 |
NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
 |
Emissions Associated with Forest, Grassland,and Agricultural Burning during the Texas Air Quality Study
Anil Katamreddy, Victoria Junquera, David Allen*
The University of Texas at Austin
*Corresponding author
An inventory of emissions of particulate matter (PM2.5), nitrogen oxides (NOX), non-methane hydrocarbons (NMHC), and carbon dioxide (CO2) from outdoor fires was performed for the period of August 1 to September 30, 2000. The domain over which fire emissions were estimated was centered on the Houston/Galveston-Beaumont/Port Arthur (HGBPA) region in Texas. Outdoor fires have been traditionally overlooked as emission sources in regional photochemical modeling, but this study has shown that fire emissions are important on an episodic basis, and that their magnitude has a strong seasonal dependence. Information on fire location and burned acreage was gathered from state and federal agencies. Fuel loadings (in tons of fuel/acre) and emission factors (in pounds of pollutant emitted/ton of fuel) were based on land use data specific for the state of Texas and emission factors from literature. Wildfires were the main source of emissions during the study period; other outdoor fires, such as agricultural, slash and prescribed burns were found to contribute relatively little to emissions because these types of burns are carried in the winter rather than in the summer months. Emissions exhibited considerable variability during the study period and were highest from August 31 to September 6. During the days of highest fire activity, September 4 and 6, the estimated emissions were 3700, 260, 330, and 50 short tons of CO, NMHC, PM2.5, and NOX, respectively. Emissions of CO and NMHC during days of high fire activity exceeded emissions from light duty gasoline vehicles in the urban areas of southeast Texas. Emissions from fires were compared with PM2.5 concentrations in the HGBPA Subdomain measured using Tapered Element Oscillating Microbalances (TEOMs). The observational data coincide qualitatively with the predictions in this study in that the maximum TEOM PM2.5 concentrations occurred on September 4 and 6.