Smoke dispersion modelling based on the Fire Emission Production Simulator and the Hybrid Single Particle Lagrangian Integrated Trajectory (FEPS-HYSPLIT) model was applied to prescribed burns in the Lake Tahoe Basin (LTB) during fall 2011. This, in conjunction with measurements at sources and real-time ambient PM
monitoring around LTB, served to evaluate the prescribed burning impacts on air quality. For a given combustion efficiency, in-plume measurements suggest FEPS to underestimate PM
emission factors by up to six-fold, though FEPS agrees relatively well with laboratory combustion of dry fuels. Prescribed burns in LTB were mostly < 100 acres; time series analysis and model prediction (with 2 km or 12 km spatial resolution) suggest generally small effects on PM
exposure of local communities due to careful selection of the burn windows. In regard to a few scenarios where significant impact (≥ 2 μg/m
hourly) is predicted, the model with 2 km resolution shows smoke arrival times more consistent with ambient observations. However, uncertainties in the model predictions should be reduced further by acquiring more accurate burn records and measuring markers specific to biomass burning at the monitoring sites.
Keywords: smoke forecast, biomass burning, emission model, PM 2.5 emission factor, WRF, IMPROVE network, USA