Meteorology and Air Quality Modeling of a 2009 Prescribed Burn Event

University of California at Riverside (UCR) previously completed an annual modeling study of Western Regional Air Partnership (WRAP) fire emissions for CY2002. The WRAP fire inventory developed included wildfire, agricultural fires, prescribed fires, and non-federal rangeland fires. Although the WRAP inventory represents one of the most comprehensive fire emissions inventory available, there remain very large uncertainties in fire emissions.

Results from the that study showed that (1) small fires (fewer than 100 acres in woodlands or fewer than 300 acres in grassland) can contribute significantly to visibility impairment in Class I areas; (2) wildfires are a much larger source of PM2.5 than either prescribed or agricultural burning and (3) observation data from actual fire plume heights are needed to evaluate the two plume-rise algorithms available in SMOKE.

Recently, new tools for estimating and managing local and regional air quality impacts from prescribed burns are being developed. As part of the development, a number of test burns of the southwestern and southeastern fuels were carried out in the Missoula laboratory during February 2009. A prescribed burn was also carried out at Vandenberg Air Force Base in November 2009.

Using new fuel consumption and emissions data developed in the lab and field studies, new emissions estimates are being produced for the prescribed fire at Vandenberg Air Force Base during November 2009. Meteorology fields used in emissions processing and air quality modeling will be produced with the Weather Forecasting and Research (WRF) model. Eulerian air quality model simulations will be performed and compared with an extensive network of monitored data for gas and PM2.5.

New scientific understanding related to characterizing fuel loading/combustion, emissions, the implications for air quality models, and local air quality impacts will be summarized and presented.