August 5, 2003 DENVER (AP) -- Ozone is posing a new health threat to Denver residents, a year after health officials said they had stamped out smog as an air pollution problem.
Unlike the brown cloud produced by smog, ozone is a colorless, odorless gas. Air quality experts say the new problem reaches north from Denver all the way to the edge of Rocky Mountain National Park, 30 miles away.
"We were stunned by it because it has been so many years since we have seen anything like this," said Richard Long, director of regional air and radiation programs for the Environmental Protection Agency.
A monitor last month recorded the highest ozone levels since 1986. So far this summer, the city has violated new, stricter federal air quality standards 33 times.
"It is a health threat," said Dr. Sverre Vedal of National Jewish Hospital, the only medical research center in the nation devoted entirely to respiratory, allergic and immune system diseases.
"It's largely from the tail pipes," he said.
For years, the brown cloud of smog defined Denver's struggle to control air pollution.
Smog -- made up of particulates like soot, road sand or ashes -- was mostly a problem in the winter. It disappeared as the state put restrictions on wood-burning fires and aerosol sprays, and introduced oxygenated gasoline. Chemicals are now used to melt road ice and any sand used to improve traction is quickly swept up.
Last summer, federal officials said Denver was the first city in the nation to get a clean bill of health for the five federal air quality standards it once violated.
Little notice was given to Long when he warned ozone levels were deteriorating.
Ozone is made up of industrial pollution and car exhaust, and it's mostly a problem on bright sunny days when the air heats up.
Experts said it is the latest headache to emerge from Denver's population boom. Long said the area's large number of sport utility vehicles contributes to the city's steady stream of ozone alerts.
Adriana Raudzens, transportation organizer for the Rocky Mountain Chapter of the Sierra Club, said Denver is the fifth-most congested city in the nation -- and getting worse.
Vicki Patton, a senior lawyer for Environmental Defense, said state officials were hasty in declaring Denver's air pollution problem solved.
"In fact the air quality monitoring this summer demonstrates that we have a serious public health problem that puts our children, elderly and those who enjoy Colorado's great outdoors at risk," she said.
Copyright 2003 The Associated Press. All rights reserved.
