removal when summer grass is replaced with winter rye grasses. According to the SCAQMD, following a series of studies, new methods were developed to remove the summer grass resulting in fugitive dust emission reduction. The SCAQMD staff believes the control measure is currently being adopted voluntarily by local golf courses, but in the event of failure of Reasonable Further Progress (RFP) or nonattainment by the year 2006 or if voluntary compliance drops, SCAQMD would propose to implement the measure with a SCAQMD rule or rule amendment.

EPA concludes that the 2002 Plan satisfies the contingency requirements, and proposes to approve the 2002 Plan's contingency provisions under section 172(c)(9).

E. Reasonable Further Progress and Milestones

The 2002 Plan must also include quantitative milestones which are to be achieved every 3 years until the area is redesignated to attainment, and show Reasonable Further Progress (RFP) toward attainment by the applicable attainment deadline. CAA section 189(c).

Table 3-4 in the 2002 Plan, “2002 PM-10 Emission Inventory by Major Source Category” shows that the total tpd emissions from all sources for 2000 year was 54.44. Table E-1 contained in Appendix E of the Plan provides a baseline inventory for 2003 which was selected by the SCAQMD as the milestone year and shows that emissions reductions resulting from the adoption and implementation of CV BCM-1 “Construction and Earth Movement Activities,” would amount to a total of 0.96 tpd, reducing the total amount of emissions from all sources in 2003 to 54.08 tpd, which represents remaining emissions by the end of 2003. assuming a 50% combined ordinance/rule penetration. The reduction in total tpd emissions from 2002 to 2003 demonstrates reasonable progress toward the attainment level projected for 2006.

The SCAQMD made a commitment in resolutions accompanying the 2002 Plan to update the plan, including emissions budgets in 2003, using the latest approved version of EMFAC and the latest approved planning assumptions.[6] In addition, CARB's Executive Order G-125-391, accompanying the submittal of the 2002 Plan, stated that CARB, “upon the timely submission by the District of an approvable revision to the 2002 Coachella Valley PM-10 State Implementation Plan and 2002 Coachella Valley PM-10 State Implementation Plan Addendum, shall process such revision and submit it to the U.S. EPA in 2003.”

We find that the assumptions regarding the control measures are reasonable. Therefore we propose to find that the 2002 Plan meets the provisions of CAA section 189(c) requiring quantitative milestones showing RFP toward attainment by the attainment date of 2006.

F. Attainment Demonstration

The SIP must provide a detailed demonstration (including air quality modeling) that the specified control strategy will reduce PM-10 emissions so that the standards will be attained as soon as practicable but no later than December 31, 2006, assuming final EPA approval of the attainment deadline extension. CAA section 189(b)(1)(A). EPA considers the area to be in attainment of the NAAQS if 24-hour concentrations are 150 μg/m3 or less and the annual arithmetic mean is 50 μg/m3 or less.

The attainment demonstration in the 2002 Plan analyzes both the 24-hour and annual NAAQS, but since the Valley has not violated the 24-hour standard during the period from 1993—2001, our review is limited to the annual standard.

A modeled attainment demonstration for the PM-10 annual standard should first estimate the temporal and spatial distribution of PM-10 and PM-10 precursor emissions reductions that result from the adopted control measures by the attainment date. It should then simulate the ambient air concentration of the remaining emissions in an air quality model and show that all locations within the nonattainment area have annual average PM-10 concentrations at or below the level of the annual PM-10 standard of 50 μg/m3. See “Guidelines on Air Quality Models,” 40 CFR part 52, appendix W, § 7.2.2 and “PM-10 SIP Development Guideline”, EPA-450/286-001, June 1987.

The attainment demonstration in the 2002 Plan relies on control measures that either are approved or have been proposed for approval and meet our SIP enforceability criteria. The emissions estimates credited to these control measures in the attainment demonstration are reasonable and the measures are being implemented on a schedule that is as expeditious as practicable and will result in attainment by the earliest practicable date. Start Printed Page 77210

A complete description of the modeling for the Valley is found in the 1996 Plan (Chapter 4). In summary, modeling was based on the following:

The SCAQMD determined primary PM-10 source apportionment by a combination of receptor models. Source apportionment information, which was used in the 1994 and the 1996 Plan was determined through receptor modeling known as the Chemical Mass Balance (CMB) model which is a USEPA approved method that matches the measured chemical components of the PM-10 samples with known chemical profiles of individual sources of PM-10 particles.

