Data Show Texas Ozone Levels Are Not Driven by Fracking

Texas Barnett and Smog Chart

The rapidly-growing Dallas-Fort Worth (DFW) metropolitan area in North Texas has struggled for years to reach attainment with federal clean air requirements for ozone, a problem that many environmental activists have blamed on hydraulic fracturing (“fracking”). But a closer review of publicly available data suggests there is no credible link between ozone nonattainment and development of the Barnett Shale, over which much of the Metroplex sits.

Ground-level ozone, also known as smog, is formed when volatile organic compounds (VOCs) and nitrogen oxides (NOx) interact with sunlight. An array of industrial activities emit NOx and VOCs, although many regulators have identified tailpipe emissions from cars and trucks as the main cause of smog.

Critics of fracking have alleged for years that oil and natural gas activities emit more ozone precursors than all of the cars and trucks on the road in DFW. Downwinders at Risk, a local environmental group, told Fort Worth Weekly in 2011 that “the gas industry now emits more smog-forming volatile organic compounds, or VOCs, than all the cars and trucks in D/FW combined.” As part of its “Don’t Frack with NY” advocacy campaign, the environmental group Riverkeeper wrote in 2012 that Barnett Shale activities “emit more smog-causing volatile organic compounds (VOCs) than all cars, trucks, buses, and other mobile sources in the area combined.” The claim was also reprinted in the New York Times in 2011 with little scrutiny.

The talking point traces its origin to a 2009 study authored by Al Armendariz, then a professor at Southern Methodist University, who hypothesized that “the oil and gas sector likely has greater [smog-forming] emissions than motor vehicles” in the five Metroplex counties with “significant oil and gas production.” Armendariz later became the head of EPA’s Region 6 office in Dallas, although he was forced to resign after a video surfaced of him explaining his strategy to use his EPA authority to “crucify” the energy industry. He now works for the anti-drilling Sierra Club.

Nonetheless, data from the Texas Commission on Environmental Quality (TCEQ) – which operates the most comprehensive air monitoring network in the area – show that vehicular emissions actually far exceed those emanating from Barnett Shale activities.

Shortly after the Armendariz study was released, TCEQ reviewed its findings, concluding that they were “based on incomparable data and exaggerate the relative significance of the emissions from the Barnett Shale with regard to ozone formation in the Dallas-Fort Worth (DFW) ozone nonattainment area.” TCEQ added that the study “over-simplifies the chemistry that underlies ozone formation in the DFW area,” because it ascribed equal weight to NOx and VOCs in the formation of smog. As TCEQ observed, “the response to NOx reductions is much stronger than the response to VOC emissions,” and “for NOx emissions, on-road mobile sources are the largest single category.”

A few years later, TCEQ took another look at emissions in the Barnett Shale region, and once again concluded that ozone precursors from mobile sources exceeded those from oil and natural gas production activities. According to TCEQ, “The estimated mobile source NOx emissions are approximately 15 times higher than the oil and gas NOx emission.” TCEQ further noted that VOC emissions from oil and gas were “half of the mobile source VOC emissions.”



On TCEQ’s “Ozone History” page for the Dallas-Fort Worth region, TCEQ notes that the “majority of NOx emissions in the DFW area come from on-road mobile sources (cars and trucks) and non-road mobile sources (such as construction equipment, aircraft, and locomotives)” — not oil and natural gas production.

In short, the paper’s conclusion that “the oil and gas sector likely has greater emissions than motor vehicles” was not only incorrect, but also rested on false assumptions about how ozone actually forms. That may also explain how ozone in the Dallas-Fort Worth region could decline as Barnett Shale production grew.

South Texas Smog

Critics have similarly linked ozone levels in San Antonio to the booming Eagle Ford Shale, located about 50 miles south of the city. Like the Metroplex, San Antonio has experienced rapid growth in recent years. In just a two year span, from 2010 to 2012, more than 90,000 people moved to the south Texas metropolis, helping to make it the fourth-fastest growing major city nationwide. Experts say the rapid growth means the physical size of San Antonio could double by 2040.

