The role of air pollution and weather changes in childhood asthma.

Eighty asthmatic children were studied for two years. Daily records of various parameters of asthma were correlated with levels of different air pollutants and such climatological factors as bad weather conditions and temperature changes. High levels of ozone and carbon monoxide significantly correlated with the number, duration and the severity of asthmatic attacks. However, all the factors combined played only a minor role in the complex etiology of asthma, accounting for only 5 percent to 15 percent of the total variance.