You've been hearing for many years about the negative effects modern living has had on the ozone layer in our atmosphere and what this means for our air quality. You may also have heard something about ground level ozone and how it is bad for us. So, I thought it might be helpful to sort out the facts about ozone and what effects it has on people with asthma and our ability to breathe well.
Ozone is a highly reactive gas, made up of 3 oxygen atoms (sometimes referred to as O3). Ozone can be "bad" or "good", depending on where it occurs in our atmosphere.
According to the Environmental Protection Agency (EPA), stratospheric ozone is formed when ultraviolet radiation from the sun reacts with oxygen. This so-called "ozone layer" lies about 6 to 30 miles above the surface of the Earth. This type of ozone is good, because it helps prevent harmful UV radiation from reaching the Earth's surface. Aerosol sprays, CFC asthma inhalers and other substances can destroy this type of ozone, which is why they have been largely banned for the past several years.
Ground level ozone forms when air pollutants, such as volatile organic compounds (VOCs) and nitrogen oxides (NOx), interact with heat and sunlight. Ground level ozone is considered bad, because it worsens air quality and affects breathing in both healthy people and those with respiratory conditions like asthma. Ground level ozone tends to be an issue mostly during the summer months, in particular May through September.
Nitrogen oxides are emitted by cars, power plants, industrial plants, and other sources. VOCs can come from:
- gasoline pumps
- chemical plants
- oil-based paints
- auto body shops
- print shops
- consumer products
- some trees
Although ground level ozone is most commonly a problem in urban areas, both small and large, it can also be found in some rural and suburban areas, even in National Parks.
Effects of Breathing Ground Level Ozone
Breathing in ground level ozone isn't healthy for anyone, not even for people with no health problems. But for those of us with already inflamed airways, it can be especially harmful. Here are some of the effects of breathing in ozone:
- It can trigger chest pain, coughing, throat irritation, and congestion.
- It can worsen bronchitis, emphysema, and asthma.
- It can can reduce lung function and inflame the linings of the lungs, or even cause permanent scarring of lung tissue.
And ozone doesn't just affect us humans. It also has a damaging effect on foliage in trees and other plants and reduces crop yields on farms. Anyone who spends much time outdoors during ozone season can be affected.
The United States government sets air quality standards in an effort to protect our health and our environment. Currently, the National Ambient Air Quality Standard for ozone concentrations is set to 75 parts per billion over an eight-hour period. However, a recent study published by the American Thoracic Society found that as little as 6.6 hours exposure to ozone concentrations of only 70 parts per billion had a significant negative effect on lung function.
That's not good news for people with or without asthma!
While the effects were fully reversible in the healthy people studied, these findings could explain why there is such a sharp increase in emergency care for asthmatics during the summer months.
What You Can Do
There ARE things we can all do to reduce ground level ozone and to protect ourselves against it. Here are some suggestions from the EPA:
- Check the air quality forecast for your area. When the Air Quality Index (AQI) is predicted to be at unhealthy levels, limit the time you spend outdoors, especially if being active. Ozone usually peaks during mid-afternoon/early evening. You can get AQI forecasts by checking your local media reports or visiting http://epa.gov/airnow.
- Make an effort to conserve energy at home and work. Set your air conditioning thermostat a little higher in the summer. Participate in local energy conservation programs.
- Keep cars, trucks, gas-powered lawn and garden equipment, boats and other engines properly tuned and maintained. Fill gas tanks during the cooler evening hours in the summertime and take care to avoid spilling gas. Drive less by carpooling, using public transportation, walking, or biking, all of which will reduce ozone pollution, especially on hot summer days.
- Use household and garden chemicals wisely. Buy low VOC paints and solvents. Read labels so that you know how to proceed with proper use and disposal of such chemical substances.
Hopefully, this has shed some light on the confusion between protecting the ozone up high and protecting ourselves from the ozone down low.
Published On: August 02, 2009