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Ozone - Highlights from the Michigan Annual Air Report

Ozone (O3) is commonly thought of as part of the upper atmosphere where it filters out harmful ultraviolet radiation coming from the sun. Unfortunately, there is also ozone at the ground level and it can be dangerous to the public and to the environment. Ground-level Ozone is the main component in “smog” and can irritate airways, reduce lung function, and damage cells lining the lungs. Ground-level Ozone is created when Volatile Organic Compounds (VOC’s) and NOx emissions react from the heat of the sun. These emissions come from engine exhaust, industrial emissions, power plants, chemical solvents, and biogenic emissions from natural sources.

Ozone is one of six criteria pollutants that are considered harmful under the federal Clean Air Act. To ensure the air quality is at or below federal guidelines the state of Michigan monitors ozone levels at more than 40 sites. Monitoring takes place during “ozone season” which is the warmer months of the year and was recently extended to include March and October. Unfortunately, ozone levels are not always below the National Ambient Air Quality Standards (NAAQS) which place ozone limits at 0.070 parts per million (ppm).

Each year the Michigan Department of Environment, Great Lakes, & Energy (EGLE) puts out an Air Quality Report (full report) that gives an overview of Michigan’s air quality, breaking down their findings by county and pollutant. In 2020 West Michigan exceeded ozone limits a total of 9 times with six in June, two in July and one in August. As we would expect, there is a strong correlation between daily high temperature and ozone exceedance with all nine of the days happening with daily high temperature above 85 degrees.

Over time the NAAQS have tightened the standards to continue improving air quality for the public. In 1997 it was reduced from 0.120 ppm to 0.08 ppm. The standard was further lowered to 0.075 ppm in 2008 and finally to 0.070 ppm at the end of 2015. These changes have forced states to get creative and find ways to reduce ozone with initiatives such as cleaner burning gasoline reformulated to reduce VOC, NOx and other pollutants; strict NOx emission limits for power plants and industrial combustion sources; enhanced vehicle inspection programs; and strict limitations on the solvent usage in factories. These initiatives have had a positive impact on air quality as average ozone levels as well as days over the limit both have a downward trend over time.

Understanding ozone and where it comes from, monitoring its levels daily, implementing emission limiting strategies, and publicly reporting on air quality are all important to maintaining the delicate balance between industry and nature. If you have questions about your air quality, CFR does Air Quality Assessments for many of our clients and we would be happy to talk to you about your situation to see if there is a potential issue at your company.


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