Increased population means additional cars and trucks on the road, along with other economic development to support new jobs. These activities all contribute to ozone formation, but environmentalists and other activist groups have focused blame on emissions from the Eagle Ford, where daily oil production has grown by over 6,000 percent since just 2010, according to data from the Texas Railroad Commission.

For example, Downwinders at Risk wrote last year that San Antonio’s public officials “deny the link between the Eagle Ford and smog in their city.”  InsideClimate News has claimed that ozone levels “began rising in 2007, with the steepest increase seen around 2011, just as the Eagle Ford boom exploded.” ICN also alleges that the Eagle Ford is an “important factor” in the region’s ozone (notably, the natural resources director for the Alamo Area Council of Governments said ICN’s claim was based on preliminary data that are “really not worth using”). In 2013, a report by Earthworks — which recently pledged a “war on fracking” —  alleged that oil and natural gas companies operating in the Eagle Ford “are allowed to release hundreds of tons of air pollutants on an annual basis,” including ozone precursors such as VOCs and NOx. A representative from the Environmental Defense Fund told the Texas Tribune: “We know that emissions from oil and gas drilling operations are contributing to increases in ozone concentrations,” including in San Antonio.

But the most comprehensive data set on regional emissions suggests that environmental groups are overstating the degree to which Eagle Ford operations contribute to San Antonio’s ozone problem.

According to a report from the Alamo Area Council of Governments (AACOG), VOC emissions from cars and trucks in the San Antonio-New Braunfels metropolitan area were more than ten times what emanated from Eagle Ford activities in 2012. That same year, automobiles emitted approximately 20 times more NOx than Eagle Ford operations. By 2018, emissions from automobiles are projected to decline significantly, but VOCs and NOx from the Eagle Ford will only account for about three percent of the region’s total emissions.

As the San Antonio Express-News reported in 2013, drilling-related emissions are largely in rural counties, and “the total air pollution produced in Bexar County alone could easily match” what’s emitted from the Eagle Ford, according to AACOG.

Activists Tell EPA to Crackdown

Last week, the U.S. Environmental Protection Agency held two public hearings on its proposal to reduce the National Ambient Air Quality Standard (NAAQS) for ozone from 75 parts per billion (ppb) to between 65 and 70 ppb. Environmental groups flooded the hearings with individuals calling for a stricter standard — 60 ppb — than what even the EPA claims would be cost-effective. An Energy In Depth analysis found that EPA inflated the net benefits of its proposed ozone rule by as much as 3,100 percent over what the Agency had determined for the same standard just three years earlier.

Many of the environmentalists testified that oil and natural gas production is a major contributor to smog in Texas. Zac Trahan, program director at Texas Campaign for the Environment, blamed “the fracking boom” for ozone nonattainment in Dallas-Fort Worth. Luke Metzger with Environment Texas told EPA that oil and natural gas production is a “major source of air pollution in Texas,” adding that drilling activity in the Eagle Ford is “putting San Antonio at risk of nonattainment.”

Based upon the data, however, the environmentalists’ claim that “fracking” is pushing major Texas cities into nonattainment is without merit.

