Health assessment of environmental pollutants: proliferative and degenerative diseases

In order to achieve a balanced approach to risk assessment between carcinogenic and non-carcinogenic health effects one must examine the risk of disease or death in the general population exposed to a particular air pollutant that can be related quantitatively to intensity and duration of exposures (National Academy of Sciences, 1983). Such risk assessment should be based upon careful evaluation of scientific findings of dose-response relationships in the chronically exposed population. Quantitative assessment of environmentally produced disease in man has proven to be complex and demanding. A variety of factors play important roles in this task. As an example, there are induction-latency periods for chronic diseases, including cancer, which may range from five to twenty-five years. The diseases themselves, whether proliferative or degenerative, may follow several stages of progression. There is only sparse epidemiological data on serious health effects that may be due to environmental as compared to occupational exposures. Exposures to chemical or radiological air contaminants do not occur singly but to a multiplicity of agents, and disease processes are frequently markedly affected by the interaction of a variety of factors, particularly that of cigarette smoking. There is growing recognition of potentially sensitive subpopulations, including the elderly and the very young, but adequate techniques for assessing the magnitude of increased risks to these groups have not yet been developed.