Airways and air pollution in childhood: state of the art.

Correlations between ambient pollutants and health effects, such as observed in SIDS, may in reality be to a larger extent the result of indoor sources. These distinctions between indoor and outdoor sources, while important, do not detract from the overall conclusion that pollution affects the airway in children directly and indirectly. Much still needs to be learned about the permanence of these effects, the mechanism by which the effect is mediated, and the conditions under which some of these effects are maximal. Two approaches seem particularly suited to shed further light on these issues. First, identification of biological markers for exposure to pollutants will yield both more accurate measures of exposure to pollutants and information about health consequences. Second, newer modeling techniques promise to predict health outcomes under a variety of environmental conditions. Shumway et al., for instance, describe a promising model predicting an increase in mortality due to ambient pollutants in the Los Angeles Basin with higher levels under extremes of temperature, especially during cold spells. Time series and factor analyses may further our knowledge as well. In the near future, large cohort studies should begin to reveal the cumulative effects of air pollution on the respiratory system, especially in relation to active smoking. Finally, studies in Black children are virtually unavailable. Given their high risk for respiratory illnesses, such studies are sorely needed.