VIII. E. Compliance Through the EGU Model Rules Is ` Better than Bart'

Commenters: The Adirondack Council, OAR 2003 0053 1699; Georgia Department of Natural Resources, Environmental Protection Division, Air Protection Branch, OAR 2003 0053 0698; Michigan Department of Environmental Quality, Air Quality Division, OAR 2003 0053 1180; Missouri Department of Natural Resources, Air Pollution Control Program, OAR 2003 0053 1251; Alabama Department of Environmental Management, Air Division, OAR 2003 0053 0680.

Comment: Several commenters believed that the Better than BART " debate" belongs in the regional haze rule making process and not within the CAIR, or felt that it was premature to make that a decision at this time on whether CAIR may substitute for BART.

Response: The EPA agrees that the final determination on whether CAIR may substitute for BART in the CAIR affected region cannot be made until the BART guidelines for EGUs and the criteria for BART alternative programs are final. Information and analysis regarding EPA's present understanding of this issue is presented in the CAIR preamble and supporting documentation in order to provide the public with as much information as possible regarding the potential implications of the CAIR.

Commenters: Clean Air Task Force, et al., OAR 2003 0053 0742, OAR 2003 0053 1762; Environmental Defense, OAR 2003 0053 0786, OAR 2003 0053 1776; Southern Environmental Law Center, OAR 2003 0053 1224, OAR 2003 0053 1224; Wild South, OAR 2003 0053 1091; Sierra Club, OAR 2003 0053 1204; American Petroleum Institute ( API), OAR 2003 0053 1829; Northeast States for Coordinated Air Use Management ( NESCAUM), OAR 2003 0053 1674; STAPPA/ ALAPCO, OAR 2003 0053 1725.

Comment: Several commenters assert the policy of allowing CAIR to satisfy BART requirements is arbitrary or otherwise not in accordance with the law. Such arguments are based on several related grounds. Commenters assert that because CAIR and BART arise from independent provisions of the CAA, and because Congress specifically identified 26 source categories for regulation under BART, EPA has no authority to supplant BART requirements with other requirements. Some commenters further elaborate or qualify that assertion by arguing that a BART alternative program could be legal if the emissions reductions required of non BART eligible sources were based on visibility considerations ( rather than other criteria such as NAAQS attainment). If BART eligible sources may avoid installing BART based on reductions otherwise required by law, BART is rendered largely superfluous, they argue. Commenters also point to Regional Haze Rule section 308( e)( 2), in support of the idea that reductions from other programs such as Title IV and NO x SIP call must be achieved in addition to, not as substitute, for BART. These commenters also cite Sierra Club v. EPA, 294 F. 3d 155 ( DC Cir. 2002), for the proposition that EPA has no authority to alter or ignore programs mandated by Congress in the CAA. Response: The policy of allowing another program to substitute for BART is not an illegal substitution of the Agency's judgment for that of Congress, but rather is based on a reasonable interpretation of the ambiguous language of CAA § 169A( b)( 2). This section provides that EPA must require SIPs to contain certain measures " as may be necessary to make reasonable progress toward meeting the national goal . . . including   " among other things, a requirement that BART eligible sources install BART. See 42 USC 7491( b)( 2). The EPA has interpreted this as meaning that BART is required only " as may be necessary to make reasonable progress." A logical corollary is that if an alternative strategy covering a given source or source sector makes greater progress than BART, then BART is not necessary for that source or sources.

In Central Arizona Water Conservation District v. EPA, 990 F. 2d 1531, ( 1993), the Ninth Circuit applied the two step Chevron test ( Chevron, U. S. A., Inc. v. NRDC, 467 U. S. 837, 842 45 ( 1984) and found that the statutory language was ambiguous and that EPA's interpretation was reasonable. 990 F. 2d at 1543. The court therefore agreed that the statute provided EPA with " discretion to adopt implementation plan provisions other than those provided by BART analyses in situations where the agency reasonably concludes that more ` reasonable progress' will thereby be attained." Id. In that case, the BART alternative in question applied to a single facility.

In CEED v. EPA, [ citation], D. C. Cir., 2005, the DC Circuit similarly applied the two step Chevron test and also found that the statutory language was ambiguous and that EPA's interpretation was reasonable. [ slip op.] at 12 13. In CEED v. EPA the BART alternative at issue ( the WRAP Annex) applied not just to one facility but to all BART eligible sources ( as well as other sources) in participating States. Therefore, the CEED v. EPA decision clarified that EPA's interpretation of 169A( b)( 2) allowing BART alternative is reasonable not only in a sourcespecific context but also in the context of larger programmatic BART alternatives. ( The court vacated the Annex on other grounds, holding that EPA did not rationally exercise its discretion with respect to the particular methodology required of States to demonstrate that the Annex would result in greater progress than BART) [ cite].

The CAIR cap and trade program for EGUs represents an intermediate case between the singlesource BART alternative in Central Arizona Water and the all BART sources alternative in CEED v. EPA. A BART alternative program can only achieve emission reductions at sources included in the program and so ( obviously) cannot achieve greater reasonable progress than BART with respect to BART eligible sources which are not covered by the program. Therefore, the relevant question for CAIR is whether it achieves greater reasonable progress from EGUs than would BART for EGUs. If it can be shown that CAIR does so, then under EPA's interpretation of 169A( b)( 2), upheld in both these cases, BART for EGUs is not " necessary to make reasonable progress." Because this finding would be applicable only to EGUs, it would not frustrate Congress' intent in identifying 26 source categories for BART applicability.

The EPA believes the analysis presented in the CAIR preamble and TSD convincingly demonstrate that CAIR achieves greater reasonable progress, with respect to SO 2 and NO x emissions from EGUs, than would source specific BART for EGUs in the CAIR region. Moreover, the EPA does not believe that it is a prerequisite of BART alternative programs that the emission reductions be developed explicitly for visibility purposes in the first place. As long as the end result is greater visibility improvement than BART, it is of no consequence that the emission reductions were initially developed to serve other air quality purposes. As the DC Circuit stated, " Congress's addition of § 169B . . . clarified that the focus of the Clean Air Act was to achieve ` actual progress and improvement in visibility,' . . . not to anoint BART the mandatory vehicle of choice." [ slip. op. at 13]. As long as visibility is actually improved more than it would be under BART, it should not matter whether the emission reductions were developed explicitly for visibility, as under BART, or for some other purpose, as under CAIR.

The EPA also does not believe that regional haze rule section 308( e)( 2) provides any support for the notion that emissions reductions from other programs must be in addition to, not substitute, for BART. We first note that the decision in CEED v. EPA necessitates revisions to 308( e)( 2), at least in the provisions requiring visibility to be evaluated on a cumulative basis in defining the BART benchmark for comparison to BART alternative programs. It remains to be seen whether 308( e)( 2)( iv), which requires that emissions reductions from the BART alternative be " surplus to reductions resulting from measures adopted to meet requirements as of the baseline date of the SIP," will be changed. Even if that section remains unchanged, CAIR complies with it. The baseline date of Regional Haze SIPs is 2002. Since any emissions reduction requirements to meet CAIR would necessarily be adopted after 2002, CAIR required reductions would be surplus to measures adopted as of the baseline year.

