EPA Finds No Additional Air Quality Regulations Needed in Maricopa County

Maricopa County scored a win this month with the Environmental Protection Agency finding that emissions from outside the United States are inflating ground-level ozone levels in the region, and if not for that uncontrollable pollution, Maricopa County would have met 2015 National Ambient Air Quality Standard (NAAQS) for ozone.

The finding on this critical issue means the region will remain a “moderate” nonattainment area instead of being reclassified to “serious,” which would have come with increased regulations and constraints on economic development.

The Clean Air Act requires the Environmental Protection Agency (EPA) to establish national primary and secondary standards for pollutants that cause or contribute to air pollution that is expected to endanger public health, such as ozone.

Maricopa County is currently designated as a moderate nonattainment area for ground-level ozone under the 2015 8-hour ozone NAAQS. This designation means ozone concentrations in parts of the county exceed the 2015 ozone standard and require air quality planning and control measures to reduce ozone precursors, volatile organic compounds (VOCs) and nitrogen oxides (NOₓ).

The EPA had been evaluating whether to reclassify the area to a “serious” nonattainment category due to continued exceedances, which would have triggered stricter control requirements.  However, Maricopa County, in partnership with the Maricopa Association of Governments and the Arizona Department of Environmental Quality, presented evidence that regional ozone levels have been impacted by international transport, wildfires, and other factors beyond local control.  Now, EPA has issued its final decision on the matter, maintaining Maricopa County’s moderate designation.

“By maintaining moderate nonattainment status, Maricopa County can continue to focus on reducing pollution and finding solutions specific to our area.  These include outreach, incentive programs for residents, practical compliance tools for business, and the pursuit of innovative emission-reduction credit rules,” said Philip McNeely, Director of the Maricopa County Air Quality Department.  “We are committed to clean air initiatives that make Maricopa County a healthier place to live.”