The recent hot weather has caused ozone levels to rise throughout Boulder County, surpassing National Ambient Air Quality Standards set by the U.S. Environmental Protection Agency and leading to health concerns for this weekend.
On Friday, when temperatures pushed into the high 80s, the Colorado Department of Public Health and Environment and the Regional Air Quality Council issued an ozone action day alert for the Front Range Urban Corridor from El Paso County north to Larimer and Weld counties, including the Denver-Boulder area, Colorado Springs, Fort Collins, and Greeley.
Although ozone concentrations remained in the good to moderate range on Friday, on Saturday ozone levels are expected to reach concentrations that are unhealthy for sensitive groups such as the elderly, children and those with respiratory problems.
The Colorado Department of Health and Environment suggested those sensitive to high ozone levels should reduce prolonged or heavy outdoor exertion between 2 and 8 p.m. on Saturday.
The highest concentrations of ozone will likely be confined to the northwestern portions of the Denver Metro area and northward along the foothills, including western Boulder, Longmont, and western Fort Collins.
“The hot and sunny weather over the past week, and due to come the rest of this week, creates a perfect environment for ozone formation,” said Cindy Copeland, Boulder County Public Health air quality specialist. “In addition to weather, ozone levels also rise when impacted by other pollutants, such as local emissions from vehicles and oil and gas production.”
The Boulder air quality monitor located at the Boulder Reservoir recorded the highest level of ground-level ozone in the Denver Metro/North Front Range area on July 10 last year, reporting 89 parts per billion..
So far in 2019, the Boulder monitoring site has measured a concentration of 72 parts per billion, still higher than the 70 parts per billion that is considered safe.
Though the monitoring station shows signs of diminishing ozone levels, Collin Tomb, the air quality team lead at Boulder County Public Health, said that doesn’t mean the situation is improving as ozone levels can be affected by many variables — including the weather.
“The bottom line is it’s still unhealthy,” she said. “But we have hope that some of the measures we are taking to better control, hydrocarbons and nitrogen oxide emissions, improve vehicle emission standards and place greater regulatory controls on oil and gas operations will help.”
On Aug. 8, the EPA announced that the Denver Metro/North Front Range ozone nonattainment area did not meet the 2008 National Ambient Air Quality Standard leading to a proposal to reclassify the region from a moderate to a serious non-attainment area.
The EPA will hold a public hearing at the Agency’s regional office in Denver on Sept. 6 to determine what actions need to be taken for the area to attain the 2008 ozone standard by July 20, 2021.
As part of the State Implementation Plan, those actions will likely include even stricter regulations such as a lower threshold for permitting large sources of emissions.
“EPA is proposing this action as required by the Clean Air Act,” said EPA Regional Administrator Gregory Sopkin. “We will continue to support the State as they revise plans and implement new measures that will reduce ozone-forming emissions across the many sources contributing to air quality impairment along Colorado’s Front Range.”
Residents can check ozone levels and learn how to be part of the solution at BoulderCountyAir.org,
