Dive into the data

We believe the citizens of Midlothian and surrounding communities will benefit from access to all of the available air quality data, collected and summarized in one place on this website.

Holcim permit application to TCEQ

full permit request Holcim.pdf

Draft of new maximum allowable emission rates for Holcim permit

Holcim submitted an update to the permit, requesting the cap (limit) of 4,303 tons per year (TPY) of carbon monoxide be removed. If the permit is approved, both kilns could release 3,500 TPY of carbon monoxide for an increased maximum of 7,000 TPY total.

MRT-8996 Holcim (Texas) LP (CAMD).docx

Draft of air modeling for Holcim permit

CompressedAQA 021420.pdf

The air modeling document submitted in February 2020 showed that PM 2.5 would increase to within 1 point of the maximum allowed by the EPA's NAAQS regulations if the permit is approved (see below).

table of air modeling predictions.docx

Revised air modeling for Holcim Permit

Response to TCEQ 2020-05-15.pdf

The air modeling document submitted in May 2020 dropped the level of PM 2.5 emissions from 34.1 to 31.6. Of interest —former EPA advisory scientists have recommended setting the NAAQS maximum for 24-hour PM 2.5 averages somewhere between 25–30.

Current maximum allowable emission rates for Holcim


MRT-8996 Holcim (Renew).docx

Carbon emissions of petroleum coke compared to other fuels

EPA emission-factors various fuels_2014.pdf

Continuous monitoring currently done by TCEQ

The monitor is positioned at 2725 Old Fort Worth Road, Midlothian, Texas.

Data reflects pollutants emitted by all industries in this area but is affected by wind speed, wind direction and many other factors.

Data is updated hourly and is highly variable, depending on weather conditions, cement production rates, etc.

See data on individual pollutants over various dates.

Understand EPA standards for air pollutants

NOTE: The EPA-published standards for air pollutants use different units of measurement than the data provided on the TCEQ site (just makes things even more complicated).

Does our air quality currently meet EPA targets?

  • We are assessing this monthly and recording on the spreadsheet below.

    • Red shading indicates values exceeding EPA targets.

    • Yellow shading indicates values at EPA target threshold.

  • EPA regulations are based primarily on average output over time, which are being met for most pollutants, including PM 2.5.

  • However, the EPA target for "safe" PM 2.5 is exceeded at some point almost every day and has been exceeded multiple days for each month on record.

    • See Health effects for recent data on health risks of PM 2.5, even at levels below EPA targets

  • The DFW area has long been an area of "non-attainment" for ozone, meaning that we are not meeting EPA targets for ozone levels — and this has recently gotten worse, as DFW was downgraded from moderate to serious non-attainment in August 2019. TCEQ's response is to try to reduce the regulation rather than fix the problem (see link below).

TCEQ response to ozone non-attainment

TCEQ MONITOR COMPARE UPDATED.xlsx