Ozone and other things that pollute the air are problems for anyone who breathes. And if a person has asthma, these pollutants can be triggers (like pollen or cigarette smoke) that cause worsening symptoms and asthma flare-ups.

What Is Ozone?

You've probably heard about the ozone layer and how we need to protect it. This layer is up high in the atmosphere, and it protects us from the sun's rays. But there's another layer of ozone closer to the ground. The ozone in this layer can irritate the lungs and cause breathing problems.

This ozone pollution is created when chemicals from cars, power plants, and factories mix with sunlight. That's why ozone tends to be higher in sunnier climates or during hot weather. It is a main part of smog, that brownish-yellow haze often seen hanging over cities on the horizon.

Ground ozone levels have gone down since 2000, according to the American Lung Association. But more than half of the people in the United States still live in areas with unhealthy ozone levels.

What Are Other Pollutants?

Particle pollution also makes the air dirty. Particle pollution is created when tiny bits of stuff hang in the air we breathe. What kind of stuff? Dust, dirt, smoke, soot, droplets from aerosol products, and acids called nitrates (pronounced: nye-trates) and sulfates (pronounced: sul-fates) are all example of things that cause particle pollution. And the smaller the particles, the deeper they can get into the lungs.

One in six of all people in the United States live in areas with levels of particle pollution that are unhealthy all year. In addition to ozone and particle pollution, the Environmental Protection Agency (EPA) also keeps tabs on the levels of the gases carbon monoxide, sulfur dioxide (pronounced: sul-fur dye-ock-side), and nitrogen dioxide (pronounced: nye-trih-jin dye-ock-side), when figuring out air quality levels. High levels of these gases can also make it tough on the lungs, especially for people with asthma.

How Poor Air Quality Affects People With Asthma

Because people with asthma have more sensitive lungs, poor air quality affects them more quickly and more severely. That's because people with asthma have a continuing problem with their airways, which are always a little swollen.

For someone with asthma, polluted air can cause flare-ups and may also increase the chance of respiratory infections, which can make asthma symptoms worse. In fact, when air quality is poor, more people with asthma end up in the hospital.

What You Can Do

If air pollution is a trigger for you, you'll want to avoid it as much as possible. You can't stop breathing, of course, but there are some things you can do to minimize your exposure to it. Talk to your doctor about strategies that can be added to your asthma action plan.

You can track air quality by consulting the Air Quality Index (AQI). It was created by the EPA to keep track of outdoor air quality and help people who are affected by air pollution decide whether they need to stay inside. In more than 900 counties across the United States, the AQI measures levels of major air pollutants. You can get AQI information from weather reports, the newspaper, or online at the AIRNow website. The system is color coded. Green or yellow means it's OK to be outside; orange, purple, or maroon means you should stay indoors.

On days when air quality is bad, run the air conditioning. Plan any outdoor activities for early in the day, when air quality tends to be better, and don't spend time in places where there is a lot of traffic.

If you play a sport that has outdoor practices in hot weather, talk to your coach about what you can do to stay out of dirty air. This may mean you need to work out in an air-conditioned gym or miss some practices. And whether you work out inside or outside, always have your rescue medications with you.

You may not be able to prevent air pollution, but you can do your part to help the environment. When air pollution levels are high:

• Don't drive. Share a ride, take public transportation, ride a bike, or walk.
• Don't put gas in your car until after 7 PM.
• Don't use outboard motors, off-road vehicles, or other gasoline-powered recreational vehicles.
• Avoid mowing the lawn or using other gasoline-powered gardening equipment when air quality is bad.

Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: October 2010