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Project-Level Conformity and Hot-Spot Analyses

Transportation
Conformity

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This page contains policy guidance, technical guidance, and other resources issued by EPA to assist agencies in completing project-level conformity analyses, including particulate matter (PM2.5 and PM10) and carbon monoxide (CO) “hot-spot” analyses.

PM Hot-spot Analyses: Guidance

  • Transportation Conformity Guidance for Quantitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas
    EPA has released final guidance for modeling the local air quality impacts of certain transportation projects on the PM2.5 and PM10 national ambient air quality standards (NAAQS). This guidance is to be used by state and local agencies to conduct quantitative PM “hot-spot analyses” for new highway and transit projects that involve significant diesel emissions. This guidance describes how to estimate project emissions using EPA’s MOVES model, California’s EMFAC model, and other methods. It also outlines how to apply air quality models (such as AERMOD and CAL3QHCR) for PM hot-spot analyses. The guidance also includes a list of additional resources that may assist agencies in conducting quantitative PM hot-spot analyses.
    Contact: Meg Patulski at 734-214-4842 or patulski.meg@epa.gov
    Technical questions about this guidance can be directed to conformity-hotspot@epa.gov.
    EPA has announced a two-year grace period for completing quantitative hot-spot analyses using MOVES and EMFAC. This grace period ends on December 20, 2012; new PM hot-spot conformity analyses required under 40 CFR 93.123(b)(1) started after this date must be quantitative rather than qualitative. See the Federal Register notice (PDF) and and EPA’s latest MOVES policy guidance for details.
  • Transportation Conformity Guidance for Qualitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas (PDF) (35 pp, 306K, EPA420-B-06-902, March 2006)
    This guidance document is a companion document for the March 10, 2006, final rule that establishes the transportation conformity criteria and procedures for determining which transportation projects must be analyzed for local air quality impacts in PM2.5 and PM10 nonattainment and maintenance areas (71 FR 12468).  The Environmental Protection Agency (EPA) and the Federal Highway Administration (FHWA) have developed this guidance to help state and local agencies meet the final rule's hot-spot analysis requirements.
    Contact: Meg Patulski at 734-214-4842 or patulski.meg@epa.gov

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CO Hot-spot Analyses: Guidance

  • Using MOVES in Project-Level Carbon Monoxide Analyses (PDF) (59pp, 2M, EPA420-B-10-041, December 2010)
    This guidance describes how to use the MOVES emissions model to estimate CO emissions from transportation projects, including roadway intersections, highways, transit projects, parking lots and intermodal terminals. This guidance can be applied when using MOVES to complete any project-level quantitative CO analysis, including hot-spot analyses for transportation conformity determinations, modeling project-level emissions for SIP development, and completing NEPA analyses.
    Contact: David Bizot at 734-214-4432 or bizot.david@epa.gov. Technical questions about this guidance can be directed to conformity-hotspot@epa.gov.

    EPA has announced a two-year grace period for completing quantitative hot-spot analyses using MOVES and EMFAC. This grace period ends on December 20, 2012; any new quantitative CO hot-spot conformity analyses started after this date outside of California must be based on MOVES. See the Federal Register notice (PDF) and EPA’s latest MOVES policy guidance for details.

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Emissions Models and Methods

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Air Quality (Dispersion) Models

  • Recommended Air Quality (Dispersion) Models for PM Hot-spot Analyses
    The following is a summary of recommended air quality models for completing PM hot-spot analyses for different types of transportation projects. This is a reproduction of Exhibit 7-2 of the Quantitative PM Hot-spot Guidance.

    Type of Project Recommended Model(s)
    Highway and intersection projects AERMOD, CAL3QHCR
    Transit, freight, and other terminal projects AERMOD
    Projects that involve both highway/intersections and terminals, and/or nearby sources AERMOD

    See Section 7 of the guidance for complete information on selecting an appropriate air quality model. See below for which model versions are currently approved for regulatory use.

