Outdoor Air Quality and Asthma

An important group of outdoor air pollutants are criteria pollutants. The criteria pollutants include six pollutants: ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide and lead. Of these six pollutants, ozone and particulate matter are most commonly linked with triggering asthma symptoms. At high levels, nitrogen dioxide and sulfur dioxide may also be asthma triggers.

Climate Change and Asthma

Climate change is increasing annual average temperatures, lengthening the allergy season, and increasing heavy rainfall and flooding. These changes affect air pollutants, like ground-level ozone and particulate matter. Health impacts of climate change include worsening of chronic heart and lung conditions, like asthma.

Learn more about climate change in Michigan and read a report, Medical Alert! Climate Change Is Harming Our Health, from the Medical Society Consortium on Climate & Health.

Ozone

What Is Ozone Air Pollution?

Ground-level ozone, sometimes referred to as “smog,” is created when a mixture of air pollutants “bake” in the hot, summer sun. Ozone forms in the atmosphere when sunlight and high temperatures act on carbon-based chemicals known as volatile organic compounds (VOCs) that combine with a group of air pollutants called oxides of nitrogen or nitrogen oxides (NOx).

Typically, ozone levels are highest in Michigan during March through October when weather conditions are right. When ozone levels are high in Michigan the following factors are usually in place:

  • Sunshine
  • Blue sky
  • High temperatures (over 90°F)
  • Gentle-to-no-wind

NOx is a by-product of burning fuel in sources such as power plants, steel mills and other factories, and vehicles. The U.S. Environmental Protection Agency’s (EPA’s) report, “Our Nation’s Air: Status and Trends Through 2021” states that about 7.6 million tons of NOx were emitted in 2021, and the three largest sources are:

  • 30% stationary fuel combustion (like electric utilities and industrial boilers)
  • 29% from on-road vehicles: cars, trucks, buses
  • 24% from non-road mobile: trains, ships, airplanes

Sources of VOC’s include auto body shops, printers, gas stations, and large industrial operations. The largest sources are industrial processes (approx. 78%).

What Are the Health Effects of Exposure to Ozone?

Although ozone is often impossible to see, smell or taste, it can have a real impact on your health. Ozone acts as a powerful respiratory irritant at levels often found in most of the nation’s urban areas during the ozone season. Ozone can aggravate asthma, causing more asthma attacks, increased use of medication, more medical treatment and more visits to the hospital and emergency departments. Typical symptoms include:

  • Shortness of breath: Ozone can constrict your breathing passages, making it harder to breathe.
  • Chest pain: Ozone reacts with lung tissue, often causing swelling of the lungs and chest pain.
  • Wheezing and coughing: High ozone levels can irritate your lungs and throat.

Based on evidence from research studies, ozone air pollution represents a serious and widespread public health problem, where some epidemiological studies show associations between ozone exposure and new cases of asthma in children. These associations were shown with both short-term and long-term ozone exposure at levels below the level of the national air quality standard for ozone, 0.07 parts per million.

Who Is At Risk?

Groups who are at particular risk from high ozone levels are:

  • People who already have respiratory diseases, such as asthma, chronic bronchitis, and emphysema
  • Infants and children
  • Older adults
  • Active people who exercise or work outside

Children are especially sensitive to the bad health effects of ozone air pollution because they:

  • Spend more time outdoors than adults
  • Spend more time engaged in vigorous activity
  • Have a higher breathing rate than adults, relative to their body weight
  • Have narrower airways than adults
  • Have more frequent respiratory infections

What Can People with Asthma do to Protect Themselves from Ozone Pollution?

Read the air quality index (AQI) information sheet for more specific information about AQI health messages and activity levels. This info is for parents, educators, coaches and caregivers of children and teens; those with cardio and/or pulmonary disease; and, adults who are sensitive to elevated concentrations of ozone and PM2.5 pollution levels.

Go to Airnow.gov

For Ozone, What is the Current State of Air Quality in Michigan?

The National Ambient Air Quality Standards for ozone help to determine whether levels of ozone are too high. Nonattainment is a term applied to an area that has ozone concentrations above the national a standards over a specific period of time. An area may also be considered nonattainment if pollution from that area is contributing to poor air quality in another area. Areas that are meeting the air quality standards are considered attainment areas. For more information about the current designations in Michigan, go to Michigan Ozone Nonattainment webpage.

