[Asthma in a population of children and its relation to airborne environmental pollutants in Mexico City. A cohort study. Mexico, 1991. Experimental design].

We developed a panel study to evaluate the association between intermittent exposure to ozone and acute attack of asthma. The population study consists in 136 asthmatic children residents in the southwest and northeast of Mexico City. They were attended in the allergic services of the two main Pediatric Hospital of Mexico City. In this paper we present the methodological issues following in the study and the results of the descriptive analysis of the relation between ozone exposure and acute attack of asthma.