Air monitor almost ready

June 20, 2009 09:59 pm

— By Janet Jacobs
Daily Sun

Navarro County’s new air monitor should be ready up and working by the end of the month — or sooner, according to a spokeswoman with the Texas Commission on Environmental Quality.
“The monitor at the airport will monitor for ozone, SO2, or sulfur dioxide, nitrous dioxide and pm 2.5 (very small particulate matter),” said Andrea Morrow with the TCEQ. “Once they get everything calibrated, it will be near real-time data available on our Web site.”
The state will use the data to determine quality of the air in the region, particularly for ozone.
Currently, 16 counties in North Texas are out of compliance for ozone pollution, albeit most are closer to the Metroplex, with its concentration of traffic and industry.
“Traditionally, we use these kinds of monitors to determine if a particular area is in compliance with these standards,” Morrow said. “We’ll use the data to determine if there are areas to be addressed.”
In March of 2008, the U.S. Environmental Protection Agency (EPA) reduced the amount of ozone an area could have, citing health concerns. Whether Navarro County will be in compliance will take some time to determine.
Under the current rules, the state and EPA use a three-year average to see if an area is within guidelines. The monitor takes readings constantly, 24-hours a day. That data is then calculated into eight-hour averages. Then, at the end of each year, the state and EPA take the fourth-highest daily 8-hour average and use that figure as the average for that year. After three years of data, then the EPA determines of an area is considered within compliance or out of attainment with the federal standard, explained Mark Sather, an environmental scientist with the EPA in Dallas.
“We look at the fourth-highest average and then do that for three years in a row,” Sather said. “Like for ozone, what we have to do is gather three years of data.”
While the other pollutants being tested in Navarro are also important, the primary concern in Texas is ozone, Sather said.
“Nitrous dioxide is an annual standard, we anticipate Navarro County meeting that. All the states meet that now,” he said. “The same is true with SO2 and participate matter. Ozone is our main pollutant of concern in Texas.”
Ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs), such as xylene, react in the atmosphere in the presence of sunlight. NOx and VOCs are called ozone precursors. Motor vehicle exhaust, industrial emissions, and chemical solvents are the major sources of these chemicals, according to an EPA fact sheet.
“And these pollutants are also helpful in looking at how ozone is created,” he said. “Nitrogen dioxide is a precursor in how ozone is formed. That’s helpful when looking at the ozone data.”
By taking the measurements and comparing to the standards, residents can see where they stand in terms of health concerns, he added.
In the past, the state and Environmental Protection Agency have relied on monitors in nearby counties to determine if Navarro is within compliance. Recently, however, the TCEQ authorized Navarro for its own monitor. The change of heart came shortly after Texas Rep. Byron Cook of Corsicana became chairman of the Environmental Regulation committee.
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Janet Jacobs may be reached via e-mail at jacobs@corsicanadailysun.com

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