FACT SHEET FINAL RULE: IMPLEMENTATION OF THE 2015 NATIONAL AMBIENT AIR QUALITY STANDARDS FOR OZONE: NONATTAINMENT AREA CLASSIFICATIONS APPROACH ACTION • On March 1, 2018, the U.S. Environmental Protection Agency issued final requirements that would apply to state, local, and tribal air agencies for implementing the 2015 National Ambient Air Quality Standards (NAAQS) for ground-level ozone. The EPA revised both the health-based and welfare- based standards for ozone on October 1, 2015. • These requirements apply to states and tribes with nonattainment areas. • Ozone nonattainment areas are classified by the severity of their air quality problem based on air quality monitoring data, with classifications ranging from "Marginal" to "Extreme." In this final rule, EPA is establishing the: o air quality thresholds that define each of the five Clean Air Act (CAA) classifications for areas designated nonattainment for the 2015 ozone NAAQS; and o attainment deadline associated with each classification. • The nonattainment area classification thresholds for the 2015 ozone NAAQS rely upon the "percent- above-the-standard" (PATS) methodology used to establish area classification thresholds for the 1997 and 2008 8-hour ozone standards. This approach is based on the classification thresholds established for the ozone standard in effect at the time of the 1990 CAA amendments. The final air quality thresholds for the 2015 ozone NAAQS for each classification are: o Marginal - from 71 ppb up to 81 ppb o Moderate - from 81 ppb up to 93 ppb o Serious - from 93 ppb up to 105 ppb o Severe - from 105 ppb up to 163 ppb o Extreme - from 163 ppb • The EPA also is setting maximum attainment dates for each nonattainment area classification consistent with the regulatory approach used for both the 1997 and 2008 ozone standards. The maximum attainment dates for each classification under the 2015 ozone standards will be: o Marginal - 3 years from effective date of designation; o Moderate - 6 years from effective date of designation; o Serious - 9 years from effective date of designation; o Severe - 15 years (or 17 years) from effective date of designation; and o Extreme - 20 years from effective date of designation. BACKGROUND • Ozone is formed from NOx and VOC in the presence of sunlight. Cars, trucks, buses, engines, industries, power plants and products, such as solvents and paints are among the major manmade sources of ozone-forming emissions. Exposure to ground-level ozone pollution is linked to a variety of significant health problems. 1 ------- • Ozone levels are most commonly elevated in the warm summer months, when hot sunny days make it more likely that ozone will form. But this isn't always the case. In parts of the western United States with high levels of local VOC and NOx emissions and unique meteorological conditions, ozone levels have been high when snow is on the ground. • The CAA directs the EPA to set and review air quality standards for common pollutants known as "criteria pollutants," which the agency has identified based on their likelihood of harming public health and welfare. The EPA established air quality standards for ozone in 1979. The EPA subsequently revised the ozone standards in 1997, 2008 and 2015 based on the most recently available scientific studies at the time. o In October 2015, the EPA strengthened the ozone NAAQS from 75 parts per billion (ppb) to 70 ppb to ensure the protection of public health and welfare • After the EPA establishes or revises an air quality standard, the agency follows a process by which states recommend area designations (i.e., as nonattainment, attainment, or unclassifiable) to the EPA. The EPA then evaluates their recommendations and air quality data and other factors prior to making its proposed and final determinations regarding area designations. • Implementation of the NAAQS is a shared responsibility of the EPA, states and tribes. This final rule interprets the requirements of the Clean Air Act (CAA) in a manner that ensures public health protection is achieved by meeting the 2015 ozone standards, while giving the EPA's partners flexibility to reduce administrative burdens, where possible. • States, and in some cases local agencies or tribes, are the primary implementers of the NAAQS. They are responsible for developing and submitting to the EPA, implementation plans that meet the nonattainment planning requirements of the CAA. The EPA promulgates implementation rules to clarify its interpretation of applicable statutory provisions. FOR MORE INFORMATION • To download a copy of the final rule from the EPA website, go to "Regulatory Actions" at the following address: https://www.epa.gov/ozone-pollution/implementation-2015-national-ambient- air-qualitv-standards-naaqs-ozone-state • Additional information on the ozone nonattainment areas is available on the EPA Green Book at https://www.epa.gov/green-book/green-book-8-hour-ozone-2008-area-information. • For more information on the final rule, contact Robert Lingard at (919) 541-5272 or lingard.robert(a),epa.gov: or Butch Stackhouse at (919) 541-5208 or stackhouse. butch®,epa.gov. 2 ------- |