UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION VIII 

Ref: 8ART-AP 

999 18th STREET - SUITE 500 

DENVER, COLORADO 80202-2466 

JUN I 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 and Maintenance (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 item 4) above. EPA encourages the State to 

adopt and implement Method 202 that was promulgated in April 

1990. 

E~A's review on the rema1n1ng revisions was limited to the 

revisions themselves. Although EPA requested background 

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 

currently approved demonstration. (EPA proposed to approve 

the PM10 SIP on December 18, 1992, 57 FR 60149; final 

approval was published on July 8, 1994, 59 FR 35036.) 

2) The proposed revisions indicate that the State is now taking 

80% credit for the solid fuel burning program. The State is 

also removing the reference to the number of inspectors for 

this program and the reference to "round the clock" 

inspections. The State has not provided documentation to 

justify the increased credit. In addition, removing the 

references to the inspections and number of inspectors 

appears to weaken the solid fuel burning program. The State 

should be aware that the 60% credit for the current program 

was based on the State having a credible enforcement program 

(see EPA document for residential wood combustion emission 

control measures, April 15, 1989.) 

3) Two versions were provided for the Utah County PM10 

Contingency Measures. One version includes enhanced 

inspection and maintenance (EIM) . Since the authority to 

implement this program is at the county level and the county 

commitment to implement the program is not included, EPA 

believes this version is not approvable. A second version 

does not include EIM. Both versions do not appear to comply 

with EPA's guidance in the General Preamble suggesting that 

contingency measures be equal to 25% of the total strategy 

adopted for the area or should be approximately equal to the 

emission reductions necessary to demonstrate RFP for one 

year. 

The State is soliciting comments on the Utah County Clean 

Air Commission's recommendation that all federal vehicles 

registered in Utah County be required to be low- or zeroemission vehicles for sulfur dioxide, nitrogen oxides, and 

PM10 within one year. The Commission also recommends vacuum 

sweeping for all roads on federal lands in Utah County. EPA 

questions the statutory authority which would allow the 

State and/or County to enforce these measures or the 

Employee Trip Reduction Program (which was specifically 

cited in one of the public hearing versions) since these 

measures appear inconsistent with the waiver of sovereign 

immunity provided by Section 118 of the Clean Air Act. In 

addition, the State and the County have not provided 

documentation that would support_the emission reduction 

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credits from these programs had they been feasible to 

implement and enforce. 

4) The 20% reduction claimed for diesel I/M is no longer 

supportable. Information on the appropriate credit was 

discussed with the State and the County staff at a meeting 

in Utah on May 27, 1993. 

5) Issues concerning growth rates for population, reentrained 

road dust, trains and planes have been identified. Issues 

have also been identified on the VMT data used and the 

emissions budgets for mobile sources. If the intent of this 

SIP revision is to address conformity, the State should use 

current data, project the road dust 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 in the PM-10 SIP with approval orders 

incorporating those specific emission limits, such approval 

orders must contain all applicable requirements that are 

specified in the PM-10 SIP. EPA has reviewed most of the 

approval orders which have been issued to sources under the 

PM10 SIP. EPA's concerns with these approval orders have 

been documented, for the most part, to the State {one 

example is the May 25, 1995 EPA letter on proposed permit 

modification for Phillips Petroleum) . The State should note 

that a review of permits, such as that performed on the 

Phillips Petroleum permit modification, is not always 

achievable given EPA staff availability. Additional 

comments on the stationary source emission limitations will 

be provided within the next two weeks. These comments could 

not be completed due to staff inspection commitments in 

Utah. 

EPA's concern with referencing approval order citations is 

in the State's ability to preserve the attainment 

demonstration of the approved PM10 SIP. EPA will be 

documenting permitting and enforcement concerns on the 

emission limitations and control equipment requirements to 

the State in its evaluation of the State PM10 milestone 

report. That review demonstrates the inconsistencies in the 

permitting and enforcement efforts with the SIP's 

limitations. Since the SIP's limitations were specifically 

included in the modeling analyses in support of the 

attainment demonstration, significant changes to these 

limitations could jeopardize the federally approved PM10 

SIP. {"Significant" in the UtaQPM10 SIPs means an emission 

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increase from that established in the SIP for the whole 

facility or at a major emission point. Significant also 

means emission decreases that are banked and later 

redistributed to a major emission point within that facility 

or used as offsets at another facility or source category.) 

