EPA Proposes Stricter Particulate Matter StandardJuly 12, 2012
The EPA has published proposed revisions to the primary and secondary national ambient air quality standards (NAAQS) for fine particulate matter (PM2.5). The proposed standards are stricter and include additional protections for urban visibility.
The EPA last revised the air quality standards for particle pollution (PM) in 2006. The EPA strengthened the 24-hour fine particle standard (PM2.5) by lowering the level to 35 micrograms per cubic meter (µg/m3), and retained the existing 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 coarse particle standard (PM10), 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 remained in effect while new standards were promulgated.
After completing additional analysis on the revised standards, EPA missed the October 2011 statutory deadline to complete review of the current NAAQS for particulate matter within the applicable 5-year period. A lawsuit was filed by states and environmental groups in the U.S. District Court for the District of Columbia in February of 2012, alleging that EPA failed to perform its mandatory duty to revise the NAAQS for PM2.5. The district court ordered EPA to sign a proposed rule setting the NAAQS by June 14, 2012 and finalize standards by December 14, 2012.
The proposed rule would set the annual health-based primary standard for fine particles in a range between 12 µg/m3 and 13 µg/m3, however the EPA is also taking comment on a primary annual standard of 11 µg/m3.
The EPA is proposing to retain the existing 24-hour primary standard for fine particulate matter at 35 µg/m3, as well as the 24-hour primary standards for coarse particulates at 150 µg/m3.
The EPA is also proposing to eliminate spatial averaging provisions, currently used in reporting the annual standard. Spatial averaging currently allows compliance with the NAAQS to be determined by averaging measurements from multiple community-wide air quality monitoring sites. The EPA has found the averaging has a disproportionate impact on at-risk populations because the highest PM concentrations tend to be measured at monitors located in areas where the surrounding population is more likely to have lower education and income levels, and higher percentages of minority populations. Thus, for an area with multiple monitors, EPA proposes that the appropriate reporting monitor with the highest design value will determine the attainment status for that area.
The EPA is proposing to add a separate 24-hour secondary standard for fine particles to protect visibility in urban areas. This standard would be measured in “deciviews,” similar to what is used in the agency’s Regional Haze Program.
The EPA is proposing two alternative levels for the visibility standard: 30 deciviews and 28 deciviews. To determine whether an area meets this standard, the EPA would calculate a “visibility index” value, using data from fine particles samples that have been analyzed to determine their chemical composition, along with information on relative humidity. An area would meet the visibility standard if the 90th percentile of 24-hour visibility index values in one year, averaged over three years, is less than or equal to the level of the standard. The agency also is seeking comment on alternative levels for a visibility index to address haze, down to 25 deciviews, along with comment on alternative averaging times (such as four hours).
EPA also is proposing to retain secondary standards for PM2.5 and PM10 that are identical to the primary standards to provide protection against other effects, such as ecological effects, effects on materials, and climate impacts.
The proposal also addresses several issues related to the proposed standards.
To ensure a smooth transition to the new standards, the EPA is proposing to grandfather preconstruction permitting applications that have made substantial progress through the review process at the time the final standards are issued.
The agency is proposing updates and improvements to the nation’s PM2.5 monitoring network that include relocating a small number of monitors to measure fine particles near heavily traveled roads. The EPA’s proposal does not require additional monitors.
The proposal would also update the Air Quality Index (AQI) for particle pollution.
Cost and Benefits
The EPA projects the standards to yield significant health benefits, valued at $2.3 billion to $5.9 billion annually for a proposed standard of 12 μg/m3 and $88 million to $220 million annually for a proposed standard of 13 μg/m3. Estimated costs of implementing the proposal are $69 million for a proposed standard of 12 μg/m3 and $2.9 million for a proposed standard of 13 μg/m3.
The EPA’s modeling identified six counties in the U.S. that would need to take additional measures to curb particulate matter pollution to meet the proposed new standards. Although it is not one of the counties identified as a potential violator, Waukesha County in Wisconsin is listed as violating the proposed primary annual fine particle standard of 12.0 μg/m3 based on monitored air quality from 2008-2010.
Once the rules are finalized, states will begin the implementation process. The EPA plans to issue nonattainment designations by December 2014, with states having until 2020 to comply with the standards.
Hearings on the proposed rule are scheduled for July 17 and 19. Comments are due August 31, 2012.
Additional information on the Particulate Matter standards is available on the Regulatory Watch website.
This post was authored by GLLF staff attorney Emily Kelchen.