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2004 and 2005 Transportation Conformity Rule Amendments Outreach Activities

Session 6: .What do I include in my PM2.5 conformity analysis?

FHWA Transportation Conformity and CMAQ Workshop
Summer 2004

Tests for PM_2.5 Areas

• Final rule is generally consistent with requirements in PM₁₀ areas without adequate or approved SIP budgets
• Final rule allows all PM_2.5 areas to choose either the:
  • build < no-build, OR
  • no-greater-than-2002 baseline year test
• A regional emissions analysis is done for direct PM_2.5 emissions and any applicable PM_2.5 precursors
  • discussed further in Session 6

Transportation PM_2.5 Emissions

• Gasoline and diesel on-road vehicles emit:
  • direct PM_2.5
    • exhaust
    • brake and tire wear
    • re-entrained dust from paved and unpaved roads
    • construction dust from highway and transit construction
  • PM_2.5 precursors from vehicles:
    • NOx, VOCs, SOx
    • ammonia (primarily emitted by gasoline vehicles)
    • will be addressed in separate final rule to be completed before PM_2.5 designations are effective

Direct PM_2.5 in Regional Analyses.(93.102(b)(1))

• All PM_2.5 regional emissions analyses address direct PM_2.5 including:
  • tailpipe and brake and tire wear emissions
• MOBILE6.2 and EMFAC2002(CA only) generate PM_2.5 emissions factors

Road Dust in PM_2.5 Regional Analyses.(93.102(b)(3) and 93.119(f))

• Before PM_2.5 SIP budgets are adequate or approved, road dust is not included in regional analyses unless found to be a significant contributor by:
  • EPA Regional Administrator, or
  • state air agency
• Road dust is included in regional analyses if adequate or approved SIP budgets include road dust emissions

What is Considered in Significance Findings?

• A finding of significance would be based on:
  • the contribution of road dust to current and future PM_2.5 nonattainment
  • the area's current design value for the PM_2.5 standard
  • whether control of road dust appears necessary to reach attainment, and
  • whether increases in road dust emissions may interfere with attainment
• A finding of significance should be made:
  • only after discussions within the consultation process
  • through a letter to state and local air quality agencies, MPO(s), DOT and EPA (if a state air agency finding)

Calculating Road Dust Emissions

• Road dust emissions can be calculated using methods described in:
  • AP-42, Fifth Edition, Volume 1, Chapter 13, Miscellaneous Sources (US EPA, December 2003; www.epa.gov/ttn/chief/ap42/ch13/)
• Or, areas may develop local calculation methods, through interagency consultation
  • must be approved by EPA
• By effective date of PM_2.5 designations, guidance will be issued on adjusting road dust emissions for SIPs and conformity to reflect true impact on regional air quality

Construction Dust in PM_2.5 Regional Analyses (93.122(f))

• Fugitive dust from construction of transportation projects is only included in regional emissions analyses if:
  • the SIP identifies these emissions as significant contributors to the regional PM_2.5 problem
• Construction emissions would be included in the area's direct PM_2.5 SIP budgets, where significant
  • consultation must be used

Calculating Construction .Dust Emissions

• Construction dust emissions can be calculated using methods described in:
  • AP-42, Fifth Edition, Volume 1, Chapter 13, Miscellaneous Sources (US EPA, December 2003; www.epa.gov/ttn/chief/ap42/ch13/)
• Or, areas may develop local calculation methods, through interagency consultation
• By effective date of PM_2.5 designations, guidance will be issued on adjusting dust emissions in SIPs and conformity to reflect true impact on regional air quality

PM_2.5 Precursors in Regional Analyses

• EPA is not finalizing any PM_2.5 precursor requirements at this time
• Requirements for PM_2.5 precursors will be finalized before PM_2.5 designations are effective
• However, June 2004 final rule provides sufficient information for potential areas to begin preparing for PM_2.5 conformity, if desired

PM_2.5 Precursors in Regional Analyses

• The November 2003 NPRM identified:
  • NOx
  • VOCs
  • sulfur oxides (SOx); and
  • ammonia (NH₃)
  as potential transportation-related PM_2.5 precursors

PM_2.5 Precursors in Regional Analyses

• The NPRM also proposed that a regional emissions analysis would be required for a precursor once
  • a SIP emissions budget for that precursor was found adequate or approved
• NPRM included two options for PM_2.5 precursors in regional analyses before SIP budgets are adequate or approved

PM_2.5 Precursors in Regional Analyses

• Option1:
  • Include NOx and VOCs unless the EPA RA or state air agency finds that one or both precursors is not a significant contributor
  • Only include SOx or NH₃ if the EPA RA or state air agency finds that one or both is a significant contributor
• Option 2:
  • Only include NOx, VOCs, SOx or NH₃ if the EPA RA or state air agency finds that one or more is a significant contributor

PM_2.5 and PM₁₀ Hot-Spots

• EPA proposed several options in the November 5, 2003 NPRM for PM_2.5 and PM₁₀ hot-spot requirements
• Supplemental proposal to be published: Summer 2004 to propose additional options for:
  • new PM_2.5 hot-spot requirements
  • changes to existing PM₁₀ requirements

Continued

Project-level Requirements in PM_2.5 Areas

• Rule to be finalized before PM_2.5 designations are effective
• Current PM₁₀ hot-spot analyses requirements continue to apply as under current practice