Therefore, in order to address our concerns, the State must 

ensure that any approval order issued to a facility and/or 

emission point that is subject to a specific PM-10 SIP 

emission limitation contains all applicable SIP limitations. 

Any modifications to such approval orders must be submitted 

to EPA as a SIP revision. Further, the State must ensure in 

issuing such modifications to approval orders that the 

changes in emissions, either at the facility or at a major 

emission point, do not compromise attainment of the PM-10 

NAAQS. This will be required in order for EPA to approve 

the revised approval orders as revisions to the SIP. In 

addition, this is required to be consistent with R307-1-

3.1.8.B of the State's new source review rules, which 

provides that the State will issue an approval order if the 

proposed installation will be in accord with the __ " ... NAAQS ... [and] .. ~ the nonattainment plan for the area." 

EPA's concern is with relaxation of the SIP. Unless the 

State can clearly demonstrate that each modified approval 

order (for sources specifically included in the SIP) 

verifies the attainment demonstration, the replacement of 

specific limitations with approval order citations is not 

acceptable. The State must also demonstrate that 

significant modifications are correctly cited in the SIP. 

There appears to be confusion as to when the SIP must be 

modified to accurately reflect the revisions to source 

emission limitations. EPA stated in its July 8, 1994 

Federal Register that it has agreed to allow the State to 

update the emission limitations section of the SIP once a 

year, i.e., by September of each year beginning 1993. The 

proposed revision under review is the first update provided 

by the State. The State can update the source specific 

emission limitations in the SIP at any time. EPA's 

agreement to the once a year update was to provide 

flexibility in the State's processing of these emission 

limitations. 

This SIP revision is greatly lacking in technical documentation. 

As stated above, EPA will be providing comments on the milestone 

report. Although the milestone 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, seriously questions 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 

granted under the assumption that BACT is always more stringent 

than RACT. In the Salt Lake PM10 SIP, RACT is what was necessary 

to demonstrate attainment and, at times, exceeds what would have 

been BACT under normal NSR. Applying BACT under NSR without 

assessing the attainment demonstration can weaken the SIP. As 

stated above, the State must demonstrate compliance with R307-1-

3.1.8 

Issues with the other source categories were alsp identified in 

the milestone report and are related to the concerns stated with 

this SIP revision. Comments on the milestone report will be 

provided within 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, especially with respect 'to conformity. The State, 

however, must also maintain the integrity of the PM10 SIP 

attainment demonstration. More detailed comments on these 

revisions are contained in Attachments I-VI. If you have any 

questions on our comments, please contact Marius Gedgaudas at 

( 3 0 3 ) 2 9 3 - 176 0 . 

Sincerely, 

~~-~#~~~ Douglas M. Skie, Chief 

Air Quality Branch 

Attachments: 

I. 

-II. 

III. 

IV. 

v. 

VI. 

Mobile Sources Comments 

Solid Fuel Burning and Contingency Measure Comments 

Section 118 Comments 

Source Apportionment Comments 

Monitoring and Other Comments 

Stationary Source Preliminary Comments 

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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 should be 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 Utah because 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 on May 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 generated by 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-opacity vehicles. 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. A more conservative approach would be to take no 

credit for it, because of the potential for NOx increases. 

The 20% reduction estimate currently in the SIP is simply 

not supported by 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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3) 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 other mobile 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 should be the same as all 

other mobile source emission categories. 

6) The 0% control and growth assumptions for trains and planes 

are outdated and should be updated. Much of the information 

needed was generated as part of the ozone maintenance plan, 

and it should be factored into this SIP as well. 

7) The 1.S% population growth rate is from the old SIP and 

should be updated (p. 73 also). 

8) The SIP should include documentation showing how the donated 

S02 emissions from Kennecott offset growth in mobile 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 old WFRC 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 year mobile 

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 inventory using 

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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