Controlled Clinical Inhalation Studies with Environmental Air Pollutants at Concentrations Commonly Found in the Ambient Air

Abstract

People are becoming increasingly aware of environmental health hazards. Air pollutants have long been at the center of interest for both the public and the scientific community. Scientific interest has concentrated mainly on acute effects of high concentrations of pollutants. This has led to relatively strict governmental regulations and, for example, maximum allowable workplace concentrations, on the one hand, and decreasing mean and peak concentrations of some of the classical pollutants such as sulfur dioxide and nitrogen dioxide, on the other (von Boehmer and Fabel 1987). This must not lead to neglect of the specific problems arising from chronic exposure to the same pollutants or the health hazard of low concentrations for groups of patients at high risk. As long as we and our volunteers or patients do not live in an ideal (“synthetic” = well-defined) atmosphere, all studies must consider the fact that only rough approximations of effects can be obtained and must be seen against the background of the atmosphere and the ambient pollutant load at the facility where the studies are performed. Nevertheless, our knowledge of the health effects of pollutants at concentrations commonly found in the ambient air is insufficient, and particularly the effects of such pollutants on the respiratory or other body functions of patients with lung or other diseases must be studied. This is true not only from the aspect of prophylaxis and prevention of disease caused by chronic exposure to pollutants but also to help in early detection of symptoms indicative of deterioration of lung or other functions due to pollutants and to provide patients with the information of the specific risks that air pollutants carry for their body.