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March 10, 2006, Transportation Conformity Rule That Addresses Requirements for Project-level Conformity Determinations in PM2.5 and PM10 Nonattainment and Maintenance Areas

This final rule, published March 10, 2006, establishes requirements for project-level conformity determinations in particulate matter (PM) 2.5 nonattainment and maintenance areas, and revises existing requirements for projects in PM10 areas. The rule requires that PM2.5 hot-spot analyses be included in project-level conformity determinations only for new transportation projects with significant diesel traffic, such as major highway projects and projects at congested intersections that handle significant diesel traffic. For example, hot-spots could occur at congested roadway intersections and truck stops. No hot-spot analyses will be required for most projects in PM2.5 areas, because most projects do not present an air quality concern. The final rule also streamlines existing PM10 project-level requirements in a similar way. This final rule is part of EPA's implementation of the current PM2.5 standards.

General information on particulate matter or PM air pollution.

Contact:  Meg Patulski at 734-214-4842 or email:

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