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EPA420-F-03-041

November 2003

Transportation Conformity Rule Amendments for the New 8-hour Ozone and

PM2.5 National Ambient Air Quality Standards and

Miscellaneous Revisions for Existing Areas

Summary of the November 5, 2003, Published Proposed Rulemaking

Note: This document provides a summary of the various proposals included in EPAÌs November

5, 2003, published notice of proposed rulemaking that addresses transportation conformity under

the new 8-hour ozone and PM2.5 air quality standards.  The summary descriptions correspond

with the individual preamble sections included in the proposal.  

Section III:  Conformity Grace Period and Revocation of the 1-hour Ozone Standard

This section discusses the statutory 1-year grace period before conformity is required after the

effective date of 8-hour ozone and PM2.5 nonattainment designations, and how this grace period

would apply in metropolitan, "donut," and isolated rural areas.  This section also discusses the

conformity impacts of EPA's June 2, 2003, proposal (68 FR 32819) to revoke the 1-hour ozone

standard in whole, or in part, one year after the effective date of 8-hour ozone nonattainment

designations.  Conformity would no longer be required in either 1-hour nonattainment or 1-hour

maintenance areas, once the standard is revoked. This section also discusses when conformity

would apply, or not apply, in areas with Early Action Compacts.  Finally, this section proposes

only minor changes to the transportation conformity rule, since it primarily discusses issues that

are already in statute, or are proposed under other rulemakings or guidance.

Section IV:  General Changes in the Interim Emissions Tests

This section proposes to amend the rule as follows:

< change the conformity ruleÌs references for Ï emission reduction testsÓ to be Ï interim

emissions tests;Ó   

< establish 2002 as the baseline year interim emissions tests for the 8-hour ozone and PM2.5

standards (i.e., for the Ï no-greater-than-2002" and Ï less-than-2002" interim emissions

tests);

< allow certain areas to utilize a "build-no-greater-than-no-build" test instead of the current

"build-less-than-no-build" test, and would not require regional emissions analyses in

future years where the transportation projects and assumptions in the build and no-build

scenarios are the same; and

< propose three options for changing the interim emissions test requirements in higher

classified ozone and CO areas as follows:

1) complete both the build-less-than-no-build and less-than-baseline year tests;

2) complete either the build-less-than-no-build or less-than-baseline year test; or

3) require that only one of these tests be met and eliminate the remaining test as an

option altogether.  
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Section V: Regional Conformity Tests in 8-hour Ozone Areas That Do Not Have 1-hour Ozone

SIPs

This section proposes to amend the rule as follows:

< Once an 8-hour ozone area has adequate or approved 8-hour SIP budgets in place, those

budgets would be used to demonstrate conformity.  

< Prior to adequate or approved budgets:

Ô marginal and below 8-hour ozone areas and areas designated under Clean Air Act

subpart 1 could do either the build-no-greater-than-no-build test or the no-greaterthan-2002 test.  

Ô EPA is requesting comment on three proposed options for moderate and above 8-

hour ozone areas, as described above in the summary for Section IV.

< EPA also proposes options for 8-hour ozone areas that qualify for EPAÌs proposed clean

data policy for the 8-hour ozone standard.  See the conformity proposal for further details.

Section VI:  Regional Conformity Tests in 8-hour Ozone Areas That Have 1-hour Ozone SIPs

This section proposes to amend the rule as follows:

< Once an 8-hour area has adequate or approved 8-hour SIP budgets in place, those budgets

would be used to demonstrate conformity.

< Prior to adequate or approved budgets, all 8-hour ozone areas covered by this section are

able to select one test option from among a menu of test options for completing the

regional emissions analysis requirement, rather than be required to complete a specific

test.   The proposal discusses several options depending upon the manner in which the 8-

hour ozone nonattainment boundary interacts with the existing 1-hour ozone boundary.

< The proposed options for conformity prior to 8-hour ozone SIP budgets are as follows:

1) Where 8-hour and 1-hour ozone boundaries are the same, conformity would be

demonstrated with either:

Ô the interim emissions tests; or

Ô the budget test using the 1-hour ozone SIP budget.

2) Where the 8-hour ozone boundary is smaller than the 1-hour ozone boundary,

conformity would be demonstrated with either:

Ô the interim emissions tests for the 8-hour area;

Ô the budget test using the 1-hour ozone budget against the entire 1-hour

area; or

Ô the budget test using a portion of the 1-hour ozone budget for the 8-hour

ozone area.  The consultation process would be used to determine whether

the budget test as described is appropriate and if so, how it should be

implemented. EPA requests comments on when using a portion of the

1-hour budget is appropriate and how this could be done in practice.

3) Where the 8-hour ozone boundary is larger than the 1-hour ozone boundary,

conformity would be demonstrated with either:

< the interim emissions tests for the entire 8-hour area; or

< the budget test using the 1-hour ozone budget against the 1-hour area, plus

the interim emissions tests for the remainder of the 8-hour area.
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4) Where portions of the 8-hour and 1-hour ozone boundaries overlap, conformity

would be demonstrated with either:

< the interim emissions tests for the entire 8-hour area; or

< the budget test using a portion of the 1-hour budget for the portion of the

1-hour area that is overlapped by the 8-hour area, plus the interim

emissions tests for the remainder of the 8-hour area. The consultation

process would be used to determine whether the budget test for this

scenario is appropriate and if so, how it should be implemented.

