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Allegheny Co. Health Dept. Announces Withdrawal of Request for EPA Attainment Determination of PM2.5 Standard

A little more than a year-and-a-half ago, we blogged about the Clean Data Determination that the U.S Environmental Protection Agency (EPA) made regarding Allegheny County’s attainment of the 2012 National Ambient Air Quality Standard (NAAQS) for PM2.5.  

By that determination, EPA confirmed that data from the air quality monitors in Allegheny County showed that all areas of the county met the 2012 NAAQS for fine particulate matter. Following EPA’s clean data determination, ACHD submitted a formal request that the county at long last be reclassified as attainment for the 2012 NAAQS for PM2.5.

Then, at the latest Air Pollution Advisory Committee meeting April 15, the Allegheny County Health Department (ACHD) said it plans to withdraw that request.

And it’s not because pollution in the county has worsened enough to prevent attainment, but because of EPA’s recent decision to revise that NAAQS downward, from 12 micrograms per cubic meter (µg/m3) to 9 µg/m3.  

Although all areas of the county have attained the 12 µg/m3 standard for several years, it appears that ACHD’s air quality monitors near U.S. Steel’s Clairton Coke Works do not attain the new 9 µg/m3 standard. 

What are the implications of ACHD’s decision to withdraw its request for an attainment designation? They are not likely to be significant.

Some background about the Clean Air Act might be helpful for understanding why: It requires that all areas in the United States be classified as being in attainment or nonattainment of each NAAQS.  

The state, local, and tribal agencies that administer the air pollution laws in areas that are nonattainment for a particular NAAQS must submit plans to EPA that generally include tighter controls on pollution sources that are designed to bring the areas into attainment of the NAAQS and special rules for new major sources of air pollution in or impacting the area. 

“All existing requirements related to nonattainment of the NAAQS for PM2.5 must remain on the books pending EPA’s formal reclassification of the county to attainment; as a practical matter, such requirements remain on the books even after an attainment designation because they are necessary to keep the area in attainment,” GASP senior attorney John Baillie explained.

So, this means that ACHD’s withdrawal of its request for an attainment designation will maintain the status quo.  

The existing air pollution rules and regulations in Allegheny County will remain in force and any new major sources of PM2.5 in or impacting Allegheny County will continue to be subject to stricter pre-construction permitting rules that pertain to nonattainment area (although we are not aware that any such sources are proposed).  


“This will be the case until ACHD develops, and then implements, any new rules that are needed to attain the revised 9 µg/m3 standard,” Baillie said. “The development and implementation of any such rules will occur over the upcoming years not months; it is even possible - at least theoretically - that ACHD’s air quality monitors will measure attainment of the revised NAAQS by the time EPA makes attainment designations for it, which could eliminate the need for more controls.”

In the meantime, we’ll continue to follow developments that flow from the revision of the NAAQS for PM2.5 and keep you posted on them here. Stay tuned.

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