The high and low of respiratory illness.

The high and low of respiratory illness 

The haze of wood smoke hangs over the valley. Picturesque? Maybe, but some scientists have reported wood-burning stoves foul the air with tiny particulates that may cause or exacerbate outbreaks of respiratory illness (SN: 5/6/89, p.277).

Now, a study by a team at the University of Washington in Seattle adds to the evidence linking wood-stove smoke and respiratory illness. Jane Q. Koening and her colleagues analyzed air samples taken near two Seattle-area elementary schools, one located high on a ridge and another situated in a valley. The team found the air surrounding the ridge school cleaner than that sampled near the valley school. In addition, most of the particulate matter collected contained chemicals characteristic of wood smoke, Koenig says.

Next, the team gave 327 children attending the two schools lung function tests, which measure breathing ability, in September and again in December--a month when most wood stoves are stoked to fight the chily Seattle air. Koening's team found no decrease in breathing ability when they looked at test scores obtained from all 327 children. However, when the team looked at asthmatic children in their study, they found those attending school in the valley showed a 9 percent drop in their December breathing test compared to test results obtained the previous September. By contrast, asthmatic children enrolled at the ridge school showed a 2 percent increase in their breathing ability during the same time period.

Koening says an area's topography plays a central role in the development of wood-smoke-linked respiratory problems. She says the valley in her study forms a bowl that traps wood smoke and bathes schools and homes with particulates that can trigger asthma attacks in children. By contrast, the right gets fresh air blown in from Puget Sound that dilutes particulates andthus reduces respiratory illness, she adds. While living in a valley near Seattle may pose a risk for asthmatic children, other parts of the country may experience similar wood-smoke smog during the winter, Koenig cautions.