< See EPAÌs outreach document entitled, Ï Boundary Scenarios for 8-hour Ozone

Nonattainment Areas Previously Designated as Nonattainment or Maintenance for the 1-

hour Ozone StandardÓ on EPAÌs website for illustrations of the four hypothetical

boundary scenarios described in the proposal and this summary.

< EPA also proposes options for 8-hour ozone areas that qualify for EPAÌs proposed clean

data policy for the 8-hour ozone standard.  See the conformity proposal for further details.

Section VII:  Regional Conformity Tests in PM2.5 Areas

This section proposes to amend the rule as follows:

< Once a PM2.5 area has adequate or approved PM2.5 budgets in place, those budgets would

be used to demonstrate conformity.  

< Prior to adequate or approved budgets, PM2.5 areas could do either the build-no-greaterthan-no-build test or the no-greater-than-2002 test for direct PM2.5 and the relevant PM2.5

precursors that apply in a given area.

Section VIII:  Consideration of Direct PM2.5 and PM2.5 Precursors in Regional Emissions

Analyses

This section proposes to amend the rule as follows:

< Directly emitted PM2.5 from motor vehicle tailpipe, brake wear, and tire wear emissions

would be considered in all conformity analyses.

< NOx, VOCs, SOx, and NH3 are identified astransportation-related precursors of PM2.5.  

< Conformity would be demonstrated for a precursor if a SIP establishes an adequate or

approved budget for that precursor.

< Prior to adequate or approved budgets, EPA proposes two options for comment:

1) conformity would be demonstrated for NOx and VOCs unless EPA or the State

air agency finds them not to be significant; or

2) conformity would only be required for NOx and VOCs if EPA or the State air

agency finds them to be significant.

< Under both precursor options, conformity would only be required for SOx and NH3 if

EPA or the State air agency finds them to be significant.

Section IX:  Re-entrained Road Dust in PM2.5 Regional Emissions Analyses

This section proposes to amend the rule as follows:

< Conformity analyses would include re-entrained road dust if a SIP establishes an adequate

or approved PM2.5 budget that includes re-entrained road dust.
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< Prior to adequate or approved budgets, EPA proposes two options for comment:

1) conformity would only be demonstrated for re-entrained road dust if EPA or the

State air agency finds it to be significant. EPA also offers a modification to this

option that would require PM2.5 areas that are also PM10 areas to include PM2.5

re-entrained road dust in their analyses, if road dust is currently included in PM10

conformity analysis.

2) conformity analyses for all areas would include re-entrained road dust unless EPA

or the State air agency finds them not to be significant.

Comment is also solicited on the method of estimating road dust.

Section X:  Construction-Related Fugitive Dust in PM2.5 Regional Emissions Analyses

This section proposes to amend the rule as follows:

< Conformity would be demonstrated for construction-related fugitive dust if a SIP

establishes an adequate or approved PM2.5 budget that includes construction-related

fugitive dust.  EPA proposes to only include construction-related fugitive dust in PM2.5

conformity analyses if EPA or the State air agency finds it to be significant.

Section XI:  Compliance with PM2.5 SIP Control Measures

This section proposes to amend the rule as follows:

< FHWA and FTA projects in PM2.5 nonattainment and maintenance areas would be

required to comply with the PM2.5 SIPÌs control measures, when such measures exist.  

The proposal is similar to the current requirement for PM10 areas.

EPA also requests information regarding how this requirement has been implemented in PM10

areas.

Section XII:  PM2.5 Hot-spot Analyses

EPA proposes two options for this issue:

1) PM2.5 hot-spot analyses would not be required in PM2.5 areas; or

2) PM2.5 hot-spot analyses would be required, but only in the types of locations

identified in PM2.5 SIPs.

EPA also requests information on the existence of transportation-related PM2.5 hot-spots, and

location types that might be identified in SIPs.

Section XIII:  PM10 Hot-spot Analyses

This section proposes four options for comment regarding the current requirement for hot-spot

analyses in PM10 areas:

1) retain the requirement to do hot-spot analyses for all projects in PM10 areas;

2) limit analyses to areas where the PM10 SIP identifies motorized vehicle emissions

as a localized problem;

3) limit analyses to certain locations or certain types of projects; and

4) eliminate the requirement to perform PM10 hot-spot analyses altogether.  

EPA invites suggestions of additional options for the current PM10 hot-spot requirement.

EPA requests information on the implementation of the PM10 hot-spot requirement and other

aspects of this issue.  Please see the proposal for further details.  
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Section XIV:  Miscellaneous Revisions for New and Existing Areas

EPA is also proposing several miscellaneous revisions that would:

< Revise current definitions for "control strategy implementation plan revision" and

"milestone," and add a new definition for "limited maintenance plan.Ó

< Incorporate existing policies for how conformity requirements are applied in areas with

insignificant motor vehicle emissions and areas with limited maintenance plans.

< Include a 2-year grace period before transportation network modeling and transportation

plan content requirements would apply in certain ozone and CO areas that are bumped-up

to higher classifications or where the urbanized population increases over 200,000.

< Clarify when the budget test must be satisfied for an adequate or approved SIP budget,

according to the March 2, 1999, court decision.  This proposal would expand on EPAÌs

June 30, 2003 proposal (68 FR 38974) on this particular issue.

< Clarify other provisions of the conformity regulation to improve implementation.