Establishing Representative Background Concentrations for Quantitative Hot-spot Analyses for Particulate Matter

The purpose of this project was to develop step-by-step methods to help transportation project analysts estimate representative background concentrations for use in particulate matter (PM) hot-spot conformity analyses. This work discusses Environmental Protection Agency (EPA) guidance, provides project analysts with a variety of methods and tools to complete the required analyses, and provides case study examples illustrating the use of the different analysis techniques. Discussions of EPA guidance may be paraphrased in this report; therefore, analysts should refer at all times to the complete EPA guidance to assess agency guidance and EPA rules and regulations where applicable. In addition to providing insight into the handling of data influenced by exceptional air quality events, this report addresses the influence of exceptional-type events on background concentration calculations. Exceptional-type events are defined in this document as events that are exceptional in nature but either did not result in an exceedance of the National Ambient Air Quality Standards (NAAQS) or resulted in an exceedance of the NAAQS, but have not been granted exclusion by the EPA. This material is presented for research purposes only – removal of exceptional-type data from background concentrations has not been approved by the EPA. Finally, this report identifies topics where additional guidance would improve the analysis process or where existing EPA guidance is limited and may benefit from additional detail or clarification.

  • Record URL:
  • Summary URL:
  • Supplemental Notes:
    • This research was sponsored by the American Association of State Highway and Transportation Officials, in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies.
  • Corporate Authors:

    Sonoma Technology, Incorporated

    1360 Redwood Way, Suite C
    Petaluma, CA  United States  94954-1169

    Louis Berger Group, Incorporated

    412 Mount Kemble Avenue
    Morristown, NJ  United States  07962
  • Authors:
    • Pasch, Adam N
    • Russell, Ashley R
    • Eisinger, Douglas S
    • Alrick, Daniel M
    • Hafner, Hilary R
    • Tidd, Leo
    • Sliker, Laura
  • Publication Date: 2014-10


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; Photos; References; Tables;
  • Pagination: 273p

Subject/Index Terms

Filing Info

  • Accession Number: 01672211
  • Record Type: Publication
  • Report/Paper Numbers: NCHRP Project 25-25, Task 89
  • Files: TRIS
  • Created Date: Jun 8 2018 2:16PM