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AACOG keeping â??watchful eye' on ozone monitoring question

Greg Harman

Right this instant, the ozone, or smog, levels in Bexar County are pretty good (right), but when EPA tightens the definition for what qualifies as clean air next year, putting the San Antonio region into near-certain non-compliance, reps from the Alamo Area Council of Government will have their eyes glued to the air monitors scattered across the county. For good reason.

San Antonio has been skating the line on the current regs, as it is. And though considered state-of-the-art, the devices used to measure ozone in the area sometimes erroneously report levels up to seven percent higher or lower than they actually are. While there are safeguards built in to help catch such lapses in accuracy, Dean Danos, deputy director of AACOG, is hoping the federal government will either improve the monitors or compensate the state for the increased staff hours that will be needed to oversee the ozone sniffers.

“From a statistical point of view, why is there a seven-percent error? Why can't they get the error rate lower?” Danos said Friday. “From a subjective point of view, we are close `to being in non-attainment with federal air quality guidelines`, and every time that there's a close issue, we have to ask the question, â??Well, what was the error rate?'”

How has the Texas Commission on Environmental Quality, which runs the monitoring program, responded to local questions about monitoring errors? “We've been squawking so loud the last few years they've been very responsive,” Danos told the Current. “They've been very responsive to San Antonio.”

Peter Bella, natural resources director for AACOG, said the process of checking and adjusting the ozone data at the TCEQ is a rigorous one. “When there is a difference of plus or minus seven percent accuracy in their readings they can adjust that data up or down,” Bella said. “They flag that data, they go out into the field, they check whether or not it's an instrument error â?¦ If it's an adjustment factor they can make, they can adjust the data for accuracy.”

However, with new regs coming down the pike it's important to get the numbers as accurate as possible, he said. “As the threshold lowers and becomes more stringent, every little bit counts. We have to be sure. Because non-attainment is black and white,” Bella said. “It's critical to ask questions. It's critical to be critical. â?¦ We're keeping a watchful eye on our systems, making sure we have the best accuracies we can get with the equipment we have.”

Attempts to reach the EPA for comment today were not successful.

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