Is this an update of the air toxics estimates EPA released in 1998 under the Cumulative Exposure Project (CEP)?
The Cumulative Exposure Project estimated ambient concentrations of 148 air toxics across the contiguous United States for the year 1990. This 1996 national-scale assessment uses the same computer dispersion model developed for the CEP to estimate ambient concentrations of 32 air toxics and diesel particulate matter across the contiguous U.S., plus Puerto Rico and the Virgin Islands, for the year 1996. The national-scale assessment includes an additional step that the CEP did not have — use of another computer model to factor in the extent to which people are exposed to these pollutants. Although the CEP and the current national-scale assessment relied on the same computer model, the two used different emissions inventory inputs. The emissions inventory used to estimate concentrations for 1996 is much improved over the 1990 data used in the CEP. It is based on extensive state and local input and includes specific information (exact locations and emission characteristics) about many mo