Finally, with respect to the decision in Sierra Club v. EPA, nothing in that case alters EPA's opinion that it has the authority to approve alternative programs in lieu of BART. Sierra Club simply represents an application of the two pronged Chevron test, in which the court found that Congress had directly spoken to some of the questions at issue and therefore remanded those matters to EPA. Because there was no ambiguity in the Act with respect to certain requirements at issue, the court applied the principle that an agency is not free to substitute its own policy judgment for that of the Congress. In contrast, as explained above, EPA's interpretation of 169A( b)( 2) under Chevron has been upheld in both the Ninth and DC Circuits.

Notwithstanding all the above, as discussed in the NFR preamble and below, the EPA recognizes that the determination that CAIR achieves greater progress than BART may not be finalized until the proposed guidelines for making BART determinations, and additional regulatory changes necessitated by the recent decision in CEED v. EPA, are final. The BART guidelines will contain presumptive levels of control for EGUs. In a separate action we will establish criteria for evaluating BART alternative programs. The current analysis in the TSD is based on the application of proposed presumptive BART controls for EGUs to all BART eligible EGUs as a conservative ( most stringent) estimate of emissions, and on the " better than BART" criteria proposed in the 2004 BART guidelines package.

Commenters: Environmental Defense, OAR 2003 0053 1776; Clean Air Task Force, et al., OAR 2003 0053 1762; South Carolina Department of Health and Environmental Control, OAR 2003 0053 1820. Comment: Several commenters stated that a categorical exclusion by EPA of BART eligible sources from BART would constrain State discretion in violation of the decision in the American Corn Growers case, because it would allow no consideration of visibility impacts on individual source basis. Others commented that the better than BART policy appears to limit the ability of state to apply additional standards ( e. g., BART) if the State participates in the cap and trade program. At least one State commented that it desires to maintain its discretion to make BART determinations.

Response: The CAIR does not constrain State discretion in making BART determinations. If EPA determines that CAIR achieves greater progress than BART for EGUs, States will be allowed to treat CAIR as an alternative in lieu of BART but will not be required to do so.

Commenter: Clean Air Task Force et al., OAR 2003 0053 1762.

Comment: Some commenters noted that CAA 169A( c) prescribes the specific conditions under which EPA may grant exemptions from BART, which have not been satisfied in this case.

Response: As also explained in greater detail in the preamble, the Better than BART policy is not properly cast as an exemption, but rather is an alternative means of complying with the CAA provisions on which BART requirements are based.

Commenter: Clean Air Task Force et al., OAR 2003 0053 1762.

Comment: Some commenters note that CAA 169A( b)( 2)( A) requires BART based on contribution to any Class I area. They point out that EPA did not demonstrate greater progress than BART at each and every Class I area, but instead modeled only certain class I Areas, and the assessed improvement on an average basis. These commenters assert there is no basis in the law or the regional haze rule to support a BART substitute which is not demonstrated to achieve greater progress at each area.

Response: This comment was addressed in the preamble. There we explained that we disagree with comments that 169A( b)( 2)' s requirement of BART for sources reasonably anticipated to contribute to impairment at any Class I area means that an alternative to BART program must be shown to create improvement at each and every Class I Area. Even if a BART alternative is deemed to satisfy BART for regional haze purposes, based on average overall improvement as opposed to improvement at each and every Class I Area, 169A( b)( 2)' s trigger for BART based on impairment at any Class I area remains in effect, because a source may become subject to BART based on " reasonably attributable visibility impairment" at any area. . In any case, the criteria we applied in our present analysis   that greater reasonable progress is defined as no degradation at any Class I area, and greater overall average improvement   has not been finalized.

Commenters: Michigan Department of Environmental Quality, Air Quality Division, OAR 2003 0053 1180.

Comment: One commenter stated that EPA did not provide sufficient information regarding the application of the BART factors to affected sources.

Response: Under the proposed Better than BART test, the pertinent question is whether the alternative to BART program makes greater reasonable progress by producing greater emission reductions and, if the distribution of reductions is different, greater visibility benefits. To determine the emission reductions and corresponding visibility improvements achievable by BART for EGUs, we used the presumptive control levels currently proposed in the BART guidelines. The statutory BART factors were applied to develop these presumptive control levels. The analysis employing these factors will be further explained in the BART Guidelines NFR, on or before April 15, 2005. Commenter: Wisconsin Department of Natural Resources, OAR 2003 0053 1799.

Comment: One commenter implied that the CAIR ultimate SO 2 reductions of 70%, with 58% reductions in 2015, fall short of the BART presumptive level of 90   95% for uncontrolled EGUs.

Response: It is not appropriate to directly compare these percentages. The CAIR reductions of 70% is for all EGUs in the affected regions, which includes not only currently uncontrolled BART eligible sources, but BART eligible sources which are currently controlled at a lesser efficiency and may not be required to achieve 95% after consideration of the BART factors, plus all other non BART eligible EGUs. The relevant point of comparison is total emission reductions, which as stated elsewhere are 2.3million tons SO 2 more per year nationwide under CAIR than under BART.

Commenter: North Carolina Division of Air Quality ( NCDAQ), OAR 2003 0053 1767.

Comment: One State commented that the SNPR modeling shows that the improvement of CAIR compared to source specific BART is so slight it may be potentially within the margin of error, and therefore insufficient for the Better than BART demonstration or to assure that no hot spots will occur.

Response: EPA has completed the refined modeling of the nationwide BART and BART + CAIR model runs using an updated 2001 modeling platform. The visibility results continue to show that the CAIR cap and trade program provides considerably more visibility improvement compared to nationwide BART ( for EGUs only). The NFR modeling results show that the average visibility improvement from CAIR on the 20% worst days at 29 Eastern Class I areas is 1.6 deciviews ( dv) compared to only a 0.7 dv improvement from nationwide BART controls. In the BART TSD we have provided modeling results for 116 individual Class I areas. The modeling shows that CAIR will not create any " hot spots". On the 20% worst days, all of the Eastern Class I areas show more visibility improvement under CAIR than under BART. In many of the Western Class I areas, BART and CAIR provide about the same visibility benefits. While the visibility benefits are similar in the West ( outside of the CAIR region), they are clearly not similar in the East, where the CAIR is predicted to achieve twice as much visibility improvement compared to BART. We do not agree with the commenter that the improvements are slight. At the four Class I area sites in North Carolina, on the 20% worst days, the modeling shows that the CAIR cap and trade program provides 2 3 times more visibility improvement compared to nationwide BART ( the CAIR visibility improvements range from 1.9 2.6 dv at the four Class I areas). The modeling also shows that CAIR will not result in any visibility degradation on either the 20% worst days or 20% best days.

Commenters: Large Public Power Council ( LPPC), OAR 2003 0053 1756; Utility Air Regulatory Group ( UARG), OAR 2003 0053 1784; Florida Municipal Electric Association ( FMEA), OAR 2003 0053 1683; Center for Energy & Economic Development, Inc., OAR 2003 0053 0371; National Mining Association, OAR 2003 0053 0705.