Since secondary particles in the Valley represent a small component of the PM-10 problem and are transported from the South Coast Air Basin and since the limited number of major sources in the Valley are already regulated for NOX, SOX and VOC emissions under existing SCAQMD rules, the SCAQMD did not model secondary PM-10 generated within the Valley. However, the impact of transported secondary particulates into the Coachella Valley from the South Coast Air Basin was projected using UAM/LC (Urban Airshed Model/Linear Chemistry).

The modeling attainment demonstration for future years in the 2002 Plan utilized a linear rollback approach for each primary source category.

Based on this modeling, the 2002 Plan (Tables 6-2 and 6-3) compares the annual and 24 hour PM design values for the years 2003 and 2006. The table provides information on 2006 concentrations both for the baseline and control scenarios as shown in Table 3 below. This modeling demonstrates attainment of the annual average PM 10 standard by the year 2006 and continued attainment of the 24-hour standard in 2006.

Table 3.—2003 and 2006 Modeled PM-10 Concentrations (μg/m3) in the Valley

Source2003 baseline annual2003 baseline 24-hour2006 baseline annual2006 baseline 24-hour2006 annual with more controls2006 24-hour with more controls
Fugitive Dust:
Paved Roads4.516.24.616.93.713.3
Unpaved Roads3.
Veg. Burning5.

In contrast to other pollutants, we have not issued detailed modeling guidelines for PM-10, nor have we established minimum performance requirements for PM-10 modeling. We have reviewed the SCAQMD's modeling approaches for both primary PM-10 and secondary PM-10, using both receptor modeling and dispersion modeling. We believe that the modeling in the 1996 and 2002 Plans provides a reasonable basis for linking emissions with air quality, for identifying an appropriate control strategy, and for determining whether the strategy delivers attainment for the 24-hour and annual PM-10 NAAQS.

The SCAQMD's modeling shows that the level of emissions after implementation of the proposed set of control strategies would result in ambient concentrations within the Valley in 2006 consistent with attainment of annual and 24-hour PM-10 NAAQS. We therefore conclude that the air quality modeling and attainment demonstration contained in Chapter 6 of the 2002 Plan are consistent with existing EPA guidance, and we propose to approve the attainment demonstration under CAA section 189(b)(1)(A).

G. Extension of Attainment Deadline

CAA section 188(e) allows states to apply for up to a 5-year extension of the serious area attainment deadline of December 31, 2001. In order to obtain the extension, there must be a showing that: (1) Attainment by 2001 would be impracticable; (2) the state complied with all requirements and commitments pertaining to the area in the implementation plan for the area; and (3) the state demonstrates that the plan for the area includes the most stringent measures (MSM) that are included in the SIP of any state or are achieved in practice in any state, and can feasiblely be implemented in the area.

As discussed in section II C above, we propose to conclude that the 2002 Plan includes BACM and MSM for each significant source category, and that the implementation schedule for each control measure is as expeditious as practicable. Using UAM/LC and chemical mass balance modeling techniques discussed above in section II F, the SCAQMD calculated the annual arithmetic mean for PM-10 based on 1999-2001 data for the two sampling sites in the area at Palm Springs and Indio. That data showed that the Palm Springs site had an expected annual arithmetic mean of 26.7 μg/m3 while the Indio site with an expected annual arithmetic mean of 51.6 μg/m3 exceeded the annual standard. Table E-2 of Appendix E of the 2002 Plan shows that by the end of 2003 the average tons per day would be 54.08. Table 3-7 of the 2002 Plan shows that in 2006 with all the SIP controls in place the tons per day emitted would be 51.11. The 2003 data are above the carrying capacity and, based on this, we therefore conclude that 2006, the requested extension date, is the most expeditious date that the Valley can attain the standard.

We find that the SCAQMD has met the CAA provisions relating to attainment date extensions, and we propose to grant, under CAA section 188(e), a 5-year attainment date extension to December 31, 2006.

H. Review of Natural Events Action Plan

Section 188(f) of the CAA provides that the Administrator may, on a case-by-case basis, waive any requirement Start Printed Page 77211applicable to any serious area under subpart 4 where the Administrator determines that anthropogenic sources of PM-10 do not contribute significantly to the violation of the PM-10 standard in the area. In May of 1996 EPA issued a Natural Events Policy (Policy) that was intended to provide guidance to air districts regarding the exclusion of ambient air quality data affected by extraordinary natural events such as volcanic and seismic activity, wildland fires and high winds.

