U.S. EPA FACT SHEET

Final Rule for San Joaquin Valley 

Attainment Demonstration for the 1-Hour Ozone Standard and

1-Hour and 8-Hour Ozone VMT Offset Demonstrations

February 25, 2016

Summary of Action

• Today, EPA is announcing a series of actions affecting the San Joaquin Valley ozone 

nonattainment area (SJV) for both the 1-hour and the 1997 8-hour ozone National 

Ambient Air Quality Standards (standards). Specifically, EPA is taking the following 

actions:

o Approving California’s new plan for attainment of the 1-hour ozone standard in the 

SJV in 2017. 

o Approving 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 trips in the SJV have been adequately offset by transportation 

control strategies and transportation control measures. 

• The 1-hour ozone plan addresses numerous requirements in the Clean Air Act (CAA) that 

will help the area attain the 1-hour standard by its November 26, 2017 deadline. In 

today’s action, EPA is approving the following elements of the plan for the SJV area: 

⋅ Attainment demonstration

⋅ Emissions inventories

⋅ Air quality modeling 

⋅ Reasonably available control measures

⋅ Provisions for transportation control strategies and measures 

⋅ Reasonable further progress (RFP) demonstrations

⋅ Contingency measures for failure to make RFP

Background

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

standards, the CAA requires California to have approved plans in place for attaining the 

1-hour standard.

• In March 2010, the EPA approved the State’s previous plan and its amendments for 

attaining the 1-hour ozone standard in the SJV area, but in December 2011, the EPA 

found that the SJV area had failed to attain the 1-hour ozone standard by its November 

15, 2010 attainment deadline. 
U.S. EPA FACT SHEET

• In response to a decision of the U.S. Court of Appeals for the Ninth Circuit in Sierra 

Club et. al v. EPA, in November 2012, the EPA withdrew its March 2010 approval of the 

prior plan. As a result, California was required to submit a new plan demonstrating 

attainment in the SJV of the 1-hr ozone standard. 

• Attainment of the 1-hr ozone standard in the SJV area is expected in 2017 as a result of 

substantial emissions reductions (i.e., 49% for nitrogen oxides (NOx) and 20% for 

volatile organic compounds (VOCs)) occurring since 2007. 

• 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 NOx and 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.

• California recently submitted to EPA a Clean Data Finding request indicating that the 

SJV has attained the 1-hour ozone standard. EPA expects to act on that request in the 

next few months.

• Despite today’s significant milestone, the State currently does not expect the SJV area to 

attain the 1997 ozone standard before 2024, and the State will also need to address the 

more stringent 2008 and 2015 ozone standards at a later date.

Next Steps

Today’s action will become effective 30 days after publication in the Federal Register.

For More Information: 

http://www3.epa.gov/region09/air/sjvalley/index.html.