Comment: Several commenters agreed with our determination that CAIR would not preclude the possibility of reasonably attributable determinations by Federal Land Managers ( FLMs) or States under the 1980 BART regulations, and that sufficient regulatory certainty could be provided to sources through a memorandum of understanding with FLMs similar to that used by the WRAP.

Response: As noted in the preamble, the EPA continues to maintain that BART based on RAVI must be retained in order to protect against the possibility of localized degradation, even though current modeling does not predict such " hot spots." We also agree that regulatory certainty may be improved by agreements with FLMs regarding the circumstances under which RAVI may be certified, coupled if necessary with " geographic enhancements" to the trading program to accommodate sources subject to RAVI BART.

Commenters: Natsource ( for Generators for Clean Air [ GCA]), OAR 2003 0053 1796; Dominion, OAR 2003 0053 1778.

Comment: One commenter believed that CAIR should be deemed to satisfy not only BART for regional haze purposes but BART for reasonably attributable visibility impairment ( RAVI) as well, without need for geographic enhancements to reconcile the cap and trade program to BART requirements triggered by RAVI.

Response: This comment is addressed in the preamble and the response to the previous comment above.

Commenter: Dominion, OAR 2003 0053 1778.

Comment: One commenter believed that geographic enhancements, if used, should not be determined on an across the board ( i. e, across all States) basis.

Response: The EPA agrees that it is not necessary to develop a uniform policy on geographic enhancements. Instead, this is appropriately left to State discretion, so we have not prescribed any geographic enhancement provisions within the cap and trade program rules.

Commenter: Florida Municipal Electric Association ( FMEA), OAR 2003 0053 1683.

Comment: Commenter stated that geographic enhancements should also be available for purposes of new source requirements. Thus, the commenter believes, visibility improvements from CAIR should be incorporated in FLM review of visibility impacts of new generating units located near Class I areas, and that EPA provide guidance to the states and FLMs on how to do so.

Response: The EPA disagrees that geographic enhancements should play any role in the context of new sources. The purpose of geographic enhancements is to accommodate the emission market to source specific retrofits required because an existing source is causing a " hot spot." Such considerations do not exist with respect to new sources. The EPA is not including guidance to States and FLMs on how to incorporate visibility improvements from CAIR into the review of new source impacts, but will continue to work with States and FLMs on these issues, primarily through the Regional Planning Organizations.

Commenters: Progress Energy, OAR 2003 0053 1726; Texas Commission on Environmental Quality, OAR 2003 0053 1827 Comment: Several commenters stated that CAIR should be deemed to satisfy BART whether or not a state participates in the cap and trade program.

Response: EPA's preliminary demonstration that CAIR gets more reasonable progress than source specific BART for EGUs is based on a comparison of emissions reductions and attendant air quality affects under BART as applied to EGUs, with those under CAIR for EGUs. If emissions reductions are achieved from other source sectors, a similar analysis would need to be conducted for those sectors before it could be determined that the reductions were better than BART for affected sources. For example, the inclusion of non EGU sources in the State's emission reduction requirement would allow more emissions from the State's EGUs. The State would have demonstrate that these increased emissions do not cause degradation at any Class I area, and still result in greater overall improvement, when considered along with the emission reductions from non EGUs. In addition, the State would have to conduct a better than BART demonstration for any BART eligible non EGUs, if the State seeks to substitute the CAIR reductions at those sources for BART requirements.

Commenter: North Dakota Department of Health, OAR 2003 0053 0945 Comment: CAIR could satisfy " regulatory requirements under the Regional Haze Program" only if the budgets established by the rule are equal or less than the emission rate achieved through the application of BART in 308 States or through the WRAP Annex.

Response: With respect to States in the CAIR region, we note that our analysis indicates that CAIR would result in 2,339,000 less tons per year of SO2 and 639,000 less tons per year of Nox in 2015 compared to emission in those states under a nationwide BART strategy. With respect to the rest of the country, this same analysis indicates that nationwide emissions would be 2,427,000 tons less SO2 and 638,000 tons less Nox under CAIR as compared to nationwide BART. With respect to the WRAP Annex, that program is currently under review in light of the DC Circuit's decision in CEED v. EPA. We note however that the BART control assumptions we modeled are more stringent, with respect to EGUs, than those utilized by the WRAP in developing the Annex. ( For SO2, our modeling reflected a 90% control level on BART eligible EGUs. The WRAP utilized a tiered approach with a maximum of 85% control on uncontrolled or undercontrolled BART eligible EGUs).

Commenter: Vermont Air Pollution Control Division, OAR 2003 0053 0714.

Comment: One State felt that allowing CAIR to substitute for BART would reward States and sources that have historically resisted emission controls.

Response: The EPA believes environmental policy should be designed to achieve environmental benefits in the most expeditious manner possible, not to assign blame or reward. Moreover, considering that source specific BART requirements have not been fully implemented at any source since the provisions were enacted in 1977, there does not appear to be much basis for distinguishing among States in terms of their performance in this area.. ( There have been a handful of cases were controls were installed as a result of settlements that halted the BART process).

Commenters: North Carolina Division of Air Quality ( NCDAQ), OAR 2003 0053 1767; National Petrochemical & Refiners Association ( NPRA), OAR 2003 0053 1816.

Comment: One commenters felt it would be inequitable to " exempt" EGUs from BART when non EGUs are subject to other requirements such as NSPS and MACT standards. One State believed this policy would disadvantage non EGU BART sources by requiring earlier compliance with them.

Response: Because non EGUs are generally not in economic competition with EGUs, it is difficult to see how varying compliance time frames would raise any equity issues. To the extent such issues exist, States may be able to address them by designing similar BART alternatives in their regional haze implementation plans. Moreover, States are not precluded from obtaining more emission reductions from EGUs for haze purposes if they believe that is the most cost effective and equitable means of achieving reasonable progress.

Commenters: Wisconsin Department of Natural Resources, OAR 2003 0053 1799; Georgia Department of Natural Resources, Environmental Protection Division, Air Protection Branch, OAR 2003 0053 0698; North Carolina Division of Air Quality, OAR 2003 0053 0779.

Comment: One State thought that the cap and trade program would result in fewer source specific reductions because economic factors favor getting reductions at newer, more base loaded units. Another State expressed that it is difficult to envision a source complying with BART solely through the purchase of allowances. Another State argued that CAIR should be deemed to satisfy BART within a State only if that State does not participate in the cap and trade program.

Response: The purpose emissions trading program is to achieve targeted emission reductions in the most cost effective manner. As long as the overall emissions reductions, and corresponding environmental benefits, are greater under the cap and trade program than otherwise, it should not matter where those reductions occur. Therefore, except for provisions necessary to address localized " hot spots," cap and trade programs should avoid geographic restrictions on trading in order to maximize the efficiency of the market.

Commenters: Central States Air Resources Agencies Administration ( CenSARA), OAR 2003 0053 1013; Cinergy Corporation, OAR 2003 0053 0762; Tennessee Division of Air Pollution Control, OAR 2003 0053 0778; Nebraska Department of Environmental Quality, Air Quality Division, OAR 2003 0053 1176; Edison Electric Institute, OAR 2003 0053 0774. Comment: Some commenters asserted that EPA should allow non CAIR affected states to opt in to the cap and trade program in order to meet BART; others further stated that this opt in should be allowed if the State shows that reasonable progress goals and BART reductions will be achieved.

