Outdoor Air Quality and Asthma
Outdoor air pollutants can be separated into two main groups, criteria pollutants and hazardous air pollutants. The criteria pollutants include six compounds: ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide and lead. Of these six compounds, 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
Extreme weather events (heat waves, storms, wild fires, etc.) and environmental disruption (habitat changes, degraded air quality, etc.) are caused by climate change. Health impacts from these events include worsening of chronic heart and lung conditions, like asthma, anxiety and water-borne diseases. Climate change affects air pollutants by changing wind patterns, increasing temperatures, lengthening the allergy season and increasing heavy rainfall and flooding.
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
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 (VOC's) that combine with a group of air pollutants called oxides of nitrogen or nitrogen oxides (NOx).
Typically, ozone levels are highest in Michigan during May through September when weather conditions are right. When ozone levels are high in Michigan the following factors are usually in place:
- Blue sky
- High temperatures (over 90°F)
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) 1997 National Air Quality Emissions Trends Report states that about 23.6 million tons of NOx are emitted each year, and the two largest sources are:
- 26% from coal-fired power plants across the nation (about 33% from coal-fired plants in Michigan).
- 30% from on-road vehicles: cars, trucks, buses
Sources of VOC's include auto body shops, printers, gas stations, and large industrial operations. The two largest sources are the transportation industry (approx. 40%) and industrial process (approx. 31.2%)
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:
- In tests, healthy adults and children exercising strongly were found to have decreased lung function after exposure to ozone even below the long-standing federal 1-hour air quality standard of 0.12 parts per million (ppm).
- Other studies of children and adults exercising outdoors suggest that lung function decreases even at ozone levels equal to or below the newer and more protective (8-hour at 0.08 ppm) health-based standard. Although monitored by the state and federal regulatory agencies, this new health-based standard is not currently regulated by state agencies in the U.S.
- Research on the effects of longer exposures to ozone levels at, or just below, the new health-based standard have found even larger reductions in lung function, worsening inflammation of the lung lining, and more frequent and severe respiratory discomfort.
- Evidence also shows that higher ozone levels may even change lung function for several days after an exposure. Recently, studies have shown adverse health effects from long-term, repeated exposures to high levels of ozone with a higher than expected loss of lung function over time.
Who Is At Risk?
Check out State of the Air
, at the American Lung Association website, to find out how Michigan is rated for outdoor air quality.
Three groups that have been identified who are at particular risk from high ozone levels are:
In the 19 counties in Michigan where ozone pollution is the most prevalent, the asthma prevalence population for children is about 138,000 (73% of total children in Michigan with asthma) and about 220,000 adults (about 62% of total adults in Michigan with asthma).
The burden of asthma has been increasing over the past 20 years, especially among children. Exposure to ozone pollution is especially harmful to people with asthma, and about one-third of people with asthma in Michigan are children.
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
The "Out of Breath Report – Health Effects from Ozone in the Eastern United States," Oct. 1999 shows the following ozone-related bad health effects data for Michigan (mean cases April-October 1997):
- Cardiovascular hospital admissions: 670
- Respiratory hospital admissions: 2,100
- Total respiratory emergency department visits: 6,300
- Asthma emergency department visits: 660
- Minor respiratory symptoms: 3,600,000
- Asthma attacks: 280,000
What Changes are Needed in Michigan to Decrease Ozone Pollution?
The electric power industry is the largest industrial source of smog-forming NOx emissions – about 33% of total NOx in Michigan. More than a dozen old coal-burning power plants continue to operate in Michigan despite outdated and poor pollution control equipment for reducing NOx. As a nation, we still depend on coal for more than half of our electricity needs.
Since ozone is moved easily over hundreds of miles from upwind regions, other upwind states such as Indiana, Illinois and Wisconsin will also have to reduce their NOx emissions greatly in order for Michigan to get reductions of dangerous levels of summertime ozone pollution. Therefore a regional solution to ozone transport must be achieved, and federal legislation, currently being proposed on Capitol Hill (e.g., S.556-The Clean Power Act), will be vital to reach this goal.
What Can You Do to Help Reduce Unhealthy Ozone Levels in Michigan?
- Carpool, bus, walk or bicycle to work; find other ways to reduce your car use. The fewer cars on our roads, the fewer pollutants in our air.
- Fill up your car's gas tank in the evening.
- Keep your car maintained to manufacturer's specifications and proper tire pressure.
- Postpone mowing your lawn on high ozone days; keep your grass cut at a higher cut level (3 inches); consider purchasing an electric lawnmower when its time to replace the old one
- Spread the word: tell your family, friends and neighbors what they can do to help and why. Consider your next automobile purchase to be a highly fuel- efficient hybrid and ultra-low emission vehicle (ULEV) or consider purchasing an alternative
fueled vehicle (AFV) that uses 85% ethanol (E85) or natural gas.
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.
Read this air quality information sheet with 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.
Sign up for Enviro Flash a service that automatically delivers air quality forecasts directly to subscribers. It provides "heads up" information so people can adjust their daily activities to match expected air quality conditions. Those enrolled get only the information they select via email or cell phone text messages.
What Is Particulate Matter Pollution?
Particulate matter – PM for short – is the familiar, often see-able pollutant that fills our city air, settles on our windowsills, and irritates 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?
In the last few years, research studies have linked serious health effects with PM at much lower levels than the current federal standard allows for. 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.
- PM shortens lives. Researchers estimate that as many as 60,000 people each year die too early because of exposure to PM. The United States Environmental Protection Agency (EPA) estimates that attainment of the new health standard for fine particles alone could save 15,000 lives each year.
What are the Air Quality Standards for PM?
The EPA is currently reviewing the National Ambient Air Quality Standards (NAAQS) for fine particulate matter (PM2.5). 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 supposed to protect the health of sensitive persons.
The NAAQS drive the nation's air pollution control programs. The Clean Air Act requires the 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. In July 2001, the EPA changed its air quality standards for particulate matter and ozone. For the first time, the EPA set specific standards for very fine particles, or PM2.5.
When the new fine particle standards were announced in 1997, the President directed the EPA to complete its review of the PM NAAQS within five years, by July 2002. At the same time, the EPA strengthened its PM research program, together with other federal agencies, states, nonprofit organizations, and industry research institutions. This schedule would allow the Agency to consider the results of emerging scientific research before new control programs took effect.
In 1999, the state of Michigan implemented a fine particulate (PM2.5) monitoring system. This system is currently working, with 25 monitoring stations located throughout lower Michigan. The annual PM2.5 standard is met when the 3-year average is less than or equal to 15.0 micrograms per cubic meter (mg/m3). State monitoring data can be reviewed at www.deqmiair.org/. The Department of Environmental Quality (DEQ) air page has more information about air quality standards and programs to keep Michigan's air clean.
Continuing Medical Education Credits (CMEs) are available online for many asthma topics, including ozone and particulate matter.