Supporting documentation for the 2011 National-scale Air Toxics Assessment can be found in the Technical Support Document.  This document describes the data and approaches used to conduct the assessment.  The document includes descriptions of how we:

• Compiled emissions data and prepared them for use as model inputs (Section 2),
• Estimated ambient concentrations of air toxics (Section 3),
• Estimated exposures to air toxics for populations (Section 4),
• Selected toxicity values (Section 5),
• Characterized human health risks and hazards (Section 6), and
• Addressed variability and uncertainty (Section 7).

This document satisfies basic documentation protocol expected of EPA products and also provides a resources for the technically-oriented user community by summarizing the data sources, methods, models, and assumptions used in the 2011 NATA.  The document does not provide quantitative results and thus presents no exposure or risk estimates.  Results and other specific information for the 2011 NATA can be found on the assessment results page. 

• 2011 NATA Supplemental Data Files (ZIP)(86 MB)
  This data folder contains supplemental data files referred to in the TSD, which include pollutant, source grouping, spatial allocation and other modeling information used  2011 NATA.

• 2011 NATA Technical Support Document (PDF)(361 pp, 14 MB, December 2015)