Air Permitting After the PM2.5 NAAQS Reconsideration

BY ERIC SHELANDER, AIR TEAM LEADER, WESTWARD ENVIRONMENTAL INC.

Original article published in Texas Asphalt Magazine SPRING 2023

Permitting air emissions for hot mix asphalt plants in Texas hasn’t changed much in the last 20 years, but a recent announcement from EPA is likely to change that. Every 5 years, the EPA is required to review the current National Ambient Air Quality Standards (NAAQS) to ensure they are still protective of public health and the environment, based on new data and studies. The EPA’s initial evaluation concluded that they should retain the current Particulate Matter (PM) NAAQS in December 2020, but in June 2021, EPA announced it was reconsidering the fine particle (PM2.5) NAAQS. On January 6, 2023, EPA announced its proposal to revise the current primary (health-based) annual PM2.5 standard down from its current level of 12.0 μg/m3 to 9.0-10.0 μg/m3.

EPA will take public comments on the proposed change for 60 days after it is published in the Federal Register. The final decision and exact change to the PM2.5 NAAQS won’t be announced until late 2023. Once a final decision is made by the EPA on the PM2.5 NAAQS, the Texas Commission on Environmental Quality (TCEQ) will be required to implement the revised PM2.5 NAAQS on all air permits after its effective date. While new permits that require modeling will see the effect immediately, standard permits will need to be amended which requires the TCEQ to conduct stakeholder meetings to solicit comments on proposed changes and to post public notices in newspapers as well as in the Texas Register.

The majority of hot mix asphalt plants in Texas utilize a standard permit to authorize their air emissions. The Standard Permit for Hot Mix Asphalt Plants hasn’t changed since it was issued in 2003. This change in the annual PM2.5 NAAQS will likely cause the TCEQ to amend the standard permit to show it is still protective of public health and the environment. Amending the Standard Permit for Hot Mix Asphalt Plants could lead to stricter permit requirements such as, but not limited to, smaller production limits, increased distance from the property line, and dryer baghouse specifications based on the results from TCEQ’s air dispersion modeling.

If the standard permit is amended, all new and modified standard permits must comply with the new requirements. Existing standard permit hot mix plants wouldn’t be required to meet the new requirements until the later of either their standard permit renewal date or 24 months after the effective date, as based on 30 Texas Administrative Code §116.605(d) (1). Standard permits with renewal dates within 24 months of the amendment may be renewed without having to comply with the new requirements but will eventually be required to demonstrate compliance no later than 24 months after the effective date of the amendment. When being renewed, if a hot mix plant can’t or doesn’t want to meet the new amended requirements, the permittee would be forced to apply for a New Source Review (NSR) permit.

NSR permits are custom permits that require air dispersion modeling to show that the plant’s emissions meet the NAAQS. Modeling will be more difficult for the annual PM2.5 NAAQS due to the high background concentrations found in many populated areas of Texas. The background concentration can be as high as 8-10 μg/m3 leaving little to no room for the NSR permit’s modeled emissions. Compared to NSRs under the current PM2.5 NAAQS, future NSR permits could require a combination of lower annual production, increased distance from property lines, better dryer baghouse efficiencies, or increased dryer stack height. Hot mix plants currently authorized by an NSR permit would only have to show compliance with the new PM2.5 NAAQS if new modeling is triggered by an amendment or alteration.

The most likely change from the EPA is for the annual PM2.5 NAAQS to be reduced to 9.0-10.0 μg/m3, but the EPA is asking for comments on further reductions of the annual PM2.5 to 8.0 μg/m3 and the 24-hour standard to be reduced from 35 μg/m3 to as low as 25 μg/m3. Even if the more conservative PM2.5 standards are not put in place now, it shows the range of changes the EPA is likely to take in the future. The EPA’s final decision later this year will likely have a big impact on future air permits in Texas, making it more difficult to find sites for plants and take longer to permit. It will be important for members of TxAPA and Westward to monitor and provide feedback on any proposed changes by the TCEQ, so that we can prepare for the future.

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