UNITED STATES ENVIRONMENTAL PROTECTIONAGENCY REGION VIII

Ref: 8ART-AP 999 18th STREET

- SUITE 500 DENVER, COLORADO 80202-2466



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### 4 1995

Mr. Russell Roberts, Director Utah Division of Air Quality 150 North 1950 West P.O. Box 144820 Salt Lake City, Utah 844114-4820

RE

. : Public Hearing Conunents to Various Revisions to the PM10 SIP

Dear Russell:

On May 18, 1995, EPA received the public hearing announcement for various revisions to the PM10 SIP for Salt Lake and Utah Counties. The revisions include: 1) PM10 Contingency Plan for Utah County (two versions are being proposed for consideration), 2) An emissions inventory update used in the attainment demonstration to show conformity for the State's longrange transportation plans for Salt Lake County, 3) A renumbering and an update of the Diesel Vehicle Inspection andMaintenance (I/M) Program, 4) An update to the compliance method for stack testing to include EPA Method 202, 5) The Employee Trip Reduction Program is added to the PM10 SIP for Utah County, and 6) Changes to Section IX.H, Emission Limitation, where the approval order citations will replace the deta1led technology and operating specifications currently in the SIP.

. EPA has no conunent on item4) above. EPA encourages the State to adopt and implement Method 202 that was promulgated inApril 1990.**E~A's** review on the rema1n1ng revisions was limited to the revisions themselves. Although EPA requestedbackground information on these revisions, no technical support documents
were provided. EPA, therefore, has identified areas of concern, as well as specific deficiencies. Unless all these issues can be adequately addressed, approval for these revisions is highly unlikely. To summarize the conunents: · 1) Major changes were made to the Salt Lake County source apportionments. The source apportionments are the first 

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step in supporting the control strategies for the attainment demonstration. Without adequate justification for the proposed source apportionment, the proposed attainment demonstration is not approvable and cannot replace the currentlyapproveddemonstration. (EPA proposed to approve the PM10 SIP onDecember 18, 1992, 57 FR 60149; final approval was published onJuly 8, 1994, 59 FR 35036.) 2) The proposed revisions indicate that the State is now taking 80% credit for the solid fuel burningprogram. The State is also removing the reference to the number of inspectors for this programand the reference to "roundthe clock" inspections. The Statehas not provideddocumentation to justifythe increased credit. Inaddition, removing the references to the inspections andnumber of inspectors appears toweaken the solid fuel burningprogram. The State shouldbe aware that the 60% credit for the current program was based on the Statehaving a credible enforcement program (see EPA document for residential wood combustion emission control measures, April 15, 1989.) 3) Two versions were provided for the UtahCounty PM10 ContingencyMeasures. One version includes enhanced inspection andmaintenance (EIM)

. Since the authority to implement this program is at the county level and the county commitment to implement the programis not included, EPA believes this version is not approvable. Asecondversion does not include EIM. Bothversions do not appear to comply withEPA's guidance inthe General Preamble suggesting that contingencymeasures be equal to 25% of the total strategy adopted for the area or shouldbe approximately equal to the emission reductions necessary to demonstrate RFP for one year. The State is soliciting comments on theUtah County Clean Air Commission's recommendation that all federal vehicles registered inUtahCountybe required tobe low- or zeroemissionvehicles for sulfurdioxide, nitrogen oxides, and PM10 within one year. The Commission alsorecommends vacuum sweeping for all roads on federal lands inUtah County. EPA questions the statutory authoritywhichwould allow the State and/or County to enforce these measures or the Employee Trip Reduction Program (whichwas specifically cited in one of the public hearingversions) since these
measures appear inconsistent with the waiver of sovereign immunityprovidedby Section 118 of the CleanAirAct. In addition, the State and the Countyhave not provided documentation that would support

_the emission reduction

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### credits from these programs had theybeen feasible to implement and enforce. 4) The 20% reduction claimed for diesel I/M is no longer supportable. Information on the appropriate credit was discussedwith the State and the County staff at a meeting inUtah onMay 27, 1993. 5) Issues concerninggrowth rates forpopulation, reentrained road dust, trains andplanes havebeen identified. Issues have alsobeen identifiedon theVMT datausedand the emissions budgets formobile sources. If the intent of this SIP revision is to address conformity, the State shoulduse current data, project the roaddust emissions to at least 2015, and demonstrate that the analysis preserves the PM10 attainment demonstration. 6) If the State is going to replace the emission limitations currently specified inthe PM-10 SIPwithapproval orders incorporating those specific emission limits, such approval orders must containall applicable requirements that are specified in the PM-10 SIP. EPA has reviewedmost of the approval orders whichhavebeen issued to sources under the PM10 SIP. EPA's concerns with these approval orders have beendocumented, for themost part, to the State {one example is theMay 25, 1995 EPA letteronproposedpermit modification for Phillips Petroleum)

