Early next year, a sophisticated air quality monitor is expected to go into operation near O.D. Wyatt High School in Fort Worth, the 11th such device deployed to measure pollutants in the Barnett Shale.The monitors, four of which were installed this year in Arlington, Mansfield and Rhome in Wise County, are part of a network of machines designed to reveal exactly what's in the air we breathe every day. Some of the chemical compounds measured can be health risks, and others can contribute to ozone formation.The recent expansion of state air monitors was announced in 2010 by the Texas Commission on Environmental Quality after prodding by legislators. The 2011 Legislature allocated millions annually to install and operate them.Since they've been in operation -- decades for measuring ozone and other urban emissions, years for measuring compounds related to natural gas production -- the data show two principal trends: Levels of chemical compounds related to natural gas development do not represent an immediate health threat and the region's ozone has been steadily improving, although not necessarily as fast as in other U.S. metro areas and certainly not enough to comply with federal standards.That's not to say that there are no problems or that the monitors are perfect. Hazardous emissions do occur.In the past three years, the Environmental Protection Agency has carried out 28 inspections of natural gas facilities in the Barnett Shale.Nine have resulted in orders to correct violations of the Clean Air Act, according to records provided by the agency to the Star-Telegram. Most cited the release of methane, the principal component in natural gas.Spot measurements by the TCEQ near natural gas facilities have also recorded emissions of compounds in excess of long-term health thresholds, leading to orders for corrective action.Those tests use summa canisters, which look something like small, shiny propane tanks and can grab an air sample in seconds or in hours.Drilling critics say they have conducted their own localized tests in response to particularly bothersome facilities or activities that don't show up on monitors.In February, some Colleyville residents said their short-term test detected a potentially harmful concentration of benzene, a carcinogen and a prime target compound of the Barnett Shale monitors. The city said tests by its consultant found some hydrocarbons, including benzene, but not at harmful concentrations.That's the kind of discrepancy that concerns drilling critics like Tim Ruggiero, who with Calvin Tillman, the former mayor of Dish, in Denton County, formed the not-for-profit company ShaleTest to provide low-cost testing to residents. Ruggiero served on the advisory board that recommended new sites for monitors. He said they "included mostly places near high schools and elementary schools, and places with higher concentrations of children or people in general."His opinion of the monitors?"I think the air monitors are more in the category of window dressing," Ruggiero said. "There's always some level of emissions," he said, even if they don't reach the threshold of representing a health threat, either long-term or short-term.Also, an area covering nine North Texas counties -- Collin, Dallas, Denton, Ellis, Kaufman, Johnson, Parker, Rockwall and Tarrant -- is already designated by the EPA as a "serious" nonattainment area for ground-level ozone, a primary ingredient in smog. The EPA added Wise County to that list, a move that has been challenged in court.In a recent study, Eduardo Olaguer of the Houston Advanced Research Center estimated that in the summer, emissions just from the big compressors powering gas pipelines could boost ozone enough to make it even harder for the area to meet EPA standards.'Most-monitored air'Mike Honeycutt, chief toxicologist at the Texas Commission on Environmental Quality, says his agency has gotten good at testing for pollutants, given the state's vast petrochemical industry along the Gulf Coast and decades of oil and gas production."There is no state that can touch the number of monitors we have," Honeycutt told the Star-Telegram in an interview. "We have four times more data than a few years ago, and we're getting more monitors out there," he said. "We have the most-monitored air in the country."The most recently installed monitors, like the four put into operation this year, are called automated gas chromatographs, or "auto GC."Elena Craft, health scientist in the Austin office of the Environmental Defense Fund, called auto GC monitors "the gold standard" of air monitoring because of their constant sampling."I would say the Barnett Shale is the best-monitored shale gas play right now, and auto GC is best practice," Craft said. Now, she said, the TCEQ should do a report on what all that data shows, and the defense fund is considering doing just that itself.Gary Rogan, a TCEQ technician who maintains one of the monitors in Fort Worth just south of Meacham Airport, told the Star-Telegram during a visit to the facility that the monitor performs two basic activities.For about 50 minutes each hour, air is captured through a snorkel on the building's roof and funneled into a collector. That sample is pumped into the heart of the unit, a gas chromatograph that can quickly analyze it for 47 compounds. This cycle continues nearly every hour, interrupted by a daily calibration check.That check, Rogan said, replaces the outside air sample with air from a canister containing known concentrations of the