EPA Issues Public Draft of
Transportation Conformity Guidance
for Quantitative Hot-spot Analyses
in PM and PM Nonattainment and
in
1U
Maintenance Areas
Overview
For the first time, the U.S. Environmental Protection Agency (EPA) has released
draft conformity guidance for quantifying the local air quality impacts of certain
transportation projects on the PM25 and PM10 national ambient air quality
standards (NAAQS). Once finalized, this guidance will be used by state and local
agencies to conduct "hot-spot analyses" for new highway and transit projects that
involve significant diesel emissions. EPA intends to finalize the guidance later
this year, and, after a grace period, quantitative hot-spot analyses would apply in
PM25 and PM10 nonattainment and maintenance areas. Until then, qualitative
analyses continue to apply in PM areas, using previously issued joint EPA-FHWA
guidance on such analyses. EPA has not issued this PM hot-spot modeling guidance
in the past because appropriate models were not available for quantifying PM
emissions from individual transportation projects. Now that EPA has released its
new MOVES2010 emissions model, an appropriate model is available for EPA
to use to develop guidance for the use of quantitative PM hot-spot analyses in
conformity determinations. EPA developed this draft guidance in coordination with
the Department of Transportation, state and local agencies, and other stakeholder
groups,
EPA is seeking public comment on all aspects of the draft guidance by July 19, 2010;
see below for further details on how to submit comments.
SEPA
Purpose of the Draft Guidance
This draft guidance describes how to complete quantitative PM hot-spot analyses,
A hot-spot analysis is an analysis of a project's impact on the NAAQS in the local
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-F-10-036
May 2010
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area of the project. A hot-spot analysis is required only for new highway and transit projects that
involve significant diesel truck or bus traffic.
This draft guidance describes how to estimate project emissions using EPA's MOVES2010
model, California's EMFAC2007 model, and other methods. It also outlines how to apply air
quality models (AERMOD and CAL3QHCR) for PM hot-spot analyses. Finally, the draft
guidance includes appendices that provide additional resources and examples that may assist
state and local agencies in conducting quantitative PM hot-spot analyses. A description of each
section of the draft guidance is included below.
Background
Transportation conformity is a Clean Air Act requirement that ensures that federally supported
highway and transit projects are consistent with state air quality implementation plans. Confor-
mity helps protect public health through early consideration of the air quality impacts of trans-
portation decisions in places where air quality does not currently meet the NAAQS or has not
met them in the past.
Steps for Completing a Quantitative PM Hot-spot Analysis
The flowchart on the next page illustrates the basic steps for completing a quantitative PM
hot-spot analysis as described in the draft guidance. In general, a hot-spot analysis compares the
air quality concentrations with the proposed project (the "build" scenario) to air quality con-
centrations without the project (the "no-build" scenario). For either scenario, it is necessary to
consider emissions from the project and any nearby sources, as well as determine background
concentrations. From this information, design values can be calculated to determine if a project
conforms. If the build design values are less than or equal to the relevant NAAQS, the project is
considered to conform. A project will also conform if the build scenario design values are greater
than the NAAQS but less than or equal to the design values for the no-build scenario.
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which can include nearby sources (e.g., locomotive emissions at a freight terminal) and other
sources of emissions not from the project itself,
Section 9: Calculating PM Design Values and Determining Conformity
This section describes how to combine all previous steps of a PM hot-spot analysis into a design
value so that a project sponsor can determine if conformity requirements are met. For confor-
mity purposes, a design value is a statistic that describes a future air quality concentration in the
project area that can be compared to a particular NAAQS,
Section 10: Mitigation and Control Measures
This section describes mitigation and control measures that could be considered by project spon-
sors to reduce emissions and any new or worsened PM NAAQS violation that is predicted in a
PM hot-spot analysis,
Appendices
The draft guidance also contains the following appendices to supplement the above sections and
assist state and local agencies when conducting PM hot-spot analyses:
• Appendix A is a clearinghouse of information and resources external to this guidance
which may be useful when completing PM hot-spot analyses,
• Appendix B gives examples of projects of local air quality concern,
• Appendix C discusses what projects need a hot-spot analysis if a state's approved
conformity SIP is based on pre-2006 requirements,
• Appendix D demonstrates how to characterize links in an intersection when running
MOVES.
• Appendices E and F are abbreviated PM hot-spot analysis examples (using MOVES) for
a highway and transit project, respectively,
• Appendices G and H are examples of how to configure and run EMFAC for a highway
and transit project, respectively,
• Appendix I includes guidance for estimating locomotive emissions in the project area,
• Appendix J includes details on how to input air quality modeling data and run AERMOD
and CAL3QHCR for a PM hot-spot analysis and prepare outputs for design value
calculations,
• Appendix K has examples of how to calculate design values and determine transportation
conformity.
Request for Comments
EPA is seeking public comment on all aspects of the draft guidance by July 19, 2010. In particular,
EPA is seeking comments on the following:
* Does the guidance provide sufficient information on how to configure and run
MOVES2010 and EMFAC2007 at the project level?
• Do the air quality modeling sections of the guidance and references to other existing
documents provide sufficient detail for air quality modelers to conduct PM hot-
spot analyses using AERMOD or CAL3QHCR?
• Is there sufficient information in the guidance to calculate design values and determine
appropriate receptors? If not, what additional information is necessary?
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• Are there issues that the draft guidance does not address that should be addressed in the
final guidance or in other EPA efforts?
• What types of outreach, training, and other technical assistance would be helpful in
implementing the final guidance?
EPA encourages those submitting comments to provide specific details and/or examples wher-
ever possible.
Submitting Comments
Comments can be submitted to EPA via the following methods:
Email: Comments can be sent electronically to PMhotspot'Comments@epa.gov
Mail: Comments sent by mail should be addressed to
Meg Patulski
State Measures and Conformity Group
Transportation and Regional Programs Division
U.S. Environmental Protection Agency
2000 Traverwood Drive
Ann Arbor, MI48105
Fax: Comments can also be faxed to the attention of Meg Patulski at (734) 214-4052,
For More Information
The draft quantitative PM hot-spot guidance can be found on EPA's Office of Transportation
and Air Quality website at: www.epa.gov/otaq/stateresources/transconf/policy.htm.
For further information on the draft guidance, please contact:
Meg Patulski
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, MI 48105
734-214-4842
E-mail: patulski.meg@epa.gov (Note that comments on the guidance should be sub-
mitted directly to PMhotspot-comments@epa.gov)
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