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BACKGROUND: The 1990 Clean Air Act regulates air toxics because they are known to or suspected of causing cancer or other serious health problems. US EPA’s 2005 National-Scale Air Toxics Assessment (NATA) provides a “snapshot” estimate of chronic inhalation exposure for numerous air toxics at each US census tract. The National Health and Nutrition Examination Survey (NHANES) obtains a complex, multistage probability sample of human subjects representative of the US population. AIMS: Estimate reference exposure concentrations of 174 air toxics, including diesel engine emissions, for a representative sample of the United States population. METHODS: Publicly available US EPA NATA 2005 air toxics exposure concentrations estimated at the census tract were geographically merged with geocoded residences of participants in NHANES 1999 – 2010 (n = 62,160). Population-weighted statistics were estimated for each air toxic. RESULTS: For a selection of air toxics, the population-weighted geometric mean (GM [GSD] in micrograms per cubic meter) of exposure concentration were estimated to be: toluene 1.6 [0.089]; formaldehyde 1.5 [0.036]; acetaldehyde 1.4 [0.027]; benzene 0.75 [0.027]; diesel engine emissions 0.24 [0.019]; acrolein 0.021 [0.0012]; and PAHs 0.0061 [0.00042]. Statistics grouped by metropolitan and non-metropolitan census tracts are also available. CONCLUSIONS: This analysis provides a comprehensive assessment of air toxics exposure for the US population potentially useful for prioritizing pollutants for further evaluation of public health impact.