U.S. EPA FACT SHEET

Proposals for California 1-Hour Ozone Plans

August 30, 2012

Summary

•	Today, EPA is proposing actions to require California to develop new plans for
attainment of the 1-hour ozone air quality standards in the South Coast and San Joaquin
Valley (SJV) extreme ozone nonattainment areas.

•	These proposals are in response to two Ninth Circuit Court of Appeals decisions
remanding EPA's previous actions on California's attainment plans for these two areas
and directing EPA to take further action to ensure that both areas have plans
demonstrating attainment of the 1-hour ozone standards, consistent with Clean Air Act
(CAA) requirements.

•	The Ninth Circuit also rejected EPA's longstanding interpretation of the CAAs
requirements for offsetting emissions from vehicle miles traveled (VMT). Today, EPA is
taking action to assure South Coast and SJV plans for both the 1-hour and 8-hour ozone
standards meet this CAA requirement consistent with the Court's decision.

• Although EPA has replaced the 1-hour ozone standard with a more health protective 8-

hour standard, the CAA anti-backsliding provisions require that California have approved
plans for attaining the 1-hour standard.

Background

•	In 2000, EPA approved California's 1997/1999 revised plan for attaining the 1-hour
ozone standard in the South Coast. In 2003 and 2008, California submitted updates to that
plan, which EPA partially approved and partially disapproved in 2009. The Court found
that these revisions called into question the plan's adequacy and obligated EPA to
reevaluate it for compliance with the CAAs attainment requirements.

•	In March 2010, EPA approved California's 2004 plan for attaining the 1-hour ozone
standard in the SJV based, in part, on emissions inventory data submitted in 2004. The
Court found that EPA's approval was arbitrary and capricious because EPA failed to
consider new emissions data submitted by California in 2007, which called into question
the earlier data.

•	The CAA requires that plans for extreme ozone nonattainment areas (such as the South
Coast and SJV) contain specific enforceable transportation control strategies and
transportation control measures to offset any growth in emissions from growth in VMT.
Historically, EPA has interpreted this requirement to be met where a plan shows that
aggregate emissions from motor vehicles decline each year during the entire period
covered by the plan. The Court rejected this interpretation and determined that the CAA


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requires additional transportation control strategies and measures whenever vehicle
emissions are projected to be higher than they would be had VMT not grown, even if
aggregate vehicle emissions are decreasing.

•	The SJV Air Pollution Control District has stated its intent to withdraw the SJV 1-hour
ozone plan promptly after EPA finalizes the withdrawal of its approval. If California
withdraws the SJV 1-hour ozone plan, EPA intends to issue a finding of failure to submit
which will subject the State to mandatory sanctions unless it submits SIP revisions
correcting the deficiency within 18 months. If California does not promptly withdraw the
plan, EPA will commence a new rulemaking to address its approvability.

•	Breathing air containing ozone can reduce lung function and increase respiratory
symptoms, aggravating asthma or other respiratory conditions. Ozone exposure also has
been associated with increased susceptibility to respiratory infections, medication use by
asthmatics, and emergency department visits and hospital admissions for individuals with
respiratory disease. Ozone exposure may also contribute to premature death, especially in
people with heart and lung disease.

•	Ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic
compounds (VOCs) react in the atmosphere in the presence of sunlight. NOx and VOCs
are called ozone precursors. Motor vehicle exhaust, industrial emissions, and chemical
solvents are the major sources of these chemicals. Ozone pollution is a concern
especially when the weather conditions needed to form it, lots of sun and hot
temperatures, occur.

Next Steps

•	EPA is providing a 30-day public comment period on these proposals. EPA will consider
all submitted comments before publishing the final rule.

For More Information

http://www.epa.gov/region9/air/actions/ca.html


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