Besides the designation given by the federal government, other agencies have also established ratings systems for outdoor air quality. Check out State of the Air to find out how Michigan is rated for outdoor air quality by the American Lung Association.

What Can You Do to Help Reduce Unhealthy Ozone Levels in Michigan?

Everyone can play their part, especially on hot and sunny days, by

  • Limiting driving with carpooling, taking the bus, riding bicycles, or other ways to reduce personal car use
  • Avoiding excessive idling of your vehicle
  • Working with your local school districts to establish a no idling policy for buses and automobiles. For more information, go to EPA’s School Bus Idle Reduction webpage
  • Purchasing a hybrid or electric vehicle.
  • Using manual or electric lawn and garden tools.
  • Fueling up vehicles and lawn mowers in the evening
  • Not using gasoline powered equipment on Clean Air Action! Days
  • Switching to more energy efficient lighting
  • Turning off lights and air conditioners when not needed

If you live in the West Michigan area, more information can be found at www.wmcac.org/take-action-1.

Ground-level ozone is one of the toughest pollution problems we face. It depends on weather conditions, many pollution sources and our own actions. Even though we cannot dream of controlling the sun, wind and clouds that contribute to the formation of ozone, we can make sure our actions are helping to reduce ozone air pollution.

Check out this lawn care tip card about keeping unhealthy ozone-forming pollutant levels down through smart lawn care.

Particulate Matter

What Is Particulate Matter Pollution?

Particulate matter – PM for short – are the dust and liquid droplets that fill our city air, settle on our windowsills, and irritate our eyes and noses. PM is:

  • a mixture of many compounds and pollutants that usually come from combustion sources such as power plants, industrial and residential smokestacks, fires, mining, construction, natural sources, diesel trucks and buses, other diesel vehicles and off-road diesel equipment.
  • made up of many atmospheric materials including soot, ashes, windblown dirt, sand, soil dust, metals, and plant matter such as pollens.
  • either given off directly from combustion sources like power plants, or is formed in the atmosphere through chemical reactions.
  • sometimes referred to as PM2.5 (particulate matter smaller than 2.5 microns in diameter – less than one-hundredth of the width of a human hair) and PM10 (particulate matter at 10 microns in diameter).

What Are the Health Effects of Exposure to Particulate Matter?

Research studies have linked serious health effects with PM at low levels. In the EPA’s evaluation of this research, they determined that there is no clear threshold for some PM2.5-related health effects.

PM2.5 is of gravest concern because the particles are so tiny that they can be inhaled deeply into the lungs, and can dodge the lungs’ natural defenses. Numerous studies over the years have linked PM2.5 to many health problems, from increased asthma attacks to hospital visits to death.

  • PM is linked with increased use of asthma medication in children, decline in respiratory function, increased emergency room visits and hospitalization for lung and heart problems. A number of studies have definitely linked fine particle pollution with increased occurrence of coughs and bronchitis, with especially severe effects in children with asthma.
  • PM is a dual threat to the asthmatic, whose airways are both constricted and inflamed – PM makes both conditions worse. Research has shown that the levels of PM do not need to be extremely high to cause these problems.
  • Long term exposure to PM has been associated with premature death, especially for people who have lung or heart disease. More recent studies have also shown associations between long term exposure to PM and increased risk of dying prematurely for racial and ethnic minority groups, like Black and Hispanic people.

What are the Air Quality Standards for PM?

The EPA is currently reviewing the National Ambient Air Quality Standards (NAAQS) for PM. The Clean Air Act directs EPA to conduct a rigorous review of the latest scientific evidence, and to set standards at levels that will protect public health with an adequate margin of safety. Standards are developed to protect the health of the general public, including sensitive groups.

The NAAQS drive the nation’s air pollution control programs. The Clean Air Act requires states and the EPA to come up with strategies for reducing air pollution from sources that contribute to air pollution in order to meet the air quality standards.

The Department of Environmental Quality (DEQ) air page has more information about air quality standards and programs to keep Michigan’s air clean.