Chemical Characterization of Prescribed Burn Emissions from a Mixed Forest in Northern Michigan

Abstract:

Prescribed burns are instrumental for wildfire hazard reduction and ecosystem restoration, and they also provide an opportunity to measure biomass burning emissions under relatively controlled conditions. In October 2017, a prescribed burn was conducted at the University of Michigan Biological Station located in Pellston, MI. Approximately 6 acres of forest, containing both deciduous and coniferous trees, were burned, and the resulting smoke was sampled with a combination of real-time trace gas and aerosol instrumentation aboard the Aerodyne Mobile Laboratory. In particular, an aerosol time-of-flight mass spectrometer (ATOFMS) and an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) measured the freshly produced smoke particles in real-time. Of the 20,145 individual particles measured by the ATOFMS, 93%, by number, were identified as biomass burning, demonstrating the major contribution from the local smoke. SP-AMS showed that submicron particles were primarily organic (93%, by mass). Periods of both flaming and smoldering fire were observed, providing an opportunity to examine aerosol chemical composition across these changing conditions. . The chemical characterization of the prescribed burn smoke compared to the fuel type and composition and burn conditions will be discussed.