To Keep the Air Clean

air quality

Air quality is an important measure identified in SEMCOG plans and programs for creating desirable communities, protecting public health, and maintaining a positive regional image for Southeast Michigan. In 2024, there were six Air Quality Action Days and zero Air Quality Alerts in Southeast Michigan.

knowing and understanding air quality

air quality pollutants

The Air Quality Advisories and Alerts are based on the amount of ozone and particulate matter (PM_2.5) in the air.

Ozone – “Good” ozone occurs naturally 10-30 miles above the earth’s surface. It makes a protective layer in the atmosphere that shields us from the sun’s harmful ultraviolent rays. Ground-level ozone is created by chemical reactions at the Earth’s surface. This type of ozone is a harmful air pollutant due to its effect on people and the environment.

Sources of ground-level ozone include emissions from cars, trucks, power plants, and other industrial sources which react with heat and sunlight. 

PM_2.5 – Particle pollution or particulate matter less than 2.5 micrometers in diameter. During a wildfire, burning vegetation and materials release large amounts of PM_2.5, significantly degrading air quality over large areas. These particles are small enough to be breathed into the deep part of your lungs, and even into your bloodstream.

Sources of PM_2.5 other than wildfire smoke include vehicle exhaust, power plants, factories, and tobacco smoke.

air quality advisories and alerts

Air Quality Advisory: Issued when Ozone, PM_2.5 or both are expected to reach or exceed the Unhealthy for Sensitive Groups (USG) threshold.  Those considered in the “USG” threshold include people with lung disease (such as asthma), children, older adults, people who are active outdoors (including outdoor workers), people with certain genetic variants, and people with diets limited in certain nutrients should reduce prolonged or heavy outdoor exertion. This is aimed to provide awareness for poor air quality, encourage people to limit activities that contribute to poor air quality, and to alert those who are especially sensitive to poor air quality.  

Air Quality Alert: Issued when Ozone, PM_2.5, or both are expected to reach or exceed the Unhealthy threshold or worse. This alert indicates a higher level of concern as everyone, not just sensitive groups, can be affected by poor air quality. 

Advisories and alerts may be issued for PM_2.5 throughout the year and ground-level Ozone from March 1 through October 31. 

what you can do

Individuals, alongside government regulations, contribute significantly to improving air quality. While regulatory measures are crucial, voluntary actions by individuals are also essential. Here are actions you can take on each type of day to stay safe and improve air quality for everyone:

ozone alert/advisory days:

• Limit outdoor activities: Especially during peak afternoon hours when ozone levels are highest.
• Reduce car use: Carpool, use public transportation, bike, or walk instead of driving.
• Avoid using gasoline-powered lawn equipment: Use manual or electric alternatives if possible.
• Refuel vehicles in the evening: This helps reduce the amount of ozone formed during the day.

PM2.5 Alert/Advisory Days:

• Minimize outdoor activities: Especially for children, the elderly, and those with respiratory or heart conditions.
• Avoid burning wood or trash: Refrain from using fireplaces, wood stoves, or burning leaves and other materials.
• Limit vehicle use: Combine errands, carpool, use public transportation, or work from home to reduce emissions.
• Stay indoors with windows closed: Use air purifiers if available and avoid using air conditioning units that draw in outside air.

Visit these resources to learn more about Ozone and PM_2.5 in Southeast Michigan:

• Learn about air quality in Michigan
• EGLE Air Quality Division
• Your Health and Wildfire Smoke
• View air quality where you live