In order to qualify for the exclusion of ambient air quality data, the Policy requires the adoption of a Natural Events Action Plan (NEAP) to minimize emissions and to protect public health. The Policy requires that the NEAP (1) establish public notification and education programs, (2) minimize public exposures to high concentrations of PM-10 due to future natural events, (3) abate or minimize appropriate contributing controllable sources of PM-10, (4) identify, study and implement practical mitigating measures as necessary, (5) periodically reevaluate the conditions causing violations of the PM-10 NAAQS in the area and the state of implementation of the NEAP and the adequacy of the actions being implemented, (6) document natural events, and (7) develop the NEAP in conjunction with the stakeholders affected by the plan.

In accordance with the requirements of the Policy, the SCAQMD included a NEAP in the 1996 Plan and submitted a revised version in the 2002 Plan. Although EPA does not require that a NEAP be submitted as part of a SIP the Policy states that final plans should be submitted to EPA for review and comment.

The revised NEAP describes the status of the commitments made in the 1996 NEAP, all of which were fully implemented with the exception of the element “Evaluation and implementation of practical mitigation measures,” which was partially implemented by an initial blowsand study. Phase 2 of that study has not been initiated to date owing to funding constraints.

We find that the NEAP in the 2002 Plan meets the requirements of the Agency's Natural Events Policy. Further, we would like to commend the staff of the SCAQMD and the CVAG on the scope of the plan and the wide cooperation and expertise that has been involved in its implementation.

I. Motor Vehicle Emissions Budgets

Rate of progress and attainment demonstration submittals must specify the maximum amount of transportation-related motor vehicle emissions allowed in each milestone year and the attainment year and demonstrate these emissions levels, when considered with emissions from all other sources, are consistent with RFP and attainment. In order for us to find these emissions levels or “budgets” adequate and approvable, the submittal must meet the conformity adequacy provisions of 40 CFR 93.118(e)(4) and be approvable under all pertinent SIP requirements.

The budgets defined by this and other plans, when they are approved into the SIP or, in some cases, when they are found to be adequate, are then used to determine the conformity of transportation plans, programs, and projects to the SIP, as described by CAA section 176(c)(3)(A). For more detail on this part of the conformity requirements, see 40 CFR 93.118. For transportation conformity purposes, the cap on emissions of transportation-related PM-10 precursors is known as the motor vehicle emissions budget. The budget must reflect all of the motor vehicle control measures contained in the attainment demonstration (40 CFR 93.118()(4)(v)), and must include PM-10 and PM-10 precursor emissions from the following sources: motor vehicles, reentrained dust from traffic on paved and unpaved roads, and emissions during construction of highway and rail projects.

A motor vehicle budget for the Valley for the attainment year 2006 is presented in Table 3-8 of the 2002 Plan and the budget for milestone year 2003 is presented in appendix E, Table E-3. Both budgets appear below in Table 4.

Table 4.—2003 and 2006 Motor Vehicle Emission Budgets for Transportation Conformity for the Valley

[PM-10 tons/day]

2003 12006
Motor Vehicles1.040.98
Reentrained paved road dust7.046.27
Reentrained unpaved road dust5.444.72
Road Construction0.060.06
1 Presents remaining emissions at the end of the year 2003 with implementation of CV BCM-1 and 50% combined ordinance/rule penetration by that time.

As discussed above in section II.B, Emissions Inventory, the motor vehicle emissions portion of this budget (the evaporative and tailpipe emissions) was developed using the EMFAC 7G motor vehicle emissions factors.

We propose to approve the motor vehicle emission budget contained in the 2002 Plan as consistent with the adequacy criteria of 40 CFR 93.118(e)(4), including consistency with the baseline emission inventory, and the reductions needed for continued attainment of the standard after the attainment deadline.

As discussed in section II.B, CARB is finalizing a revised version of EMFAC, and both CARB and SCAQMD have committed to adopt and submit a comprehensive revision to the PM-10 plan in 2003, using the new EMFAC, incorporating the latest planning assumptions on vehicle fleet and age distribution, and incorporating the latest activity levels. This revised plan will include revised budgets, based on the new inventory and attainment demonstration. Assuming that these new budgets are adequate and approvable, the new budgets will soon replace the budgets in the current submittal.

