AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Performance of High Resolution Time-of-Flight Aerosol Mass Spectrometer during Chemical Characterization of Particle Emissions from Controlled Biomass Burning
POORNIMA DIXIT, Seyedehsan Hosseini, Ping Tang, David R. Cocker III, Li Qi, University of California, Riverside
Abstract Number: 552 Working Group: Remote and Regional Atmospheric Aerosols
Abstract A total of forty-nine burns were conducted at the Missoula Fire Sciences Lab consisting of nine fuel types; i.e., chamise scrub oak, ceanothus, maritime chaparral, coastal sage scrub, California sage brush, Manzanita, oak savanna, oak woodland and masticated mesquite. This paper focuses on assessing the performance of the high resolution Time-of-flight Aerosol Mass Spectrometer in determining the chemical characterization of fine particle emissions collected for flaming, mixed and smoldering phases of biomass burning. Levoglucosan, an anhydrous sugar evolves during wood burns, which was used as a tracer to evaluate PM emissions from the burns. The AMS reported an interference ion in the UMR m/z 73, a fragment normally attributed to levoglucosan. The sum of ions C$_(2)H$_(4)O$_(2) $^+ (m/z 60.021) and C$_(3)H$_(5)O$_(2) $^+ (m/z 73.029) performed better in estimating the contribution of levoglucosan on an online basis. For our offline analysis, we used a Gas chromatography mass spectrometer to quantify levoglucosan collected on quartz filters during all of the wood burns. Both the online and offline were compared using the amount of levoglucosan quantified, to understand the performance of the HR-TOF-AMS. The online and the offline co-relation for the amount of levoglucosan showed a factor of 0.67, which was considered a good estimate. Additionally the polycyclic aromatic hydrocarbons and organic carbon content from both the online and offline measurements were compared to get a more distinctive understanding of the performance of HR-AMS-TOF. Nitrates, sulfates & Ammonia evolving from the different phases of real time wood burns were instantaneously measured by the HR-TOF-AMS. Those measured values provided a deeper knowledge of emissions from real time biomass burning. The results of the offline and online comparisons showed an agreement, thus strengthening the measurement abilities of the HR-TOF-AMS for instantaneous real-time analyses.
Keywords: HR-TOF-AMS, levoglucosan, offline GC-MS