Nonattainment Areas
In 1987, the EPA set new air-quality standards for PM10 of 150µg/m3 over a 24-hour period and an average of 50 µg/m3 annually. Utah was initially unable to meet the 24-hour standard and was required to prepare State Implementation Plans for Salt Lake and Utah County. Ogden City was designated nonattainment on September 26, 1995, but was able to monitor attainment and suspend related planning requirements through EPA’s Clean Data Policy. Utah never violated the annual PM10 standards, which were revoked in 2006.
Attainment Areas
State Implementation Plans (SIP) were written and promulgated in 1991, and included control strategies that were responsible for the marked decrease in PM10 concentrations observed in the early 1990s.
State Implementation Plans
Salt Lake and Utah County PM10 State Implementation Plans
On November 14, 1991, Utah submitted a SIP for the Salt Lake and Utah County nonattainment areas. The SIP demonstrated attainment of the PM10 standard for 10 years: 1993 through 2003. EPA published approval of the SIP on July 8, 1994, and Utah achieved attainment of the standard in both areas by 1996. The control measures adopted as part of those plans have proven successful. Both the Salt Lake and the Utah County areas continue to show compliance with the federal health standards for PM10.
In 1991, SIPs for the Salt Lake and Utah Counties added control measures for industries, including smelters, refineries, and power plants. Some industries were required to burn natural gas instead of coal during the winter inversion season. A wood-burning restriction program also was added at that time, and improvements were made in the vehicle emissions inspection and maintenance program. At this time, PM10 was primarily a winter problem, with a large percentage of the particulates due to secondary particulate matter and wood smoke. These controls addressed particles that would be considered PM2.5 today.
The EPA approved those SIPs in 1994, and both areas have been in compliance with the NAAQS since 1996.
Ogden City
Ogden City PM10 State Implementation Plan
Ogden City was re-designated nonattainment from unclassifiable on September 26, 1995. This re-designation triggered the state’s requirement to develop a nonattainment SIP with an attainment date of December 31, 2001.
In 1997, a new standard for PM10 was promulgated by the EPA. Based on the revised form of the standard, Ogden City would have never been out of compliance. However, a 1999 ruling by the D.C. Circuit Court vacated the new 1997 standard. In response to the D.C. Circuit ruling, EPA gave areas like Ogden City another avenue to satisfy its Part D attainment planning requirements under Title I of the Clean Air Act under EPA’s Clean Data Policy. This policy allowed EPA to make a determination of attainment regarding a specific area. Utah submitted a letter in 2000 requesting that EPA make a determination under the policy. In 2013, EPA determined that the Ogden City nonattainment area was currently attaining the 24-hour standard for PM10. In 2020 Ogden City was redesignated to attainment for the PM10 NAAQS.
Ogden City PM10 Maintenance Plan
The Air Quality Board also adopted a maintenance plan for Ogden City on December 2, 2015, demonstrating attainment through the year 2030. Like the Utah and Salt Lake County plans, the Ogden City plan also requests that the nonattainment area status be re-designated as attainment. Ogden City has been designated attainment and a maintenance plan has been approved by the EPA.
Maintenance Plans
When a state submits a request to EPA to re-designate a nonattainment area as attainment, it must submit a maintenance plan to the EPA that demonstrates that the area can maintain the air-quality standard for at least 10 years following the effective date of re-designation. Utah completed PM10 maintenance plans in 2015 for all areas that showed it expects to remain in compliance for the next 10 years. These plans have been approved by EPA.
PM10 Maintenance Plans
On December 2nd, 2015, the Air Quality Board adopted revisions to the SIP as maintenance plans for the Utah County nonattainment areas. These plans demonstrate attainment through the year 2030. The plans have been approved by EPA and both Salt Lake and Utah County have been designated as maintenance areas.
- PM10 Maintenance Plan for Utah County (2015)
- PM10 Maintenance Plan for Salt Lake County (2015)
- PM10 Maintenance Plan for Ogden City (2015)
There are point sources in the PM10 SIPs that were singled out for RACT control. The resulting emission limits and operating practices were incorporated into the SIP here in Part H. Part H also includes PM2.5 provisions at subsections H.11-13.