• EPA Proposes Tighter Standards for Particulate Matter
  • January 3, 2006 | Author: Robert J. Martineau
  • Law Firm: Waller Lansden Dortch & Davis, LLP - Nashville Office
  • The U.S. Environmental Protection Agency (EPA) has proposed revisions to the primary and secondary national ambient air quality standards for particulate matter (PM). As outlined below, EPA has proposed a myriad of changes to the PM standards, but the most significant aspect of the proposal would reduce the 24-hour fine particle standard by almost 50 percent (from 65 |g/m3 to 35 |g/m3). Once EPA finalizes and promulgates the new PM standards, areas designated nonattainment will be required to establish and implement emissions control programs in order to achieve the standards by the federally mandated deadline. Generally, nonattainment areas must control the expansion of existing sources and development of new ones if they meet a threshold of PM emissions. These and other federally mandated requirements for nonattainment areas could affect new development and growth.

    The proposed revisions address two categories of PM: fine particles (PM2.5), which are smaller, at 2.5 micrometers in diameter; and larger, inhalable, course particles (now referred to as PM10-2.5), which are between 2.5 and 10 micrometers in diameter. For each category of PM, the proposal addresses two types of standards: primary standards (to protect public health) and secondary standards (to protect public welfare, such as crops, vegetation, wildlife and visibility). EPA is soliciting public comments on the proposal for 90 days following publication in the Federal Register, which will occur in the very near future. EPA is under a court order to issue the final standards by September 2006.

    EPA is proposing revisions as well as taking comments on a range of standards concerning PM2.5 and PM10-2.5. For each PM category, the proposed revisions and request for comments include:


    EPA has two primary standards for PM2.5, an annual standard and a 24-hour standard. EPA is proposing to retain the current annual standard for PM2.5 (15 |g/m3), but is seeking comment on a range of alternatives. For the 24-hour standard, EPA is proposing to reduce the acceptable ambient concentrations from the current level of 65 |g/m3 to 35 |g/m3. However, EPA is soliciting comment on a wide range of alternatives, including retaining the current standard.

    EPA's proposal would set the secondary standard for both the annual and 24-hour PM standards at levels identical to the primary standards. EPA is seeking comment on whether to set a separate standard designed specifically to address visibility.


    EPA's current standards -- an annual standard of 50 |g/m3 and 24-hour standard of 150 |g/m3 (referred to as PM10 standards) -- were set in 1987 and apply to PM that is 10 micrometers in diameter or smaller (including smaller than 2.5 micrometers). Because this caused duplicative regulation of fine particulate matter, EPA is proposing a revised definition for this standard covering only particulate matter between 2.5 and 10 micrometers in diameter (i.e., PM10-2.5). EPA's revision defines PM10-2.5 to include only those particles that come from high-density traffic, industrial sources and construction activities-not particles from agricultural and mining sources.

    EPA's proposed new PM10-2.5 primary standard would be a 24-hour standard of 70 |g/m3. EPA is not proposing an annual standard for this PM category. The proposed secondary 24-hour standard would be identical to the primary standard.

    EPA is proposing to revoke the current 24-hour PM10 standard for all areas except those with violating monitors and a population of 100,000 or more. This standard would remain in place until the agency has completed its designations for PM10-2.5. EPA is taking comment upon whether the 24-hour PM10 standard should be retained in smaller areas (population less than 100,000) that are dominated by one or more large industrial sources. In addition, EPA is seeking comment on a number of other options, including whether it should retain the current PM10 standards.

    The proposal sets a general timeline for implementing the standards. If EPA finalizes the new standards in September 2006, EPA will make the final designations for PM2.5 by November 2009. States would have until April 2015 to meet the standards. For PM10-2.5, final designations would not be made until May 2013 and the designations would become effective in July 2013. States would have to meet the standards by July 2018.

    The Tennessee Department of Environment and Conservation, in its preliminary assessment of EPA's proposal, estimates Tennessee will have no new or additional nonattainment areas for PM. Those counties/areas already designated nonattainment for PM2.5 (Hamilton, Knox, Loudon, Blount, Anderson, and Roane(part)) are expected to be nonattainment areas under EPA's proposal. The Department is currently reviewing the monitoring data for Shelby County to determine if this area is at risk to be designated nonattainment.