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Ozone and Your Child's Asthma

For many people who live in urban areas, air-quality problems are often an annoyance. For children with asthma, however, polluted air can have serious health effects.

One of the main signs of poor air quality is a high concentration of ozone, a gas that forms when certain pollutants react with heat and sunlight. Ground-level ozone is different from ozone in the stratosphere, which makes up the "ozone layer," a beneficial barrier that reduces the amount of ultraviolet radiation that reaches the Earth's surface.

Breathing high levels of ground-level ozone can result in respiratory problems, such as coughing, throat irritation, and airway inflammation. Children with asthma may experience more severe symptoms than adults or experience symptoms at lower ozone concentrations. They are also more likely to experience an asthma attack when ozone levels are high.

Because the formation of ozone is more likely with higher air temperatures, these problems tend to occur more frequently during the summer months--when children are outdoors more often. Ozone levels may spike from April through October. In some parts of the country, including mountainous and southern states, levels may be high year round.

The harm from ground-level ozone is far reaching. In 2005, for example, experts estimated that ozone contributed to about 800 premature deaths, 4,500 hospital visits, and 900,000 school absences that year.

Girl holding inhaler

How parents can help

If your child has asthma, you can take a number of steps to reduce his or her chances of experiencing asthma symptoms linked to ozone and poor air quality. Start by making a daily check of the air quality index (AQI), a national report that measures the concentration of common air pollutants across the U.S. When the AQI is greater than 100, limit the amount of time your child spends outdoors. The AQI is published in many local newspapers, aired on local TV and radio stations (often as part of the weather forecast), and found online.

On serious "ozone action days," the EPA recommends that children (and adults) with asthma exercise indoors in a well-ventilated area, preferably one that's air-conditioned. On other poor air-quality days, you may also want to limit your child's time outside during the afternoon and early evening hours, when ozone levels tend to be at their highest. Early in the morning and after sunset are better times for outdoor play.

Avoiding common ozone sources can also be helpful in reducing symptoms. Keep children away from high-traffic areas, such as playgrounds that are near busy freeways, when ozone levels are high. Also, don't use gasoline-powered tools like lawnmowers when children are outside, and seal the lids of all household cleaners and other chemicals to keep fumes from escaping.

If your child suffers from wheezing, coughing, and other asthma symptoms during high-ozone days, asthma medications can help. Researchers are also investigating the possibility of new medications to help treat pollution-triggered asthma attacks.