Garfield County air study finds low levels of pollutants
December 18, 2007
GLENWOOD SPRINGS ” A two-year study into air quality in Garfield County found no violations of federal air quality standards and that the levels of air pollutants in the area were “generally very low.”
But a preliminary health risk assessment provided with the study said that some oil and gas sites in the area appear “to present significantly higher cancer risk than urban and rural” areas. The assessment also said there were potential impacts from benzene, a known carcinogen, across oil and gas development areas of the county.
The Garfield County Ambient Air Quality Study, which has cost about $325,000, was commissioned to evaluate air quality in the county because of the burgeoning local oil and gas industry and growth in the area.
The study investigated air quality and meteorological conditions at dozens of sites across the county from June 2005 to May 2007. It found that PM10 and volatile organic compounds (VOCs) levels are similar to or lower than levels in other areas in Colorado.
PM10 is a health hazard consisting of fine particulate matter under 10 millionths of a meter (10 microns) in size. VOCs are pollutants produced by gas development, automobile engines and other causes.
Jim Rada, the county’s environmental health manager, presented results of the study during a Garfield County commissioners meeting Monday.
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The preliminary health risk assessment, utilizing data from Garfield County collected for the study, showed there were few noncancer risks from pollution in the area, Rada said during his presentation.
But cancer risk estimates in the area are at or slightly above the high-end of EPA’s acceptable risk level, Rada said.
“We are kind of at the top edge of cancer risks in some locations,” said Rada, stressing the need for continued air monitoring in the county.
Cancer risks and noncancer hazards in rural areas in general also appeared to be “significantly lower than those across oil and gas development areas” and urban areas, according to the assessment.
Rada pointed to the risk assessment in calling for continued efforts to monitor air quality in the county. There are plans to reduce the number of monitoring locations in 2008, but to continue to track PM10 levels in Rifle and Parachute, along with VOC levels in Parachute, Rifle and other locations.
During the course of the study, stations monitored PM10 levels at seven locations for 24 hours every third day. There were no violations of federal air quality standards and the “estimated health risks are minimal,” the report said.
“In terms of particulate matter 10 microns or less, we are in pretty good shape across Garfield County,” Rada said.
Concentrations of PM10 were generally highest in western Garfield County and in Rifle and Parachute, the study found. Driving of vehicles and other human activities are likely the largest contributors to PM10 levels in the area.
Monitoring of VOCs occurred at 14 locations for 24 hours once per month, and at other areas based on odor complaints. Compounds that had the highest concentrations were acetone and the BTEX group, which include benzene, toluene, ethylbenzene and xylenes.
The report said concentrations of the compounds were “occasionally higher in rural oil and gas development areas than urban areas,” but that the compounds were detected more often in urban areas.
“In general, VOC levels detected were extremely low for all routine samples,” the report said.
Donna Gray, community relations representative for Williams Production RMT, the county’s largest natural gas producer, listened to the presentation of the air quality study and said the company was happy the report came out.
“It gives us a picture, albeit an incomplete picture, of what is happening in the county,” said Gray, who is going to give her copy of the study to air quality specialists with the company. “It is a good thing the county is doing this.”