PHOENIX (AP) -- Federal environmental regulators are poised to approve an air-quality plan that has led Maricopa County to meet U.S. health standards for dust levels.
The Environmental Protection Agency announced Wednesday that it would approve the county's Five Percent Plan.
The plan, a revised version of which was submitted to the EPA in 2012, sought to reduce dust emissions by at least 5 percent each year between 2007 and 2013.
Officials in Phoenix and surrounding cities say they have been implementing aggressive dust-control policies.
Mesa Mayor Scott Smith, who is the chairman of the Maricopa Association of Governments, said "collective efforts have resulted in dramatic improvements in the concentration of dust in the valley, improving the quality of life for all of the county's residents."
The Arizona Republic reports that getting "non-attainment" status lifted for metropolitan Phoenix was crucial to retaining billions of dollars in federal transportation funding. Some local and county agencies postponed transportation planning because levels of PM10 dust particulates, which are about one-tenth the width of a human hair, were still above federal limits.
Maricopa County air-quality officials say the county had failed to meet federal standards for dust since the Clean Air Act was amended in 1970.
State and county officials also argued that "exceptional events" such as regional dust storms during monsoon season were beyond any dust control. As a result, the EPA has excluded dust storms from consideration under the Clean Air Act.
The proposal will be sent to the Federal Register for publication as a proposed rule and include the EPA's analysis. There will also be a 30-day public comment period. EPA will make its final decision on the plan after reviewing public comments.
The EPA says dust is a public health concern because particulate matter affects the respiratory system.
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