  • Jim Schermbeck
    Posted at 22:44h, 04 February Reply

    Nice try. Except that of course, the information about VOCs that you cite from is totally misleading. On page ES-1 of the TCEQ 2011 DFW SIP, ON ROAD MOBILE accounts for 80 tons per day of VOCs in 2012, while Oil and Gas sources accounts for 114 tons per day. Only when you combine all ON ROAD and NON ROAD vehicles – two separate categories in every SIP every submitted and which are never combined unless it’s convenient for the industry – do you get a larger number, just barely, of 123 tons per day for ALL vehicles vs the 114 tpd from Oil and Gas. In August the TCEQ presented information to the Council of Governments for its 2015 DFW SIP that showed a total of 55 tpd of VOCs from ON-ROAD mobile vs 58 tpd of VOCS from Oil and Gas by 2018 . In its final summary, submitted in January, the TCEQ has “readjusted” those numbers. ON ROAD mobile accounts for 55 tpd while Oil and Gas accounts for 50 – the second single industrial largest source of VOCs in 2018. DFW ozone levels stopped declining in 2009, as your chart here points out, and even rose in 2011 – corresponding to the rise of gas production within the DFW non-attainment area – not just the Shale play itself. Every other source of emissions had gone down by 2009 – except gas. DFW air quality progress was stagnated precisely because of the emissions from the gas industry. The TCEQ demonstrated this fact itself in an August presentation to the Council of Governments when it decreased its forecast for 2018 emissions for O&G pollution based on RRC data and tied it directly to a decrease in the ozone levels of air quality monitors, including the one in Denton that’s driving the entire regions “design value.” No amount of obfuscation, by the industry or state government can mask the impact of the industry’s large volumes of smog-forming pollution on regional air quality.

    • Steve Everley, Energy In Depth
      Posted at 22:53h, 04 February Reply

      Thanks for reading Jim. We couldn’t help but notice your insistence on VOCs, which — as the post notes — the TCEQ has identified as having a smaller impact on ozone than NOx. So in terms of “obfuscation,” it’s important to note that your comment is focusing on the wrong indicator. With that said, if you have information on NOx that you’d like to share here, we’d be happy to publish it.

      Thank you also for confirming that the latest data show oil and gas activities contribute fewer VOCs than on-road mobile sources, contrary to what Downwinders and other environmental activists have claimed.

      As for your claim about ozone levels rising in 2011 in correspondence with the increase in shale gas production, that’s frankly a very weak response. Are we to ignore the years of opposite trajectories — ozone values declining, shale gas production increasing — because there was one anomaly in the trend? Remember also that in 2011, Dallas broke the record for most 100-degree days in a year. Since ozone formation requires certain weather conditions as well (i.e. sunlight), it’s easy to see how 2011 could show a deviation from previous declines in ozone values.

      Again, thanks for taking the time to read our research.

      • Jim Schermbeck
        Posted at 14:30h, 06 February Reply

        Steve, you should really stick to stuff you know something about. First, the nature of what’s causing ozone in DFW is changing, from primarily NOx to more VOCs – something even the TCEQ folks admit with their latest modeling. This is why when they, at the last minute, decreased their O&G emission estimates for the 2018 SIP based on 2013 RRC data, the Denton and other monitors’ ozone levels fell as well. If there wasn’t a causal link between the two, there would be no response from the monitors in the modeling. And the staff admitted that. Whether that decease in estimated future emissions was appropriate or not is another question. The point is that TCEQ itself established a clear relationship between O&G pollution and DFW ozone levels. Then there’s the UNT study that shows monitors in the Fracking Region of DFW have higher ozone readings and more exceedences of the 75 ppb std than monitors in the Non-Fracking regions of DFW. The claims your industry makes that there’s absolutely no connection between O&G pollution and ozone levels defy credibility given the volumes of both NOx and VOCs produced – you still release more smog-forming pollution than all the cement plants and local power plants combined, sources we know impact the ozone levels in DFW. So please explain why the same kind of pollution in greater amounts from the O&G industry wouldn’t have an impact? Because you sprinkle fairy dust on yours as it goes out the compressor stacks? The fact that, for the first time since the late Oughts , the TCEQ is estimating that the O&G industry will emit slightly less VOC pollution than all the cars and trucks on the road in 2018 , is, I suppose, reason for celebration, but this estimate is based on market and technical assumptions that may or may not exist in real life – and BTW, rests on assumptions about lower Barnett Shale production over the next four years with which your own spokespeople disagree. Kind of a dilemma from y’all’s POV – either you agree that the Shale is being exhausted faster than you’ve admitted to Wall Street, or you’re causing more air pollution than you want to admit to EPA. Finally, after coming down over a number of years in fits and starts , ozone levels in DFW began stagnating in 2008 – not 2011. 2011 was the first year severe drought conditions were felt. It won’t be the last. But the trend was started before that year and continued until this last summer’s wetter and cooler weather gave us a break. Combine this five year trend of stagnation with the UNT results that show the Fracking Region monitors separating themselves out from the rest of the region beginning in 2008, and you have some pretty convincing circumstantial evidence pointing to the one source of pollution that wasn’t decreasing, but actually increasing in volume – again according to the TCEQ numbers. The Commission really wants to help you guys out, it’s true, but when they have to submit hard data to the EPA, it gets much harder to hide the truth. You should really make it to more of those regional air quality meetings.

