Proposal to Affirm EPA’s October 2006 PM-10 Attainment Determination San Joaquin Valley, California


U.S. Environmental Protection Agency - Region 9
FACT SHEET
Proposal to Affirm EPA's October 2006 PM-10 Attainment Determination
San Joaquin Valley, California
August 15, 2007
Today's Action
•	EPA is today proposing to affirm its October 2006 determination that the San Joaquin Valley (SJV)
has attained the federal ambient air quality standard for particulate matter less than 10 microns in
size (PM-10).
•	This proposal provides the public with an opportunity to comment on EPA's evaluation of and
proposed concurrence with "flagged" exceedances that occurred through the end of calendar year
2006 at various PM-10 monitors in the SJV.
•	Specifically, this proposal addresses PM-10 exceedances that occurred in September, October
and December 2006 at various monitors in the SJV that we believe, based on documentation
submitted by the State, were due to high wind exceptional events.
•	Our proposal also addresses PM-10 exceedances that occurred in September and October 2006
at the Santa Rosa Rancheria, tribal lands located in the SJV. We believe that, for purposes of
comparing data to the PM-10 standard, the monitor at the Santa Rosa Rancheria was not properly
sited during this time due to nearby construction activity. We also believe that the construction
activity that caused the exceedances was an exceptional event.
•	The State and the Tribe have "flagged" these exceedances in EPA's Air Quality Database as
being due to natural/exceptional events and would like to exclude these data from regulatory
consideration, including consideration of whether the SJV has attained the PM-10 standard.
•	EPA does not generally issue notice and comment rulemaking when affirming an attainment
determination; however, we are doing so here because EPA indicated in its October 2006
attainment determination that we would reassess that determination once we received quality-
assured data from the State regarding the September 2006 exceedances, and because of
subsequent petitions regarding the PM-10 attainment status of the SJV.
•	EPA in this proposed rule is also addressing issues raised in those petitions for reconsideration
and withdrawal of EPA's 2006 determination of attainment, filed by Earthjustice on behalf of the
Sierra Club, Latino Issues Forum and others.
•	EPA's proposed rule provides detailed discussions on each of the exceedances described above,
as well as on issues raised in the petitions. EPA requests comments within 30 days of the date of
publication of this notice in the Federal Register, which should occur by the end of this month.
•	In this proposed rule, EPA is not proposing to redesignate the SJV to attainment because we do
not yet have an approved maintenance plan or a determination that the area has met other Clean
Air Act requirements for redesignation. Therefore if we take final action to affirm our 2006
attainment determination, the SJV would remain a serious nonattainment area until such time as
EPA determines that California meets the Clean Air Act requirements for redesignation of the SJV
to attainment.

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Background
• On May 8, 2006, the State submitted to EPA a request to make a finding that the SJV attained the
PM-10 standard based on data from 2003-2005. On October 17, 2006, EPA made a final
determination that the SJV had attained the PM-10 standard.
• In February 2007 the SJV Air Pollution Control District (SJVAPCD) developed the first drafts of the
necessary documents for demonstrating that each of the exceedances was due to high wind
events. Following a public comment period, the SJVAPCD revised the documents and submitted
them to the State. The State then submitted the documents to EPA. The documents provide
technical analyses of the exceedances that occurred on September 22, 2006 as well as of the
exceedances on October 25 and December 8, 2006 that occurred after EPA's attainment
determination.
• Earthjustice provided EPA with extensive comments on these and other exceedances in the SJV
via petitions for reconsideration and withdrawal.
• EPA has worked with the Santa Rosa Rancheria Indian Tribe to evaluate the cause of the PM-10
exceedances on tribal lands. Based on information from tribal representatives, we concluded that
the exceedances were caused by construction activity in very close proximity to the tribal monitor.
Since the completion of the construction activity, the tribal monitor has not recorded any more
exceedances and the PM-10 levels have dropped significantly.
Air Quality in the San Joaquin Valley
• While we continue to believe the SJV has attained the PM-10 standard, the Valley must still
implement the PM-10 control measures that have helped clean the air.
• Efforts to improve air quality are far from over as the SJV is continuing to address other air quality
standards (ozone and PM-2.5). These efforts should further reduce PM-10.
Further Information
• A copy of the proposed rulemaking will soon be available in the Air Programs section of EPA
Region 9's website, http://www.epa.qov/reqion09/air/, and on www.requlations.gov.
• For more information, please contact Doris Lo, U.S. EPA Region 9, Air Planning Office, at 415-
972-3959; lo.doris@epa.qov or Bob Pallarino, U.S. EPA Region 9, Technical Support Office, at
415-947-4128; pallarino.bob@epa.gov.

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