## State of California

Staff Report



# Analysis of the Coso Junction PM10 Redesignation Request and

Maintenance Plan

Release Date: June 7, 2010 Scheduled for Consideration: June 24, 2010 California Environmental Protection Agency 

# AIR RESOURCES BOARDThis document has been reviewed by the staff of the California Air Resources Board

and approved for publication. Approval does not si gnify that the contents necessarily reflect the views and policies of the Air Resources Board, nor does the mention of trade names or commercial products constitute endorsement or recommendation for use.TABLE OF CONTENTS

I. BACKGROUND.........................................

................................................... .......... 1

II. REDESIGNATION REQUIREMENTS ......................... ........................................... 1

III. EVALUATION OF THE COSO JUNCTION PLAN ............... .................................. 2

A. Coso Junction Attains the 24-Hour PM10 Standard....

...................................... 2

B. The State Has Met Applicable Act Requirements..................

..................... 3

C. Improvement in Coso Junction’s PM10 Air Quality is Due to Permanent and

Enforceable Reductions in Emissions ................

............................................... 3

D. Maintenance Plan...................................

................................................... ........ 4

1. Attainment Emission Inventory......................

................................................ 4

2. Maintenance Demonstration..........................

................................................ 5

3. PM10 Monitoring Network ............................

................................................. 5

4. Verification of Continued Attainment ...............

.............................................. 5

5. Contingency Plan ...................................

................................................... .... 5

IV. STAFF RECOMMENDATION ............................... ................................................. 61

I. BACKGROUND

The Coso Junction Planning Area (Coso Junction) was initially designated as a PM10 nonattainment area in 1987 along with the Indian We lls Valley and Trona areas. Together they comprised the Searles Valley PM10 non attainment area. The Great Basin Unified Air Pollution Control District (Distr ict) adopted the first PM10 attainment plan for the Coso Junction portion of the Searles V alley PM10 nonattainment area in

November 1991. The Coso Junction attainment demonst ration was based on controlling dust from Owens Lake. In August 2002, the US Enviro nmental Protection Agency (U.S. EPA) redesignated the Searles Valley into thr ee separate PM10 nonattainment areas; Coso Junction, Indian Wells Valley, and Tron a.

On May 19, 2010, the U.S. EPA finalized its determi nation in the Federal Register that

Coso Junction attained the 24-hour PM10 standard. B ased on their clean data finding,

U.S. EPA has determined that certain nonattainment area requirements do not apply, including those for reasonable further progress (RF P), an attainment demonstration, reasonably available control measures (RACM), and c ontingency measures, because these provision’s sole purpose is to achieve attain ment of the standard. On May 17, 2010, the District adopted the PM10 Redesignation R equest and Maintenance Plan (Plan) for Coso Junction. The Plan officially reque sts that this area be redesignated to

attainment for the PM10 standard and charts the cou rse for continued maintenance of the standard. The concerted adoption of controls o n Owens Lake resulted in the Coso Junction attaining the 24-hour PM10 standard based on 2007-2009 PM10 data.

II. REDESIGNATION REQUIREMENTS

Air Resources Board (ARB) staff reviewed the Coso J unction PM10 Maintenance Plan within the context of the Clean Air Act (Act), whic h identifies the following requirements an area must meet to be redesignated to attainment:

A. The PM10 standard has been attained; B. The District has an approved State Implementatio n Plan (SIP) and the State has met all applicable Act requirements for PM10 in the nonattainment area; C. The improvement in PM10 air quality is due to pe rmanent and enforceable emission reductions; and D. U.S. EPA has approved a maintenance plan.

The Act also sets the general framework for mainten ance plans 1 . Each PM10 maintenance plan must provide for continued mainten ance of the PM10 standard for ten years after redesignation and includes the foll owing components:

1. Attainment emission inventory;

1 Calcagni, John, Memorandum, Procedures for Processing Requests to Redesignate A reas to Attainment, Office of Air Quality Planning and Stan dards , Research Triangle Park, North Carolina, September 4, 1992. http://www.epa.gov/ttn/oarpg/t5/memoranda/redesignm em090492.pdf2

2. Maintenance demonstration; 3. Commitment to continue the monitoring network op eration;

4. Commitment for verification of continued attainm ent; and 5. Contingency plan to promptly correct any violati on of the PM10 standard that occurs after the area has been redesignated.