target compounds. The auto GC's measurements are then compared with the air's known compounds.Finally, the auto GC sends each hour's test results to the TCEQ. Within hours, they appear on a website that is tracked by agency employees and can also be viewed by anyone on the Internet. Dozens of additional monitors in North Texas measure ozone, volatile organic compounds, lead and heavy metals, but not with such specificity.Enough monitors?There are only 10 -- soon to be 11 -- auto GC monitors in the Barnett Shale, which covers more than 5,000 square miles and 18 counties, by the Texas Railroad Commission's count. Three more are planned at locations yet to be determined, but likely in Dallas, Tarrant and Johnson counties, said Robert Kent, director of environmental programs for the North Texas Commission, which was picked by TCEQ to administer the new monitors.Is that enough to provide credible data?In the view of several experts, including one pollution specialist often critical of industry, it is."If a well emits a lot, or if a lot of wells emit a little, these monitors are very well-placed to pick that up," Honeycutt said.Wilma Subra, a Louisiana-based chemist and environmental consultant, said the monitors in North Texas do what they are designed to do.But that doesn't mean they pick up every release of dangerous chemicals."They do show trends of what's going on," said Subra, who received a MacArthur Fellowship in 1999 for helping residents understand and combat environmental threats. The network is "meant to show the general condition" of air in a region, she said, and an individual monitor can be quite sensitive."It'll pick up an event at least a mile away" if the wind is blowing the right way, she said.Mark Sather, an environmental scientist with the EPA's Region 6 office in Dallas, said it's surprising how useful a relatively small number of monitors can be."There are only about 20 ozone monitors" in the Dallas-Fort Worth area, he said. "It's really good coverage, as far south as Corsicana," which is in Navarro County, not officially part of the DFW area."It's way over the minimum" needed for good data, Sather said.Those ozone measurements have generally been declining in North Texas in the past decade.That progress is attributed to stronger vehicle emission rules and pollution control requirements for power plants as well as businesses ranging from dry cleaners and service stations to big "point sources" like factories.The region's performance meeting ozone standards is based on three-year averages. The average includes each year's fourth-highest daily reading for an eight-hour period at any monitor in the region. The number, often set by the same monitor year after year, is the region's official "grade."In 2000-02, North Texas' average peak ozone was 99 parts per billion, well over the EPA's National Ambient Air Quality Standard of 85 ppb, set in 1997.By 2010, it was down to 86. But the agency had a new ozone standard of 75 ppb.Next year, the EPA is expected to ask for a standard of 70.The record heat of 2011 pushed the ozone rating higher in many areas, and North Texas' measure for 2009-11 jumped to 90 ppb. For 2010-12, not yet complete, it has averaged 87 ppb.For nearly all those three-year periods, dating to 1986-88, the highest ozone reading has occurred in either Tarrant County or Denton County, according to EPA figures. And more than half the time, the EPA's ozone monitor in Keller has held or tied for the highest reading.Ozone and natural gasSather said the agency has long noticed Keller's record of high ozone readings, which predates natural gas development in Tarrant County by close to two decades.The monitor is just east of North Beach Street between Heritage Trace Parkway and Golden Triangle Boulevard."That site is optimally downwind" from the urban area and the main sources of chemical compounds that help form ozone, given the region's prevailing southeasterly winds, he said.When a monitor was installed at Denton County Airport in the mid-1990s, Sather said, that site often recorded DFW's highest ozone readings, but Keller has again held the top spot in recent years.In making progress toward lower ozone, DFW is slower than average among all nonattainment areas.According to EPA data, DFW's ozone concentration declined 9.1 percent from 2000 to 2011, lagging the 14.9 percent average decline in the same period seen for all 47 nonattainment areas.Those include many of the nation's largest metropolitan areas.Sather said North Texas' performance might be somewhat better than it looks."With Dallas-Fort Worth, the population growth has been really high," and that means more vehicles on the road and generally more emissions, he said.But ozone standards "are all related to health," he said, and given the area's nonattainment, "there's still work to be done." The new auto GC monitors and other monitors being installed will be part of that."They'll be useful tracking the precursors of ozone, NOx [nitrogen oxides] and VOCs [volatile organic compounds]," Sather said. "We're just starting to get that detailed data for the Barnett."Jim Fuquay, 817-390-7552Twitter: @jimfuquay
Number of inspections of natural gas facilities in the Barnett Shale. Nine have resulted in orders to correct violations of the Clean Air Act.
Number of target compounds that each air monitor detects.
Amount that DFW's ozone concentration declined from 2000 to 2011.
Average amount that ozone concentration declined from 2000 to 2011 among all nonattainment areas in U.S.