Robert Esworthy
Specialist in Environmental Policy
On June 29, 2012, the Environmental Protection Agency (EPA) published a proposal to revise the National Ambient Air Quality Standard (NAAQS) under the Clean Air Act (CAA) for particulate matter (PM), in response to a June 6, 2012, order issued by the U.S. Court of Appeals for the District of Columbia Circuit. Environmental and public health advocacy groups and 11 states had petitioned the agency, and subsequently filed suit in the D.C. Circuit alleging that EPA failed to perform its mandated duty to complete the review of the PM NAAQS within the statutory deadline. EPA has agreed to issue final revised PM NAAQS by December 14, 2012. EPA’s review of the PM NAAQS has generated considerable debate and oversight in Congress.
The June 2012 proposal would strengthen the existing (2006) annual health-based (“primary”) standard for “fine” particulate matter 2.5 micrometers or less in diameter (or PM2.5), lowering the allowable average concentration of PM2.5 in the air from the current level of 15 micrograms per cubic meter (μg/m3), to a range of 12 to 13 μg/m.3 The annual PM2.5 NAAQS is set so as to address human health effects from chronic exposures to the pollutants. The existing 24-hour primary standard for PM2.5 that was reduced from 65 μg/m3 to 35 μg/m3 in 2006 would be retained, as would the existing standards for larger, but still inhalable “coarse” particles less than 10 micrometers in diameter or PM10. “Secondary” standards that provide protection against “welfare” (non-health) effects, such as ecological effects and material deterioration, would be identical to the primary standards the same as in 2006, but the June 2012 proposal included two options for a 24-hour PM2.5 standard to improve visibility.
In developing the June 2012 proposal, EPA reviewed scientific studies available since the agency’s previous review in 2006. EPA determined, and the independent scientific advisory committee mandated under the CAA (Clean Air Scientific Advisory Committee, or CASAC) concurred, that evidence continues to show associations between particulates in ambient air and numerous significant health problems, including aggravated asthma, chronic bronchitis, non-fatal heart attacks, and premature death. Populations shown to be most at risk include children, older adults, and those with heart and lung disease, and those of lower socioeconomic status.
EPA expects that the potential benefits of the proposed revisions would range from an estimated low of $88.0 million to a high of $5.9 billion dependent on the concentration level and other factors, and estimated costs would range from $2.9 million to $69.0 million. Some stakeholders and some Members express concerns that the cost impacts will be more significant than EPA estimated in those areas unable to comply with the new standards. EPA’s establishment of or revisions to the PM NAAQS do not directly regulate emissions from specific sources, or compel installation of any pollution control equipment or measures, but indirectly could affect operations at industrial facilities and other sources throughout the United States.
Final revised PM NAAQS will start a process that includes a determination of areas in each state that exceed the standard and must, therefore, reduce pollutant concentrations to achieve it. Following the determination of “nonattainment” areas (primarily counties) based on multiple years of monitoring data and other factors submitted by the states, state and local governments must develop (or revise) State Implementation Plans (SIPs) outlining measures to attain the standard. These often involve promulgation of new regulations by states, leading to the issuance of revised air permits. The process typically takes several years. Based on statutory scheduling requirements, designation of areas as nonattainment for any revised PM NAAQS would not be determined until the end of 2014, and states would have until at least 2020 to achieve compliance.
Date of Report: September 5, 2012
Number of Pages: 44
Order Number: R42671
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