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Area Designations for 1997 Fine Particle (PM2.5) Standards

Fact Sheet

Information provided for informational purposes only Note: EPA no longer updates this information, but it may be useful for historical purposes. See the PM Designations Home Page for more recent information about PM Designations.

National Air Quality Standards for Fine Particle Pollution:
Changes to Designated “Nonattainment” or “Unclassifiable” Areas
Standards for Fine Particle Pollution Become Effective


  • On April 5 2005, the Environmental Protection Agency (EPA) announced the addition of 12 areas including 21 counties across nine states as “attainment areas” under EPA's national air quality standards for fine particle pollution or PM2.5. The nonattainment designations made in December 2004 are now effective for the remaining 39 areas comprised of 208 counties across the country.
  • Across the United States, there are 30 states designated as “in attainment.” These areas are home to over 197 million people. The twelve additional newly designated attainment areas are home to over 5 million people and represent continued progress towards cleaner air and improved public health.
  • These changes update the designations made by EPA in December 2004, which were based on 2001-2003 air quality data. Because PM2.5 designations occurred close to the end of 2004, EPA provided states an opportunity to submit updated data for calendar year 2004 which could demonstrate changes to those areas designated as “non attainment” or “unclassifiable.”
  • The new designations announced on April 5, 2005 are based on an evaluation of the updated, certified air quality data submitted by nine states for calendar years 2002-2004.
  • These 21 counties join over 2,900 other counties that meet the national air quality standards for fine particles. Citizens in these areas are realizing the benefits of breathing cleaner air. Meeting the PM2.5 standards nationwide will prevent at least 15,000 premature deaths; 75,000 cases of chronic bronchitis; 10,000 hospital admissions for respiratory and cardiovascular disease; hundreds of thousands of occurrences of aggravated asthma; and 3.1 million days when people miss work because they are suffering from symptoms related to particle pollution exposure.
  • The following areas previously identified as not attaining the standards are now designated as “attainment” for the national air quality standards for fine particles. These areas include 17 counties in 8 states and are home to over 5 million people:

    Area Name County, State
    Columbus, GA-AL Russell, AL
    San Diego, CA San Diego, CA
    Athens, GA Clarke, GA
    Columbus, GA-AL Muscogee, GA
    Elkhart, IN Elkhart, IN
    St. Joseph, IN
    Lexington, KY Fayette, KY
    Mercer (partial), KY
    Toledo, OH Lucas, OH
    Wood, OH
    Youngstown-Warren, OH-PA Columbiana, OH
    Mahoning, OH
    Trumbull, OH
    Youngstown-Warren, OH-PA Mercer, PA
    Marion, WV Marion, WV
    Monongalia (partial), WV
    Harrison (partial), WV
  • EPA is also designating the following four areas as “attainment” — these areas were identified in December 2004 as “unclassifiable” based on incomplete 2001 — 2003 data and violating data for 2000 — 2002. These four single-county areas are home to 337,000 people.

    Area Name County, State
    Dekalb County, AL Dekalb, AL
    Gadsden, AL Etowah, AL
    Muncie, IN Delaware, IN
    McMinn County, TN McMinn, TN
  • The Greenville-Spartanburg, SC area is the only remaining unclassifiable area for the PM2.5 air quality standards. Monitoring data for the area has not yet been certified. EPA will review the designation status of this area later in 2005.


  • In July 1997, EPA issued National Ambient Air Quality Standards for Fine Particles (PM2.5). The standards are designed to protect the public from exposure to PM2.5 at levels that may cause health problems.
  • The standards include an annual standard set at 15 micrograms per cubic meter, based on the 3-year average of annual mean PM2.5 concentrations and a 24-hour standard of 65 micrograms per cubic meter, based on the 3-year average of the 98th percentile of 24-hour concentrations.
  • Fine particle pollution, also called PM2.5 , is a mixture of microscopic solids and liquid droplets suspended in air. Fine particles can be emitted directly (such as smoke from a fire) or formed in the atmosphere from power plant, industrial and mobile source emissions of gases such as sulfur dioxide and nitrogen oxides.
  • The health effects associated with exposure to fine particles are significant. Scientific studies have shown significant associations between elevated fine particle levels and premature death. Effects associated with fine particle exposure include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days), lung disease, decreased lung function, asthma attacks, and certain cardiovascular problems such as heart attacks and cardiac arrhythmia. While fine particles are unhealthy for anyone to breathe, people with heart or lung disease, asthmatics, older adults, and children are especially at risk.
  • Areas not meeting the national air quality standards are called nonattainment areas. These areas have had (or have contributed to) PM2.5 levels higher than allowed under EPA's national air quality standard.
  • States and tribes with designated nonattainment areas must submit plans that outline how they will meet the PM2.5 standards. Those plans are known as State or Tribal Implementation Plans, or SIPs/TIPs. States and tribes must submit their plans to EPA within three years — by April 5, 2008.
  • Areas are required to attain clean air as soon as possible, but no later than 2010. EPA may grant attainment date extensions of up to five years in areas with more severe PM2.5 problems and where emissions control measures are not available or feasible.
  • Nonattainment areas are subject to a measure known as “transportation conformity,” which requires local transportation and air quality officials to coordinate planning to ensure that transportation projects, such as road construction, do not affect an area's ability to reach its clean air goals. Transportation conformity requirements become effective one year after an area is designated as nonattainment.
  • Once designated, nonattainment areas also are subject to New Source Review requirements. New Source Review is a permitting program for industrial facilities to ensure that new and modified sources of pollution do not impede progress toward cleaner air.
  • Areas designated as “attainment” have monitored air quality that meets the level of EPA's health-based national air quality standards for fine particle pollution and/or do not contribute to air quality problems in other areas. While these areas will not have to take steps to improve air quality, they must prevent their air quality from significantly deteriorating.

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