Since these revised budgets will be based on the most current and accurate motor vehicle emissions data, we intend to allow expedited use of the updated budgets in transportation conformity determinations. Therefore, we propose to limit our proposed approval of the budgets in the current submittal to last only until we find adequate the new budgets that are expected to be adopted in 2003 as part of the revised PM-10 plan for the Valley. On the effective date of our adequacy finding for the new budgets, our approval of the budgets in the current submittal would terminate and thus the new budget would apply for purposes of transportation conformity. 67 FR 69139 (November 15, 2002).

III. Summary of EPA's Proposed Action

We are proposing to approve the serious area PM-10 SIP submitted by the State of California for the Valley. Specifically, we are proposing to approve the 1996 Plan and the 2002 Plan with respect to the CAA requirements for emissions inventories under section 172(c)(3); control measures under section 110(k)(3), as meeting the requirements of sections 110(a) and 188(b)(1)(B); RFP under section 189(c); contingency measures under section 172(c)(9); demonstration of attainment under section 189(b)(1)(A); and motor vehicle emissions budgets under section 176(c)(2)(A). We are also proposing to approve the State's request for an extension of the attainment date from December 31, 2001 to December 21, 2006 under CAA section 188(e). We show the proposed approvals in Table 5 “Proposed Approvals of South Coast Start Printed Page 77212PM-10 Submittals for the Coachella area.”

Proposed Approvals of South Coast PM-10 Submitttals for the Valley

CAA sectionProvisionSIP submittalPlan citation
172(c)(3)Emission Inventories2002 Plan2002 Plan, Ch 3.
110(a), 188(e), and 189(b)(1)(B)Control Measures1994 Plan, 1996 Plan, 2002 Plan1996 Plan, Ch. 4, 2002 Plan, Ch. 4, Ch. 5.
189(c)Reasonable Further Progress2002 PlanAppendix E-3, Table E-2.
172(c)(9)Contingency Measures2002 Plan2002 Plan, Ch. 4, Ch. 5.
189(b)(1)(A)Attainment Demonstration2002 Plan2002 Plan, Ch. 6.
176(c)(2)(A)Motor Vehicle Emissions Budget2002 Plan2002 Plan, Ch. 3 Appendix E 2002 Table E-3.
188(e)Attainment Date Extension2002 Plan2002 Plan, Ch. 8.

IV. Administrative Requirements

Under Executive Order 12866 (58 FR 51735, October 4, 1993), this proposed action is not a “significant regulatory action” and therefore is not subject to review by the Office of Management and Budget. For this reason, this proposed action is also not subject to Executive Order 13211,“Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355, May 22, 2001). This proposed action merely approves state law as meeting Federal requirements and imposes no additional requirements beyond those imposed by state law. Accordingly, the Administrator certifies that this proposed rule will not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.). Because this rule proposes to approve pre-existing requirements under state law and does not impose any additional enforceable duty beyond that required by state law, it does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Public Law 104-4).

This rule also does not have tribal implications because it will not have a substantial direct effect on one or more Indian tribes, on the relationship between the Federal Government and Indian tribes, or on the distribution of power and responsibilities between the Federal Government and Indian tribes, as specified by Executive Order 13175 (65 FR 67249, November 9, 2000). This action also does not have Federalism implications because it does not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). This action merely proposes to approve a state rule implementing a Federal standard, and does not alter the relationship or the distribution of power and responsibilities established in the Clean Air Act. This proposed rule also is not subject to Executive Order 13045, “Protection of Children from Environmental Health Risks and Safety Risks” (62 FR 19885, April 23, 1997), because it is not economically significant.

In reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. In this context, in the absence of a prior existing requirement for the State to use voluntary consensus standards (VCS), EPA has no authority to disapprove a SIP submission for failure to use VCS. It would thus be inconsistent with applicable law for EPA, when it reviews a SIP submission, to use VCS in place of a SIP submission that otherwise satisfies the provisions of the Clean Air Act. Thus, the requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) do not apply. This proposed rule does not impose an information collection burden under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

Start List of Subjects

List of Subjects

40 CFR Part 52

  • Environmental protection
  • Air pollution control
  • Incorporation by reference
  • Intergovernmental relations
  • Particulate matter
  • Reporting and recordkeeping requirements

40 CFR Part 81

  • Environmental protection
  • Air pollution control
  • National parks
  • Wilderness areas
End List of Subjects Start Signature

Dated: December 6, 2002.

