Development and application of risk analysis methods to stationary sources of carcinogenic emissions for regulatory purposes by the South Coast Air Quality Management District.

Abstract

Desirable qualities of a risk assessment procedure for use in routine assessment of the impact of new and modified stationary sources of carcinogenic emissions are: (1) readily available analysis techniques and (2) simplicity when applied to small sources. Regulatory Gaussian models have these qualities but are limited by their accuracy at large distances and the difficulty of calculating the cancer incidence. Calculation of risk for the maximally exposed individual (MEI risk) and cancer incidence is discussed, and the relations found among MEI risk, de minimus individual risk, cancer incidence, population density, carcinogenic source strength, release conditions, maximum distance to de minimus individual risk, release period, and distance to nearest receptor found from application of these models to a typical situation are described. Suggestions for setting values for maximum allowable MEI risk, maximum allowable cancer incidence and de minimus individual risk are also presented. Several types of carcinogenic sources are examined for their cancer impact. The effect of various maximum allowable exposure parameter values on the source's acceptability is also examined. Screening methods for both MEI risk and cancer incidence is discussed. Application of the analysis method to numerous sources is presented, including use of an empirical equation for cancer incidence.