. The State shouldnote that a reviewof permits, suchas that performedon the Phillips Petroleumpermitmodification, is not always achievable givenEPA staff availability. Additional comments on the stationary source emissionlimitations will beprovidedwithinthe next twoweeks. These comments could not be completeddue to staff inspection commitments in Utah.
EPA's concernwith referencing approval order citations is in the State's ability topreserve the attainment demonstration of the approved PM10 SIP. EPA will be documentingpermittingand enforcement concerns on the emission limitations and control equipment requirements to the State in its evaluationof the State PM10 milestone report. That reviewdemonstrates the inconsistencies inthe permittingand enforcement efforts with the SIP's limitations. Since the SIP's limitations were specifically included in themodeling analyses in support of the attainment demonstration, significant changes to these limitations couldjeopardize the federally approved PM10 SIP. {"Significant" in theUtaQPM10 SIPsmeans an emission

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### increase from that established in the SIP for the whole facility or at a major emissionpoint. Significant also
means emissiondecreases that arebanked and later redistributed to a major emissionpoint within that facility orused as offsets at another facility or source category.) Therefore, inorder to address our concerns, the Statemust ensure that any approval order issued to a facility and/or emissionpoint that is subject to a specific PM-10 SIP emission limitation contains all applicable SIP limitations. Any modifications to suchapproval ordersmust be submitted to EPA as a SIP revision. Further, the Statemust ensure in issuing suchmodifications to approval orders that the changes in emissions, either at the facility or at a major emissionpoint, do not compromise attainment of the PM-10 NAAQS. This will be required inorder for EPA to approve the revised approval orders as revisions to the SIP. In addition, this is required tobe consistent withR307-1- 3.1.8.B of the State's new source reviewrules, which provides that the Statewill issue an approval order if the proposed installationwill be inaccordwith the

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### the nonattainment plan for the area." EPA's concern is with relaxation of the SIP. Unless the State can clearlydemonstrate that eachmodifiedapproval order (for sources specificallyincluded in the SIP) verifies the attainment demonstration, the replacement of specific limitations withapproval order citations is not acceptable. The Statemust also demonstrate that significantmodifications are correctly cited inthe SIP.
There appears tobe confusionas towhen the SIPmustbe modified to accuratelyreflect the revisions to source emission limitations. EPA statedin itsJuly 8, 1994 Federal Register that ithas agreed to allowthe State to update the emission limitations sectionof the SIP once a year, i.e., by September of eachyearbeginning 1993. The proposedrevisionunder review is the first updateprovided by the State. The State canupdate the source specific emission limitations in the SIP at any time. EPA's agreement to the once a yearupdate was toprovide flexibility in the State'sprocessing of these emission limitations.
This SIP revision is greatly lacking in technical documentation. As statedabove, EPAwill beproviding comments on themilestone report. Although themilestone report is the State's report on the implementation of the PM10 SIP, the report demonstrates the inconsistencies in interpreting the SlP's requirements and

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therefore, seriouslyquestions the viability of the attainment demonstration. Permits appear to address best available control technology (BACT) as outlined in the new source review (NSR) regulations. The SIP specifies reasonably available control technology (RACT)

. The permits issued appear to have been grantedunder the assumption that BACT is always more stringent thanRACT. In the Salt Lake PM10 SIP, RACT is what was necessary to demonstrate attainment and, at times, exceeds what wouldhave beenBACT under normal NSR. Applying BACT underNSR without assessing the attainment demonstration canweaken the SIP. As statedabove, the Statemust demonstrate compliance withR307-1- 3.1.8
Issues with the other source categories were alsp identified in themilestone report and are related to the concerns statedwith this SIP revision. Comments on themilestone report will be providedwithin the next two weeks. The State should review those comments as they apply to the proposed SIP revisions.
EPA encourages the State to continue to address the PM10 SIP issues, especiallywith respect'to conformity. The State, however, must alsomaintain the integrity of the PM10 SIP attainment demonstration. More detailed comments on these revisions are contained inAttachments I-VI. If you have any questions on our comments, please contactMarius Gedgaudas at ( 303) 2 9 3 -1760

. Sincerely,

# ~~-~#~~~ Douglas M. Skie, Chief Air QualityBranch
Attachments:

I.

- II. III. IV. 

