NATA estimates are based on computer modeling. For cancer, estimates indicate the additional number of people who may develop cancer given a lifetime exposure to a toxic air pollutant. Other factors, such as genetics and lifestyle, are not considered in these estimates. The results are presented in the number of cases per million population.
Estimates for non-cancer health effects are determined by summing effects of exposure to the same group of organs. The non-cancer results are reported as a "hazard index" where a value of less than one represents a low probability of causing adverse health effects.
NATA provides a snapshot of how airborne concentrations of air toxics, exposure and risk vary throughout the United States. The study does not focus on individuals, or on the variation in exposure and risk among individuals. It focuses on variation between well-defined geographic areas, such as counties or states.
Comparison of results between NATA study years is not recommended because computer model methodologies used and source data are not the same from year to year.
The 2011 NATA is now available through EPA’s web page at https://www.epa.gov/national-air-toxics-assessment . EPA has included a mapping program that includes similar information for NC to the information presented below for 1999, 2002 and 2005.
Select a year from the drop down menu to view North Carolina cancer and non-cancer results maps from 1999, 2002 or 2005 NATA, as well as information related to Inhalation Exposure to Hazardous Air Pollutant by NC County. 2011 NATA data can be found at https://www.epa.gov/national-air-toxics-assessment.