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EPA redesignates Phoenix area as attaining 1-hour ozone standard

Release Date: 3/14/2005
Contact Information: Wendy L. Chavez, (415) 947-4248,

Area reports eight years of clean data

SAN FRANCISCO -- The U.S. Environmental Protection Agency today proposed to redesignate the Phoenix metropolitan area as having met the federal health standard for 1-hour ozone.
Photo of Mobile sources cause the majority of the Phoenix valley’s volatile organic compounds and nitrogen oxides emissions
The Phoenix area has not violated the federal 1-hour ozone standard in the last eight years, despite its growth into one of the country's major metropolitan areas. The EPA also proposed to approve the state's plan that shows how the region will continue to maintain healthy levels of 1-hour ozone in the area.

The agency also approved a boundary change to exclude the Gila River Indian Community from the Phoenix 1-hour ozone maintenance area given topography, meteorology, population and expected growth, and other factors show that the area is and continues to be isolated from historic 1-hour ozone problems associated with the Phoenix area north of the reservation.

"The state and local community have worked hard to improve Phoenix's air quality and we commend that effort," said Wayne Nastri, the regional administrator for the EPA's Pacific Southwest office. "We must now build on this progress to address additional regional air pollutants, such as coarse particulate matter and 8-hour ozone, for all Phoenix residents."

"This is good news for Valley residents, who have seen their air quality improve dramatically over the past eight years," said Maricopa Association of Governments Chair Keno Hawker, Mayor of the City of Mesa. "Cleaner air means an improved quality of life. We have worked hard at both the local and regional level to implement the control measures needed to reduce ozone pollution, and the redesignation is the result of a strong partnership among municipal governments, the Governor's Office, State Legislature, Maricopa County, business and industry in addressing regional issues."

"This is great news for everyone in the Valley,"Arizona Department of Environmental Quality Director Steve Owens said. "The steps we have been taking to cut down on the emissions that conbtribute to the formation of ozone pollution clearly are working."

Area sources and on-road and non-road mobile sources cause the majority of the Valley's volatile organic compounds and nitrogen oxides emissions, precursors to1-hour ozone.

Ozone is a gas that occurs naturally in the upper atmosphere to protect earth from the sun's harmful ultraviolet rays. At ground level, ozone is created by a chemical reaction involving sunlight, high temperatures and pollutants such as car exhaust, oil and gas vapors, and paint and hairspray fumes.

Ozone pollution aggravates 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.

State and local agencies run a number of innovative programs that have reduced VOCs and nitrogen oxide emissions, including a nationally recognized vehicle emissions inspection program, a cleaner burning gasoline program, pollution reduction measures for commercial and industrial sources, and woodburning restrictions.

After the 1990 Clean Air Act amendments, the Phoenix area did not meet the moderate 1-hour ozone standard by the Nov. 15, 1996 deadline. In 1997, the EPA reclassified the area to serious, with a new attainment date of November 15, 1999. The Phoenix metropolitan area has not exceeded the 1-hour ozone standard since 1996.

For more information, see .

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