## v. VI. Mobile Sources Comments Solid Fuel Burning and ContingencyMeasure Comments Section 118 Comments SourceApportionment Comments Monitoring and Other Comments Stationary Source PreliminaryComments



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# I I I I Attachment I Mobile Source Comments

Issues: Table IX.A.14, page 39 1) General comment: The mobile source emission reduction percentages in this table are from the original SIP and are outdated. They shouldbe recalculated using the PARTS model, which incorporates the effects of all the Clean Air Act-required emissions controls and fuels programs.

2) Updating these percentages using PARTS would be advantageous for conformity purposes, since PARTS will ultimately be required for use in conformity determinations.

The 23.8% diesel reduction is**f~om** the old SIP, and includes
our old estimates for diesel sulfur control and for diesel I/M. The 20% reduction claimed for diesel I/M is no longer supportable. EPA Region VIII, the Office of Mobile Sources, and the State of Colorado conducted an exhaustive review of the information available on diesel I/M in late 1992. (This level of review was not possible for Utahbecause of the timing constraints imposed by the lawsuit.) EPA and Colorado agreed on fleetwide emission reduction credits that range from about 1% for heavy duty vehicles to**approximat~ly** 4.S% for light duty vehicles, depending on the type of testing network used. This information was documented in an October 28, 1992 letter to the State of Colorado (Utah was cc'd on this letter), and was also provided in summary form and discussed in detail with State and county staff at a meeting in Utah onMay 27,· 1993. Also, these reductions are only applicable for that portion of the fleet subject to I/M. The SIP should factor down these reductions further to account for diesel VMT generatedby out-state and out-ofstate vehicles.

In addition, one of the studies of diesel I/M included in the Utah PM10 SIP TSD noted NOx increases resulting from repair of high-opacityvehicles. While the ambient impact of these NOx increases has not been studied, they certainly offset at least some of the direct PM10 benefit of diesel I/M. At a minimum, Utah should not take more credit for diesel I/M than Colorado has taken for their similar program. Amore conservative approach wouldbe to take no credit for it, because of the potential for NOx increases. The 20% reduction estimate currently in the SIP is simply not supportedby the limited scientific data available on diesel I/M.

The PM emission reductions attributed to diesel fuel sulfur control should be updated using PARTS. 

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13) The emission reductions for reentrained road dust need to be documented. 4) The growth rate for reentrained dust emissions should not be different than the growth rates for othermobile source emission categories. State staff have previously indicated that the growth rate is lower because sanding emissions (a component of the reentrained dust category) were assumed to not grow; however, subsequent studies in Denver have shown that sanding-related emissions do increase with increasing VMT. In addition, assuming no growth for sanding-related emissions serves to artificially constrain the PM10 emission budget; this may make future conformity determinations more difficult. Taking reentrained dust out to only 1997 doesn't solve WFRC's conformity problem, since they also have to consider dust·out to 201S and later. Have the State considered this? Note: with the change to MOBILES, dust is about S% of the overall mobile source problem (in 1997), since NOx is a much greater contributor. S) The source of the 0.1% emission reductions for secondary nitrate (NOx) must be documented. MOBILES must be used to calculate this percentage, if it has not been. In addition, the growth rate for this category shouldbe the same as all other mobile source emission categories. 6) The 0% control and growth assumptions for trains and planes
are outdated and shouldbe updated. Much of the information needed was generated as part of the ozone maintenance plan, and it shouldbe factored into this SIP as well. 7) The 1.S% population growth rate is from the old SIP and shouldbe updated (p. 73 also).
8) The SIP should include documentation showing how the donated S02 emissions from Kennecott offset growth inmobile source emissions.
Other Issues

Given the State's strident concerns over the NOx impacts of oxygenated fuels, it's curious that they didn't factor any estimated NOx increases into the attainment demonstration. They must be assuming that the oxy waiver for the Salt Lake-Ogden area is permanent.
The SIP must include specificially stated emissions budgets for mobile source PM10 (including sanding and reentrained dust), NOx and SOx, to facilitate future conformity findings.What VMT data were used, the oldWFRC estimates? If so, this could cause future conformity problems. If the updated data
are available, they should be used.

Since no TSD has been submitted, it's not clear whether the State is revising the emission inventories as well as the attainment demonstration. The inventories should be updated, using MOBILES and PARTS for base year and future yearmobile
source emissions, and EPA's nonroad inventory and the FAEED aircraft emissions model for nonroad emissions. In addition, the State may either continue to use the Denver emission factors for reentrained dust, or update this part of the inventoryusing the new AP42 road dust emission factor equation. There may be conformity advantages to using the new equation. Finally, as noted above, road dust emissions should be carried out to at least 201S to ensure that the area's conformity problems are

.fully resolved through this SIP revision, if this is the State's

intent.

Reviewer: Jeff Houk



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