Response: As explained in the CAIR NFR preamble at section VII, allowing states outside the CAIR region which have not been shown to contribute significantly to non attainment to participate in the cap and trade program could result in emission shifting to states in the CAIR region. To prevent this, States outside the CAIR region are not allowed to participate in the program. Any expansion of the CAIR cap and trade region must be done not based on individual State opt ins, but rather in a systematic way which takes into account the potential for emission shifting. The EPA may consider such an expansion for the purpose of addressing haze in a subsequent rule making.

Commenters: NiSource Inc, OAR 2003 0053 1766; Cinergy Corp., OAR 2003 0053 1779.

Comment: One commenter stated that the policy of allowing CAIR to substitute for BART should not be limited to States that are affected by CAIR for both SO 2 and NO x. The commenter was concerned that in NO x SIP call States that chose to meet some of their NO x reduction requirements from non EGUs, it was likely that NO x reductions under CAIR would also be obtained in part from these non EGUs, thereby disqualifying the State from participating in the cap and trade program and thus from satisfying BART. Similarly, one commenter thought that CAIR affected EGUs should also be " exempt" from BART for VOC and direct PM.

Response: Because BART eligibility is based on, among other criteria, the emissions of 250 tons per year or more of any visibility impairing pollutant, a BART alternative program ( such as CAIR in this case) satisfies BART only for those pollutants regulated. Therefore a source subject only to summertime NO x controls cannot be considered to have satisfied BART with respect to SO 2. With respect to VOC and PM, we note that we are considering including in the BART guidelines a de minimus policy for pollutants other than those on which the BART determination is based.

Commenters: Northeast States for Coordinated Air Use Management ( NESCAUM), OAR 2003 0053 1674; Ozone Transport Commission ( OTC), OAR 2003 0053 1772. Clean Air Task Force, OAR 2003 0053 0742 Comment: A few commenters stated that the CAIR should use an approach similar to OTC's NOx Budget Program, whereby Phase I of the program required the installation of RACT on EGUs and large industrial boilers greater than 250 MMBtu/ hr in order to establish a benchmark control level, and after RACT was installed at all participating sources additional reductions were pursued using a cap and trade program. One commenter urged that EPA preserve the requirement that BART be installed on all individual sources for which it is appropriate under the Agency's BART Guidelines.

Response: The EPA is not changing the requirements for BART in this rulemaking. As explained in the preamble and elsewhere in this document, the EPA has determined that CAIR will achieve greater average visibility improvement with respect to EGUs in the CAIR region than would BART, as defined by the presumptive EGU control levels proposed in 2004. Once the final BART guidelines for EGUs and the criteria for BART alternative programs are final, EPA will determine whether CAIR achieves greater reasonable progress than BART and may therefore substitute for BART for EGUs. Whether or not EPA makes that determination, nothing will preclude States from deciding at their own discretion that BART controls are needed at specific sources in order to achieve reasonable progress under the regional haze program. In addition, as also previously noted, the requirements of BART for reasonably attributable visibility impairment continue to apply.

However, any requirements dictating where emission reductions occur tend to undermine the purpose of the emission trading programs   reducing emissions in the most cost effective manner. Therefore it is preferable to avoid superimposing source specific requirements onto trading programs to the extent possible. If EPA determines that CAIR may substitute for BART, then EPA will leave it to the discretion of States to decide whether it is appropriate to require BARTeligible sources in the CAIR region to install BART controls, or whether to allow the market to determine the most cost effective emission reductions without interference.

We also disagree with the commenter's suggestion that BART be implemented first, with further reductions from the trading program coming later. The CAIR emission reductions are required before BART implementation is required under the CAA and regional haze rule, therefore the only way to integrate the requirements is to implement the CAIR cap and trade program first. In addition, because CAIR achieves both greater and earlier reductions, it is a better alternative than that suggested by the commenter.

Commenters: Center for Energy & Economic Development, Inc., OAR 2003 0053 0371; Jackson Kelly PLLC for Midwest Ozone Group ( MOG), OAR 2003 0053 1064; Dominion, OAR 2003 0053 1099.

Comment: Several commenters stated that if CAIR is not allowed to substitute for BART, then BART determinations should start with a consideration of controls resulting from CAIR, and then consider the incremental costs of additional controls.

Response: As noted, the EPA believes that once the BART guidelines are finalized, it will be demonstrated that CAIR makes greater reasonable progress than BART and therefore may substitute for BART for affected sources and pollutants. In the event this does not occur, or for States that choose not to accept our final better than BART determination, the BART determination process pursuant to CAA 169A( b)( 2) provides for consideration of existing controls at a particular source. Controls installed for compliance with CAIR would be considered under these provisions, and in accordance with the BART determination guidelines.

Commenter: Pennsylvania Department of Environmental Protection, Office of Air, Recycling and Radiation Protection, OAR 2003 0053 0949.

Comment: One commenter stated that EPA analysis indicates it will be difficult to achieve cost effective emission reductions from non EGUs, therefore EPA must set the CAIR reduction levels to assure visibility goals met.

Response: The CAIR emission reductions requirements were based on cost effective emission reductions at all EGUs in the affected regions, not just BART eligible units. Because the cost effectiveness of emissions reductions is not dependent on purpose of the reductions ( unlike a benefit cost analysis), it is difficult to envision how cost effective emissions reductions based on visibility could be any greater than for reductions based on health effects. Moreover, as stated elsewhere, States are not constrained to accept the better than BART determination and may seek greater reductions from BART eligible EGUs if deemed necessary to fulfill the State's obligation to make reasonable progress.

Commenters: North Carolina Division of Air Quality ( NCDAQ), OAR 2003 0053 1767; Adirondack Mountain Club, OAR 2003 0053 0624.

Comment: One commenter stated that because CAIR extends BART compliance past 2015, due to banking of allowances, reasonable progress towards the national visibility goal will be jeopardized.

Response: The EPA first notes that CAIR reductions will commence earlier than would BART reductions, that is, in 2010 rather than 2014 or 2015. Therefore, in the short term, reasonable progress will be accelerated. Moreover, although banking of allowances will delay the achievement of the full reductions required by CAIR, the reductions achieved in 2015 will under CAIR will still far outweigh those projected under BART alone. Specifically, CAIR would result in 2,339,000 less tons per year of SO2 and 639,000 less tons per year of Nox in 2015 compared to emission in those states under a nationwide BART strategy


[Federal Register: August 14, 2008 (Volume 73, Number 158)]
[Proposed Rules]
[Page 47561-47563]
[DOCID:fr14au08-12]

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.

========================================================================

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0589; Directorate Identifier 2008-NE-17-AD]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney (P&W) PW4000 Series 94-
Inch Fan Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for P&W PW4052, PW4056, PW4060, PW4062, PW4152, PW4156A, PW4158,
PW4460, and PW4462 turbofan engines. This proposed AD would require a
onetime visual inspection of all EEC-131 model electronic engine
controls (EECs). This proposed AD would require the EECs to be
identified, categorized by group number, marked, and replaced using a
fleet management plan. This proposed AD results from a report of an
uncommanded engine in-flight shutdown due to defective EEC pulse width
modulator (PWM) microcircuits. We are proposing this AD to prevent
uncommanded in-flight engine shutdowns which could result in loss of
thrust and prevent continued safe flight or landing.

