Respiratory effects of air pollutants: experimental studies in humans

Epidemiological and environmental chamber studies in man, and toxicological studies in animals, have provided valuable insights into the biological effects, the mechanisms of action, and the dose-response characteristics of some major air pollutants. This review describes the information currently available on air pollutant effects in man, as the result of experimental studies. There are certain advantages, as well as some limitations, in human chamber exposure studies, but if carefully designed and based upon relevant background data they may give information that is valuable for understanding the effects of air pollutants in man. Reversible effects on the airway mechanics, the responsiveness of the airways to methacholine and allergen have been shown to be caused by air pollutants. Furthermore, significant changes have been demonstrated in airway permeability, bronchoalveolar lavage, nasal lavage, and peripheral blood cells and inflammatory markers. Currently, human toxicology to air pollutants is a progressive research area.