Analyzing, Documenting, and Communicating The Impacts of Mobile Source Air Toxic Emissions in the NEPA Process

An increased awareness and concern for motor vehicle air toxic emissions has prompted state transportation agencies for the need to address air toxic emissions as part of their environmental review process. This study develops information and guidelines on available analytical models and techniques to assess mobile source air toxic (MSAT) impacts and how this information can be communicated in the environmental assessment. The study reviews and provides recommendations on available analytical modeling tools to use in MSAT assessments along with the identification of model strengths and weaknesses. A methodology has been developed which guides the transportation analyst in identifying the appropriate level of analysis using typically available information and potential level of exposure based on the size of the transportation project. Five potential levels of analysis are identified based on both technical and policy considerations so as to guide the transportation analyst in applying a consistent set of criteria for developing a MSAT assessment. Details are presented on how to conduct the MSAT assessment as well as on the amount of information which should be included at each level of analysis. Recommendations are provided on how best to communicate these findings as part of an environmental assessment document.

  • Record URL:
  • Summary URL:
  • Supplemental Notes:
    • This study was requested by the American Association of State Highway and Transportation Officials (AASHTO), and conducted as part of the National Cooperative Highway Research Program (NCHRP) Project 25-25. Project 25-25 is intended to fund quick response studies on behalf of the AASHTO Standing Committee on the Environment.
  • Corporate Authors:

    ICF International

    9300 Lee Highway
    Fairfax, VA  United States  22031
  • Authors:
    • Carr, Edward L
    • Ernst, David A
    • Rosenbaum, Arlene
    • Glass, Geoffrey
    • Hartley, Seth
  • Publication Date: 2007-3


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 260p

Subject/Index Terms

Filing Info

  • Accession Number: 01499269
  • Record Type: Publication
  • Report/Paper Numbers: NCHRP Project 25-25, Task 21
  • Files: TRIS
  • Created Date: Nov 12 2013 1:35PM