DATES: We must receive any comments on this proposed AD by September
15, 2008.

ADDRESSES: Use one of the following addresses to comment on this
proposed AD.
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the instructions for sending your
comments electronically.
     Mail: Docket Management Facility, U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax:<PHONE_NUMBER>.
    You can get the service information identified in this proposed AD
from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone
(860) 565-8770; fax<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: V. Rose Len, Aerospace Engineer,
Engine Certification Office, FAA, Engine & Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803; e-mail:
<EMAIL_ADDRESS>telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or
arguments regarding this proposal. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2008-0589; Directorate
Identifier 2008-NE-17-AD'' in the subject line of your comments. We
specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of the proposed AD. We will consider
all comments received by the closing date and may amend the proposed AD
in light of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact
with FAA personnel concerning this proposed AD. Using the search
function of the Web site, anyone can find and read the comments in any
of our dockets, including, if provided, the name of the individual who
sent the comment (or signed the comment on behalf of an association,
business, labor union, etc.). You may review the DOT's complete Privacy
Act Statement in the Federal Register published on April 11, 2000 (65
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Operations office (telephone<PHONE_NUMBER>) is
the same as the Mail address provided in the ADDRESSES section.
Comments will be available in the AD docket shortly after receipt.

Discussion

    In May of 2006 we received a report of an uncommanded engine in-
flight shutdown of a P&W PW4152 turbofan engine. The investigation of
this event determined that certain EECs were built with defective PWM
microcircuits. The defective microcircuits degrade over time as a
result of thermal cycling while operating within their certified
temperature range. In operation, the EEC system tests the functional
capability of the PWM in Channel A. If the Channel A PWM fails the
test, the EEC automatically switches to the Channel B PWM. In this
case, both of the EEC PWMs are degrading similarly and the Channel B
PWM is also likely to fail, at which time the EEC automatically shuts
down the engine. Based on a risk analysis provided by P&W which we
reviewed and concurred, this condition, if not corrected, could result
in uncommanded in-flight engine shutdowns, which could result in loss
of thrust and prevent continued safe flight or landing.
    The defective PWMs are the result of a change from the original PWM
design introduced by a single microcircuit supplier before 1993. Our
investigation showed that the supplier returned to the original PWM
design between 1993 and 1994. The EEC supplier determined the
population of affected EECs by testing model EEC-131 EECs built after
the introduction of the PWM design change. The EEC supplier performed
destructive testing of the PWMs, and identified four distinct groups of
EECs by serial number:
    Group 1: EECs with a high concentration of PWMs that failed during
testing.
    Group 2: EECs with a low concentration of PWMs that failed during
testing.
    Group 3: All EECs not in Group 1 or Group 2 but may contain suspect
PWMs due to board swapping during the repair or refurbishment of the
EEC.

    Group 4: EECs have been inspected for defective PWMs and repaired
if required.
    To facilitate the timely removal of the defective PWMs from the
fleet, all of the EECs must first be identified, categorized, and
marked by their group number so that the higher risk EECs will be
replaced before the lower risk EECs are replaced. Group 4 EECs have
been inspected or repaired, so they are not subject to the same PWM
problem. However, they still require further internal and external
labeling for tracking purposes. Labeling will be done using P&W Alert
Service Bulletin (ASB) No. PW4ENG 73-216, dated April 8, 2008.

Relevant Service Information

    We have reviewed and approved the technical contents of P&W ASB No.
PW4ENG A73-214, Revision 2, dated May 23, 2008. That ASB describes
procedures for inspecting, identifying, categorizing, and marking all
EEC-131 model EECs that are identified by part number and serial number
into four groups. The Group 1 EECs have a high probability of having
defective PWM microcircuits, while the other groups have a lower
probability of having defective PWM microcircuits.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other products
of this same type design. We are proposing this AD, which would require
a onetime visual inspection of all EEC-131 model EECs. The proposed AD
would also require the EECs to be identified, categorized by group
number, marked, and replaced using a fleet management plan. The
proposed AD would require you to use the service information described
previously to perform these actions.

Costs of Compliance

    We estimate that this proposed AD would affect 730 P&W PW4000
series 94-inch fan turbofan engines installed on airplanes of U.S.
registry. We also estimate that it would take about 1 work-hour per
engine to inspect, categorize, and mark each of the 730 EECs, and 1
work-hour per engine to replace up to 730 EECs. The average labor rate
is $80 per work-hour. Required replacement parts would cost about $400
per engine. Based on these figures, we estimate the total cost of the
proposed AD to U.S. operators to be $467,200.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in
subtitle VII, part A, subpart III, section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that the proposed AD:
    1. Is not a ``significant regulatory action'' under Executive Order
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979); and
    3. Would not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to
comply with this proposed AD. You may get a copy of this summary at the
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the
Federal Aviation Administration proposes to amend 14 CFR part 39 as
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new
airworthiness directive:

Pratt & Whitney: Docket No. FAA-2008-0589; Directorate Identifier
2008-NE-17-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive
comments on this airworthiness directive (AD) action by September
15, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney (P&W) PW4052, PW4056,
PW4060, PW4062, PW4152, PW4156A, PW4158, PW4460, and PW4462 turbofan
engines. These engines are installed on, but not limited to, Airbus
A300-600 and A310-300, and Boeing 747-400, Boeing 767-200, 767-300,
and MD-11 series airplanes.

Unsafe Condition

    (d) This AD results from a report of an uncommanded engine in-
flight shutdown due to defective electronic engine control (EEC)
pulse width modulator (PWM) microcircuits. We are issuing this AD to
prevent uncommanded in-flight engine shutdowns which could result in
loss of thrust and prevent continued safe flight or landing.

Compliance

    (e) You are responsible for having the actions required by this
AD performed within the compliance times specified unless the
actions have already been done.

Onetime Visual Inspection and Reporting Requirements

    (f) Within 600 operating hours after the effective date of this
AD:
    (1) Perform a onetime visual inspection of the EEC-131 model
EECs to identify, categorize, and mark them as a Group 1, Group 2,
Group 3, or Group 4 EEC.
    (2) Use paragraphs 1 through 7 in the Accomplishment
Instructions of P&W Alert Service Bulletin No. PW4ENG A73-214,
Revision 2, dated May 23, 2008, to inspect, categorize, and mark the
EECs.
    (3) Within 30 calendar days of completing paragraph (f)(1) of
this AD, report all inspection findings to V. Rose Len, Engine
Certification Office, Engine & Propeller Directorate, 12 New England
Executive Park, Burlington, MA 01803.
    (4) The Office of Management and Budget (OMB) has approved the
reporting requirements and assigned OMB control number 2120-0056.

Replacement of Group 1 EECs

    (g) Replace Group 1 EECs with a serviceable EEC before reaching
2,000 cycles-in-service (CIS) since new, but not later than one year
from the effective date of this AD.

