Possible mechanisms for the respiratory tract effects of noncarcinogenic indoor-climate pollutants and bases for their risk assessment

Abstract

This review outlines the effects of pollutants on the lungs. Mechanisms and effects relevant to the assessment of indoor-air risk are especially dealt with. Important mediators have also been considered. Concentration-effect relationships exist for toxic reactions, sensitization reactions, and neurogenic effects. If Harber's Law is used for extrapolations from higher concentrations to the lower indoor-air levels, the indoor-air risk estimate may exceed the real risk. Additivity seems to apply to toxic and neurogenic effects of low doses. Only already sensitized subjects and possible subjects with a profound alpha1-antitrypsin deficiency appear to be extremely sensitive, and a safety factor of 10 seems adequate: for the protection of other groups. Thus combining occupational exposure limits (OEL), Harber's Law, and the safety factor suggests that no direct lung effects should be expected from a substance if the exposure level does not exceed 1/40 . OEL.