This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute.

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In a story about oil fires set in trenches around Baghdad, a BBC News Online reporter recently quoted a British environmental chemist talking about the health affects of the smoke.

“Being in Baghdad just now must be like living in a bus garage, with all the engines running at full throttle,” said Ian Colbeck of the University of Essex.

An Alaskan scientist has studied the impact of oil fires on a grander scale, after Iraqi soldiers set fire to more than 600 oil wells as they retreated from Kuwait in February 1991. Iraqi soldiers fighting the 2003 war had ignited fewer than 10 oil wells as of April 2, 2003.

Cathy Cahill is a University of Alaska Fairbanks Geophysical Institute assistant professor of chemistry and atmospheric science who wrote her master’s thesis on the Kuwait oil fires. Scientists expected smoke from the 1991 fires to have worldwide impact, such as the spread of respiratory illnesses and a “nuclear winter,” during which the smoke would block sunlight all over the globe. That did not happen.

In the end, all that nightmarish smoke had little affect on the planet, Cahill said. The oil smoke did not reach the stratosphere, an area from about 12 to 30 miles above ground where wind currents would have ferried the smoke and particulates around the globe. The smoke dissipation showed Earth’s remarkable ability to clean itself.

“Most of it got swept out over the Indian Ocean and rained out during the monsoon season,” Cahill said.

In 1991, Cahill was a graduate student at the University of Washington. To write her thesis, she used data collected by scientists who flew a C-131A aircraft through the smoke plumes in Kuwait after the war. The researchers captured smoke and other solid particles from the fire in plastic bags mounted within the plane. She found that the oil smoke consisted of soot, organic carbon, salt, soil, sulfate, and trace metals.

Other researchers found that the Kuwait fires consumed the equivalent of 4.6 million barrels of oil and gas each day, and though the smoke did not affect the global community, the local effects were dramatic. Those working to cap the oil wells were coated with oil that rained from the plumes, oil and soot coated the desert, and the ground temperatures below the smoke plume cooled by about 5 degrees Celsius.

Cahill found that the foul black air over Kuwait in 1991 contained less junk than the average air over some of the world’s most polluted cities.

“The concentrations we were dealing with in Kuwait were high, but they were less than in Beijing at times,” she said.

Cahill found that air samples from the smoke plumes over Kuwait in 1991 contained as much as 1113 micrograms of particles per cubic meter of a whitish plume from burning natural gas and brine, and as little as 50 micrograms per cubic meter of an oily black plume. In studies of air quality, Mexico City registered a maximum 24-hour concentration of 542 micrograms of particles per cubic meter of air in 1997, and Beijing averaged 364 micrograms per cubic meter of air for the entire year in 1996. An ongoing study at Denali National Park shows an average yearly concentration of 1.4 micrograms per cubic meter of air.

Dust is probably a greater airborne irritant than oil smoke during the 2003 Iraq war, Cahill said. Windstorms whip up enough dust particles to blot out the sun at times, and many of those particles are smaller than 2.5 microns, the size at which particles enter the lungs.

“You hear a lot of reporters coughing on TV,” she said. “They’re not used to breathing in particulates.”

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