42 3.4 Organic Compounds Supplementary Information (“Elements” sheet in the 36 dataset). In other experiments, Othman and Latif analyzed eight elements (Cd, Cu, Zn, Fe, Al, Pb, Cr and Ni) in PM10 from laboratory chamber combustion of Malaysian peat soil, and indicated that the dominant element was found to be Zn, followed by Al and Fe. Das et al.84 analyzed 14 elements (Mg, Al, Ca, V, Cr, Fe, Co, Ni, Cu, Zn, Se, Sr, Sn and Pb) in PM from Indonesian peat burning by controlled laboratory experiment. They showed the emission ratios (mass fraction in PM) of Ca (516 ± 247 μg g-PM-1) to be highest, followed by those of crustal elements Fe (189 ± 117 μg g-PM-1) and Al (34 ± 18 μg g-PM-1). Major elemental concentrations and mass fractions in PM are shown in Figs.S3 and S4 in the Supplementary Information. According to the dataset, the Al/Pb ratios of PM2.5 collected during IPF-derived haze periods at receptor sites and at a fire site were mostly much lower (3−50) than the Al/Pb ratios of TSP118 during haze (4,721) and non-haze (669) periods, and the ratios of the fresh laboratory-generated particles Indonesian and Malaysian peat combustion ranged from 11 to 98 in the dataset. The discrepancy in the Al/Pb ratios between the above TSP samples and fine particles in the dataset can be explained: Because of uplifting and suspension of surface soil particles during wildfires (wind erosion), mineral dust is mainly confined in a coarse mode, while biomass burning-derived mineral particles are smaller (in a fine mode) with different average bulk compositions (Jahn et al., 2021). Atmospheric deposition is an important nutrient source for freshwater and aquatic ecosystems, and excessive loading of nutrients accelerates eutrophication (Swackhamer et al., 2004). The chemical composition of nutrients (total N and P, organic N and P, and ions) in TSP (and rainwater) was determined during IPF-derived hazy and non-hazy days to quantify their dry (and wet) deposition fluxes to the coastal water of Singapore30. The average concentrations of nutrients (N and P species) increased by a factor of three to eight on hazy days when compared with non-hazy days (total-N: 13 µg m-3, total-P: 0.5 µg m-3) 30. This finding reflects a remarkable elevation of total PM2.5 mass concentration on hazy days (24 to 113 µg m-3) because there is little difference in their PM2.5 mass percentages between hazy and non-hazy days. Both of the estimated mean dry atmospheric fluxes of total N and P during the hazy days were about tenfold higher compared to the non-hazy days. In this section, the target organic compounds are analyzed by widely-used offline (conventional) analysis methods such as gas chromatography-mass spectrometry (GC-MS). The results analyzed by online aerosol mass spectrometer (AMS) are presented in Section 4. There are several reports of organic compounds aside from PAHs in from Y. FUJII and S. TOHNO PM during IPF-induced haze events in Indonesia28, 89, Malaysia2, 20, 21, 50, 56, 64, 76, 88, 105 and Singapore7, 16, 25, 27, 29, 40, 43, 65, 89, 107. The target compounds, however, have differed considerably between researchers. More data on levoglucosan (LG) are available compared to other compounds. LG is a typical cellulose pyrolysis product and has been widely used as a useful biomass burning marker (Simoneit et al., 1999). In Indonesia, Tham et al.89 conducted sources (approximately 2 km downwind from IPF sites) in Jambi, Sumatra Island, and a high LG concentration (840 ± 700 ng m-3) in PM2.5 was observed. In Bangi, Malaysia, Fujii et al.56 showed significant differences in LG concentrations in TSP between haze (strong haze: 1,078 ng m-3, light haze: 352 ± 22.9 ng m-3) and non-haze (207 ± 39.3 ng m-3) samples. Similar results have also been obtained at other locations in Malaysia such as Kuala Lumpur20, 88 and Petaling Jaya50. In Singapore, Engling et al.43 reported that the LG concentrations in TSP during haze events (1150.9 ± 917.2 ng m-3) were much higher than those during the non-haze periods (15.3 ± 5.7 ng m-3). Similar results were also obtained in Singapore29, 40, 89, 107. Aside from LG, Fujii et al.50 quantified many organic compounds derived from biomass burning and n-alkanes through annual observations of PM2.5 in Petaling Jaya, Malaysia, including IPF-induced haze periods. They then showed significant increases in the concentrations of mannosan (MN), galactosan (GL), vanillin (V), vanillic acid (VA), p-hydroxybenzoic acid and n-alkanes with carbon numbers from 23 (C23) to 33 (C33) for PM2.5 affected site. For p-hydroxybenzoic acid, through intensive observations of TSP in Bangi, Malaysia, Fujii et al.56 reported even during light-haze acid concentrations were significantly higher than those during non-haze periods, showing it to be a more useful indicator for IPFs compared to LG, MN and GL. Regarding n-alkanes, through comparison of molecular distributions of particulate n-alkanes obtained IPFs and vehicle-related emission sources, Fujii et al.49 showed particularly that C27, C28 and C29 mass fractions in particulate IPF-source samples collected in Riau, Sumatra, Indonesia were 4.57– 26.6 those of other emissions. Jayarathne et al.77 also agreed that n-alkanes could be used to distinguish IPF emissions from other types of biomass burning or other combustion sources. times higher The EF of LG was reported as 4.21–2,500 mg kg-fuel-1 based on laboratory chamber combustion experiments of Indonesian26 or Malaysian peat90, 98. The EFs of other organic compounds such as MN26, 90, GL26, lignin pyrolysis products26, 98 and n-alkanes26, 98 are also provided in the Supplementary Information (“Organic Compounds” sheet in the dataset). Chow et al.83 and Watson et al.90, respectively, reported the species abundances in PM2.5 mass and EFs of several organic PM2.5 sampling at the by IPFs p-hydroxybenzoic periods, the total n-alkanes (C20-C33) of than near IPF receptor from

元のページ  ../index.html#48