Replacement of Groups 2, 3, and 4 EECs

    (h) Replace the following groups of EECs with a serviceable EEC,
or any EEC that does not violate the EEC installation procedure as
provided by paragraphs (k), (l), and (m) of this AD, as follows:
    (1) Group 2 EECs, before reaching 4,000 CIS since new, but not
later than 2 years after the effective date of this AD.
    (2) Group 3 EECs, before reaching 14,000 CIS since new, but not
later than 6 years after the effective date of this AD.

Definition of Serviceable EECs

    (i) A serviceable EEC is an EEC that does not violate the EEC
installation procedure as provided by paragraphs (k), (l), and (m)
of this AD, or is marked as Group 4 per P&W ASB No. PW4ENG 73-214,
Revision 2, dated May 23, 2008, or has been repaired per P&W Service
Bulletin (SB) No. PW4ENG 73-216, dated April 8, 2008. Once an EEC
has been repaired, it is viewed as a Group 4 EEC.
    (j) Information on obtaining a serviceable EEC can be found in
P&W SB No. PW4ENG 73-216, dated April 8, 2008.

EEC Installation Prohibition

    (k) Do not install any Group 1 EEC after 1 year from the
effective date of this AD or any Group 1 EEC that has reached 2,000
CIS since new.
    (l) Do not install any Group 2 EEC after 2 years from the
effective date of this AD or any Group 2 EEC that has reached 4,000
CIS since new.
    (m) Do not install any Group 3 EEC after 6 years from the
effective date of this AD or any Group 3 EEC that has reached 14,000
CIS since new.

Alternative Methods of Compliance

    (n) The Manager, Engine Certification Office, has the authority
to approve alternative methods of compliance for this AD if
requested using the procedures found in 14 CFR 39.19.

Related Information

    (o) Contact V. Rose Len, Aerospace Engineer, Engine
Certification Office, FAA, Engine & Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803; e-mail:
<EMAIL_ADDRESS>telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>, for
more information about this AD.

    Issued in Burlington, Massachusetts, on August 8, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
 [FR Doc. E8-18811 Filed 8-13-08; 8:45 am]

BILLING CODE 4910-13-P


No.	EPA Comment	Research Group Response

1

We have two key concerns that address some of the initial study
objectives as stated in the report. Our first concern is with the
following objective:

"Quantify personal exposures to motor vehicle gasoline evaporative and
combustion emissions in micro environments, (MEs) representing the upper
end of the population exposure. frequency distribution (99th +
percentile) of such exposures," (p. 1-2)

It would be very helpful to evaluate whether the study accomplished this
objective by comparing its findings to other exposure studies. A table
comparing average and "high end" concentrations from this study to those
reported in other studies would be useful in addressing whether this
study captured the "99th+ percentile" exposure concentrations. Studies
that might be appropriate for comparison include population-based
sampling programs such as the National Human Exposure Assessment Survey
(NHEXAS) Phase I studies, the Relationship of Indoor, Outdoor, and
Personal Air (RIOPA) study, and others provided in the attached
reference guide. Studies addressing specific microenvironments addressed
in the 211 (b) report should also be noted (see attached reference
guide).

 In regards to this same concern, it would be useful to define with
specificity the operational definition of "99th+ percentile" for
evaluation of the study objective. For instance, what averaging time
should be considered appropriate for assessing this factor? What metric
(micro-environmental concentration, inhaled dose, etc.)?

We are unable to compare “average and high end concentrations from
this study” since no average exposures were sampled during the study.
 Sampling locations and conditions were chosen to reflect high end
exposures in all cases.  Where average values are mentioned in the
report they refer to averages of replicate high end samples.  The
sampling criteria used to identify high end conditions are described at
page 1-3 and in Appendix A (pp. 3-13 to 3-17) of the report.

Since we sampled only high end conditions, we’re unable to determine
the precise percentile range of high-end values from the data collected.
 Early discussions with Agency staff during protocol development lead to
the decision to characterize ‘high end’ exposures as ≥ 99th
percentile.  This rationale followed from the compounding effect of
multiple independent selection criteria used to identify high end
conditions. For example, if a single sampling criterion led to exposures
at the 80th or 90th percentile, then samples that met several such
criteria should plausibly exceed the 99th percentile when compounded.
We believe this to be a conservative estimate since a number of
individual sampling criteria (e.g., low to calm wind speeds, down-wind
locations, cold start situations, congested rush-hour conditions) could
by themselves on occasion change near-source exposures 100-fold from
their opposite extremes.

Agency reviewers suggest that direct comparisons to studies of similar
MEs and averaging times would be helpful.  Such preliminary comparisons
were provided earlier to EPA in the Table 4-1 of the 3/14/2003 interim
Atlanta S211b exposure report.  Model ME factor comparisons in Tables
3-2 to 3-4 of the final report also offer additional perspective.
However, other study values must be adjusted for changes in fuel
composition and vehicle fleet emissions for such comparisons to be
informative and not misleading.  Such an approach is described in the
VCCEP benzene study [  HYPERLINK
"http://www.tera.org/peer/VCCEP/Benzene/BenzeneWelcome.html"
http://www.tera.org/peer/VCCEP/Benzene/BenzeneWelcome.html  (Appendices
A-2 & B)] that uses a Mobile 6 model-based adjustment procedure.
However, such supplemental analysis is beyond the scope of the Tier 2
study.

The operational averaging times should be taken in the breathing zone
for periods comparable to those typically spent in such high end MEs.
For example, refueling ME sampling times were about 20 minutes to
reflect time spent at the service station and in-cabin exposures on
congested freeways were sampled for about 40 minutes to reflect rush
hour commuting trips (see EPA Exposure Factors Handbook:
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=20563) Reconstructed
1-minute data were provided in the final report to facilitate exposure
model evaluations of alternative behavioral patterns.

2	The other study objective that should be further addressed is:

"Extrapolate study data to other cities and other oxygenated fuels," (p.
1-2)

It is unclear how such extrapolation could be performed for some of the
analyses undertaken. Given the lack of a traditional "balanced"
statistical design, covariance of fuel type and climate is likely to
limit the range of extrapolation. The report should include the
investigators' assessment of the suitability of the various types of
data collected for application.

The presentation of data is in descriptive and graphical form, rather
than statistical. While EPA will employ these data in other contexts for
specific application, some of the tables in which average values are
compared for several variables (e.g., Table 4.3-1 1) would be better
presented using statistical techniques such as ANOVA or mixed models.
Presentations of the average values in the tables are helpful, but the
reader would be better served if significance and statistical power were
explicitly addressed. Furthermore, graphical presentation of statistical
distributions of data (e.g., box plots, cumulative probability
distributions) would be helpful even in interpreting summarization of
data in the absence of statistical comparisons.

As noted above, application of this high end ME exposure data to other
times and locations will have to address interim changes in fuel and
fleet characteristics as well as case-by-case similarities and
differences in MEs, fuel component properties, and meteorological
conditions between locations. Extrapolation of the study data to other
cities and other oxygenated fuels is beyond the scope of this Tier 2
study report.

