Smoke plumes associated with wildland fires are difficult to characterize due to the non-linear behavior of the variables involved. Plume chemistry is largely modeled using emission factors to represent the relative trace gas and aerosol species emitted. Plume dynamics are modeled based on assumptions of plume vertical distribution and atmospheric dispersion. In the studies presented here, near and in-source measurements of emissions from prescribed burns are used to characterize the variability of emission factors from low-intensity fires. Emissions factors were found to be in the same range as those from other, similar studies in the literature and it appears that the emission factors may be sensitive to small differences in surface conditions such as fuel moisture, surface wind speed, and the ratio of live to dead fuels. We also used two coupled fire atmosphere models, which utilize the Weather Research and Forecasting (WRF) model called WRF-Fire and WRF-Sfire, to investigate the role that atmospheric stability plays in influencing plume rise as well as developing a technique for assessing plume rise and the vertical distribution of pollutants in regional air quality models. Plume heights, as well as rate of growth of the fire, were found to be sensitive to atmospheric stability while fire rate of spread was not. The plume center-of-mass technique was demonstrated to work well but has slightly low estimates compared to observations.

Many agricultural fields are burned in the Willamette Valley of Oregon during the summer for economic reasons. A major air pollution problem results from these burnings. The purpose of this study was to develop relations between the maximum plume height and some of the independent variables affecting this plume height, such as, burn rate, wind velocity and atmospheric stability. By applying the proper relations found in this study, one could predict the maximum height a field burning plume would reach. The higher the plume rise, the lower the concentration of the plume effluents at ground level. If a relationship between the maximum plume height and the ground level concentration is known, for an accepted limit of ground concentration, the issuance of permission for the burning of a certain field could be given knowing the environmental variables. Three equations for different environmental conditions were developed through dimensional analysis. Their constants of proportionalities were obtained experimentally.