AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Laboratory and Field Measurements of Physical and Optical Properties of Open Biomass Burning and Cook Stove Aerosols
CHRISTIAN CARRICO, Oluwatobi Oke, Sonia Kreidenweis, Paul DeMott, Ezra Levin, Gavin McMeeking, Chelsea Stockwell, Robert J. Yokelson, New Mexico Institute of Mining and Technology
Abstract Number: 494 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Biomass smoke from wild land fires and cook stove emissions are both growing air quality concerns of global significance. Laboratory experiments in 2012 (Fire Lab At Missoula Experiment, FLAME IV) focused on the effects of fuel type, stove type, and modified combustion efficiency (MCE) in real-time in-situ measurements of both cook stove and open burning emissions. Additionally, we examined these same properties using ambient measurements during several western US smoke events including the High Park Fire in Colorado. Measurement of the particle light scattering and absorption coefficients employed a photoacoustic extinctiometer (PAX, DMT, Inc., Model 870nm). Using a fast mobility particle sizer (FMPS, TSI, Inc., Model 3091), we also measured the 1-sec particle size distribution over particle diameters from 5.6 to 560 nm. Excess concentrations of CO and CO2, which quantify the MCE, were measured in parallel with an open-path Fourier transform infrared spectrometer (OP-FTIR). We observed light absorbing aerosols, often associated with a dominant flaming phase, were emitted in a soot mode with diameters of approximately 20 nm. Interestingly, some highly absorbing aerosols also featured much larger modes with diameters approaching 100 nm. Overall, measurements demonstrated dynamic shifts in particle sizing and accompanying shifts in optical properties during combustion dynamics. Flaming vs. smoldering combustion, as quantified by the MCE, strongly influenced both particle size distribution and optical properties, while fuels combusted were of less importance to size distributions. Such aerosol physical properties, and their relation to combustion characteristics, determine the resulting aerosol impacts on human health, visibility, and significance to climate.