        • Steve Everley, Energy In Depth
          Posted at 14:45h, 06 February Reply

          Thanks Jim.

          I haven’t found any instance of Energy In Depth claiming “absolutely no connection” between ozone formation and oil and gas activity. As noted in this post, drilling and its related processes do result in emissions (none of the graphs show 0% for oil and gas activity). But those emissions, as indicated by the data, are dwarfed by other sources. It would be far more helpful to this discussion if you would avoid straw man arguments.

          I noticed you also found a way to work in the Wall Street/ “bubble” talking point (populism, whether real or manufactured, is indeed a powerful source of activism). But the latest research shows that the Barnett is going to be quite productive for many more years to come.

          Even that estimate presumes little-to-no additional innovation, which was also the reason why people were saying just ten years ago that the United States would have to import increasing supplies of natural gas. As it turns out, American ingenuity is far more powerful than scripted lines predicated upon the discredited theory of Peak Oil. Demand for cheap energy drives innovation, be it in fossil fuel technologies or renewables — a point on which I hope we can both agree.

          Finally, just so our readers know, the UNT study you cited had some important shortcomings, which we highlighted here:

          Thanks again, Jim. It was a nice try!

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  • Kim Feil
    Posted at 16:59h, 06 February Reply

    ewe…ewe…ewe…Mr Kotter….. I have some information on fracking NOX!!!
    Lets compare how GM needs 1,479 yrs to = 10 yrs of NOX from Barnett Shale JUST with the use Diesel Drilling Rigs.

    The TCEQ emissions inventory Phase 1 and 2 did not include preproduction emissions such as drilling, fracking and flowback….go figure. Arlington’s major gas producer, Chesapeake, presented a NOMAC (contracted driller) presentation at the 2012 AADE Technical Symposium on how much money and emissions they could save using electricity during the drilling phase. FINALLY I can verify one of the PRE-PRODUCTION emissions figures.

    I will concentrate on the Volatile Organic Compounds (VOC) and Nitrogen Of oXide/dioxide (NOX) figures that have eluded me over the last seven years that I’ve been studying urban drilling.

    The Nomac presentation touted the electric drilling rig to eliminate emissions per well as follows…

    63 tons of CO2 per well (4.2 tons of CO2 per rig per day x ave 15 days to drill each well) plus

    4.6 tons of NOX per well


    .2 tons of VOC per well

    = 67.8 tons per well (of which 93% is CO2 which is bad for Climate Change).

    Multiply 67.8 tons x about 18,000 Barnett Shale gas wells estimated at the end of 2013 thus far, and we have added about 1.2 million tons of pollution from diesel emissions just during the drilling phase.

    The Barnett Shale breakdown of these 1.2 million tons is….

    1,134,000 tons CO2

    82,800 tons NOX (big time ozone reactor)

    3,600 tons VOC’s

  • Kim Feil
    Posted at 17:02h, 06 February Reply

    GM as in General Motors and their emissions that I get PIR’s on just so we can compare industry to industry…..oh and that doesn’t include their ON-site gas well emissions…they don’t claim those. Happy Entertainment District breathing in Arlington GAsland/Ozone hell Texas.

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