Garfield County’s air quality monitoring program turned up no violations of federal standards in 2013, according to an analysis of data from five collection sites located in different parts of the county over the course of last year.
Though there was a slight increase in the amount of benzene detected in the air, on average, compared to the previous two years, that and other volatile organic compounds (VOCs) remained well below safe levels, according to a preliminary air quality report presented to county commissioners on Monday.
The readings for last year were also still below average readings during 2008 and 2009, near the height of natural gas production in Garfield County.
A final report for 2013 will not be completed until June, said Cassie Archuleta, project scientist with Air Resource Specialists, which analyzes the data collected by the Garfield County Environmental Health Department.
But the preliminary report shows no violations of national ambient air quality standards in Garfield County for the year, she said.
Annual trends also indicate most VOCs, including hazardous air pollutants such as benzene, a known cancer-causing agent, “are decreasing at statistically significant measurable rates,” Archuleta said in her report.
Ozone pollution only slightly exceeded the national standard of 75 parts per billion (ppb) on a couple of days, but those numbers were not sustained and did not result in any violations, the report also indicated.
Likewise, readings for particulate matter dropped compared to recent years, and the county recorded no days in the “unhealthy” categories on the Air Quality Index.
David Ludlam, executive director for the West Slope Colorado Oil and Gas Association, said the lower readings in recent years compared to 2008-09 can be attributed to improvements in technology and innovation within the industry, though he acknowledged the slowdown in drilling activity in recent years also likely played a part.
“If I had to predict what we’ll see when activity picks back up, it’s that the efficiencies we’ve gained as an industry have made a difference,” Ludlam said.
He also praised Garfield County for providing data through its air monitoring program that goes above and beyond that done in other parts of the state.
Archuleta and county environmental health specialist Morgan Hill said it’s hard to nail down why there was a slight increase in benzene concentrations from 2012 to 2013.
“What we’re probably seeing is some stabilization in the readings,” Archuleta said of the slightly higher annual average reading for benzene of 0.58 parts per billion at the Parachute monitoring station last year, compared to an annual reading of less than 0.4 ppb in 2012.
Similar spikes in the annual average reading for benzene were also detected at the Battlement Mesa and Rifle stations, as well as at a remote station site south of Silt. All were still well within the range considered safe by the EPA.
“The results still indicate a statistically significant downward trend from 2008 to present,” Hill said.
Bob Arrington of the Grand Valley Citizens Alliance said he would be curious when the higher levels were detected, noting that the preliminary report does not include a quarterly breakdown.
He questioned whether the spike may have occurred during the Parachute plume incident in early 2013, when a faulty valve on a pipeline operated by Williams Midstream up Parachute Creek resulted in more than 10,000 gallons of hydrocarbons being leaked into the ground.
Federal and state agencies reported after the spill that concentrations of benzene had been found in the soil and in water samples in Parachute Creek, but there was no mention of air contamination as a result of the spill.
Arrington said he also still questions the effectiveness of the county air monitoring program.
“They’ve got four [stationary] monitoring stations, and none of them are really strategically located in my opinion,” he said. “I think there are handicaps to the program, and they tend to take bits and pieces of the information.”
At the same time, Arrington applauded some in the industry for working hard to capture ozone-causing pollutants and VOCs at well sites, and preventing them from escaping into the air.
“Those things make a difference,” he said.