CMAQ-Daysmoke as a Smoke and Air Quality Management Technique: A Case Study of a Prescribed Burning in Georgia

Wildland fire emission is an important source for PM2.5 and ozone precursors that cause air quality degradation in the Southeast. To evaluate the air quality effects of fires, especially prescribed burning, in this region, the Southern Smoke Simulation System (SHRMC-4S) has been constructed at the USDA Forest Service Southern High-Resolution Modeling Consortium. SHRMC-4S simulates smoke transport and dispersion and the related chemical and physical processes using the Community Multiscale Air Quality (CMAQ) model coupled with Daysmoke. In this study, a simulation of prescribed burning on March 6, 2002 in Georgia with CMAQ-Daysmoke is presented to illustrate the capacity and limitations of this smoke and air quality management technique in understanding the air quality effects of wildland fires. Smoke plume rise and the vertical distribution of smoke particles are estimated using Daysmoke, which is a dynamical model to simulate movement and deposition of smoke particles injected from fires, as well as other plume rise schemes. The simulation displays a high-resolution spatial pattern and temporal variation of PM2.5 and ozone generated from the fire emissions. It is found that the specification of smoke plume rise and vertical profile is one of the major uncertainty sources in modeling the air quality effects of wildland fires. Sensitivity experiments are conducted to understand the uncertainties in the CMAQ-Daysmoke simulation.