A modeling analysis has been conducted by the USDA Forest Service, Region 6, PNW Research Station, and Earth Tech, to estimate the impacts of wildfire and prescribed fire on air concentrations of particulate matter and visibility in the Interior Columbia River Basin. The predicted concentrations for the prescribed burn scenarios were substantially lower than wildfire scenarios for several reasons:

1. The acreages burned with prescribed fires are generally lower;
2. Dispersion conditions during the spring and fall prescribed burn episodes are better;
3. Emissions per acre from prescribed burns are less than wildfires because they are burned at higher fuel moisture content; and
4. There are larger numbers and a larger spatial distribution of prescribed fires resulting in better dilution of the fire emissions.