Page 376 - Industrial Ventilation Design Guidebook

5.3 TOXICITY AND RISKS INDUCED BY OCCUPATIONAL EXPOSURE TO CHEMICAL COMPOUNDS 3 3 i

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FIGURE 5.57 Results of alternative extrapolation models for the same experimental data. (Reprinted
with permission from Risk Assessment in the Federal Government. Copyright 1983 by the National Academy of
Sciences. Courtesy of the National Academy Press, Washington, DC.)

hausts of power plants, and indoor and outdoor emissions of the chemical
industry are the greatest concerns. In the occupational environment, one deals
with relatively high exposure levels, whereas among the general public, one deals
with very low exposure concentrations but large exposed populations, which
complicates the assessment of the additional risks caused by the exposure. Also,
the magnitude of risks may vary widely. The excess risks of the general population
due to air pollution (nitric and sulfur dioxide, ozone, small particles) in Europe
and the United States are between one and five percent in terms of excess
mortality. In Europe this corresponds, however, to between 50 000 and 100 000
extra deaths. In occupational environments, the exposure levels may be several
fold as compared to environmental risks, perhaps even orders of magnitude
higher, but usually the exposure levels are relatively low when compared with the
situation 20 or 30 years ago. Also, in occupational environments, the exposed
populations can be clearly defined, and appropriate measures can be undertaken
to avoid excessive exposure. In industrialized countries, the exposures are nowa-
days much better regulated than before. This does not imply that toxicity and risk
assessment are any less important for guaranteeing chemical safety for workers