title: Projection of hazardous air pollutant emissions to future years.
abstract: Projecting a hazardous air pollutant (HAP) emission inventory to future years can provide valuable information for air quality management activities such as prediction of program successes and helping to assess future priorities. We have projected the 1999 National Emission Inventory for HAPs to numerous future years up to 2020 using the following tools and data: the Emissions Modeling System for Hazardous Air Pollutants (EMS-HAP), the National Mobile Inventory Model (NMIM), emission reduction information resulting from national standards and economic growth data. This paper discusses these projection tools, the underlying data, limitations and the results. The results presented include total HAP emissions (sum of pollutants) and toxicity-weighted HAP emissions for cancer and respiratory noncancer effects. Weighting emissions by toxicity does not consider fate, transport, or location and behavior of receptor populations and can only be used to estimate relative risks of direct emissions. We show these projections, along with historical emission trends. The data show that stationary source programs under Section 112 of the Clean Air Act Amendments of 1990 and mobile source programs which reduce hydrocarbon and particulate matter emissions, as well as toxic emission performance standards for reformulated gasoline, have contributed to and are expected to continue to contribute to large declines in air toxics emissions, in spite of economic and population growth. We have also analyzed the particular HAPs that dominate the source sectors to better understand the historical and future year trends and the differences across sectors.
authors.affiliation: Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States. strum.madeleine@epa.gov
authors.forename: Madeleine
authors.initials: M
authors.lastname: Strum
authors.forename: Rich
authors.initials: R
authors.lastname: Cook
authors.forename: James
authors.initials: J
authors.lastname: Thurman
authors.forename: Darrell
authors.initials: D
authors.lastname: Ensley
authors.forename: Anne
authors.initials: A
authors.lastname: Pope
authors.forename: Ted
authors.initials: T
authors.lastname: Palma
authors.forename: Richard
authors.initials: R
authors.lastname: Mason
authors.forename: Harvey
authors.initials: H
authors.lastname: Michaels
authors.forename: Stephen
authors.initials: S
authors.lastname: Shedd
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004781:Environmental Exposure; D005390:Fires; D005544:Forecasting; D015386:Hazardous Substances / Q000032:analysis; D008962:Models, Theoretical; D009369:Neoplasms; D018570:Risk Assessment; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D015386:Hazardous Substances; D001335:Vehicle Emissions