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U.S. EPA announces Imperial County meets ozone health standard

Release Date: 11/17/2009
Contact Information: Nahal Mogharabi, 415/947-4307,

(11/17/09--SAN FRANCISCO) The U.S. Environmental Protection Agency today announced that Imperial County, Calif., has met the 1997 federal 8-hour ozone standard—demonstrating improved air quality in the area.

The announcement is based on three years of certified clean air monitoring data between 2006-2008, that shows Imperial County meets the 0.08 parts per million federal 8-hour ozone standard established in 1997.

As long as Imperial County continues to uphold the standard, the Imperial Air Pollution Control District is no longer required to submit certain plans related to the 8-hour standard including attainment demonstrations, progress plans, and contingency measures. The area will still be required to update New Source Review and Reasonably Available Control Technology rules for stationary sources such as power plants and manufacturing operations.

Data are reported to the EPA from the California Air Resources Board and the Imperial Valley Air Pollution Control District’s official air monitoring network. The network consists of five monitoring sites from Calexico to Niland, operated in accordance with the EPA’s regulations and guidelines to ensure precision and accuracy.

Cleaner air in Imperial County is the result of federal, state and local actions, including stringent state and federal engine and fuel standards that reduce pollution from cars, trucks and other vehicles. In addition, Imperial County Air Pollution Control District regulates pollution from stationary sources, such as power plants and manufacturing operations. Controlling emissions from these sources has been critical in reaching the 1997 8-hour ozone health-based standard.

In 2008, the EPA updated the 8-hour ozone standard based on recent scientific studies. The EPA is now in the process of reconsidering the level of that standard. Emission controls will continue to be important to meet the new 2008 ozone standard in the future.

Ozone is a major element of urban smog and is created by the interaction of volatile organic compounds and nitrogen oxides, or NOx, in the presence of sunlight. It can reduce lung function and aggravate respiratory illnesses such as asthma, bronchitis and emphysema. Healthy people who are active outdoors on high ozone days may experience coughing, nasal congestion and itchy eyes.

For more information, please visit the EPA’s Web site at

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