EPA Releases 2014 NATA Results

August 22, 2018 – EPA has made publicly available the results of the 2014 National Air Toxics Assessment (NATA), which is a screening tool that provides estimates of exposures and risks related to 180 of the 187 hazardous air pollutants listed under the Clean Air Act, as well as diesel particulate matter (PM). The risks analyzed as part of NATA include both cancer and non-cancer health effects based on chronic exposure from outdoor sources of the listed pollutants and the non-cancer health effects related to diesel PM. NATA is developed by entering the data from the National Emission Inventory into inhalation exposure and risk models. Based on NATA, the estimated national average cancer risk in 2014 was 30 in one million.  Fewer than 1 percent of the census tracts in the U.S. had an estimated cancer risk of greater than or equal to 100 in one million and in those areas that did, the risk was driven primary by point source emissions of ethylene oxide (EtO), cholorprene and coke oven emissions. With respect to EtO, in many cases the elevated risk estimates result from a 2016 update to EPA’s risk value for the chemical.  About one half of the national average cancer risk was the result of secondary formation (formaldehyde and acetaldehyde) from both anthropogenic sources (stationary and mobile) and biogenic sources.  State and local air quality agencies participated in the development of NATA by reviewing and providing information for the inventory and the modeled results.