## R esponses to Comments Not Addressed in the Preamble to the Final Rule: Transportation ConformityRule PM 2.5 

## and PM 10



## Am endments

February 5, 2010 Docket ID No. EPA - HQ - OAR - 200 8 - 0 540Docket ID No. EPA -HQ - OAR - 2008 - 0540

2 Comment : One commenter was concerned that the grace period for newl y designated areas would not leave sufficient time for their agency to complete and adopt a TIP based on the agency ’s schedule. The commenter wrote that if the designations were made in “ October 2009, ” and the one - year grace period expires in “ De cember 2009, ” there would be insufficient time to demonstrate conformity and adopt the 2010 TIPs. Response : The preamble to the final rule clarifies the applicable dates. The commenter’s assertion that the grace period expires in December of 2009 is incorrect. EPA’s final rule designating areas nonattainment for the 2006 PM2.5 NAAQS was published in the Federal Register on November 13, 2009, and effective December 14, 2009. The one ye ar conformity

grace period for newl y designated areas begins on De cember 14, 2009, and ends on December 14, 2010. Comment : The commenter notes that serious health impacts are associated with exposure to fine PM. More than enough research has been done that shows that some types of transportation projects can emit enough PM 2.5 to cause or contribute to violations of the NAAQS. Given the compelling evidence that diesel exhaust may be the most hazardous of all PM components, it is imperative that EPA fulfill its responsibility to control PM 2.5 emissions from transpo rtation projects. Response : EPA has fulfilled its responsibility regarding PM 2.5 emissions from transportation projects b y implementing the Clean Air Act conformity requirements for PM 2.5 . Comment : One commenter thought that EPA’s proposed optio n to define the baseline y ear related to the SIP or AERR process would not reduce EPA’s need to issue guidance in the future. Response : EPA intends to issue guidance to clarify the baseline y ear for an y future new or revised PM 2.5 NAAQS. Such guidance will be needed to explain how the regulation finalized today

(which define s the baseline ye ar with respect to the AERR) should be implemented for a specific new or revised PM 2.5 NAAQS. However, today ’s regulation removes the need for EPA to revise its ba seline year regulation for an y future new or revised PM 2.5 NAAQS.Docket ID No. EPA -HQ - OAR - 2008 - 0540

3 Comment : A commenter suggested that if EPA finalizes the proposed option 2 for the baseline year , EPA should align the baseline ye ar for the 2008 8 - hour ozone NAAQS with the baseline year for the 2006 PM 2.5 NAAQS. Response : EPA did not propose to revise the baseline ye ar for any future new or revised ozone NAAQS , and therefore this comment is outside the scope of today ’s action. Comment : A commenter that supported the option fina lized in today ’s rule noted that EPA’s Office of Air Quality

Planning and Standards has not recommended a single SIP modeling base ye ar as a reason for their support of this option . Response : EPA notes that there is no requirement that the baseline y ear for the conformity baseline year test and the base year used for SIP modeling be the same y ear. The baseline year for the baseline year test for the 2006 PM 2.5 areas is 2008 , as described in the preamble of today ’s rule. Comment : One commenter noted that either interim emissions test is adequate as long as the same emissions model and assumptions are used for the build scenario and the comparison scenario, i.e., either the no - build scenario or the baseline year. Response : EPA agrees that the sam e model has to be used for both the build case and the comparison case , given differences in model results between MOBILE6.2 and MOVES using the same or similar inputs. EPA believes it is unlikely that an y area would want to use different model s for the b uild and comparison cases in a single regional emissions anal ys is given the additional time involved . Inany case , models for conformity anal ys es must be decided through the interagency consultation process, of which EPA is a member , and that consultation process will help ensure that consistent models and assumptions are used . Comment : The commenter noted that areas are likely to need to use interim tests in upcoming ye ars because most areas do not have adequate or approved budgets for the 1997 PM 2.5 NAAQS. In addition, this commenter noted that the court’s remand of the CAIR program still needs to be addressed . This commenter also noted that the introduction of MOVES will require rerunning some inventories for consistency purposes.Docket ID No. EPA -HQ - OAR - 2008 - 0540

4 Response : EP A agrees that many

areas will need to use one of the interim emissions tests because adequate or approved budgets are not yet available for the 1997 PM 2.5 NAAQS. EPA’s response to the CAIR remand is outside the scope of today ’s rulemaking. In areas that have adequate or approved budgets for the 1997 PM 2.5 NAAQS, SIPs may need to be updated using MOVES. EPA believes that the 2006 PM 2.5 NAAQS nonattainment areas must use MOVES in developing SIPs for this NAAQS, therefore such inventories will not need to be redone when MOVES is required for transportation conformity

