Asthma costs the country nearly $13 billion dollars a year and affects 14 million people. It is currently the most common chronic condition among children. The inner cities are some of the hardest hit areas, where it has been estimated that anywhere from one quarter to one third of children have asthma. Because it is easier to test for controlled indoor elements such as dust, pet dander, or food allergies, most studies link these factors to the onset or exacerbation of the disease—but there is little research on how air quality impacts people with asthma. Researchers from Yale University sought to remedy that, studying children in southern New England.

What the researchers wanted to know: How do environmental factors, specifically ozone and fine particles in the air, affect children with asthma?

What they did: The researchers studied 271 asthmatic children under the age of 12 living in Connecticut and Springfield, Mass., during the summer of 2001. About half of the children had severe asthma, defined by the use of daily medication, and all of the childrens' mothers kept track of their symptoms (and treatments when necessary) on a daily basis. In addition, the researchers used information on the air quality in the region, using the state Departments of Environmental Protection measures of daily ozone concentration, temperatures, and level of fine particles in the air.

What they found: For the children with severe asthma, the level of ozone corresponded to worse symptoms—chest tightness, shortness of breath, and wheezing. They experienced symptoms even when the air pollution levels were within the recommended Environmental Protection Agency guidelines. For the children with less severe asthma (not requiring daily medication) there was no significant change due to environmental factors.

What it means to you: As the authors say, "There is little doubt that children with asthma are especially vulnerable to high levels of air pollution." An accompanying editorial chastises physicians for not recognizing the potential harm of air pollution for asthmatic patients. There is little that a person with severe asthma can do to control the outside environment, but experts recommend staying indoors on extremely hot days or days with high ozone levels (see web link below).

Caveats: The authors used data from 14 regional sites to measure ozone levels, but within each region ozone could vary slightly. Also, they didn't ask the children how much time they spent outdoors so they never really got a clear picture of exactly how much ozone an individual child was exposed to and how much it affected his or her asthma.

Find out more: Daily national and local ozone level reports are available at the Environmental Protection Agency's website.

The American Lung Association has information on dealing with the disease, including some of the latest research and treatment options.

Read the article: Gent, J.F. et al. "Association of Low-Level Ozone and Fine Particles With Respiratory Symptoms in Children With Asthma." Journal of the American Medical Association. Oct. 8, 2003, Vol. 290, No. 14, pp. 1859-1867

Abstract online: http://jama.ama-assn.org