Alexis Strauss,

Acting Regional Administrator, Region IX.

End Signature End Supplemental Information


1.  EPA revised the NAAQS for particulate matter on July 1, 1987 (52 FR 24672), replacing standards for total suspended particulates with new standards applying only to particulate matter up to 10 microns in diameter (PM-10). At that time, EPA established two PM-10 standards. The annual PM-10 standard is attained when the expected annual arithmetic mean of the 24-hour samples averaged over a 3-year period does not exceed 50 micrograms per cubic meter (μg/m3). The 24-hour PM-10 standard of 150 μg/m3 is attained if samples taken for 24-hour periods have no more than one expected exceedance per year, averaged over 3 years. See 40 CFR 50.6 and 40 CFR part 50, appendix K.

On July 18, 1997 EPA reaffirmed the annual PM-10 standard and slightly revised the 24-hour standard (62 FR 38651). In the same action, EPA also established two new standards for PM, both applying only to particulate matter up to 2.5 microns in diameter (PM-2.5).

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2.  The two PM-10 standards are independent and must be addressed independently by states in their SIPs. This independence was highlighted by the Ninth Circuit Court of Appeals in Ober v. EPA, 84 F.3d 304 (9th Cir. 1996).

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3.  There were exceedances of the 24-hour PM-10 standard during 2000-2001 but not in 1999. Those exceedances were caused by high wind events and were flagged by the SCAQMD under the provisions of EPA's Natural Events Policy which is discussed in detail in Section III of this proposed action. If EPA concurs that data were properly flagged under that policy, the data are not used for purposes of determining attainment of the NAAQS or for computing a design value for the area. EPA has received documentation from CARB justifying the flagging of each of these events under the Natural Events Policy and concurs with CARB's justification. Given the flagging of all the 24-hour exceedances during 2000 and 2001, EPA concludes that there was no violation of the 24-hour standard during the period from 1999-2001.

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4.  When a moderate area is reclassified to serious, the requirement to implement RACM in section 189(a)(1)(C) continues to apply. Thus, a serious area's PM-10 plan must provide for the implementation of RACM as expeditiously as practicable to the extent that the RACM requirements have not been satisfied in the area's moderate plan. We are not making an independent assessment of the Plan's control measures against the RACM and RACT requirements since the plan will meet RACM and RACT requirements if it is found to meet the BACM requirement.

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5.  EPA originally approved a version of Rule 403 into the SIP on June 14, 1978. The SCAQMD subsequently revised the rule in 1992, 1993 and February 14, 1997. On August 11, 1998 (63 FR 42786) EPA proposed granting limited approval and limited disapproval of Rule 403 as amended on February 14, 1997 because it did not fully meet the CAA provisions regarding plan submissions and requirements for nonattainment areas. EPA gave final limited approval and disapproval of Rule 403 on December 9, 1998 (63 FR 67784). Following another amendment that was submitted by the SCAQMD as a SIP revision on May 13, 1999, EPA granted full approval of the Rule on February 17, 2000 (65 FR 8057).

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6.  Resolution No. 02-21 adopted by the SCAQMD Board June 21, 2002:

BE IT FURTHER RESOLVED, that the South Coast Air Quality Management District Governing Board directs the Executive Officer to update the 2002 CVSIP, including emissions budgets in 2003, using the latest approved motor vehicle emissions model and planning assumptions; and

BE IT FURTHER RESOLVED, that the South Coast Air Quality Management District Governing Board requests that the U.S. EPA approve the District's commitment to forward to the CARB for review and submittal to the U.S. EPA as a revision to the State Implement Plan by 2003 the update to the PM-10 emissions inventory portion of the 2002 CVSIP, including revised emission budgets using the latest approved motor vehicle emissions model and planning assumptions; and

BE IT FURTHER RESOLVED, that the South Coast Air Quality Management District requests that the U.S. EPA approve the emissions budgets based on the 2002 CVSIP for use only until the U.S. EPA finds adequate the revised budgets for the same years submitted as part of the 2003 revision to the 2002 CVSIP.

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[FR Doc. 02-31679 Filed 12-16-02; 8:45 am]