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DEQ Works With Partners to Address Ozone Non-Attainment; ALA Ranking Tells Part of the Story

MI Environmental map of Michigan designating ozone nonattainment areasApril 4, 2019

The Michigan Department of Environmental Quality's Air Quality Division (AQD) is working with stakeholders and partners in 10 counties across Michigan to address the United States Environmental Protection Agency's (EPA) designation of nonattainment for the ozone standard. As part of the ongoing work to bring those regions below the current federal standard for ozone, DEQ continues to work toward improving the state's air quality.

In its soon to be released annual "State of the Air" report, the American Lung Association (ALA) gives Michigan a failing grade. However, according to AQD Director Mary Ann Dolehanty, the report only reflects part of the story.

"It is definitely true that ozone level reductions need to continue in many parts of the state," said Dolehanty. "However, we believe the ALA report only tells part of the story. It uses a different standard of measurement than the EPA regulations that we are required to follow. We are working in every one of the 10 counties with nonattainment designations to ensure that we are addressing ways to protect the health of Michiganders and to bring those regions into attainment. It does not reflect the time and effort being spent to work with stakeholders and partners to get air quality in these areas below the current standards. We maintain our commitment to fulfilling our mission to protect the environment, as well as the health of the people in each of these areas."

The ALA report, which is slated for publication in April 2019, focused on measured air pollution levels of ozone and particulate matter (PM) (size fraction of 2.5 microns and smaller or PM2.5) for 2015-2017. The ALA's letter grading methodology utilizes the Air Quality Index (AQI) to calculate a factor that resulted in a low or failing letter grade for several counties in Michigan. The AQD considers the true assessment of air quality is reflected in comparison to the health protective National Ambient Air Quality Standards (NAAQS) rather than the AQI, which is designed for real-time public notification.

To monitor air quality, the AQD operates a network of air monitors throughout Michigan. The continuous monitoring instruments for ozone and PM2.5 in this network, as well as other networks throughout the nation, provide data to the EPA's AirNow Web site to display the AQI values. The EPA has assigned a color to each AQI category to demonstrate air quality, from 'Good' to 'Hazardous,' based on real-time air pollution monitors. The AQI categories describe potential health effects the public could experience within a few hours or days after breathing polluted air. The EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, the EPA has established the longer term NAAQS to protect public health.

In October 2015, the EPA revised the NAAQS for ozone from 0.075 to 0.070 parts per million (ppm). The AQD made recommendations to the EPA in October 2016 for ozone nonattainment areas based on reviewed and validated data from 2013-2015. The data from 2016 did not change the recommendations. Five monitors in Michigan were above the standard of 0.070 ppm: Coloma, Holland, Muskegon, New Haven, and Port Huron, located in Berrien, Allegan, Muskegon, Macomb, and St. Clair counties, respectively. Based on a weight-of-evidence analysis, including those monitors that were not meeting the standard, the AQD recommended that 10 counties or portions of counties be designated nonattainment for the ozone NAAQS. Five additional counties were deemed to contribute to neighboring nonattainment areas. Those counties included Livingston, Monroe, Oakland, Washtenaw, and Wayne.

The EPA made their final designations of nonattainment for the seven-county area in southeast Michigan and Berrien County on the west side of the state. Partial county designations were made for Allegan and Muskegon Counties. Furthermore, the remaining 73 Michigan counties were determined to be meeting the ozone standard or deemed unclassifiable due to a lack of monitoring data. The AQD is working with local partners and stakeholders to develop strategies to bring these areas into attainment with the ozone standard. The AQD’s PM2.5 monitors are showing compliance with the NAAQS and all areas of the state are classified as attainment for this pollutant.

While the regulatory standards have been lowered, which has caused some areas to be classified as nonattainment for ozone, historic trends show that the air quality continues to improve across Michigan. There is still work to be done, and the AQD is committed to reducing air pollution for the citizens of Michigan.? More information about air monitoring is available at



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