Dirty air spurs warnings even for the healthy

Todd Hartman, Rocky Mountain News

Published February 13, 2007 at midnight

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Dirty air over the metro area could linger into today, prolonging a rare stretch of pollution that has prompted warnings even for healthy people.

Air monitors have recorded unprecedented levels of tiny particles in the air since last Wednesday. A monitor in downtown Denver recorded pollution levels in excess of the federal health standard for five straight days - and Monday could make six when the data are compiled.

"This is really a rare occurrence," said Mike Silverstein, a regulator at the state health department's air pollution division. He said the area hasn't experienced levels of this type of pollution over such a long period since 1997, when monitoring began.

"We are praying for winds," he said.

The tiny particles in the air are produced mainly by combustion - wood-burning stoves, cars and trucks, and industrial emissions. They are microscopic in size: less than 1/30th the width of a human hair. A weather phenomenon called a temperature inversion has trapped the dirty air over the metro area, allowing the pollution to accumulate.

The gritty air, combined with foggy conditions and the stubbornly stagnant air mass, have made for hazy, lung-irritating days, particularly for people with respiratory problems. However, regulators have urged even healthy people to limit their time outdoors.

For years in the 1980s and 1990s, the region struggled with larger, or "coarse," particulates tied to street sanding and industrial emissions and other sources. But this marks the first time the region has seen such long-running spikes in tiny, or "fine" particles.

An environmental group this weekend expressed alarm over the high pollution, and said regulators should crack down on coal-burning utilities and contributors to pollution.

"With the health of our children and our communities at stake, this is simply inexcusable," said Jeremy Nichols, director of Rocky Mountain Clean Air Action. "The state needs to wake up, smell the bad air, and move quickly to finally adopt the safeguards we need for our health."

Regulators note, however, that the Denver area hasn't formally violated standards set by the Environmental Protection Agency, which worries most about long-term exposure to the fine particles.

The EPA calculates violations of tiny particle standards by looking at three years of data. And prior to this unusual spike, the region hasn't seen the sustained high levels that might trigger federal intervention, state health officials said.

Air scare

35 micrograms per cubic meter is the federal health standard for tiny particles in the air, averaged over a 24-hour period.

74 micrograms per cubic meter is the highest level recorded at any air quality monitor. It was measured at the 21st and Broadway monitor on Friday.

4 air monitors across the metro area - from Chatfield Reservoir north to Boulder - have recorded levels of tiny particles above federal limits since Wednesday.

hartmant@RockyMountainNews.com or 303-954-5048

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