Biomass Burning Fuel Consumption and Emissions for Air Quality

Biomass burning emissions estimates of gas and aerosol air pollutants are used in modeling and forecasting smoke and air quality. These emissions originate from combustion of the fuels found in the landscape and vary based on the terrain, weather, fuel type, and condition of the fuelbed, including the arrangement of fuels, during the fire event. Combustion describes the flaming and smoldering burning phases of a fire that, summed over the duration of the event, equals the fuel consumed. This chapter provides a review of approaches to quantify fuel consumption from biomass burning relevant for air quality assessment. The indirect approach estimates consumption based on the difference between pre- and post-fire fuel loads within the burn area or models it by applying a burning efficiency to the pre-fire fuel load. The direct approach uses a combustion factor to translate fire radiative power (FRP) measured from thermal infrared instruments into the consumption rate; temporally integrating FRP over the duration of the fire provides fire radiative energy (FRE), which the same combustion factor translates to total consumption. Methods to map the location, strength, and composition of fire emissions, which are a function of fuel characteristics and fire environment, are provided. This chapter provides a discussion on the uncertainty of biomass burning emissions inventory products and considers new approaches for improving fuel consumption mapping.