  • Approved Versions of Air Quality (Dispersion) Models
    The following is a summary of currently approved versions of air quality (dispersion) models for quantitative PM hot-spot analyses, as recommended by EPA’s “Guideline for Air Quality Models” (Appendix W to 40 CFR Part 51). This is only a summary; refer to the appropriate guidance and model websites for more information about the applicability and use of these models. Draft or unapproved versions of models cannot be used to complete hot-spot analyses for regulatory purposes.

    Air Quality Model Version/date Link to Model Information
    AERMOD Version Dated 12345 www.epa.gov/ttn/scram/dispersion_prefrec.htm#aermod
    CAL3QHCR Version dated 12355 www.epa.gov/ttn/scram/dispersion_prefrec.htm#cal3qhc

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Tools for Completing Project-level Analyses

  • Tool to generate EMISFACT portion of an AERMOD input file
    EPA has developed a MySQL script called “MOVES2AERMOD” to automate the process of generating the EMISFACT portion of an AERMOD input file using MOVES output. The tool is intended to be used as part of a quantitative PM hot-spot analysis and can be run directly through the MOVES GUI. To obtain the tool and for more information, see the MOVES tools page.
  • MySQL 24-hour PM2.5 Design Value Script
    EPA has developed a MySQL script to calculate design values for the 24-hour PM2.5 NAAQS for PM hot-spot analyses. The readme file in the download package describes how to “install” the tool as well as providing instructions on using it for PM hot-spot analyses.

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Training and Other Resources

  • Quantitative PM Hot-spot Analysis Training
    EPA and DOT have developed a three-day training course on implementing EPA’s guidance. This technical, hands-on course is geared toward state and local agencies and focuses on using emission models (including EPA's MOVES model) and air quality models (AERMOD and CAL3QHCR) for quantitative PM hot-spot analyses. The PM hot-spot analysis training page provides more information.
  • MOVES Model Information and Training
    • The EPA’s MOVES page provides complete information about the model, including downloads, technical guidance, and tools.
    • The MOVES listserv provides updates on MOVES and other mobile source emissions models. Sign up here
      • .
    • EPA has developed a two-day, hands-on course geared toward state and local agencies who will use MOVES for developing SIPs and regional conformity analyses, as well as a shorter web-based course for people interested in a general overview of MOVES. The MOVES training page contains information about this and other MOVES training information, courses, and webinars.
  • Air Quality Model Information
    • More information about dispersion models (including AERMOD and CAL3QHCR), meteorology preprocessors, and related tools, guidance, and outreach can be found on EPA’s Support Center for Regulatory Atmospheric Modeling (SCRAM) website.
    • The SCRAM RSS feed provides updates on recent posting and additions to the SCRAM website. Sign up here.
  • Presentations
  • Additional conformity-related training information and presentations can be found at www.epa.gov/otaq/stateresources/transconf/training.htm.

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Frequently Asked Questions (FAQs)

  • EPA FAQs
    The following are frequently asked questions about conducting hot-spot analyses for transportation conformity purposes. EPA will update these periodically.
  • Federal Highway Administration PM2.5 FAQs
    FHWA has developed a series of FAQs specifically for PM2.5 project-level conformity and hot-spot analyses. These FAQs were coordinated with EPA. The FHWA PM2.5 Project-Level Conformity and Hot-Spot Analyses FAQs webpage has more information.

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Contact Information

  • EPA Regional Conformity Contacts
    EPA regional conformity staff are the primary EPA contacts for project sponsors completing project-level analyses for conformity purposes and should be contacted first for information and questions about these analyses. For the complete list of contacts by region, please see www.epa.gov/otaq/stateresources/transconf/contacts.htm.
  • Technical questions about using MOVES for project-level analyses can be directed to mobile@epa.gov.
  • Other technical questions on completing PM or CO project-level conformity analyses can be directed to conformity-hotspot@epa.gov.
  • EPA’s Office of Air Quality Planning and Standards maintains a list of state air quality modeling staff who have experience that may be useful to a project sponsor when completing a hot-spot analysis, including running the selected air quality model and finding representative background data for a project. See OAQPS’s state contacts page for more information.

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