See the latest EHS federal and state regulatory updates due to COVID-19

When working on a new construction permit (New Source Review [NSR] permit) or NSR permit amendment, it is important to ask whether or not the project will require refined atmospheric dispersion modeling or effects review (i.e., Health Effects Evaluation). If the project emits contaminants that do not have state or federal ambient air quality standards, the Texas Commission on Environmental Quality (TCEQ) Modeling and Effects Review Applicability (MERA) guidance document can be used to determine the required scope of the modeling and effects review for each compound required to be included in the evaluation.[1]

The MERA guidance document is used on a compound-by-compound basis and is a tool to evaluate human health and welfare impacts associated with emissions from the project. As a result, the MERA guidance requires comparison to the Effects Screening Level (ESL) for each compound under consideration.

Historically, ESL values have been obtained from TCEQ's Toxicology Division (TD) website; however, the TCEQ will no longer publish the ESL List Excel spreadsheet online. The ESL values can now be obtained through the Texas Air Monitoring Information System (TAMIS).

Based on information provided by the TCEQ Air Dispersion Modeling Team (ADMT), the three-month transition/beta release phase ended on March 1, 2017 and future NSR permits and amendments will need to obtain ESL values from the TAMIS. The transition to the TAMIS will allow applicants to obtain the current ESL values immediately as opposed to having to wait for the TCEQ to post updated ESL Lists on a quarterly or annual basis (improve data entry and retrieval).

Once the ESL values are downloaded from TAMIS, the applicant will need to note the date of retrieval. The TCEQ will honor the ESL values based on the date the ESL values were obtained when the applicant submits the NSR permit or amendment. As the NSR permit or amendment undergoes its technical review, the TCEQ will validate the ESL values based on the download date and determine whether or not the ESL values have subsequently changed after the submittal date. If any ESL value decreased, the TCEQ TD will determine whether or not the impacts are acceptable and notify the applicant if the impacts are unsatisfactory.

For more information on how to download and analyze the new ESL Reports, you can download the TCEQ Toxicology Database:  How to Access and Retrieve Information user guide posted on April 4, 2017. Additionally, if you need assistance determining whether or not refined atmospheric dispersion modeling or effects review is required for your permitting project, or have any questions regarding Trinity's modeling capabilities, please contact Ashley Demko at (361) 883-1668, Ext. 102.


[1]  TCEQ, Modeling and Effects Review Applicability:  How to Determine the Scope of Modeling and Effects Review for Air Permits, APDG 5874, July 2009.