Fine Particle Georgetown International Environmental Law Review Pollution and the NAAQS Revision Process


Fine Particle Pollution and the NAAQS Revision Process

By Daniel Shaw, Staff Contributor

Governmental efforts to reduce air pollution in the United States are progressing in the form of a new round of revisions to the National Ambient Air Quality Standards. Although lowering the acceptable levels of particle pollution is a good step, the government may not be lowering them enough to make a true impact on the state of air pollution in the United States.

Since 1970, the Environmental Protection Agency (EPA) has administered the National Ambient Air Quality Standards (NAAQS). The six primary pollutants regulated by NAAQS are carbon monoxide, lead, nitrogen dioxide, ozone, sulfur dioxide, and particle pollution. Particle pollution is subdivided into two categories, which are based on the size of the particles. Particle pollution composed of fine particles, i.e., those less than 2.5 microns in diameter, are regulated under the PM-2.5 standard, while particle pollution caused by coarse particles, i.e., those between 2.5 and 10 microns in diameter, are regulated under the PM-10 standard.

“Fine particle pollution … poses some of the greatest health risks to the general public.”

Fine particle pollution is caused primarily by chemical combustion processes such as through the operation of traditional motor vehicles, wood fires, and coal power plants. It poses some of the greatest health risks to the general public and is particularly harmful to children, the elderly, and asthmatics of any age. These risks differ depending on whether exposure is long-term or short-term. Long-term exposure increases the risk of cardiovascular disease, lung cancer, and infant mortality, among others. Short-term exposure is extremely dangerous for children with asthma, and can even cause lung inflammation in healthy adults. Additionally, fine particle pollution, especially in the form of sulfate and nitrate particles, is a significant cause of acid rain.

The PM-2.5 standard was revised in December 2012, lowering the annual PM-2.5 standard from 15 µg/m3 (micrograms per cubic meter) to 12 µg/m3. The EPA suggests that this change in the annual standard will reduce risks from both short-term and long-term exposure to fine particle pollution. The EPA’s own air quality measurements from 2009 to 2011, however, indicate that only 66 of the roughly 3,000 counties in the United States currently fail to meet the new “strengthened” standard. Although this type of slow, incremental improvement may save money for attainment regions (as described below) in the short run, the goals of the Clean Air Act could be better served by more ambitious regulation aimed at reducing particle pollution more quickly.

“The PM-2.5 standard and other NAAQS are only part of the solution for reducing the harms from fine particle pollution nationwide.”

Once the EPA sets or revises a particular NAAQS, the ponderous machinery of implementation lurches into action. The Clean Air Act requires the agency to issue designations as “attainment/unclassifiable” (meeting the standard or expected to be meeting the standard despite a lack of monitoring data), “nonattainment” (not meeting the standard), or “unclassifiable” (insufficient data to classify) for individual areas of the nation. Prior to this, the agency solicits the states’ own proposals for each region as to which designation it should receive. For the current cycle of particulate matter NAAQS revisions, the state designations were due to the agency by December 13 of last year. In August 2014, in response to the states’ proposals, the EPA sent letters to states informing the EPA’s intended designations, in which the EPA intended to designate 14 areas in six states as nonattainment. The EPA plans to issue their final designations on December 12, 2014. Once areas are designated as “nonattainment,” the state or local governments of designated areas must develop a plan to improve its air quality.

The PM-2.5 standard and other NAAQS are only part of the solution for reducing the harms from fine particle pollution nationwide. Because attainment is assessed on a county-by-county, state-by-state basis, and because the air quality in one area is directly affected by the air coming in from surrounding regions, a region may be designated as nonattainment due to emission sources that are entirely beyond the control of the local government. To address this issue, the Clean Air Act requires that State Implementation Plans prevent in-state emissions in amounts that will contribute significantly to air pollution in other states. The so-called “Good Neighbor Provision” has been implemented by the EPA through the Cross-State Air Pollution Rule, the current form of which was upheld recently by the Supreme Court in Environmental Protection Agency v. EME Homer City Generation. The Court held, 6-2, that the EPA’s rule was within the limits of its authority under the Clean Air Act. The decision is a good step towards allowing the EPA to effectively lower air pollution levels; the burden is now on the EPA to do so in a meaningful way.