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Support for Air Regulations and Policies
Additional Information
Current Research Tasks
NAAQS Implementation
The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS). After setting the NAAQS, ambient monitoring is used to identify areas of the country that exceed the levels in the NAAQS. For those locations that do not meet the NAAQS (non-attainment areas), State Implementation Plans (SIPs) are developed and evaluated that identify appropriate actions to improve air quality in non-attainment areas. Research is needed to reduce the uncertainty and improve the effectiveness of these implementation activities. The Human Exposure and Atmospheric Sciences Division (HEASD) conducts research to support implementation of the NAAQS in the areas of atmospheric measurement methods, atmospheric chemistry, and receptor modeling for source apportionment.
Current research by scientists in HEASD involves (1) developing and evaluating the ambient monitoring methods used to measure compliance for the upcoming coarse PM (PM10-2.5) NAAQS, (2) characterizing key atmospheric chemical processes that are involved in the formation of PM2.5 for the 1997 PM2.5 NAAQS, and (3) developing and applying receptor-oriented models to identify sources contributing to air pollution. Ultimately, by enhancing the implementation activities for the NAAQS, this research will enhance EPA’s ability to improve air quality, thereby reducing exposures to PM and improving public health. Details of NAAQS Implementation
Support for Mercury Regulations and Policy
Excessive levels of mercury in the nation’s waters is a significant source of water quality impairment in the US. Mercury is emitted to the atmosphere where it is transported and deposited. Atmospheric deposition of mercury is the largest contributor of mercury to sensitive ecosystems. Research conducted by HEASD on atmospheric mercury helps EPA better understand the magnitude of mercury deposition and the amount of mercury deposition that can be attributed to anthropogenic sources, such as coal-fired utilities.
Current mercury research in HEASD involves evaluating a method to measure dry deposition of mercury and understanding the impact of coal combustion on atmospheric mercury. Typically, measurements of mercury deposited in precipitation (wet deposition) have been used to characterize inputs of mercury to sensitive ecosystems. Dry deposition of mercury has been poorly characterized, but likely delivers as much mercury to ecosystems as wet deposition. The method evaluated in this research will be used nation-wide by EPA to monitor dry deposition of mercury. Research activities also include determining the contribution of coal combustion to mercury deposition and understanding the atmospheric processes affecting the fate of gas phase mercury emitted from coal-fired utilities. Details of Mercury Regulations and Policy