The basic objective of the Tier 2 high end exposure study is to provide
exposure data to EPA for their subsequent analysis.  The descriptive
statistics and data summary presentations were provided as a courtesy to
the Agency.  The supplemental statistical analysis suggested by
reviewers is beyond the scope of the Tier 2 study report.

3	p. ES-5, top:

Background exposure measurements were made during the first 10 minutes
without the test vehicle. What was the rationale for 10 minutes? What
time of day were these made? How was seasonal and other variability
accounted for in the decision to use a single 10-minute measurement as
background? That is, it appears that the study assumes that background
concentrations do not vary in time.

The trailing vehicle experiments are described in Section 5 of the final
report. The 10 min period was selected to match other 10 min segments of
the trailing vehicle test protocol. These measurements were used to
establish the initial in-cabin concentrations prior to each run. The
ambient background is not relevant in this context.

4	p. ES-5, line 3:

Change "include" to "included" in "Each trailing vehicle run include
three scenarios. . . ."

This typographical error has been corrected.

5	p. ES-5, second paragraph:

We assume that the vehicles parked in a closed garage with the gasoline
powered lawnmower and gasoline storage container all were filled with
the same fuel, but the report should explicitly state whether or not
this is the case.

Also, please further explain the meaning of semi-continuous measurement.

The assumption is correct.  A statement to this effect is added at page
ES-5 and is noted in the full description of the attached garage
experiments in Section 4 at page 4-2 of the final report.

Semi-continuous measurement by solid phase micro-extraction (SPME) is
listed in Table E-1 at page ES-3 and described in detail in Appendix C.
Semi-continuous (10 minute average) is now parenthetically defined at
ES-5.

6	p. ES-5:

The twelve microenvironments appear to be sufficiently diverse to
characterize near-road exposures.

The term "urban canyon" is used here and throughout the report, but
"urban canyon" is never defined or fully characterized. Urban dispersion
is highly variable from one city to the next (e.g., Houston's will be
quite different from Atlanta's) and even within one city (e.g., we
observed significant differences between two nearby urban canyons in NYC
- Rockefeller Center and Madison Square Garden). Thus, the term should
be defined generally and the specific urban canyon (i.e., ME2) in this
study should be fully characterized (e.g., height of buildings, baffling
and obstructions, distance between structures, etc.). Perhaps an
appendix could be added with photographs of the urban canyon monitoring
sites.

A general expanded description of the urban canyon microenvironment and
the selection criteria used to identify appropriate locations in the
cities tested are provided at page 3-13 of Appendix A.  Earlier
city-specific reports [May 5, 2004 Data Report – Summer 2003 Chicago &
Atlanta Field Studies – Appendix A; March 5, 2004 Data Report –
Summer 2002 San Antonio & Houston Field Studies] provided to EPA
identified specific street canyon loops selected for testing that are
now footnoted specifically at pages 1-7 to 1-9 for these cities in the
final report.  Although the lengths of the routes for this ME were too
long for any detailed description of the buildings to be meaningful for
pollutant dispersion purposes, a Google Map link at (  HYPERLINK
"http://maps.google.com/maps?hl=en&tab=wl"
http://maps.google.com/maps?hl=en&tab=wl ) provides satellite
photography and street views that can be used to characterize these
Atlanta, Chicago, and Houston street canyon loops.

7	p. ES-9, ES- 14, and 4-5, Figure E- 1 :

It might be helpful to make a general statement about the distribution
of the four

species in BTEX. For example, it appears from Figure E-4 on page ES-14
that the

ratios in Houston in the summer and winter are consistent among benzene,
toluene and the xylenes. However, are they evenly distributed across the
twelve MEs, or does one (e.g., benzene) or two dominate in some MEs
while others dominate in other MEs (e.g., xylenes)? Perhaps a discussion
linking the fuel variability (Table 4.3-1 on page 4-5) would be
worthwhile. Similarly, the report may provide some data to answer how
much of the concentration and spread is attributable to fuel effects.

In Figure E-4, the Houston ME/monitor BTX ratios appear similar (within
measurement error) across season for the exhaust dominated MEs as the
reviewer suggests.  However, the summer BT ratios do appear larger than
X ratios for ME3 and ME7 which are dominated by refueling evaporative
emissions, although the winter ratios appear less so.  While the fuel
specifications provided in Table 4.3-1 are typical of these cities and
relevant to the garage and trailing vehicle tests discussed in Sections
4 and 5 of the report, they are not directly applicable to the ME
measurements discussed in Section 3 which arise from actual but unknown
mixtures of locally available fuels.  Although seasonal fuel sampling of
local vendors is available in annual surveys for these cities, modeling
of fuel effects in fleet emissions is beyond the scope of the Tier 2
study report.

8	p. ES- 15, line 17:

The word "below" is misspelled.

This typographical error has been corrected.

9	p. ES- 16:

Can the 2.2 times higher in-cabin exposure levels for the trailing
vehicle relative to the normal emitter mode be attributed to the
differences in ventilation? Or, does vehicle type come into play here
(even though the test vehicles seem to show no significant difference)?

We are unsure that average in-cabin levels were minimally affected by
different vehicles or fuels except for an MTBE fuel effect. Comparing
the values for "truck only" and "car only" in Table E-2 on page ES-17,
it appears that 1,3-butadiene, orthoxylene, carbon monoxide and
formaldehyde differ substantially. Also, fuel type seems to vary
substantially for toluene (Chicago = 1.32, whereas Atlanta = 2.79) and
ethylbenzene (Chicago = 0.120, whereas Atlanta = 0.51), and Chicago fuel
was much lower for the xylenes. It may rest on what is meant by
"minimally affected."

The 2-fold higher exposures trailing a malfunctioning lead vehicle are
likely not attributable to cabin ventilation differences given the
efforts made to conduct the experiments under similar meteorological
conditions (e.g., calm or low wind speeds) and identical protocols
regarding ventilation conditions. The relatively higher cabin levels
would be anticipated as a result of higher emissions from a
malfunctioning lead vehicle.

‘Table E-1’ typo is changed to Table E-2 on page ES-16.

We agree with the reviewer’s comment and modified the statement on
page E16 as follows: “Average in-cabin levels were affected by both
state of maintenance of the vehicle and fuel composition. Use of Atlanta
fuel resulted in higher BTEX concentrations in the trailing vehicle
cabin, which is consistent with higher aromatic contents of Atlanta
fuel, especially in summer. Similarly BTEX concentrations were
consistently higher during the summer, which is also in concert with
higher aromatic contents of summer fuels, especially for Atlanta.
Averaging over the fuels and vehicles, the high emitter mode resulted in
2.2 times higher in-cabin exposure levels for the trailing vehicle than
the normal emitter mode except for HCHO which was relatively unchanged
from background.” Also, the text in Section 5 (page 5-12 and 5-14) was
modified accordingly to reflect this conclusion.

The differences between “car only” and “truck only” seem to be
less consistent and less pronounced than fuel effect.

10	p. ES-18 and 19:

The conclusions appear to be scientifically sound. The statement that
"although

overall the average population time spent in these high end MEs is
likely the shortest"

is important and should not be left to conjecture. The actual activities
associated with

exposures to evaporative eniissions should be characterized. Activity
patterns often

dictate actual exposures. Concentrations alone tell only part of the
exposure story.

