US EPA

191774 

Technical Report 

EPA Report 

Risk and exposure assessment for review of the secondary National Ambient Air Quality Standards for oxides of nitrogen and oxides of sulfur 

U.S. Environmental Protection Agency :: U.S. EPA 

2009 

Yes 

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division 

Research Triangle Park, NC 

EPA/452/R-09/008A 

522 

English 

The U.S. Environmental Protection Agency (EPA) is conducting a joint review of the existing secondary (welfare-based) National Ambient Air Quality Standards (NAAQS) for nitrogen oxides (NOx) and sulfur oxides (SOx).1 EPA has decided to jointly assess the scientific information, associated risks, and standards relevant to protecting the public welfare from adverse effects associated with NOx and SOx because NOx, SOx, and their associated transformation products are linked from an atmospheric chemistry perspective, as well as an environmental effects perspective, and because the National Research Council (NRC) has recommended that EPA consider multiple pollutants, as appropriate. This is the first time since the NAAQS were established in 1971 that a joint review of these two pollutants has been conducted.