Newsroom | Region Reclassified for Ozone Pollution

MAG News

The Environmental Protection Agency (EPA) announced a final determination Sept. 16 that moves the region up the severity ladder for ozone pollution, reclassifying the region from “marginal” to “moderate” nonattainment.

Moves up in severity rating

Environment, Ozone, Pollution, Air Quality

The Environmental Protection Agency (EPA) announced a final determination Sept. 16 that moves the region up the severity ladder for ozone pollution, reclassifying the region from “marginal” to “moderate” nonattainment for the ozone pollution standard. While more protective of public health, it could pose additional challenges for the region in meeting the most recent, more stringent ozone standard.

“We have made significant strides in reducing ozone pollution over the years, but meeting the tighter standards implemented in 2015 has been challenging,” said Avondale Mayor Kenn Weise, chair of the Maricopa Association of Governments. “We believe, however, that with the ongoing concerted and innovative efforts by the Valley residents and businesses, we will overcome these challenges in our continuing pursuit to improve air quality.”

In 2015, the EPA tightened the ozone pollution standard from 75 parts per billion to 70 parts per billion. The more stringent standard went into effect in December 2015 and the deadline for the region to attain that standard was August 2021. The region, which includes Maricopa County and portions of Pinal County, missed that deadline.  

“We can have both strong economic development and lower pollution levels to maintain healthy communities,” said Maricopa County Air Quality Department Director, Philip McNeely. “At Maricopa County, we are focused on regulatory controls that reduce harmful emissions, while also working with the community, schools, and industry to develop outreach programs, education campaigns and pollution reduction incentives to protect people’s health and local business growth.” 

When a region is found to be in nonattainment of federal air quality standards, it is classified on a rising level of severity that begins with marginal and goes up to moderate, serious, or severe. Each more stringent nonattainment classification increases regulatory requirements, impacting drivers and businesses. The final rule issued today in the Federal Register reclassifies the Maricopa nonattainment area from marginal to moderate for the ozone pollution standard after the region failed to meet the 2021 deadline.

“Working together, Maricopa County businesses and residents have done a fantastic job of reducing ozone pollution by 12.5 percent since 2000, even as our population and economy have grown significantly,” said Arizona Department of Environmental Quality Air Quality Division Director Daniel Czecholinski. “But we have more work to do. Each of us can play a role in further reducing air emissions by taking personal actions to improve air quality, which in turn, protects public health and helps us ensure continued economic prosperity.”

The moderate nonattainment area classification requires new actions and measures, including:

  • New control measures to reduce the types of emissions that create ozone.
  • Emission offset requirement for new, large facilities locating in the nonattainment area and major expansions to large, existing facilities, which are required to offset every ton of emissions by 1.15 tons.
  • Contingency measures (i.e., measures to be deployed if the nonattainment area does not meet yearly emission reduction milestones).
  • Potential emission controls for intrastate facilities or other emission sources located outside the Phoenix-Mesa nonattainment area.

Many urban areas across the nation are facing similar challenges with ozone. A major contributor to ozone pollution is vehicle emissions. Every resident can take steps to reduce ozone emissions by doing the following:

  • Reduce the number of miles driven. Drive as little as possible: carpool, use public transit or telecommute.  For information on transportation alternatives, visit Valley Metro at
  • Fuel your vehicle after dark or during cooler evening hours.
  • Use low-VOC (Volatile Organic Compounds) or water-based paints, stains, finishes and paint strippers.
  • Delay big painting projects until high pollution advisories or health watches have passed.
  • Make sure containers of household cleaners, garage and yard chemicals and other solvents are sealed properly to prevent vapors from evaporating into the air.
  • Eliminate wood burning in fireplaces, stoves, chimineas, and outdoor fire pits.
  • Avoid using leaf blowers.
  • Conserve electricity.
  • Make the switch from gasoline to electric or battery powered lawn and garden equipment. For information on the Mowing Down Pollution and Commercial Lawn and Garden Programs, visit

Published September 16, 2022