What is the national-scale air toxics assessment?
The national-scale air toxics assessment is designed to help EPA, state, local and tribal governments and the public better understand and set priorities among hazardous air pollutants and their sources. The assessment focuses on a single year, and includes four steps: • An inventory of air toxics emissions (1999 in this case), • Estimates of annual average outdoor air toxics concentrations, • Estimates of exposure concentrations (what people are estimated to breathe), • A characterization of potential public health risks. The 1999 national-scale air toxics assessment (released in 2005) is an update to the 1996 national-scale assessment (released in 2002). EPA expects to release a new national-scale assessment about every three years.
