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PM2.5 State Implementation Plan Development

On December 3, 2014 the Air Quality Board approved PM2.5 SIPs meeting the moderate area planning requirements of both Subparts 1 and 4, of Part D, of title 1, of the Clean Air Act. A separate SIP was adopted for each of Utah’s three nonattainment areas. Also adopted were amendments to SIP Subsections IX.H. 11, 12, and 13, which contain emission limits and operating practices for the large stationary sources specifically addressed by the SIPs for the Salt Lake City and Provo nonattainment areas. There were no such sources located in the Logan nonattainment area.

Recap of Actions

The preceding paragraph describes the most recent action taken by the AQB regarding PM2.5.  Some background may be useful in understanding what the Board did and how that action fit within the overall context of PM2.5 SIP development.

New Standard

In 2006, the EPA tightened the 24-hour PM2.5 standard from 65 µg/m3 cubic meters to 35 µg/m3.  All or parts of seven Utah counties did not meet this new 24-hour standard.   The state had been attaining the old 24-hour standard, and continues to attain the annual PM2.5 standard at all locations. 

Area Designations and SIP Call

Following promulgation of a new or revised national ambient air quality standard (NAAQS), it is incumbent on the EPA to make designations concerning areas of each state that are: attaining the standard, not attaining the standard, or which may be unclassifiable.  These designations are to be made no later than 2 years following promulgation, and are to be informed by initial recommendations made by the Governor of each state.
EPA ultimately designated three areas of the state as nonattainment areas for the 2006 24-hour PM2.5 standard.  These designations became effective on December 14, 2009.

SIP Goals and Deadlines

Once these areas were designated as nonattainment, the Clean Air Act required Utah to control fine particle pollution, and to prepare plans detailing how and when the 24-hour PM2.5 standard would be met.  Those plans, known as state implementation plans (SIPs) were due to EPA within three years of the agency’s final designations (December 14, 2012.)  The nonattainment areas were required to meet the new standard by 2014, although EPA could grant extensions of the attainment date for up to five additional years in areas with more severe PM2.5 problems and where emission control measures are not available or feasible.

Stakeholder Process

The Division of Air Quality (DAQ) began a three-year process to develop its State Implementation Plans to bring fine particulate levels below the standard.

DAQ employed an inclusive public involvement process to assist the agency in its SIP development.  More than 100 participants from each of the seven nonattainment counties met several times during the SIP development process to provide ideas and recommendations for emission control strategies that would complement community needs.

Initial reductions resulting from workgroup recommendations reduced PM2.5 levels to within a few micrograms of the standard. DAQ spent another year identifying controls beyond these recommendations to bring areas into attainment.

Subpart 1 SIPs

A SIP for the Logan nonattainment area was completed on-time in December of 2012, and SIPs for the Salt Lake City and Provo nonattainment areas were finally completed, a year later, in January of 2014.

Each of these SIPs showed that the respective areas would ultimately achieve compliance with the revised 24-hour health standard, within the timelines prescribed by the Clean Air Act.  Such compliance was demonstrated, even in the face of Utah’s rapid growth, because of emission control measures adopted as part of these plans as well as continued improvement in motor vehicle emission performance (Tier 2) mandated at the federal level.
Specifically, emission control measures adopted into these SIPs included the following:

  • 23 new Area Source Rules which in combination are projected to reduce over 15,000 tons of annual emissions.
  • Source specific Point Source Controls which combine to reduce a projected 4,600 tons of annual emissions.
  • A new Vehicle Inspection / Maintenance program in Cache County.

Court Decision

As the Subpart 1 SIPs for Salt Lake City and Provo were nearing completion, the D.C. Circuit Court of Appeals found that EPA had incorrectly interpreted the Clean Air Act when determining how to implement the National Ambient Air Quality Standards (NAAQS) for PM2.5.  The January 4, 2013 court ruling held that the EPA should have implemented the PM2.5 NAAQS based on both Clean Air Act (CAA) Subpart 1 and Subpart 4 of Part D, title 1.  EPA had (incorrectly) required states to develop their SIPs based only on subpart 1. 

Utah was therefore required to supplement its three SIPs to address the additional requirements of Subpart 4. 

In the wake of the decision by the D.C. Circuit, EPA issued a “deadlines” rule that helped clarify the additional requirements.  It specified a deadline of December 31, 2014 for SIP submission, and further required that the areas would have to attain the 2006 24-hour PM2.5 standard by December 31, 2015.