III. EVALUATION OF THE COSO JUNCTION PLAN

Based on review of the Coso Junction PM10 Maintenan ce Plan and the District’s supporting technical analysis, ARB staff concurs th at the Plan meets the Act’s requirements. The following sections describe the major elements of the Plan and the redesignation request.

A. Coso Junction Attains the 24-Hour PM10 Standard

PM10 is measured at one monitoring station in Coso Junction (Figure 1). A TEOM (tapered element oscillating microbalance) collects hourly PM10 samples at this site.

The 24-hour standard is met when the estimated numb er of exceedances measured over a three year period averages one or less per y ear. Daily PM10 monitoring data collected at Coso Junction over the last 3 years ha s shown on average no more than 1 exceedance of the PM10 standard per year as require d to demonstrate attainment of the federal standard. Figure 1 illustrates the Cos o Junction PM10 nonattainment area, monitor locations, and the area’s close proximity t o Owens Lake.

Figure 1. PM10 Monitoring Stations in Coso Junctio n3

On three days over the 2007 to 2009 period, the 24- hour standard was exceeded due to high wind conditions that suspended fugitive dust f rom an unpaved parking area and from Owens Lake. The owner of the unpaved parking a rea was notified and the area was graveled in 2008 and surfaced with asphalt in 2 009 to control fugitive dust. Table 1

shows the maximum 24-hour concentration at the Coso Junction site between 2007 and 2009 and average exceedance days, demonstrating att ainment.

Table 1

. Coso Junction PM10 Data from 2007 to 2009

Monitoring

Station Observed Maximum 24-hour

Concentration ( μ g/m 3 ) 24-Hour Exceedance Days 3-year Average Exceedance Days

2007 2008 2009 2007-2009 2007-2009

Coso Junction 283 137 168 3 1

B. The State Has Met Applicable Act Requirements

ARB and the District have met all of the Act requir ements applicable for a moderate

PM10 nonattainment area to be considered for redesi gnation. Due to the clean data finding, this Plan will serve as meeting the requir ement of an approved SIP.

C. Improvement in Coso Junction’s PM10 Air Quality is Due to Permanent and

Enforceable Reductions in Emissions

Coso Junction is an isolated area with a population of roughly 100 people. The main source of PM10 pollution in Coso Junction is transp ort of fugitive dust from the Owens Valley. In 1998, the Owens Valley SIP was adopted a nd approved by the U.S. EPA including a control strategy that required dust con trols on 16.5 square miles of the lakebed. Under the Owens Valley SIP, the City of Lo s Angeles is responsible for mitigating the dust generated from Owens Lake in or der to bring the area into attainment with the PM10 standard. (GBUAPCD, 1998) The Owens Valley SIP was revised in 2003 to expand dust controls to 29.8 squ are miles of the lake bed by December 31, 2006. The City of Los Angeles successf ully implemented these control measures by the required deadline.

In 2008, the Owens Valley SIP was amended to expand control requirements to a total of 43.1 square miles of the Owens Lake bed. The Cit y of Los Angeles is expected to have dust control measures implemented on 39.6 squa re miles of the lakebed by April 1, 2010, and then to expand the control area to 43.1 square miles by October 1, 2010. Overall, PM10 emissions from the Owens Lake bed have been reduced by 90% since 2000 when the City of Los Ange les initiated efforts to control windblown dust at Owens Lake. Thus, the improvement in Coso Junction is due to permanent and enforceable reductions.4

D. Maintenance Plan

The Coso Junction PM10 Maintenance Plan includes th e following components: emission inventory; commitment to continue monitori ng network operation; commitment for verification of continued attainment; and conti ngency plan.

