AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Chemical Characterization of Organic Aerosol Emitted from Combustion of Indonesian Peat and Biomass
SRI HAPSARI BUDISULISTIORINI, Matthieu Riva, Michael Williams, Jing Chen, Masayuki Itoh, Haris Gunawan, Jason Surratt, Mikinori Kuwata, Nanyang Technological University
Abstract Number: 157 Working Group: Aerosol Chemistry
Abstract Indonesia peatland fires during the 2015 El Niño caused haze pollution over Southeast Asia region. Characterization of organic aerosol (OA) composition within biomass burning emissions is useful for source apportionment of atmospheric aerosols and evaluating environment impacts of haze pollution. Previous studies have investigated chemical composition of Indonesian peat aerosols, however, during wildfires various types of fuel are burned concurrently. We report chemical characterization of OA from biomass burning using peat, partially decomposed litters and soil, leaf, and charcoal fuels collected in Riau and Central Kalimantan provinces, Indonesia. Fuel was ignited under laboratory-controlled conditions and smoke was mixed with particle-free air. The diluted smoke was measured by a Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) for chemical composition of non-refractory submicron particulate matter (NR-PM$_1). Filter samples were simultaneously collected during combustion for identification of OA constituents at the molecular level using gas chromatography coupled to electron ionization mass spectrometry (GC/EI-MS) and ultra-performance liquid chromatography interfaced to both a diode array detector and an electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in negative ion mode (UPLC/DAD-(-)ESI-HR-Q-TOFMS). NR-PM$_1 mass concentrations from peat combustions are larger than other fuels, but all are dominated by OA, accounting for ~99% of total mass. OA mass spectra are not highly oxidized, as indicated by the predominant ion at m/z 43 (mostly C$_2H$_3O$^+) over m/z 44 (mostly CO$_2$^+). Interestingly, ratio of biomass burning marker ions, m/z 60 (mostly C$_2H$_4O$_2$^+) to m/z 44, is dependent of fuel type, suggesting differences in chemical composition. Concentrations of levoglucosan and other polyol compounds are higher in aerosols from peat combustion compared to other fuels. Moreover, identification of organosulfates might indicate multiphase chemical processes within peat and biomass burning smoke. Nitroaromatics and UPLC-DAD traces reveal the formation of brown carbon (BrC) chromophores from peat and biomass fires.