In spite of being faced with a tougher standard for clean air, Denver’s summer ozone-pollution season ended with the fewest days of high levels of the corrosive gas of the past four years, according to state data.
The Denver region recorded 20 days with ozone above the new federal health standard of 75 parts per billion, according to preliminary state data.
In 2007, there were 24 summer days above the previous standard of 85 parts per billion; in 2006, there were 34.
“This has been one of the cleanest summers we’ve had,” said Ken Lloyd, director of the Regional Air Quality Council.
“But we still have a lot of work to do.”
The ozone season starts June 1 and runs until September.
Ozone is created when volatile organic chemicals from sources such as tailpipes and gas wells, and nitrogen oxides from smokestacks, interact with heat and light.
The pollutant can impair breathing and increase the risk of death at even low levels.
The elderly, infants and people with respiratory problems are most vulnerable to ozone.
The city, six surrounding counties and parts of Weld and Larimer counties are under orders mandated by the federal Clean Air Act to come up with a plan to cut the pollutants that create ozone and smog.
The Regional Air Quality Council is set to meet Monday to review and approve that plan, which then must be approved by the state Air Pollution Control Board.
Once the board passes the plan, it then must be approved by the state legislature.
Problem is spreading out
Despite the reduction in the total number of days with one or more monitors getting ozone readings out of compliance, the new standard showed that the area’s ozone problem is widespread.
Last year, only one monitor, in Jefferson County, measured ozone exceeding the old standard of 85 parts per billion.
Data for this year is still being analyzed, but it appears that nine of 14 monitors in the region will have registered readings that were out of compliance with the new reduced ozone measurement on at least one day.
“This was expected,” said Christopher Dann, a spokesman for the state health department.
“While the new standard is tougher, the key is that the ozone problem isn’t getting worse.”
Mark Jaffe: 303-954-1912 or mjaffe@denverpost.com
