Particulate Matter
Most Recent Action
The White House OMB is reviewing a proposed rule that addresses the implementation of the 1997 Ozone and fine particulate matter National Ambient Air Quality Standards (NAAQS).
EPA approval of modifications to Wisconsin's September 2009 Particulate Matter SIP, January 31, 2011.
Background
The EPA originally set air quality standards for particulate matter in 1971 and they were not significantly revised until 1987, when the EPA changed the standards to regulate inhalable particles smaller than, or equal to, 10 micrometers in diameter (which is about one-fourth the size of a single grain of table salt).
Ten years later, the EPA revised the PM standards, setting separate standards for fine particles (PM 2.5). The 1997 standards were retained, but slightly revised. The standards for PM10 which were intended to regulate “inhalable coarse particles” that ranged from 1.5 to 10 micrometers in diameter were kept; however, contain both fine and coarse particles.
The EPA again revised the air quality standards for particle pollution in 2006. The EPA strengthened the 24-hour fine particle standard by lowering the current level of 65 micrograms per cubic meter (µg/m3) to 35 µg/m3, and retained the current annual fine particle standard of 15 µg/m3. The EPA retained the existing 24-hour PM10 standard of 150 µg/m3. The agency revoked the annual PM10 standard, citing the lack of evidence suggesting a link between long-term exposure to PM10 and health problems.
On February 24, 2009, the United States Court of Appeals struck down the EPA’s PM2.5 primary annual standard of 15 micrograms per cubic meter (µg/m3) and remanded for reconsideration. The court ruled that the EPA “did not adequately explain why an annual level of 15µg/m3 is sufficient to protect public health while providing an adequate margin of safety from short-term exposures and from morbidity affecting vulnerable subpopulations.”
Because 2006 standards were remanded, not vacated, they remain in effect until new standards are promulgated. The EPA is scheduled to review the PM standards in 2011. The likely range of any proposed rule will be 12 to 14 micrograms per cubic meter (µg/m3).
This rule is part of a group of rules known as the EPA's Regulatory Train Wreck.
Authority
42 USC Sec. 7409 (CAA) – National Primary and Secondary Ambient Air Quality Standards: December 31, 1970. This section of the CAA provides the EPA authority to promulgate National Ambient Air Quality Standards (Primary and Secondary) or, NAAQS.
Standard
40 CFR Part 50 – National Ambient Air Quality Standards for Particulate Matter; Final Rule: July 17, 1997. Federal Register notice regarding revised NAAQS for particulate matter (PM2.5).
40 CFR Part 50 – Revisions to National Ambient Air Quality Standards for Particulate Matter; Final Rule 71 Fed. Reg. 61144; Oct. 17, 2006. Federal Register notice regarding revised NAAQS for particulate matter (PM2.5).
Fact Sheet: 2006 Revisions to Ambient Air Monitoring Regulations
Related Documents
Increments, Significant Impact Levels (SILs), and Significant Monitoring Concentration (SMC) for Prevention of Significant Deterioration for Particulate Matter less than 2.5 Micrometers (PM2.5), October 20, 2010
The EPA gave notice that 29 states, including Wisconsin, did not submit SIPs, May 28, 2010
Letter from Gov. Jim Doyle to EPA: Designation of PM2.5 Nonattainment Areas in Wisconsin; Oct. 20, 2008.
EPA Letter to Gov. Jim Doyle - designating five Wisconsin counties as PM2.5 nonattainment areas, and a portion of a sixth county (Columbia); Dec. 22, 2008.