You are here:
Impact of fuel type and combustion phase on the chemical composition of particulate matter emissions from wildland fires
Citation:
George, I., B. Gullett, V. Rao, AND J. Aurell. Impact of fuel type and combustion phase on the chemical composition of particulate matter emissions from wildland fires. American Association for Aerosol Research Conference, Portland, Oregon, October 14 - 18, 2019.
Impact/Purpose:
The chemical composition of wildland fire smoke is an important factor determining the impact of fires on human health and air quality. The dependence of smoke properties on the combustion conditions and the fuel type is not well known limiting our ability to accurately model emissions from fires and estimate their impact. This study combined lab and field measurements to identify the major factors that determine the chemical composition of wildland fire smoke.
Description:
EPA’s 2014 National Emission Inventory reports emissions by flaming and smoldering combustion phases. The mass fraction of each chemical constituent is derived from EPA’s SPECIATE database, which does not account for combustion phase and represents a minimal range of fuel types. Particulate matter emissions have exhibited wide variation across combustion conditions and fuel types. However, limited data exist on the variation of the chemical composition of particulate matter emissions and almost no information is available on the trace elemental composition. While these elements are emitted at low concentrations, the large amount of smoke generated by fires makes them a significant source to the atmosphere. In this work, both field and laboratory fire sampling for a range of fuels (southeastern pine, western pine, tallgrass prairie, and peat) was used to understand how fuel characteristics and combustion conditions impact particulate matter emissions. A range of combustion conditions in the field were achieved by sampling emissions near back burns, head fires, and smoldering fuels. In the laboratory, air flow, fuel structure, and fuel moisture were varied to obtain a range of flaming and smoldering conditions with the same fuel. Particulate matter emission factors were strongly correlated with modified combustion efficiency and increased over an order of magnitude for smoldering versus flaming conditions for a single fuel type (5 – 50 g/kg). The minor elemental composition (e.g., K, Cl, Zn) exhibited poor correlation with combustion conditions and appeared to be more dependent on fuel type. These results demonstrate that both the fuel type and combustion conditions govern the particulate matter emissions from wildland fires and need to be accounted for in emissions inventories. The views expressed in this abstract are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.