On days when the city of Houston declares that levels of ozone — a type of air pollution — are dangerously high Melissa McDonald, who has asthma, closes her car windows if she must be out and driving. She also sets the air system to “recirculate,” a step she says helps her maintain good asthma control. “I think every asthmatic has problems on days when the air quality is really poor,” explains McDonald, who had her first allergic asthma attack at age 4.
According to research, McDonald is not alone. Ozone undermines good asthma control for people in cities and towns all over the country.