Air Trends

Air Quality Design Values

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What is a Design Value?

A design value is a statistic that describes the air quality status of a given location relative to the level of the National Ambient Air Quality Standards (NAAQS).

  • Design values are defined to be consistent with the individual NAAQS as described in 40 CFR Part 50.Exit
  • Design values are typically used to designate and classify nonattainment areas, as well as to assess progress towards meeting the NAAQS. To view a list of areas designated nonattainment, see EPA's Green Book site.
  • Design values are computed and published annually by EPA's Office of Air Quality Planning and Standards and reviewed in conjunction with the EPA Regional Offices. Some of these design values can change after the date of publication for a variety of reasons, including but not limited to:
    • EPA agreement that certain data were influenced by exceptional events and therefore not subject for comparison with the NAAQS,
    • states retroactively entering or changing erroneous data based on later findings, and/or
    • notification of a monitoring issue (e.g. network design, site combination, change in the regulatory status of a monitor) that would prompt a revision.
  • The information listed in these reports and in these tables is intended for informational use only and does not constitute a regulatory determination by EPA as whether an area has attained a NAAQS.
    • The information set forth in this report has no regulatory effect.
    • To have regulatory effect, a final EPA determination as to whether an area has attained a NAAQS or attained a NAAQS as of its applicable attainment date can be accomplished only after rulemaking that provides an opportunity for notice and comment.
    • No such determination for regulatory purposes exists in the absence of such rulemaking.
    • This report does not constitute a proposed or final rulemaking.

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2015 Design Value Reports

Each spreadsheet in the table below contains six tabs that provide design values for the most recent period, unless otherwise noted:

  1. Areas Previously Designated Nonattainment
  2. Violating Monitors in Areas Not Previously Designated Nonattainment
  3. Trends for Previously Designated Nonattainment Areas (last 10 design value periods)
  4. County-Level 
  5. Monitor-Level
  6. Monitor-Level Trends (last 10 design value periods)
2015 Design Value Reports Contacts
Carbon Monoxide Design Values, 2015 (XLSX)(206 K, July 29, 2016)   David Mintz
(919) 541-5224
Lead Design Values, 2015 (XLSX)(1 pg, 105 K, August 29, 2016) Halil Cakir
(919) 541-2416
Nitrogen Dioxide Design Values, 2015 (XLSX)(315 K, July 29, 2016)   Ben Wells
919) 541-7507
Ozone Design Values, 2015 (XLSX)(511 K, July 29, 2016) Ben Wells
919) 541-7507
PM10 Design Values, 2015 (XLSX)(591 K, July 29, 2016)   Brett Gantt
(919) 541-5274
PM2.5 Design Values, 2015 (XLSX)(1 MB, July 29, 2016) Brett Gantt
(919) 541-5274
Sulfur Dioxide Design Values, 2015 (XLSX)(439 K, July 29, 2016) Doug Solomon
(919) 541-4132

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2015 Design Value Map Services

Map services for the 2015 Design Value Update are available in ArcGIS desktop, Google Earth, ArcGIS JavaScript, ArcGIS Explorer and

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Previous Design Value Reports

Design Value period ending: Design Value Reports

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