By Matthew Holloway |

Maricopa County officials announced that a recent determination from the Environmental Protection Agency (EPA) will not trigger additional air quality regulations for the region, maintaining its current “moderate” nonattainment classification under federal ozone standards.

According to Maricopa County, it remains designated as a “moderate” nonattainment area under the 2015 8-hour ozone National Ambient Air Quality Standards (NAAQS), meaning ozone levels in parts of the region continue to exceed federal limits. However, the county has avoided a “serious” classification, which would increase regulatory burdens on industry.

The Clean Air Act requires areas that exceed those standards to implement measures to reduce ozone-forming pollutants such as nitrogen oxides (NOₓ) and volatile organic compounds (VOCs).

The EPA had been evaluating whether to reclassify the Phoenix-Mesa area since at least 2024. The agency has now issued its final determination that the region would have met federal standards if not for emissions originating outside the United States and other uncontrollable factors, allowing Maricopa County to avoid additional mandates. As a result, the county will continue operating under its current regulatory framework.

“For years, Maricopa County has taken significant steps to reduce air pollution through outreach programs and practical compliance tools for businesses. But we don’t think we should face further regulations that harm business for the types of pollution we can’t control,” Board of Supervisors Chair Kate Brophy McGee stated. “I’m pleased the EPA agrees with our position. We remain committed to pursuing programs and initiatives that improve air quality in Maricopa County.”

County officials said the decision reflects years of local mitigation efforts, including outreach programs, compliance tools for businesses, and coordination with regional and state air quality agencies.

The announcement follows a series of state and federal actions related to air quality policy that Arizona leaders have closely monitored.

Then-Congresswoman Debbie Lesko and other officials pushed back in late 2024 against a potential EPA reclassification of Maricopa County, warning that stricter standards could have economic and national security implications.

In December 2025, the EPA moved to vacate a contested Biden-era air quality rule as part of a multi-state legal challenge, signaling a shift in federal regulatory posture.

Arizona lawmakers have also raised concerns at the federal level. Earlier this year, State Sen. Frank Carroll (R-LD28) urged Congress to clarify the EPA’s authority over air quality standards, warning that regulatory uncertainty could impact economic growth in the state.

“Americans deserve clean air, land, and water, but they also deserve an economy that can grow without unnecessary federal interference,” Carroll said in a statement at the time. He added, “While the Clean Air Act allows for specific emissions regulations, the EPA must not exceed its authority or violate fundamental principles of separation of powers. By preventing bureaucratic overreach, we can protect both the environment and the economic opportunities Arizona families and businesses rely on.”

The issue has also intersected with Arizona’s economic development efforts, with Congressman Abe Hamadeh (R-AZ08) highlighting the importance of regulatory stability in May 2025 as major employers, including semiconductor manufacturer TSMC (Taiwan Semiconductor Manufacturing Co.), continue to invest billions of dollars in facilities in the Phoenix area.

Air quality regulations tied to ozone nonattainment status can influence permitting requirements, industrial expansion, and transportation planning, making federal classification decisions a key factor in long-term economic planning.

Maricopa County was reclassified from “marginal” to “moderate” nonattainment status in 2022 according to the Arizona Department of Environmental Quality (ADEQ) after failing to meet federal ozone standards, triggering additional planning requirements under the Clean Air Act.

County officials said they will continue pursuing strategies to reduce emissions and improve air quality while working within the existing regulatory framework.

Philip McNeely, Director of the Maricopa County Air Quality Department, said, “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. We are committed to clean air initiatives that make Maricopa County a healthier place to live.”

Matthew Holloway is a senior reporter for AZ Free News. Follow him on X for his latest stories, or email tips to Matthew@azfreenews.com.