Air Permitting Requirements for Particulate Matter Less Than 2.5 Microns
Most Recent Action
The EPA originally set air quality standards for particulate matter in 1971. 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 singe 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). 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.
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 currently reviewing the rule and is projected to issue revised PM2.5 standards in December 2010. The likely range will be 12 to 14 micrograms per cubic meter (µg/m3).
The DNR is implementing rules consistent with the 2006 standard, so these rules will have to be modified again when the EPA releases new standards.
Section 227.14(1m)(b), Wis. Stats.
, allows the DNR to use the format of federal regulations in preparing a proposed rule if it determines that all or part of a state environmental regulatory program is to be administered according to standards, requirements or methods which are similar to standards, requirements or methods specified for all or part of a federal environmental program.
Section 285.11(16), Wis. Stats.
, requires the DNR to promulgate rules, consistent with but no more restrictive than the federal clean air act, that specify the amounts of emissions that result in a stationary source being classified as a major source.
Section 285.11(17) Wis. Stats.
, requires the DNR to develop and implement rules that define the term modification in a manner consistent with the clean air act.
- Defines major source thresholds for PM2.5 and significant emission increase level for PM2.5.
- Establishes significant impact levels and increment consumption thresholds for PM2.5.
- Establishes inter-pollutant trading ratios for PM2.5, SO2 and NOx.
- Clarifies existing non-attainment area permitting rules for permitting in PM2.5 non-attainment areas (presently Milwaukee, Waukesha and Racine counties are PM2.5 non-attainment areas and subject to non-attainment area new source permitting for PM2.5).
Currently, PM2.5 is not regulated under the new source review program in PM2.5 air quality attainment areas. Under federal law and this rule, PM2.5 will be regulated for all emission sources, with a permitting threshold at levels comparable to those previously set for larger particulate matter (PM and PM10).
Increases in PM2.5 emissions will potentially trigger the need to obtain an air pollution control construction permit, including requirements to control emissions to levels which represent best available control technology or lowest achievable emission rate.
Permitting rules have been in effect in the three-county PM2.5 non-attainment area since that area was designated by the EPA in December 2009. This proposal clarifies existing rules by defining a significant increase and establishing emission offset requirements.
The PM2.5 rules will make the regulations consistent with the equivalent Federal rules with one exception. That exception is the inclusion of a maximum air quality impact that can be allowed to be exempt from pre-construction monitoring. The proposed value in this order is based on the lowest value proposed by the EPA.
Additionally, the rule package includes some cleanup changes to otherwise unaffected existing rules. These changes are proposed to include up-to-date test methods and definitions in these existing rules.
Clearinghouse Review of Rule
Final Rulemaking Order Filed
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