The San Antonio metro area has come under closer review regarding the ground-level NAAQS ozone standard.
In 2015, the EPA lowered the federal National Ambient Air Quality Standard (NAAQS) for ground-level ozone from 0.075 ppm to 0.070 ppm (EPA, 2015 National Ambient Air Quality Standards (NAAQS) for Ozone, United States Environmental Protection Agency, (Oct 26, 2015), https://www.gpo.gov/fdsys/pkg/FR-2015-10-26/pdf/2015-26594.pdf). In particular, Bexar County in the San Antonio area is currently under review by the EPA to determine a new NAAQS designation for ground-level ozone.
NAAQS are standards set by the EPA that reflect concentrations of pollutants generally thought to be safe. NAAQS have been established for six pollutants (EPA, NAAQS Table, United States Environmental Protection Agency (Dec 20, 2016), https://www.epa.gov/criteria-air-pollutants/naaqs-table):
- Ground-level ozone (O3) (0.070 ppm as of 2015, lowered from 0.075 ppm);
- Particulate matter (PM-2.5, PM-10, etc.);
- Carbon monoxide (CO);
- Lead (Pb);
- Sulfur dioxide (SO2); and
- Nitrogen dioxide (NO2)
State agencies are tasked with enforcing these standards through the vehicle of State Implementation Plans (SIPs), which subject to EPA oversight. State agencies can impose more stringent (but not more lenient) standards of their own. (42 USC § 7407-7408)
Using ambient air monitoring data, each county (or sometimes, portion of a county) in the United States is evaluated against the thresholds set for each NAAQS, and designated either “Attainment,” “Nonattainment,” or “Unclassifiable.” When a county’s ambient air concentration is found to be below NAAQS thresholds for a given pollutant, the county is classified as “Attainment” for that pollutant. If a county is designated as “Unclassifiable,” there is insufficient information in the area to determine the county’s attainment status. When classified as “Nonattainment,” a county’s ambient air concentration exceeds NAAQS thresholds. (EPA, Required SIP Elements by Nonattainment Classification, United States Environmental Protection Agency, (Feb 26, 2017), https://www.epa.gov/ozone-pollution/required-sip-elements-nonattainment-classification.)
New Ozone NAAQS
Ground-level ozone is not a directly emitted pollutant but is formed through reactions of other “ozone precursor” constituents such as nitrogen oxides (NOx) or volatile organic compounds (VOCs), and often transported into more rural areas from urban areas (EPA, Ozone Pollution, United States Environment Protection Agency, https://www.epa.gov/ozone-pollution). For the 2015 ozone NAAQS, nonattainment is classified in several levels of severity, depending on the degree of the exceedance:
- Marginal (3-year plan: >= 0.070 ppm < 0.081 ppm)
- Moderate (6-year plan: >= 0.081 ppm < 0.093 ppm)
- Serious (10-year plan: >= 0.093 ppm < 0.105 ppm)
- Severe (15 year plan: >= 0.105 ppm, < 0.111 ppm; 17 year plan: >= 0.111 ppm <0.163 ppm)
- Extreme (20-year plan: >= 0.163 ppm)
(EPA, Required SIP Elements by Nonattainment Classification, United States Environmental Protection Agency, (Feb 26, 2017), https://www.epa.gov/ozone-pollution/required-sip-elements-nonattainment-classification.)
For the ozone NAAQS, 8-hour average concentrations are used when assessing compliance. The annual fourth-highest daily maximum 8-hour concentration is then taken from each year and averaged over three years. This 3-year rolling average of the fourth-highest daily maximum is compared to the ozone standard of 0.070 parts per million. (EPA, NAAQS Table, United States Environmental Protection Agency (Dec 20, 2016), https://www.epa.gov/criteria-air-pollutants/naaqs-table.)