Subpart 4 Moderate Area SIPs

UDAQ spent the summer of 2014 revising all three SIPs so as to now also meet the moderate area planning requirements of Subpart 4.  They were approved by the UAQB in December and submitted to EPA by the deadline specified in the rule.

From the standpoint of the emission control strategies, these SIPs are fundamentally no different from what had been previously adopted by the Board.  However, Subpart 4 allows for either a demonstration that an area will attain the standard by the end of 2015, or alternately, that such attainment is impracticable.    

The Logan area SIP demonstrates that it is possible to attain the PM2.5 NAAQS by the attainment date specified in the deadlines rule (December 31, 2015.) 

For the Salt Lake City and Provo nonattainment areas, UDAQ prepared SIPs demonstrating that attainment by 2015 is in fact impractical.  These analyses are consistent with the previously completed Subpart 1 SIPs for these areas that showed attainment would not be possible until the end of 2019.  None of the emission control strategies already adopted as part of the Subpart 1 SIPs were abandoned in preparing these impracticability demonstrations. 

What’s Next?

Should any of Utah’s moderate PM2.5 nonattainment areas be unable to attain the 24-hr health standard by the December 31, 2015 attainment date, Subpart 4 allows EPA to re-classify that area as a serious PM2.5 nonattainment area.
Once re-classified, the attainment date for the area would revert to December 14, 2019, and it would become incumbent on UDAQ to submit a new serious area SIP wherein the control strategies would need to be re-evaluated to address an expectation of best available control measures and technologies (BACM / BACT).
The date upon which such serious area SIP would be due to EPA is dependent on a number of uncertainties, but could be required as early as 2017.  EPA was expected to re-issue its implementation rule for the PM2.5 standards sometime in 2014.  UDAQ expects that EPA will provide much more clarity in that rule concerning the requirements of Subpart 4 as it relates to PM2.5.

Logan PM2.5 SIP

The Utah Air Quality Board adopted the Logan, UT-ID PM2.5 Nonattainment SIP on December 3, 2014.  It includes area source control strategies and a new motor vehicle emission inspection and maintenance (I/M) program to meet the PM2.5 NAAQS by the end of 2015.

Salt Lake PM2.5 SIP

The Utah Air Quality Board adopted the Salt Lake City, UT PM2.5 Nonattainment SIP on December 3, 2014.  It includes new control measures affecting large stationary sources as well as smaller area sources to mitigate PM2.5 emissions, but does not predict attainment of the PM2.5 NAAQS by the end of 2015.

Provo PM2.5 SIP

The Utah Air Quality Board adopted the Provo, UT PM2.5 Nonattainment SIP on December 3, 2014.  It includes new control measures affecting large stationary sources as well as smaller area sources to mitigate PM2.5 emissions, but does not predict attainment of the PM2.5 NAAQS by the end of 2015.

Emission Limits and Operating Practices for Large Stationary Sources

As part of its emission control strategy, the SIP ensures that reasonably available control strategy (RACT) is applied to large stationary sources within the PM2.5 nonattainment areas. Large stationary sources were identified in the Salt Lake City and Provo nonattainment areas but not in the Logan area.  The terms of these emission controls are made enforceable by including source-specific emission limits and operating practices in the SIP, and these appear at Section IX Part H. Limits and practices specific to PM2.5 may be found in subsections 11, 12, and 13 of Part H.

Rulemaking for the SIP

The Air Quality Board adopted many rules that became part of the SIP.  These rules largely affected area sources rules and largely targeted emissions of volatile organic compounds (VOC) which assist in the chemical formation of PM2.5 during winter months as well as ozone in the summer.  All of these rules are currently in effect.

Technical Support Documents

The DAQ has completed a Technical Supports Document (TSD) for the three Subpart 4 moderate area SIPs.  A TSD is not a part of the SIP, but is a companion piece that serves as the technical basis for the decisions made in the SIP.  It describes the emissions inventories, modeling, and control strategies.  Since all three nonattainment areas were included in the same air quality modeling analysis this TSD supports all three SIPs.  To request a copy of a TSD on a CD, please make a request to Ryan Stephens.

Additional PM2.5 Development Information

The Division produced a short informational video and companion booklet in 2012 to provide the public with information about the PM2.5 SIP development process.  The video, booklet, and an additional fact sheet are linked below.

Information about proposed SIPs, rules, public comment periods, and public hearings is also published in the State Bulletin

Related Resources

  • Interactive Data Explorer
    This service is available for an in-depth look at the emissions inventory used in the air quality modeling analysis.

For more information or questions contact Ryan Stephens (801) 536-4419.