We agree that HAPEMS factors may need to be updated based on these
findings, and

we will provide the final version of this report to the Office of Air
Quality Planning

and Standards who are responsible for the HAMPEM model, which was
recently

upgraded to HAPEM6, http://www.epa.gov/ttn/fera/huma-nh apem.htm1.

Other EPA documents provide adequate support for this statement which
need not be repeated in the report.  For example, Table 15-106 of the
EPA Exposure Factors Handbook (EPA/600/P-95/002Fc) reports that 157
(18-64 y) subjects, who had visited a gas station the day before in a
survey population of  9386, averaged 10 minutes (median) outside the
service station with an inter-quartile range of 5-15 minutes (
HYPERLINK "http://www.epa.gov/ncea/efh/pdfs/efh-chapter15.pdf"
http://www.epa.gov/ncea/efh/pdfs/efh-chapter15.pdf ).

The HAPEM5 comment refers to ‘high end’ aspects of the 1998 Rodes et
al. (p. xi) CARB study where the driving protocol highlighted trailing
diesel city buses and HDD trucks when possible, a counter-intuitive
practice for most drivers.  Current HAPEM factors should be lowered to
simulate ‘typical’ behaviors where commuters are more likely to
avoid such vehicles.  Since the current report is also focused on
‘high end’ exposures (see response #1), comparisons with corrected
HAPEM simulations should be restricted to ‘high end’ model
projections.  Report findings should not be used to derive HAPEM factors
thought to characterize average or typical conditions.

11	p. 1-20, final paragraph:

Figure 1.3.2-5 is missing.

There is no figure 1.3.2-5. The text on p. 1-20 was corrected
accordingly.

12	p. 1-21:

P-values should include at least two significant figures.

The p-values have expanded significant figures at page 1-21 and 1-22.

13	p.2-5:

Note that "OMS" has changed its title to "OTAQ (Office of Transportation
and Air Quality).

‘OMS’ has been changed to ‘OTAQ’ in Table 2-1 caption at page
2-5.

14	p.2-9:

How were the "error bars" in Figure 2-9 calculated? What components of
uncertainty are accounted for here? Sampling? Instrument precision?
Error propagation?

Presumably this question concerns Figure 2-1, as there is only one
figure in this section… A brief discussion of how uncertainties
associated with Figure 2-1 were determined is added to the initial
paragraph at page 2-4.

15	p. 3 - 1, second paragraph:

The 1999 NATA does not assume constant background concentrations of all
pollutants. See http://www.epa.gov/ttn/atw/natal999/background.html for
additional detail.

The report does not claim that a uniform background concentration is
assumed for all pollutants.

16	p. 3-3, first paragraph, last sentence:

The italicized text should be evaluated in light of the "general
comment" above.

Notably, this text is appropriate if, in comparison to other studies
looking at similar microenvironments, the concentrations in this study
are higher. The italicized text is likely inappropriate if this
comparison does not suggest that the micro-environmental exposures
presented herein are "extreme."

We removed the italicization of the text. However,  as noted in
responses #1 & 10, the ‘high end’ study protocol was designed to
sample under conditions leading to more ‘extreme’ exposures that
those thought ‘typical’ or average.  To be informative, the
comparisons suggested with earlier studies, some of which themselves
sampled under ‘high end’ conditions (e.g. Rodes et al., 1998),
should be adjusted for interim changes in fuel composition and fleet
emissions: however, such extended analysis  is beyond the scope of this
report.

17	p. 4-7 – 8, Table 4.3-6,7:

The tables and text do not seem to identify whether these non-aldehyde
data are from SMPE or canister samples.

The report has been edited (p. 4.7) to identify absorption tube,
canister, and SPME values.

18	p. 5 - 1 4, last paragraph:

". . .after the change to low ventilation.. . little change in the
in-cabin concentration.. ."

This text appears to contradict language on p. 5-1 8, second to last
paragraph, where it is noted that the range of concentrations differed
under high ventilation situations.

Please clarify the intended meaning, which appears to suggest that while
average concentrations were unaffected, variability in concentration was
affected by ventilation.

The latter reading grasps the meaning intended; language at p. 5-14 has
been clarified to state that although on average the integrated in-cabin
levels were similar for high and low ventilation, the variability (peaks
and valleys) of the in-cabin concentrations was larger during the high
ventilation condition.


[Federal Register Volume 87, Number 60 (Tuesday, March 29, 2022)]
[Notices]
[Page 18063]
[FR Doc No: 2022-06596]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Railroad Administration

[Docket Number FRA-2017-0127]

Petition for Extension of Waiver of Compliance

    Under part 211 of title 49 Code of Federal Regulations (CFR), this
document provides the public notice that on March 1, 2022, Dakota,
Missouri Valley & Western Railroad (DMVW) petitioned the Federal
Railroad Administration (FRA) for an extension of a waiver of
compliance from certain provisions of the Federal railroad safety
regulations contained at 49 CFR 229.47, Emergency brake valve. The
relevant FRA Docket Number is FRA-2017-0127.
    Specifically, DMVW requests an extension of relief from the
requirement that an emergency brake pipe valve be installed adjacent to
the rear door of a locomotive for five EMO SD50 locomotive units
(Numbers 5408, 5418, 5439, 5451, and 5454) and three EMO SD60
locomotive units (Numbers 5500, 5501, and 5544). The eight units are
all of the same car body type and are not equipped with the rear
conductor brake valve. Each of the units have rear walkways and switch
style steps, thus allowing the engineer to see the person riding on the
back along with radio communication. These units will be used in road
service and will always be paired together.
    A copy of the petition, as well as any written communications
concerning the petition, is available for review online at
www.regulations.gov.
    Interested parties are invited to participate in these proceedings
by submitting written views, data, or comments. FRA does not anticipate
scheduling a public hearing in connection with these proceedings since
the facts do not appear to warrant a hearing. If any interested party
desires an opportunity for oral comment and a public hearing, they
should notify FRA, in writing, before the end of the comment period and
specify the basis for their request.
    All communications concerning these proceedings should identify the
appropriate docket number and may be submitted at http://www.regulations.gov. Follow the online instructions for submitting
comments.
    Communications received by May 13, 2022 will be considered by FRA
before final action is taken. Comments received after that date will be
considered if practicable.
    Anyone can search the electronic form of any written communications
and comments received into any of our dockets by the name of the
individual submitting the comment (or signing the document, if
submitted on behalf of an association, business, labor union, etc.).
Under 5 U.S.C. 553(c), the U.S. Department of Transportation (DOT)
solicits comments from the public to better inform its processes. DOT
posts these comments, without edit, including any personal information
the commenter provides, to www.regulations.gov, as described in the
system of records notice (DOT/ALL-14 FDMS), which can be reviewed at
https://www.transportation.gov/privacy. See also https://www.regulations.gov/privacy-notice for the privacy notice of
regulations.gov.

    Issued in Washington, DC.
John Karl Alexy,
Associate Administrator for Railroad Safety, Chief Safety Officer.
[FR Doc. 2022-06596 Filed 3-28-22; 8:45 am]
BILLING CODE 4910-06-P