Emergency room visits of asthmatic children, relation to air pollution, weather, and airborne allergens.

Background: The worldwide increase in the incidence, prevalence, and severity of asthma may suggest that environmental factors play a role in these epidemiologic changes.

Objective: To examine the correlations between air pollutants, weather conditions, airborne allergens, and the incidence of emergency room (ER) visits of children with acute asthma attacks.

Design: One-year prospective study.