Regional Air Quality Planning

 
Regional Air Quality Planning
Image of an Excavator in the desert making dust

MAG was designated by the Governor of Arizona in 1978, certified by the Arizona Legislature in 1992, and recertified by Governor Ducey in 2016 to serve as the lead regional air quality planning agency for the MAG region.

In this role, MAG develops regional air quality plans to address the National Ambient Air Quality Standards for carbon monoxide, ozone, and particulate matter.

These air quality plans are prepared in cooperation with regional partner agencies including the Arizona Department of Environmental Quality, Arizona Department of Transportation, Maricopa County Air Quality Department, Pinal County Air Quality Control District, and the Sun Corridor Metropolitan Planning Organization.

MAG Commitment to Air Quality

Did you know that MAG has been designated by the Governor as the lead air quality planning agency for the region since 1978? For almost fifty years, MAG has been planning and modeling policy actions and measures to improve air quality throughout the region.

Over the decades, the region has made tremendous progress in improving air quality. Since 2000, emissions of total air pollutants across Maricopa and Pinal County have decreased by 50 percent - even as population, economic activity, and vehicle traffic rapidly expanded.

Line chart titled 'Comparison of Growth Factors with Emissions in the Phoenix Metropolitan Statistical Area, 2000-2023.' The graph illustrates the relationship between regional economic/population growth and total carbon emissions over two decades.

Which Air Pollutants Does MAG Prepare Plans for?

Under state law, MAG is responsible for preparing regional air quality plans that are designed to show attainment with the Environmental Protection Agency (EPA) National Ambient Air Quality Standards (NAAQS) for three pollutants: carbon monoxide, ozone, and particulate matter. MAG prepares air quality plans with input and review from the MAG Air Quality Technical Advisory Committee and policy direction from the MAG Management Committee and Regional Council.

Carbon Monoxide (CO)

Colorless, odorless gas emitted by combustion sources, primarily vehicle exhaust. 
Exposure to CO can reduce oxygen-carrying capacity of the blood. 

Ozone (O3)

Main ingredient in "smog," created by chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight.
Exposure to O3 can inflame and damage airways and aggravate lung disease.

Particulate Matter (PM–10 and PM–2.5)

PM-10 is associated with sources of "dust" in the MAG region, while PM–2.5 is more closely linked to combustion and sources of "smoke."
Exposure to PM–10, and in particular PM–2.5, can negatively impact both respiratory and cardiac functions. 

How has Air Quality Improved in the Region?

MAG, in coordination with air quality partners at the Arizona Department of Environmental Quality, the Arizona Department of Transportation, Maricopa County, and Pinal County, has an impressive record in improving air quality. Below are a few of the region’s air quality achievements.

  • In 2005, EPA redesignated the MAG region as a maintenance area for carbon monoxide. The region celebrated 20 years of maintenance with the standard in 2025.
  • The MAG region has demonstrated attainment with four progressively stricter EPA ozone standards:
    • In 2001, EPA determined the region attained the one-hour ozone standard of 120 parts per billion (ppb) and redesignated the area to maintenance in 2005.
    • In 2014, EPA redesignated the region as a maintenance area for the eight-hour ozone standard of 80 ppb.
    • In 2019, EPA determined the region attained the eight-hour standard of 75 ppb.
    • In 2026, EPA determined the region would have attained the eight-hour standard of 70 ppb by August 2024, but for the impact from international emissions.
  • EPA determined the region attained the PM-10 (dust) standard in 2014.
  • EPA determined the region attained the 24-hour PM-2.5 (smoke) standard in Pinal County in 2019.

What is MAG Focused on Currently to Improve Air Quality?

While EPA determined in 2026 that the MAG region would have met the latest EPA ozone standard but for the impact of international emissions, MAG and its partner agencies continue to work to identify scientifically-sound and policy-relevant actions that can help reduce the portion of ozone under regional control. In 2025, MAG partnered with and invested $750,000 in the Arizona Ground Level Ozone Research (GLOR) Project, designed to provide scientific insights into why ozone levels in Arizona increase even when the local manufactured emissions that contribute to ozone formation continue to decrease.

MAG also launched a fireworks awareness campaign in late 2025 to highlight the serious PM-2.5 health impacts from the use of consumer fireworks during the winter holidays. The MAG region had the worst air quality in the nation on January 1, 2025, due to the use of consumer fireworks – public reduction in the use of consumer fireworks can have immediate health impacts and help assure the region continues to attain EPA PM-2.5 standards.