1. Attainment Emission Inventory

An emission inventory is a critical tool used to su pport evaluation, control, and mitigation of air pollution which is comprised of a systematic listing of the sources of air pollutants along with the amount of pollutants emitted from ea ch source or category over a given period of time. Emission inventories are estimates of the air pollutant emissions released into the environment – they are not direct ambient concentration measurements. To determine the expected emissions in future years, emission inventories incorporate the effects of growth and e xisting regulations (baseline inventories). An attainment inventory identifies t he level of emissions during the period when air quality data show attainment.

The Coso Junction PM10 Maintenance Plan presents an updated 2009 attainment inventory of direct PM10 emissions split by source subcategory. Inventory updates include the latest point, area, and mobile source e missions for the Coso Junction. Total PM10 emissions are estimated at 1,427 pounds per da y for the Coso Junction, which is less than 0.1% of the emissions caused by windblown dust from Owens Lake. In addition to the 2009 adjusted baseline PM10 emissio ns, the Coso Junction PM10 Maintenance Plan provides emission projections out to 2025. No significant growth or changes in the emission inventory are expected for Coso Junction through the year

2025.

Table 2. Coso Junction PM10 Emissions Inventory

Daily PM10 Emissions for 2009 through 2025
Stationary Sources Pounds/day
California Lightweight Pumice 167
China Lake Naval Air Weapons Station 84
Coso Operating Company 953

Halliburton Services 20

Twin Mountain Rock 58

Area Sources
Unpaved Roads 33

Paved Roads 101

Mobile Sources

On Road Motor Vehicles 12

Total PM10 (pounds per day) 1,4275 2. Maintenance Demonstration

Coso Junction is projected to maintain attainment w ith the PM10 standards due to ARB, District, and other State and local control measure s already in place. No significant growth or changes in the emission inventory are exp ected for Coso Junction through the year 2025. Thus, Coso Junction is expected to maint ain the PM10 standard. In addition, regional PM10 emissions are projected to decrease e ven further in the future as a result

of the additional controls on Owens Lake.

3. PM10 Monitoring Network

The District commits to continue PM10 monitoring to verify continued attainment of the PM10 standard. The existing PM10 monitoring network in Coso Junction includes a PM10 TEOM monitor located at the Highway 395 rest a rea in Coso Junction (Figure 1). Federal regulations require daily sampling at the s ite reporting peak PM10

concentrations. This real-time PM10 monitor meets t his daily monitoring requirement.

4. Verification of Continued Attainment

To verify continued attainment of the PM10 standard , the District commits to continue daily PM10 monitoring at the Coso Junction rest are a to help ensure new sources of PM10 are identified and controlled, if necessary.

5. Contingency Plan

The Act requires the maintenance plan to include co ntingency provisions for prompt correction of any PM10 standard violation that migh t 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 effe ct without further state action as is required in attainment SIPs. Instead, for maintenan ce plans, the area must have a plan to ensure that contingency measures are adopted onc e they are triggered.

District staff believes the control strategy and co ntingency requirements in the 2008 Owens Valley PM10 SIP are adequate to protect air q uality in the Coso Junction area. Therefore, no additional contingency measures will be needed to ensure future compliance with the federal PM10 standard in Coso J unction.6

IV. STAFF RECOMMENDATION

ARB staff has reviewed the PM10 Redesignation Reque st and Maintenance Plan for

Coso Junction and consulted with District staff dur ing this review. ARB staff finds that

the Coso Junction PM10 Maintenance Plan meets all a pplicable Act requirements. ARB staff believes that implementation of this Plan wil l continue to maintain PM10 levels below the national air quality standard in Coso Jun ction. Therefore, we recommend that the Board adopt the Coso Junction PM10 Maintenance Plan as a revision to the

California SIP for submittal to U.S. EPA. In addit ion, ARB staff recommends that the Board approve the District’s request that Coso Junc tion be redesignated from

nonattainment to attainment for the national PM10 s tandard.