Find Your Fit

Did you know the EPA is considering revisions to air quality designations under the 2015 ozone NAAQS? If so, did you realize the EPA intends to expand the Weld County, Colorado nonattainment designation and designate El Paso County, Texas as nonattainment? Well, it’s true.

Counties in Colorado and Texas are being pulled into a larger EPA effort affecting 14 counties in seven ozone nonattainment areas (in addition to Colorado and Texas). These actions are being taken by the EPA to address a July 10, 2010, D.C. Circuit Court Decision which remanded (but did not vacate) EPA’s April 30, 2018 designations under the 2015 ozone standard.

In late May 2021, the EPA provided notifications to both Colorado and Texas of their intent to:

  • Extend the existing nonattainment designation for Weld County, Colorado to cover the entire county (currently, only a portion of the county is designated nonattainment), and
  • Designate El Paso County, Texas as nonattainment and combine it with the previously designated Dona Ana County, New Mexico.

The EPA also stated they will make their final determinations regarding the status of El Paso County and Weld County no earlier than 120 days from the date they notified the states of their intent. The EPA sent notifications directly to Texas and Colorado on or about May 24, 2021.

Both El Paso and Weld counties will most likely become marginal ozone nonattainment counties; however, keep in mind that 2021 is an attainment year for the 2015 ozone standard. It is possible that one, or both, of them may be bumped-up to moderate ozone nonattainment depending on the ambient monitoring results for the respective counties.

A nonattainment status with a classification of moderate would mean that these counties would have a major source threshold of 100 tons/year of either VOC and/or NOx, a major modification threshold of 40 tons/year, and a netting trigger threshold of 40 tons/year. The difference between the marginal and moderate ozone nonattainment classifications is the offset ratio. A marginal ozone nonattainment classification has an offset ratio of 1.10 to 1 whereas a moderate ozone nonattainment classification has an offset ratio of 1.15 to 1.

Stay tuned as Spirit Environmental continues to track these, and other important issues affecting air authorizations. If you have any questions, feel free to reach out to our environmental professionals.

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