By Brett Rosenberg
April 26, 2004

The Environmental Protection Agency (EPA) issued final non-attainment designations for the new 8-hour ground-level ozone standard April 15 in part or all of 474 of the nation's 2,668 counties.

Areas that exceed the EPA national air quality standard for ozone receive the non-attainment designation, as do areas that contribute ozone pollution to other areas. States were required to submit to the EPA air quality monitoring data and recommendations for ozone non-attainment by July of last year. The EPA's designations are based largely upon these recommendations. An estimated 159 million Americans live within an area designated as non-attainment.

A state or region that receives a non-attainment designation for ozone is required to submit a State Implementation Plan, or SIP, to the EPA by April of 2007. The SIP must outline the steps it plans to take to achieve air quality that meets the new standards. According to the EPA, once a non-attainment classification takes effect, it plays an important role in alerting the public about air quality in a region. It also triggers important components of state, tribal and local efforts to reduce ground-level ozone and its precursors. Such efforts can involve addressing power plant emissions, controlling gasoline vapors at filling stations, or offering incentives for using public transportation.

Non-attainment with the new ozone standard can also prompt certain federal actions, such as new source review and transportation conformity, which can affect commercial and industrial development efforts in a region. Federal law can require that power plants and some industrial equipment receive the most updated pollution control technology when facilities upgrade or expand; in a sense, these facilities become new pollution sources. Similarly, the federal Clean Air Act requires that highway and transit projects that receive federal assistance are consistent with, or "conform" to clean air goals established in a region's State Implementation Plan.

Ground-level ozone occurs when nitrogen oxides, also known as NOx, and volatile organic compounds, or VOCs, from vehicle and industrial emissions react with heat and sunlight. This chemical reaction can cause serious health problems, particularly for people with sensitive immune systems, like children and the elderly. As a major component of smog, ozone can also have harmful effects on visibility and ecological functions. It is known to travel across long distances as the wind carries it, leading to attainment challenges away from the original sources. Cities that regularly experience hot, sunny days or that are downwind of those that do are particularly vulnerable to ozone pollution.

The EPA's designation process is meant to further protect human health. Several recent studies indicate that the former standard, based on a 1-hour monitoring period, was inadequate to ensure and maintain a level of safety while improving air quality. Similar studies determined that an 8-hour monitoring period would provide an acceptable level of protection. According to EPA Administrator Mike Leavitt, "These new rules are about our new understanding of health threats; about our standards getting tougher and our national resolve to meet them."

The former ozone standard will be phased out over the next year. The transition process has requirements to prevent "backsliding," or preventing deterioration in air quality as regions comply with the new standards.

Depending on the location and severity of the problem, the EPA has established several non-attainment classifications. The most general, a basic non-attainment classification, reflects that an area was in compliance with the 1-hour standard but will be out of compliance with the new 8-hour standard. These areas will have fairly broad and flexible requirements for moving toward attainment, with 5 — 10 year compliance schedules. The other classifications, marginal, moderate, serious, severe, or extreme have more specific compliance requirements and deadlines, once the EPA receives the specific State Implementation Plans. Generally, a region will need to meet the 8-hour ozone standard between 2007 and 2021.

Cities within non-attainment regions should work with their counties, states and the EPA in developing State Implementation Plans to meet clean air goals.

For more information, contact Brett Rosenberg at 202-861-6782 or by email at brosenberg@usmayors.org. or visit the Environmental Protection Agency's eight-hour Ground-level Ozone Designation website at http://www.epa.gov/ozonedesignations/.

A complete listing of all non-attainment areas is available on The United States Conference of Mayors website at http://www.usmayors.org/cleanair/.