Harmful pollutants in Michigan's air continue their long-term decline, according to a report recently released by the Michigan Department of Environment, Great Lakes, and Energy (EGLE).
The federal Clean Air Act requires the federal Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards for six criteria pollutants considered harmful to public health and the environment: carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, lead, and particulate matter.
EGLE's air monitoring network measures these criteria pollutants to determine compliance with the national air quality standards.
Long-term trends show a continued decline in harmful pollutants. Even areas of Michigan considered to be in nonattainment for sulfur dioxide and ozone under the Clean Air Act have seen decreases in these pollutants.
Nonattainment areas are those classified by the EPA as having concentrations over the national air quality levels. Parts of Wayne and St. Clair counties are in nonattainment for sulfur dioxide. Areas of nonattainment for ozone as of Aug. 3, 2018, were Allegan, Berrien, and part of Muskegon counties, and a seven-county area in southeast Michigan (Livingston, Macomb, Monroe, Oakland, St Clair, Washtenaw, and Wayne).
In addition to the criteria pollutants, the Air Quality Division monitors for a wide variety of air toxics and/or hazardous air pollutants. Under the Clean Air Act, the EPA addresses a group of 187 hazardous air pollutants. Air toxics are categories such as metals, organic substances, and other compounds such as asbestos. The division manages a robust network of metals monitors, and conducts limited sampling for volatile organic compounds, aldehydes and ketones, and polyaromatic hydrocarbons.
Michigan residents can find out which pollutants are being measured in their area by referencing the Annual Air Quality Report's list of monitor locations around the state. The report also details the concentrations of air pollutants and pollutant trends.
The report contains information on other monitoring projects, outside of what is required by the EPA. For instance, chapter 10 of the report includes findings from a special EGLE Community Monitoring Program in the 48217 ZIP Code in Detroit. Results of a second special project, the Near-road Air Toxics Grant, will be available soon on the EGLE website.
Additionally, in 2018, EGLE established three new air monitoring sites around the Gordie Howe International Bridge linking the US and Canada. The goal is to begin air monitoring during the early phases of construction and continue for several years after the bridge is open to traffic. The new sites measure carbon monoxide, sulfur dioxide, nitrogen dioxide, particulate matter, lead, trace metals, and black carbon which is a component of diesel exhaust.