This post was written by Mark Mustian.
On June 14, the U.S. Environmental Protection Agency (USEPA) published a proposed rule that would modify current air quality standards for fine particulates (PM2.5). The proposed changes are the result of a remand by the U.S. Court of Appeals for the District of Columbia Circuit from litigation over standards set by USEPA in 2006.
The proposed rule would slightly reduce the annual final particulate primary standard from 15 µg/m3 to a range of 12-13 µg/m3. Primary standards provide public health protection, including protecting the health of "sensitive" populations such as asthmatics, children, and the elderly. USEPA is also modifying the secondary standard for fine particulates. Secondary standards are intended for public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. Currently, EPA sets secondary standards for PM2.5 at the same levels as the primary standards. Under the new rules, compliance will be based upon the current secondary standard, and a compliance standard based upon a calculated visibility index. This would use speciated PM2.5 mass concentrations and relative humidity data to calculate PM2.5 light extinction. In other words, the secondary standard will be based upon visibility impairment.
USEPA is also proposing changes to the current fine particulate monitoring program. USEPA would require all urban areas of greater than 1 million people to install or move monitors to locations adjacent to heavily traveled roads because USEPA identifies cars and heavy duty diesel trucks and buses as significant sources of fine particulates, and expects PM2.5 levels to be higher near heavily traveled roads.
Know that compliance with NAAQS is determined on a county-by-county basis. Counties which are considered to be in nonattainment with the standards must develop state implementation plans (SIPs) showing how they will meet the standards. Major stationary sources within nonattainment areas are required to undergo Nonattainment New Source Review (NNSR) for major modifications to their facilities. A major modification is "a physical change or a change in the method of operation of an existing stationary source that is major for the nonattainment pollutant and that results in a significant net emissions increase of that nonattainment pollutant." To comply with NNSR, facilities must install technology that meets the lowest achievable emission rate (LAER), secure appropriate emissions reductions to offset the proposed emissions increases, and perform other analyses as required under Section 173 of the Clean Air Act.
Major stationary sources which are located in attainment areas must comply with the Prevention of Significant Deterioration (PSD) program. Under PSD, new major sources and major modifications must apply best available control technology (BACT) for each applicable pollutant and conduct an air quality analysis to demonstrate that the proposed construction will not cause or contribute to a violation of any NAAQS. To avoid delays in permitting, EPA is proposing to grandfather permit applications if a draft permit or preliminary determination has been issued for public comment by the date the revised PM standards become effective.
Based upon analysis of current air data showing only a few additional counties would be in nonattainment under the new standards, USEPA believes that the proposed regulation would only have a minor cost impact. Furthermore, USEPA believes that other air quality regulations in effect, and compliance efforts required by the current standards will result in most of the country showing compliance by 2020. USEPA projects that 2-6 counties would not be in compliance by 2020 but this determination does not take into account one potentially significant factor. The data analyzed by USEPA does not include measurements of particulate matter in the new monitoring locations adjacent to heavily traveled roads. The Agency expects this data to show higher concentrations of PM2.5, and is likely to result in more counties moving out of attainment. Without the actual data, there is no way to predict the impact of the new monitoring data, and there is no way to predict the impact on attainment with the NAAQS. It is at least possible that this change will result in a significant increase in the number of counties in nonattainment, and as a result a possible significant increase in the cost of compliance for major sources in these areas.
USEPA will take comments on the proposed rules for nine weeks (63 days) after the proposal is published in the Federal Register and hold two public hearings, in Philadelphia and Sacramento, California. USEPA expects to issue final standards by December 14, 2012.