(i.e., at the end of the two - ye ar MOVES grace period). Comment : One commenter was concerned that there is no SIP strategy designed to reduce emissions near roadway s to the levels needed to attain the NAAQS, and EPA’s proposed interpretation of CAA 176(c)(1)(B)(iii) fails to require the highway project to reduce emissions in the area affected b y the project. The commenter suggest ed that if EPA were to modify its SIP guidance to require stat es to model the incremental impact of highway emissions near highway s, and develop a control strategy designed to remedy

these violations, then EPA’s interpretation of CAA 176(c)(1)(B)(iii), to require an air quality assessment focused on whether emissions from the proposed project would cause or contribute to new violations or worsen existing violations, would be reasonable. However, the commenter believes that EPA has created a set of SIP policies that allows states to ignore elevated levels of PM 2.5 and resulting NAAQS violations near highways. And, as long as these policies remain in effect, the commenter believes that there is no basis for interpreting (B)(iii) as allowing projects to proceed if emissions from those project continue to cause or contri bute to future NAAQS violations. Response : For the reasons described in the preamble to today’s action, EPA disagrees that its regulations fail to satisfy

CAA section 176(c)(1)(B)(iii). Further, the commenter’s assertions regarding the alleged shortcomi ngs of the SIP process are outside the scope of today ’s rulemaking. Comment : One commenter was c oncerned that introduction of MOVES would result in an inability to pass conformity . This commenter states that the area experienced three non conformity determinations from 1996 - 2003 , because SIP budgets were initially calculated using M OBILE 4 but subsequent EPA models effectively doubled calculated emission s , resulting in “technical” mismatch with budgets. This commenter stated that they are not ye t able to assess their potential situation because MOVES is not y et available. Response : Because a new emissions model can produce different emissions results, the conformity

rule includes a provision for a grace period before the new model must be used for conformity

determinations. This grace period can be from three months to twoDocket ID No. EPA -HQ - OAR - 2008 - 0540

5 ye ars, depending on the degree of change between the existing model and the new model. In the case of MOVES, EPA intends to provide the maximum length grace period of two ye ars. EPA release d MOVES2010 in December 2009, and will be establishing a two ye ar grace period, which should give areas sufficient time to address issues. Furthermore, EPA believes SIPs for the 2006 PM 2.5 NAAQS must be developed using MOVES. EPA is provid ing SIP and conformity guidance for the transition to the MOVES model, as well as other information and training regarding the use of MOVES. See EPA’s website: http://www.epa.gov/ot aq/models/moves/trainingsessions.htm for information about upcoming training sessions. Also note that other MOVES related guidance, including user guides and other technical information is available on EPA’s website at: http://www.epa.gov/otaq/models/moves/index.htm , and http://www.epa.gov/otaq/stateresources/transconf/policy .htm . Comment: One commenter suggeste d that air quality model ing process used in transportation conformity

should be reformed to use the most recent air qualit y data available , rather than prediction - based models . This commenter also suggested that emissions budgets have a built - in level of flexibility , such as a 10 to 15 percent cushion, to allow for increases in emissions . Third, this commenter suggested that hot - spot analy sis should be removed from the regulations. Response : EPA did not in this rulemaking propose an y regulatory revisi ons addressing air quality modeling, and therefore the first comment is outside the scope of this rulemaking. However, EPA believes that the current requirements to model future transportation activity and resulting emissions is required by the Clean Air Act. Section 176(c)(2)(A) of the Act requires that “emissions expected from implementation of such plans and programs are consistent with estimates of emissions from motor vehicles and necessary emissions reductions cont a ined in the applicable air quality implementation plan...” In other words, conformity is to examine future transportation sector emissions, rather than an area’s overall air quality , which is affected by not just the transportation sector but other sources of emissions as well as topograp hical and meterological factors. Furthermore, EPA does not believe that it is possible to use an area’s current air quality data to estimate emissions as distant as 20 years in the future. As described above, an area’s current air quality data results f

rom all sources of emissions . While the transportation sector’s emissions are included, they result from current levels of vehicle miles traveled (VMT) and the emissions characteristics of the vehicle fleet on the road today . Neither VMT nor vehicle emis sions will be the same in the future as they are today . The conformity

rule’s requirements for preparing a regional emissions analy sis result in a reasonable estimate of future emissions that result from planned transportation. EPA’s new emissions mod el, MOVES, does include the most recent data about vehicle emissions under different conditions. EPA believes that this model improves the accuracy of predicted emissions.Docket ID No. EPA -HQ - OAR - 2008 - 0540

6 Further, EPA did not propose in this rulemaking any revisions to the conformity budget test regulations and did not propose substantive changes to the hot - spot requirements. Therefore, the comments on those issues are outside the scope of today ’s action.