U.S. EPA FACT SHEET

Proposed Approval of the South Coast 1-Hour Ozone Attainment Demonstration,
Proposed Approval of the South Coast 1-Hour and 8-Hour Ozone VMT Offset Demonstrations, and

Interim Final Determination to Defer Sanctions

May 5, 2014

Summary

•	Today, EPA is announcing a series of actions affecting the South Coast ozone nonattainment area for
both the 1-hour and the 1997 8-hour ozone national air quality standards.

o EPA is proposing to approve California's new plan for attainment of the 1-hour ozone standard in the
South Coast extreme ozone nonattainment area. The revised plan demonstrates attainment of the 1-hour
ozone standard in the South Coast nonattainment area in 2022.

o EPA is also proposing to approve vehicle miles traveled (VMT) emissions offset demonstrations, for the
1-hour and the 1997 8-hour ozone standards, showing that emissions resulting from increased VMT and
vehicle trips in the South Coast have been adequately offset by transportation control strategies and
transportation control measures that reduce emissions.

o Lastly, because of the proposed approval of the VMT offset demonstrations, EPA is issuing an interim
final determination to defer sanctions resulting from EPA's disapproval of the previously submitted VMT
offset demonstrations for the South Coast. The sanctions were scheduled to go into effect in October
2014.

•	Although EPA has replaced the 1-hour ozone standard with a more health protective 8-hour standard, the Clean
Air Act (CAA) requires that California have approved plans in place for attaining the 1-hour standard in 1-hour
ozone nonattainment areas.

•	Air quality has been steadily improving in the South Coast. Since 1985 there have been 95% fewer exceedances
of the 1-hour ozone standard. See trend chart below.

Background

•	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.

•	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.

•	In 2012 the Ninth Circuit Court of Appeals found that the 2003 and 2008 revisions called into question the
1997/1999 plan's adequacy and directed EPA to take further action to ensure that the South Coast has an
approved plan demonstrating attainment of the 1-hour ozone standard, consistent with CAA requirements.


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•	As a result, on January 7, 2013, EPA published a final rule requiring California to submit revision to correct the
deficiencies in the State Implementation Plan (SIP). This is referred to as a SIP call.

•	On March 28, 2013 and in response to a remand by the Ninth Circuit Court of Appeals in Association of Irritated
Residents v. EPA, EPA finalized the withdrawal and disapproval of previously submitted South Coast VMT
emissions offset demonstrations. This action triggered deadlines for a new submittal by the State and approval by
EPA in order to avoid sanctions.

•	Today's proposed approvals are in response to EPA's SIP call and disapprovals and California's subsequent
submittal of a SIP revision addressing the deficiencies.

•	EPA is providing a comment period of 30 days on the proposed rules and interim final rule. We will respond to all
comments in the final rules.

•	For the interim final rule, if no comments are submitted that change our assessment, then all sanctions and
sanction clocks will be permanently terminated on the effective date of the interim final rule.

For More Information visit: http://www.epa.gov/region9/air/actions/ca.html

Figure 1: There lias been a 95% reduction in the number of 1 -hour ozone exceedances in the South Coast since 1985.

US EPA REGION 9 AIR QUALITY TRENDS, 1985-2013
1-HOUR OZONE DESIGN VALUES FOR SOUTH COAST AQMD, CALIFORNIA

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Source: US EPA's Air Quality Systems (AQS) database (February 24, 2014).

The 1979 national ambient air quality standard (NAAQS) level for 1-hour ozone was 0.12 parts per million (ppm), and was revoked in 1997. The standard is
attained when the expected number of days per calendar year with maximum hourly average concentration greater than 0.12 ppm, averaged over a consecutive
three-year period, is equal to or less than 1. The air quality monitor that has the highest design value for each year in the South Coast Air Quality Management
District is shown here; X-axis labels represent the last year of a monitor's 3 year time period. All exceptional event data (e.g., high winds and wildfires) that EPA
has concurred on have been excluded from design value calculations. Data from 2013 are preliminary and have not been reviewed by EPA.


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