WASHINGTON, D.C., Dec. 10, 2004 — EPA is publishing a Supplemental Notice of Proposed Rulemaking with optional methods and procedures for determining localized concentrations of particulate matter (PM) in areas where transportation conformity is required for PM2.5 and PM10. Transportation conformity is required by the Clean Air Act (CAA) to ensure that federally supported highway and transit project activities do not cause new air quality violations, worsen existing violations, or delay timely attainment of an air quality standard.
The options included in this proposal apply to PM2.5 and PM10 nonattainment areas, which are those areas that do not meet the national ambient air quality standards for PM2.5 and PM10. These options also apply to PM2.5 and PM10 maintenance areas, which are those areas that previously did not meet the standard but do so now. EPA is publishing this notice with options for requirements because it is possible that concentrations of particulate matter that violate the PM standards could occur on a local, rather than regional, basis, such as at road intersections and truck stops.
EPA is requesting further comment on options it previously proposed and is proposing several additional options for states regarding this type of local analysis. Such analysis is currently required in nonattainment areas for carbon monoxide and PM10 and is part of broader requirements concerning transportation conformity. Transportation conformity is a CAA requirement that ensures federally supported highway and transit project activities are consistent with (“conform to”) a state’s air quality implementation plan (SIP).
Conformity requires that planned activities do not cause new violations, worsen existing violations, or delay timely attainment of an air qualitystandard. The agency is seeking public review and comment on this proposal. For additional information, go to: www.epa.gov/otaq/transp/traqconf.htm.