Point sources are large, stationary sources of air pollution, such as factories, power plants, etc. The definitions of point sources for criteria and hazardous air pollutants are similar but not identical.
POINT SOURCES - HAZARDOUS AIR POLLUTANTS
EPA's National-Scale Air Toxics Assessment defines point sources as major stationary facilities that emit or have the potential to emit 10 tons of any one toxic air pollutant or 25 tons of more than one toxic air pollutant per year. NATA does not provide a breakout of more detailed point source categories. NATA also does not include information on diesel emissions from point sources.
POINT SOURCES - CRITERIA AIR POLLUTANTS
Scorecard's criteria air pollutant reports are based on EPA's National Emissions Trends database. Definitions of EPA's point source category are provided in its National Air Pollutant Emissions Trends Report, 1900-1996.
To support Clean Air Act regulations, EPA has assigned Source Classification Categories (SCCs) for air pollution generating activities. These classifications are used to develop estimates and projections of air pollution by pollutant type. Presented below is a brief description of the point source categories used by Scorecard:
External Combustion Boilers: Electric utility power generation, industrial power generation.
Internal Combustion Engines: Electrical generators, industrial power generators, commercial and institutional power generation, and engine testing operations.
Industrial Processes: Chemical manufacturing, food and agricultural processes and primary metal production.
Petroleum and Solvent Evaporation: Petroleum refining processes, surface coating operations, degreasing, industrial dry cleaning and organic chemical storage.
Waste Disposal: Municipal solid waste disposal, commercial and institutional solid waste disposal, industrial solid waste incinerators including hazardous waste incinerators.
MACT Source Categories: Food and agricultural processes, agricultural chemical production, styrene and methylacrylate production, use of cellulose based resins.
ONLINE POINT SOURCE RESOURCES
EPA's Office of Air Quality Planning and Standards:
Emissions Monitoring Center
US EPA's Toxic Release Inventory
EPA's Acid Rain Program:
Emissions Data from Electrical Utilities