Three air-monitoring sites in the Baton Rouge area recordedozone concentrations that exceeded the Environmental ProtectionAgency standard, according to a Sept. 29 Louisiana Department ofEnvironmental Quality press release.
Jim Hazlett, a DEQ senior environmental scientist, saidair-monitoring sites in the Capital area, LSU and the town ofCarville, La. recorded the exceedance for more than one hour, whichviolates the one-hour standard mandated by the EPA.
The Capital area exceedence resulted from an apparent release of13 butadiene, a highly reactive organic compound, and caused anarrow plume of high ozone. Hazlett said the compound, which isused in certain manufacturing processes, decomposes in the air andis considered air toxic.
The DEQ Technical Review Team still is trying to determine wherethe 13 butadiene source originated, Hazlett said. They will beconducting an investigation at different industries around theCapital area.
Industries responsible for ozone increases could be in troublefor these exceedances, depending on how the chemical was released,Hazlett said.
Hazlett said it is unclear whether industries causing the ozoneexceedances will receive legal penalties because the EPA may revokethe one-hour standard in favor of an eight-hour standard.
Shih Hsu, a professor of meteorology at the University, said theeight-hour standard is more realistic because people usually areexposed to the outside environment for eight hours.
Hazlett said if the one-hour standard remains, industriescausing ozone exceedances will receive certain sanctions andpenalty fees.
The Sept. 29 Capital area exceedance is not related to LSU andCarville, a town about 15 miles south of Baton Rouge along theMississippi River, Hazlett said.
At LSU, monitors recorded elevated amounts of hydrocarbons andsignificant amounts of volatile organic compounds and nitrogenoxides, which react to sunlight and warm temperatures to createozone, Hazlett said. Wind transported these amounts from the westside of the Mississippi River in West Baton Rouge Parish and acrossthe LSU monitor.
Hazlett said the elevated volatile organic compounds combinedwith oxide and nitrogen from Interstate 10 to form these high ozonelevels.
The same plume of ozone affected the Carville monitor, Hazlettsaid.
Although the LSU site only has exceeded the one-hour standardonce this year, this is LSU’s fifth exceedence over a three-yearperiod, which violates the DEQ’s law mandating each site to exceedthe ozone standard no more than three times during a three-yearperiod.
To more accurately track ozone areas, the DEQ funds theUniversity’s “Upper-Air Sounding” program, which launches weatherballoons to measure the physics of the atmosphere on days with highozone levels, Hsu said.
Hsu said New Orleans has a large population and refineries, butit is situated on Lake Ponchartrain, which circulates the ozoneaway from the city. Though Lake Maurepas is close to Baton Rouge,it is too small to effectively circulate wind in the city.
Hsu said the balloons carry a package of instruments thatmeasure air temperature, atmospheric pressure, humidity, wind speedand direction every 10 feet until the balloon reaches an altitudeof 45,000 feet. Researchers launch balloons four times per dayduring ozone alert days, at 6 a.m., 10 a.m., 2 p.m. and 6 p.m, with2 p.m. being the height of ozone levels.
A radar tracks the location of the balloon, and “sniffer”monitors alert Hsu and other researchers when the balloon is in anarea that exceeds the ozone level standard mandated by the EPA.
Hsu said LSU’s monitor is located near the parking lot of KirbySmith Hall, and the exhaust from cars elevates the ozone levels forthat area.
“Many people park there, and the station should be moved,” Hsusaid. “It is not very fair.”
Rodney Mallett, communications director for DEQ, said ozone isformed by more than one element. While car exhaust does add toozone formation, data shows exhaust alone has little influence onmonitor readings.
“There were 300,000 cars stopped on Interstates 10 and 12 duringHurricane Ivan,” Mallett said. “No monitors registered anyexceedances.”