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SLO COUNT~J Air Pollution Control District

apCu San Luis Obispo County

May 19, 2015

Richard W. Corey

California Air Resources Board

P0 Box 2815

1001 “1” Street

Sacramento CA 95812

SUBJECT: Request for Extension of July 20, 2015 Marginal Attainment Date

Dear Mr. Corey,

Pursuant to Section 1 81(a)(5) of the Clean Air Act (CM), the San Luis Obispo County Air

Pollution Control District (SLOCAPCD) requests that the Air Resources Board (ARB) submit

a letter to the United States Environmental Protection Agency (U.S. EPA) for a one-year

extension of the Eastern San Luis Obispo (SLO) County’s July 20, 2015 marginal attainment

date for the 2008 8-hour ozone standard.

According to Section 1 81(a)(5) of the CM, the U.S. EPA Administrator may grant a

nonattainment area a one-year extension of the area’s attainment date upon application

by the State if two conditions are met:

1. The State must comply with all requirements and commitments pertaining to the

area in the applicable implementation plan (Section 181(a)(5)(A)). The SLOCAPCD

has complied with all requirements and commitments pertaining to the area in the

applicable ozone implementation plan; and

2. The Eastern SLO County nonattainment area’s 4th highest daily 8-hour monitored

value during the attainment year (2014) is less than 0.075 ppm.

On May 21, 2012, U.S. EPA designated Eastern SLO County as marginal nonattainment for

the 2008 8-hour ozone standard, effectiveJuly 20, 2012(77 FR 30088). SLOCAPCD’s

marginal attainment date is July 20, 2015, three years after the designation effective date.

Attainment is based on three years of quality assured, complete and certified ambient air

quality monitoring data.

For Eastern SLO County, the defined three years to demonstrate attainment of the

marginal attainment date are 2012, 2013 and 2014. SLOCAPCD did not acheive the 2008

8-hour ozone standard by the attainment date; however, in the 2014 attainment year, the

4th highest daily maximum 8-hour value for the area is 0.073 ppm, which is below 0.075

ppm.

805.781.5912 805.781 .1002 slocleanair.org 3433 Roberto Court, San Luis Obispo, CA 93401
SLOCI4PCD Extension Request

May 19, 2015

Page2of2

SLOCAPCD has met both of the criteria to qualify for an extension of its 2008 8-hour ozone standard

marginal attainment date and requests ARB’s assistance to petition U.S. EPA to grant this extension.

We look forward to U.S. EPA approval of this request for a one-year extension of the attainment

date. If you have any questions, please call Aeron Arlin Genet at 805-781-5998.

LNga/arr

CC: Carol Sutkus, CARB (via email, carol.sutkuscoarb.ca.gpv)

Monica Lewis, CARB (via email, monica.lewisaarb.ca.gov)

Larry Allen

Air Pollution Control Officer

H:~PLAN~Attainment_PIanning\ozone~ozone1yrExtensjon2o1 5\OnevearExtensionRequestsLocounty.docx
Table I

Fourth Highest 8-hour Ozone Average Daily Maximums

and Design Values

for Eastern San Luis Obispo County

(parts per million)

Fourth-Highest

Monitoring 201 2-2014 8-hour Average

Site Design Value Ozone_Concentration

___________________ 2012 2013 2014

Carrizo Plains 0.070 0.075 0.067 0.068

Red Hills 0.076 0.081 0.075 0.073