Industry-level compliance measures and practices are significantly affected because the state must develop a State Implementation Plan (SIP), based on requirements set forth in the Clean Air Act, to demonstrate how the state will reach attainment standards within the timeframe given through new regulation. For marginal nonattainment, the state must reach attainment standards within three years; for moderate, the state has six years to achieve attainment. As a general rule, nonattainment counties must prioritize emissions reduction over economic impact (thus LAER, Lowest Achievable Emission Rate, is usually required). (EPA, Required SIP Elements by Nonattainment Classification, United States Environmental Protection Agency, (Feb 26, 2017), https://www.epa.gov/ozone-pollution/required-sip-elements-nonattainment-classification)
San Antonio: Attainment or Nonattainment?
The San Antonio metro area - consisting of Atascosa, Bandera, Bexar, Comal, Guadalupe, Kendall, Medina, and Wilson counties - has come under closer review regarding the ground-level ozone standard. EPA is currently evaluating whether Bexar County should be designated nonattainment for the 2015 ozone NAAQS. If the county is designated nonattainment, companies may need to comply with additional reporting requirements, additional regulatory requirements, and more stringent permitting requirements. Facilities not currently reporting emission inventories could be required to report their yearly actual emissions by default, and any new sources would have to comply with stricter standards to offset ozone concentrations.
After the ozone NAAQS was lowered in 2015, all states were required to recommend attainment classifications for each county. After receiving recommendations, the EPA makes the final designations (42 USC § 7407). In September 2016, the Texas Commission on Environmental Quality (TCEQ) initially recommended only Bexar County in the San Antonio metro area to be designated as nonattainment. The state recommended that the remaining surrounding seven counties be designated “unclassifiable” as there was insufficient data specific to each county to make a designation (Governor Abbot, Greg, Re: State Designation Recommendations for the 2015 National Ambient Air Quality Standards (NAAQS), United States Environmental Protection Agency, (Sept 30, 2016), https://www.epa.gov/sites/production/files/2016-11/documents/tx-rec.pdf). Federal courts mandated that the EPA issue a decision by July 17, 2018 for Bexar County (Isdal, Anne, Texas: San Antonio: Intended Area Designations for the 2015 Ozone National Ambient Air Quality Standards (NAAQS) Technical Support Document (TSD), United States Environmental Protection Agency, (March 19, 2018), https://www.epa.gov/sites/production/files/2018-03/documents/san_antonio_naaqs_epa_ltr_3_19_2019.pdf).
Below is a timeline of the correspondence between the TCEQ and the EPA (click on the image at the bottom of the post to see full size):
Effects of a Nonattainment Designation
If a nonattainment designation is placed on the San Antonio metro area, the classification is likely to be "marginal" or "moderate." Requirements associated with a “marginal” nonattainment designation apply to both marginal and moderate designations. Emissions inventories will certainly become an integrated part of any SIP. (Dr. Nivin, Steve, Dr. Roman, Belinda, & Dr. Turner, David, Potential Cost of Nonattainment in the San Antonio Metropolitan Area, (Feb 21, 2017), https://www.aacog.com/DocumentCenter/View/41742/Contract_582-16-60180_Deliverable_5-2_Cost_of_Nonattainment_Analysis_Rev0)
SIPs for new 2015 nonattainment states/counties are due "Late 2019" according to the EPA rubric (EPA, State Implementation Plan (SIP) Checklist Guide, United States Environmental Protection Agency, (Jan 4, 2017), https://www.epa.gov/ozone-pollution/ozone-naaqs-timelines). The SIP would have to demonstrate how Bexar County will reach attainment concentration levels of ozone within the timeframe given for its nonattainment classification. Currently, according to the TCEQ’s projections, Bexar County stands to achieve attainment with the 2015 ozone standard by 2020 without further regulatory actions. (Governor Abbot, Greg, Re: Ozone Designations for Rockwall County, Liberty County, and Waller County, EPA-HQ-OAR-2017-0548, United States Environmental Protection Agency, (Feb 28, 2018), https://www.epa.gov/sites/production/files/2018-03/documents/18-000-5538.pdf)
