4 The record articles

TCEQ Air Quality 101 Blog Series – Back to School Edition

Posted: October 5th, 2018

Authors: Frank D. 

TCEQ Updates: New Chairman, Modeling and Effects Review Applicability (MERA), and Effect Screening Levels (ESL)

With summer having come to a close and students heading back to the classroom, it’s an appropriate time to do some fall refreshing and reflecting.  Not surprisingly, there have been several important updates in 2018 pertaining to air quality in Texas.  For this “Roundup-Style” September installment of our Texas Commission on Environmental Quality (TCEQ) Air Quality 101 Blog Series, we provide a brief overview of 2018 updates related to: Leadership Changes at TCEQ, Modeling and Effects Review Applicability (MERA) and the Effects Screening Level (ESL) Database.

TCEQ Leadership Changes

On August 31, 2018, Governor Greg Abbott designated Jon Niermann as the new TCEQ Chairman.  In addition to the new Chairman, Governor Abbott also appointed Emily Lindley as the new Commissioner of TCEQ.  As an “internal” hire, Mr. Niermann is not anticipated to change the direction of TCEQ.  Likewise, Ms. Lindley most recently served as Chief of Staff at the U.S. Environmental Protection Agency (EPA) Region 6 office in Dallas, but previously worked for TCEQ as a Special Assistant. These appointments coincide with the retirement of former Chairman, Dr. Bryan Shaw, who served as TCEQ Chairman for almost nine years.  The recent staff changes have been updated on the TCEQ organizational chart.   ALL4 will monitor how the new leadership will address air quality and air permitting challenges in Texas.

Please note that the act of changing leadership at TCEQ could impact the timing of a final permit being issued.  For example, a final pending air quality permit could be delayed while in the TCEQ “signature chain” because the TCEQ official permit letterhead may not reflect the most recent most recent appointments.  This is a rare occurrence, but valuable knowledge to have.

Updates to TCEQ Modeling and Effects Review Applicability (MERA)

ALL4 attended the TCEQ Environmental Trade Fair back in May 2018 where TCEQ presented updates to the MERA that were finalized in March 2018.  For those that may not be familiar, the MERA is found in the TCEQ Air Permit Reviewer Reference Guide (APDG) 5874 (Version 5, Revised 3/2018), located online here.  APDG 5874 states that “if there are no state or national ambient air quality standards for a contaminant, [Project-related emissions increases are] evaluated through the TCEQ’s MERA process.  During the MERA process, the scope of air dispersion modeling and effects review is determined” (APDG 5874 pg. 1).

The MERA process consists of eight steps.  Through these steps, the health effects of a certain air containment for a project are evaluated.  A MERA evaluation must be conducted for each contaminant that exhibits an increase in emissions rate from any emissions point because of a project.  Before the March 2018 MERA Guidance was finalized, the last update occurred in July 2009.  The changes highlighted by TCEQ in the new MERA include improved ease of use and clarity, removal of infrequently used steps, revision of the multi-point equation in (the previous) Step 5.  Chemical species with no ESL are now exempt from a MERA evaluation.

Regarding the MERA process in general, I would be remiss without sharing some tips and reminders that you can implement when completing a MERA analysis yourself.  While the bullets below only summarize some tips used for tanks emissions, I found them helpful to share:

  • When calculating and modeling tank emissions do not forget to include individual ESLs for the components of the material in the tank. For example, when permitting a diesel fuel tank, evaluate the ESL for diesel fuel #2 along with the constituents (e.g., benzene, etc.) experiencing an emissions increase.
  • When calculating and modeling tank emissions, be sure to consult APDG 6250 and APDG 6419 for fixed roof and floating roof tanks emission estimation methods, respectively. These are the same guidance documents that TCEQ permit reviewers use to evaluate emissions increases from tanks.
  • If a MERA analysis is being conducted for an emissions point and a corresponding tank, remember to use the appropriate unit impact multiplier on the screening tables. For example, use the stack height for the emissions point and use the vent stack height for the corresponding tank to determine the maximum ground level concentration for each unit.
  • If an annual operating limit is being proposed, be sure to annualize ground level concentrations. For example, for an annual emissions increase, convert the tons per year (tpy) emissions increase into a pound per hour (lb/hr) emissions rate to evaluate the maximum ground level concentration.

Updates to the ESL Database

Over the past year, TCEQ has (thankfully) streamlined the ESL Database.  In previous years, TCEQ would publish ESL Databases in the form of an Excel spreadsheet.  Each successive Excel spreadsheet was periodically published online.  The problem with this revision approach was that each successive Excel spreadsheet version would need to be re-issued in its entirety to reflect changes, revisions or updates. To avoid re-publishing multiple versions of Excel spreadsheets, TCEQ transitioned the ESL Database into an online dynamic database.  What does this mean for you?  It means there are more specific search options (i.e., effective dates, CAS#’s, etc.).  It also means that more steps are required to download the ESL Database.  While the steps to download the database are easy to follow, more stages are involved.  Users now need to download the database via a text file, convert this text file into an Excel spreadsheet, finalize filtering options using a “text-to-columns” function, and then format the spreadsheet.  While this may seem tricky, it is not too complicated.  If you need any assistance walking through the steps, feel free to give me a call.

I hope you enjoyed reading the “Back-to-School” edition of our TCEQ Air Quality 101 Blog.  Don’t worry there’s no homework on your end, except if you do have questions on this blog, be sure to reach out to me using my phone number 281-937-7553 x302 or my email fdougherty@all4inc.com.  Thanks for reading.


    Sign up to receive 4 THE RECORD articles here. You'll get timely articles on current environmental, health, and safety regulatory topics as well as updates on webinars and training events.
    First Name: *
    Last Name: *
    Location: *
    Email: *