# Presentation: 106479

## Session 4: Regional Emissions Tests for the New Standards  

- FHWA Transportation Conformity and CMAQ Workshop
- Summer 2004

## General:Regional Emissions Analyses

- No adequate or approved SIP budgets:
- interim emissions test(s) – baseline year and build/no-build tests)
- Adequate or approved SIP budgets:
- budget test
- Final rule updates interim emissions tests and provide flexibility

## General Changes to Baseline Year Tests

- Baseline year test updated from 1990 to 2002 for 8-hour ozone and PM2.5
- Consistent with EPA establishing 2002 as the baseline year for SIPs for new standards
- Latest 2002 baseline motor vehicle emissions must be used as decided through consultation process
- 1990 still applies for 1-hour, CO, PM10, and NO2 areas

## General Changes toBuild/No-Build Test

- Test changed to build _<_ no-build test for all areas except higher classifications of ozone and CO
- the build_<_no-build test is waived altogether for these areas for analysis years when projects and planning assumptions are exactly the same in the build and no-build scenarios
- provides flexibility to areas with fewer Clean Air Act (CAA) requirements
- helps these areas when build and no-build scenarios are exactly the same
- these areas still need to make conformity determinations and look at all analysis years
- Test remains build<no-build for ozone and CO areas of higher classifications

## Areas Covered by Final Rule

- Final rule describes regional regional emissions analysis tests before and after new SIP budgets are available for:
- 8-hour ozone areas without 1-hour ozone SIP budgets
- 8-hour ozone areas with 1-hour ozone SIP budgets
- PM2.5 areas

## Tests for 8-hour Areas without 1-hour SIPs

- Final rule is generally consistent with requirements in 1-hour ozone areas without adequate or approved SIP budgets
- Marginal and subpart 1 (“basic”) areas without 1-hour SIPs can choose between:
- build_<_no-build, OR
- no-greater-than-2002 test

## Tests for 8-hour Areas without 1-hour SIPs

- Moderate and above areas without 1-hour SIPs complete both:
- build<no-build AND
- less-than-2002 tests
- Because the CAA requires that transportation activities in moderate and above ozone areas must also “contribute to annual emission reductions....”
- For all 8-hour areas using interim emissions tests, a regional emissions analysis is done for:
- volatile organic compounds (VOCs), and
- nitrogen oxides (NOx), unless EPA has issued a NOx waiver under CAA section 182(f) for the 8-hour ozone standard (1-hour NOx waivers are not applicable for the 8-hour standard)

## 8-hour Areas with 1-hour SIPs

- Final rule requires that existing 1-hour SIP budgets be used for 8-hour conformity before new 8-hour SIPs are in,
- unless another test is deemed more appropriate for meeting CAA requirements
- Using adequate and approved 1-hour SIP budgets will ensure that these areas continue current air quality progress and attain the 8-hour standard on time
- Final rule is described through four boundary scenarios:
- areas where the 8-hour boundary = 1-hour boundary
- areas where the 8-hour boundary < 1-hour boundary
- areas where the 8-hour boundary > 1-hour boundary
- areas where portions of 8-hour and 1-hour boundaries overlap

## 8-hour Areas with 1-Hour Budgets

- 4 potential boundary scenarios:

## Scenario 1 -- 93.109(e)(2)(i)

- Area uses 1-hour budgets as-is since boundaries are the same

## Slide 11

## Scenario 2 -- 93.109(e)(2)(ii)

- Area calculates regional emissions and uses budgets from 1-hour SIP for either:
- the 8-hour area,
- if the appropriate portions of the budgets can be identified through consultation
*	**	**	**	**OR*
- the entire 1-hour area,
- and any additional reductions, beyond those strategies in the SIP, must come from within the 8-hour area

## Scenario 3 -- 93.109(e)(2)(iii)

- Area uses budgets from 1-hour SIP for the portion they cover, *AND*
- the interim emissions test(s) for either:
- the entire 8-hour area, *OR*
- for the portion not covered by 1-hour budgets, *OR*
- for the portion of the 8-hour area in a state (only for cases with separate 1-hour SIP budgets for each state)

## Slide 14

## Scenario 4 -- 93.109(e)(2)(iv)

- If possible:
- use 1-hour budgets for portion that has them, if portions can be identified through consultation, *AND*
- the interim emissions test(s)
- for the remainder, *OR*
- for the whole 8-hour area, *OR*
- for the portion of the 8-hour area in a state (only for cases with separate 1-hour SIP budgets for each state)
- If not possible:
- use the interim emissions test(s), for the portion of the 8-hour area where 1-hour budgets are not identified

## Slide 16

## Before Areas Have 8-hour SIPs:General Principles

- Use budget test (93.118), with the 1-hour budgets for 8-hour conformity
- where they exist, and
- as possible, given the boundary scenario
- because in most cases, budgets ensure air quality progress is maintained (especially if they are currently being used for 1-hour conformity determinations)

## Before Areas Have 8-hour SIPs:General Principles

- Use the interim emissions test(s) (93.119)
- where part of an 8-hour area isn’t covered by 1-hour budgets
- where boundary changes make it impossible to determine what portion of the 1-hour budgets apply (Scenario 4 only)
- when it is determined through the consultation process that such tests better meet the CAA requirements for analysis years addressed by the SIP budgets (limited cases expected) (93.118(e)(2)(v))

## When may a 1-hour SIP budget not be appropriate?

- Primary criterion is whether a 1-hour SIP budget meets CAA requirements to not worsen air quality or delay timely attainment of the 8-hour standard
- A 1-hour budget cannot be considered inappropriate simply because:
- it is difficult to pass for 8-hour conformity purposes
- it is based on older planning assumptions or emissions models
- Interagency consultation process must be used to determine appropriate test for a given analysis year
- May be cases of areas with 1-hour SIP budgets where one budget is appropriate and another is not for a given analysis year

## Examples of when a 1-hour SIP budget not be appropriate

- Where a 1-hour SIP budget is currently not used in 1-hour conformity determinations
- a 1-hour maintenance area that is marginal for 8-hour with:
- 1999 1-hour attainment budgets
- 2009 1-hour maintenance plan budgets
- 2007 8-hour attainment year
- in this case, it may be appropriate to do 8-hour conformity with:
- 2002 baseline test for 2007 8-hour attainment year since 2002 baseline may be lower than 1999 budgets
- 2009 maintenance budgets for all future years
- _Rationale:_  If a 1-hour SIP budget is currently not used to maintain current air quality progress, it may not be appropriate to meet CAA requirements for the 8-hour standard.
- Where it is impossible to determine what portion of the 1-hour SIP budget applies to the 8-hour area (in Scenario 4 areas only)

## Once Areas Have 8-hour or PM2.5 SIPs

- Once adequate or approved SIP budgets are available for new standards, they must be used (93.118)
- existing interim emissions tests and/or 1-hour budgets (where applicable) for the pollutant or precursor addressed by the new SIP budget
- 					...*no longer apply*

## Once Areas Have SIP Budgets

- Area has budgets when:
- State submits the SIP, and
- EPA has found the budgets adequate or approved the SIP
- Adequacy criteria in 93.118(e)
- Adequacy procedures:  now in 93.118(f), but remain the same as under guidance

## Timely Implementation of TCMs

- Timely implementation requirement applies for a TCM in the approved SIP, including SIPs for all pollutants and standards
- TCMs in a 1-hour SIP still apply even after the 1-hour standard is revoked
- They must still be implemented in a timely manner
- They must still be accounted for in conformity determinations