The purpose of the study was to correlate environmental factors that may play a role in triggering asthma attacks requiring admissions. A retrospective analysis of 320 asthmatic admissions from January 1987 to December 1989 was conducted in two community hospitals in our area. Information from the U.S. Weather Bureau pertaining to temperature, barometric pressure, wind velocity, and precipitation was analyzed. The readings from the Puerto Rican Environmental Agency for Total Suspended Particles (TSP-10) during that period were also reviewed. Our results indicate that the female patients accounted for the majority of the asthmatic admissions: 74.3% versus 26% in males. Eighty-four percent of the patients had a history of asthma attacks and 67% had previous hospitalizations due to asthma exacerbations. Correlation between asthma family history and age was found in only two age groups, 31-40 and 71-80 years. Rhinitis and asthma exacerbations were strongly linked only in the age group of 31-40 years. Active cigarette smoking was strongly associated with asthma exacerbations only in the age group of 61-70 years. Environmental data indicated that there was not a consistent pattern of monthly admissions; however, there was a significant association between admissions and increased precipitation, high counts of annual TSP-10, and decreased wind velocity. In view of our findings, asthmatics living on islands such as Puerto Rico might be affected by an additive effect of pollutants, by local and mainland emissions that are transported by the air currents, leading to a higher incidence of asthma exacerbations.