Mechanisms of pollutant-induced airways toxicity.

The paper has focused on interactions of inhaled agents with airway surfaces. The respiratory mucosa is directly exposed to relatively high concentrations of inhaled substances and pollutant-related increases in incidence of infections and bronchospasm may reflect dysfunction of this barrier. Although the description of the mechanisms of toxicity to this surface are preliminary, it is clear that the challenge for the future will be to identify such toxic mechanisms. Too many environmental compounds are of concern and too many protocols are required to thoroughly study the toxicology and human health effects of individual compounds. An understanding of mechanisms is needed to categorize these compounds toxicologically to predict interactions between compounds in their effects on airways, and perhaps, to deal with the genetic variability of response demonstrated by individual subjects. A challenging need in future research will be to utilize observations on mechanisms made in animal models and in vitro to design well-focused experiments with human subjects.