Nevertheless, if a nonattainment designation is issued a revised SIP (approved by the EPA) would be put in place to achieve attainment with the 2015 ozone NAAQS. If a nonattainment designation is given the area can, at best, be designated “attainment/maintenance” after achieving the ozone standard. Another SIP submission or “maintenance plan” could be required to demonstrate how the area will remain in compliance with the standard. (42 USC §7407-7408)
For the San Antonio area, the TCEQ uses data from several regulatory monitoring sites. Currently the 3-year average for the ambient concentration of ozone from 2015-present averages to approximately 0.07 ppm (TCEQ, Compliance with Eight-Hour Ozone Standard, Texas Commission on Environmental Quality, (May 15, 2018), https://www.tceq.texas.gov/cgi-bin/compliance/monops/8hr_attainment.pl). The EPA has until mid-July to determine San Antonio’s attainment status as more monitoring data comes in. According to the EPA, numbers from previous years including 2014-2016 data averaged out to a higher concentration of approximately 0.08 ppm. (Isdal, Anne, Texas: San Antonio: Intended Area Designations for the 2015 Ozone National Ambient Air Quality Standards (NAAQS) Technical Support Document (TSD), United States Environmental Protection Agency, (March 19, 2018), https://www.epa.gov/sites/production/files/2018-03/documents/san_antonio_naaqs_epa_ltr_3_19_2019.pdf)
Emission sources in Bexar County are currently required to submit emission inventories following a formal request from the TCEQ if the source emissions exceed thresholds of 25 tpy NOx and 10 tpy VOC. If the area is designated nonattainment for ozone, emission inventories would be required for all sources exceeding thresholds. A specific request for the inventory is not necessary. The reporting thresholds would remain the same for actual emissions of 25 tons per year (tpy) NOx and 10 tpy VOC (30 TAC §101.10).
Other pollutants that can trigger reporting requirements include criteria pollutants (i.e., those for which a NAAQS has been issued), and hazardous air pollutants (HAPs). (30 TAC §101.10) Facilities that do not currently submit emission inventories could be required to submit their actual emissions inventories yearly. The TCEQ no longer accepts paper emission inventories: all must be submitted electronically through the state of Texas Environmental Electronic Reporting System (STEERS), either directly through the STEERS form or as a delta file. (TCEQ, Frequently Asked Questions [Emissions Inventories], Texas Commission on Environmental Quality, (October 2016), https://www.tceq.texas.gov/assets/public/implementation/air/ie/pseiforms/faqs.pdf)
Further compliance practices include Nonattainment New Source Review (NNSR) permitting. Typical sources that trigger a need for an NNSR permit include glycol dehydrators, stationary engines, and loading operations. For areas designated marginal or moderate nonattainment for ozone, the NNSR applicability thresholds for major sources are 100 tpy for NOx and VOC. NNSR permits require the implementation of lowest achievable emission rate (LAER), emission offsets, and the opportunity for public comment on the proposed permit. (EPA, Nonattainment NSR Basic Information, United States Environmental Protection Agency, (Nov 29, 2016), https://www.epa.gov/nsr/nonattainment-nsr-basic-information)
As of April 2018, the seven San Antonio metro counties are classified as “Attainment/Unclassifiable,” but the attainment status of Bexar County remains under review. According to EPA correspondence, either designation could be likely. In December 2017, the EPA stated clearly that it will designate any counties in violation of the standard as “nonattainment,” but communicated in March 2018 the possibility of “Unclassifiable” being considered for Bexar County (Coleman, Samuel, EPA’s Response to Texas, United States Environmental Protection Agency, (Dec 22, 2017), https://www.epa.gov/ozone-designations/ozone-designations-2015-standards-texas-state-recommendations-and-epa-response). Companies may want to prepare for the prospect of required emission inventories, new source reviews, and tighter compliance practices in the San Antonio metro area.
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