Inland Northwest farmers may be breathing a little easier after seeing the results of a Washington State University and University of Washington study that showed no statistical increase in asthmatics’ health problems during several field burning events in 2002. Researchers from WSU’s Laboratory for Atmospheric Research, the UW School of Public Health and Community Medicine, and the Northwest Center for Particulate Air Pollution and Health presented their findings at two public meetings in June in Pullman and Spokane.

The study examined exposure levels in 33 asthmatic adults to atmospheric pollutants from field burning in the Palouse region. With the help of funding from the Environmental Protection Agency and the Washington State Department of Ecology, researchers placed particle monitors in backpacks worn by asthmatic volunteers to measure their individual exposure levels to particulate matter in the air for eight weeks during the fall 2002 field-burning season. They also placed particle monitors in volunteers’ homes. At the same time, they carefully monitored the symptoms and lung function of the volunteers.

The researchers noted that the results of the study should be viewed with caution. While it found no significant health effect from the field burning, neither did the study answer the question of why that might be. Perhaps recent burning has been more carefully controlled than in past years. Peak exposures were lower in 2002 than in the two previous years, the researchers said. For the past two burn seasons (2002, 2003), Idaho and Washington, as well as the Nez Perce and Coeur D’Alene Indian tribes, have used the Clear Sky Smoke Forecast System developed at WSU. Burn coordinators can go online and submit information on acreage that they would like to burn. The forecast system then integrates the information with weather forecasts to provide a prediction of where smoke from the burn will travel.

Another reason their study failed to detect health effects from field burning, the researchers noted, might be that the young adults with asthma who participated in the study were less susceptible to health problems than other groups, such as young children or the elderly. Or the health effects from burning wheat stubble might be different than those from bluegrass.

In any case, data from the agricultural burning study can be used by the Department of Ecology to set exposure standards for particulate matter to protect public health.