10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Comprehensive Assessment of Carbonaceous PM2.5 in Malaysia during Haze Events Influenced by Indonesia Peatland Fire and Non-Haze Period
KURITA HIROKI, Fujii Yusuke, Tohno Susumu, Saito Nozomi, Kamiya Yuta, Takayuki Kameda, Regina Hitzenberger, Haller Theresa, Ikeda Kazuhiro, Sakai Nobumitsu, Sulong Nor Azura, Mohd Talib Latif, Ohura Takeshi, Kyoto University
Abstract Number: 488 Working Group: Carbonaceous Aerosol
Abstract Biomass burning (BB) is one of the major sources of PM2.5 in Southeast Asia. Especially, haze from peatland fire in Indonesia frequently causes serious environmental problems such as human health impact, visibility impairment and regional climate change in ASEAN countries during dry season. Carbonaceous components are the dominant species of BB aerosols and their comprehensive characterization is indispensable to assess their effects on environment or conduct effective source apportionment. In this study, twenty four-hour PM2.5 filter samples were obtained by annual sampling in Kuala Lumpur, Malaysia (sampling site: 3° 8′ 20.4′′ N, 101° 41′ 12.6′′ E, 56 m above sea level) from June 2015 through May 2016 with a total of 139 samples. Detailed information of sampling site in this study has been provided in the previous report (Sulong et al., Sci. Total Environ., 601-602, 556-570, 2017). The samples were subjected to chemical analysis of elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), carbon content of humic-like substances (HULIS-C), polycyclic aromatic hydrocarbons (PAHs) and their derivatives, other biomass pyrolysis-derived compounds, and components of biogenic secondary organic aerosols (SOA). EC and OC were analyzed by a thermal-optical reflectance method with IMPROVE_A protocol. Black carbon (BC) and brown carbon (BrC) were also determined by an integrating sphere method (see Wonaschütz et al., Environ. Sci. Technol., 43, 1141-1146, 2009).
PM2.5 mass concentrations ranged from 7.4 to 241 μg m-3 with an annual average of 38.2 μg m-3. OC was the dominant component of PM2.5 and the concentrations varied from 1.3 to 40 μg m-3. EC concentrations were in the range of 0.3 to 6.1 μg m-3, while BC concentrations were from 0.22 to 2.4 μg m-3. There was significant discrepancy between EC and BC concentrations of the most samples collected in the peatland fire season (August – October), however, EC concentrations agreed well with those of BC during non-fire periods (June, July, and November – May). BC concentrations was virtually constant of around 2 μg m-3 for the samples whose EC concentrations were higher than 3 μg m-3, or concentrations of levoglucosan, a typical BB marker were higher than 0.5 μg m-3. This result suggests that higher concentrations of BB components have influence on the thermogram of the EC/OC analysis and contribute to the positive potential bias in EC determination resulting from the slipping of residual OC into the He/O2-mode and its potential evolution after the split point by maximizing the evolution and/or pyrolysis of OC at high temperature in the He-mode (Cavalli, F. et al., Atmos. Meas. Tech., 3, 79-89, 2010). Effect of HULIS-C is also discussed. We have quantified 20 PAHs, 35 nitro-PAHs (NPAHs), 20 oxygenated PAHs (OPAHs) and 20 chlorinated PAHs (ClPAHs) in PM2.5. Annual average total concentrations of PAHs, NPAHs, OPAHs and ClPAHs were 1.37, 0.70, 1.19 and 0.037 ng m-3, respectively. Total concentrations of each PAHs showed remarkable increase for haze samples (PM2.5 concentration is larger than 100 μg m-3) compared with non-haze samples (PM2.5 concentration is less than or equal to 30 μg m-3). Regarding biogenic SOA tracers, β-caryophyllinic acid (β-caryophyllene ozonolysis product) concentrations of haze samples were much higher than those of non-haze samples.