USE OF HUMAN LUNG-TISSUE FOR STUDIES OF STRUCTURAL-CHANGES ASSOCIATEDWITH CHRONIC OZONE EXPOSURE - OPPORTUNITIES AND CRITICAL ISSUES

Definitive information on the chronic effects of exposure to ozone (O- 3) in humans is not available. There is a strong concern that ozone co uld produce chronic lung damage in humans on the basis that exposures are ubiquitous at levels that produce transient symptoms, function def icits, and lung inflammation in humans and chronic lung damage in labo ratory animals. Both prospective and national population surveys sugge st an association between chronic O-3 exposure and reduced lung functi on, and a pilot investigation of autopsied lungs of accident victims i n Los Angeles reported an unexpectedly high incidence of disease in th e centriacinar region, the lung region known to receive the highest do se of inhaled O-3 This paper discusses the advantages and limitations of further studies of structural changes in human lung tissue in relat ion to chronic O-3 exposure. The major advantages of such studies are that a) measurable effects may be related to realistic chronic exposur es, b) the effects may be described quantitatively and compared direct ly to those obtained in chronic animal inhalation exposures, and c) ev idence for chronic effects may be obtained much more rapidly than in p rospective studies. The major limitations are the difficulties in obta ining sufficient reliable information on residential history, physical activity out-of-doors, and smoking and other confounding exposures to lung irritants from next of kin, and limited availability of adequate air quality data for determining ambient concentrations at places of residence and/or outdoor exercise. The paper also discusses approaches to minimizing these limitations in the design of specific studies.