Reclassification of San Diego County as Severe Nonattainment Area for Ozone

October 9, 2020

By: Carol Kawa

San Diego Air Pollution Control District (APCD) prepared a proposed final Ozone Attainment Plan and is receiving public comments through the public hearing date of October 14, 2020. Upon submittal of this Attainment Plan to EPA, the California Air Resources Board (CARB) will request that San Diego County be reclassified as a Severe Nonattainment Area for both 2008 and 2015 ozone National Ambient Air Quality Standards (NAAQS). This reclassification will likely have significant permitting implications on new and existing volatile organic compounds (VOC) and nitrogen oxides (NOx) emitting facilities within the region.


San Diego County is currently designated as a Serious and Moderate Nonattainment Area for the 2008 and 2015 ozone standards, respectively. However, the Clean Air Act (CAA) allows states to request a higher classification to extend the time to achieve the emission reductions necessary for attainment. Air modeling indicated that additional time was necessary to attain each ozone standard; therefore, CARB is requesting the higher classification, which will necessitate more stringent permitting requirements for stationary sources.


Reclassification as a severe nonattainment area will impose more restrictive permit requirements on both new and existing VOC- and NOx-emitting facilities.

  1. Existing Major Sources: The major source threshold for existing sources will be lowered from ≥100 to ≥25 tons of VOC or NOx per year. In short, additional facilities will be subject to additional monitoring and reporting requirements.
  2. New/Modified Major Sources: The major source threshold for new/modified sources will be lowered from ≥50 to ≥25 tons of VOC or NOx per year. In short, additional facilities will be subject to advanced controls and a more stringent emissions offset ratio, increasing to 1.3-to-1 from 1.2-to-1.

San Diego APCD anticipates that EPA will act on the reclassification request prior to the current attainment date (for serious nonattainment) of July 20, 2021.

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Carol Kawa, P.E.
Senior Engineer
Carol has 10 years of experience in the chemical engineering and environmental compliance field, including industry experience and environmental consulting. Carol has conducted compliance audits, maintained air quality compliance systems, performed greenhouse gas and criteria pollutant inventories, and completed regulatory and compliance reporting documentation for facilities in a variety of industries.

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