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Designations & Attainment

Learn about air quality in Massachusetts relative to the National Ambient Air Quality Standards (NAAQS).

The U.S. Environmental Protection Agency (EPA) makes final determinations (called designations) as to whether states meet the National Ambient Air Quality Standards.

EPA publishes these determinations in the Federal Register and they are contained in the Code of Federal Regulations (CFR). For Massachusetts, they are published at: 40 CFR Section 81.322

While the CFR is the final record of designations, EPA also maintains web sites for individual pollutants that are generally easier to use.

For additional information, see: Nonattainment Areas for Criteria Pollutants (Green Book)

Attainment Status Update

In 2015, EPA established a new NAAQS primary ozone standard of 70 parts per billion (ppb). Monitored concentrations in Massachusetts currently meet the new standards. EPA plans to make final designations regarding attainment status for the 2015 ozone standards by October 1, 2018.  

Exceptional Events Demonstration

On May 25 and 26, 2016, the Massachusetts Department of Environmental Protection (MassDEP) measured ozone levels at its Ware and Chicopee monitors that exceeded the 2015 Ozone National Ambient Air Quality Standards (NAAQS). During this same period, smoke from the Fort McMurray wildfire in Alberta, Canada, affected these monitors. 

In accordance with 40 CFR 50.14: Treatment of Data Influenced by Exceptional Events, MassDEP prepared an Exceptional Events Demonstration that shows the Fort McMurray wildfire affected ozone concentrations at the Ware and Chicopee monitors on the dates in question and these data should be excluded from determinations of exceedances and violations of the ozone NAAQS. 

MassDEP made a draft demonstration available for public comment from April 19 to May 19, 2017, as required by 40 CFR 50.14(c)(3). MassDEP received no substantive comments on the draft. MassDEP submitted the final demonstration to the U.S. Environmental Protection Agency Region 1 on May 25, 2017.

Additional Resources for Exceptional Events Demonstration

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