If your child has asthma, you probably understand triggers — those things that make your child's asthma symptoms worse, like cold weather, pet dander, or being around smoke. But poor air quality can also trigger flare-ups, so it's important to know how to take precautions.

How Does Air Quality Affect Asthma?

Pollutants in the air can have the same effect on kids with asthma as other triggers. They irritate the airways, making them swell and tighten up, and cause breathing problems.

Pollutants can also make kids more likely to catch upper respiratory infections (like colds), which can bring on asthma symptoms. If allergens in the air are an asthma trigger, pollutants can make the lungs even more sensitive to them.

What Pollutants Affect Breathing?

You've probably heard about the ozone layer and how it protects us from the sun's rays. But there's a different layer of ozone that’s closer to the ground called ground-level ozone.

Ground-level ozone can harm the lungs. It forms when chemicals from cars, power plants, and factories mix with sunlight. This "ozone pollution" is a main part of smog — the brownish-yellow haze often seen hanging over cities on the horizon. It's worse on warmer days or in warm parts of the country.

Particle pollution also can cause breathing problems. It's created when tiny bits of dust, dirt, smoke, soot, and other stuff hang in the air (for example, from wildfires). The smaller the particles, the deeper they can get into the lungs and cause breathing problems.

Other pollutants include gases (such as carbon monoxide, nitrogen dioxide, and sulfur dioxide) that come from the burning of different types of fuels. High levels can affect lung function.

How Can I Help My Child?

Check the Air Quality Index

If you live in an area with poor air quality, pay attention to pollution levels. You can get daily information from weather reports (online or in the newspaper) or by visiting the Environmental Protection Agency at www.airnow.gov.

The EPA's Air Quality Index (AQI) report measures the levels of:

• ground-level ozone
• particle pollution
• carbon monoxide
• sulfur dioxide
• nitrogen dioxide

The AQI varies from season to season, from day to day, and even from morning to evening. In cities with more than 350,000 people, state and local agencies are required to report the index to the public daily. But many smaller communities also report the AQI. It uses a color-coded system to indicate when air quality is dangerous: Green or yellow are for acceptable conditions; orange, red, purple, or maroon mean people with asthma should limit their time outdoors. In many places, the next day's index is also reported, so you can make plans.

Other Tips

On days when air quality is poor, run the air conditioning and limit your child’s outdoor activities, if possible. Plan any outdoor activities for early in the day — when air quality tends to be better — and avoid spending time in areas with a lot of traffic. If you must spend time in a car, close the windows and vents and run the air conditioning instead.

If your child is in a sport that practices outside during hot weather, talk to the coach about other arrangements, such as working out in an air-conditioned gym. Also, make sure your child always has the medicine used for quick relief of symptoms (called quick-relief, rescue, or fast-acting medicine) on hand.

Improving the air quality in your home is also wise. You can do this by using an air cleaner, venting all gas appliances to the outside, and avoiding wood fires in your house.

Talk to your doctor about increasing medicine during times when air pollution is high. These changes can be included as part of your child's asthma action plan.