Analysis of air toxics emission inventory: Inhalation toxicity-based ranking

Air toxics emission inventories play an important role in air quality regul atory activities. Recently, Minnesota Pollution Control Agency (MPCA) staff compiled a comprehensive air toxics emission inventory for 1996. While acq uiring data on the mass of emissions is a necessary first step, equally imp ortant is developing information on the potential toxicity of the emitted p ollutants. To account for the toxicity of the pollutants in the emission in ventory inhalation health benchmarks for acute effects, chronic effects, an d cancer were used to weight the mass of emissions. The 1996 Minnesota emis sions inventory results were ranked by mass of emissions and by an index co mprised of emissions divided by health benchmarks. The results show that si x of eight pollutants ranked highest by toxicity were also the pollutants o f concern indicated in environmental monitoring data and modeling data. Mon itoring data and modeling results did not show high impacts of the other tw o pollutants that were identified by the toxicity-based emission ranking me thod. The biggest limitation in this method is the lack of health benchmark values for many pollutants. Despite uncertainties and limited information, this analysis provides useful information for further targeting pollutants and source categories for control.