title: 2013 Southeast Asian smoke haze: fractionation of particulate-bound elements and associated health risk.
abstract: Recurring biomass burning-induced smoke haze is a serious regional air pollution problem in Southeast Asia (SEA). The June 2013 haze episode was one of the worst air pollution events in SEA. Size segregated particulate samples (2.5-1.0 μm; 1.0-0.5 μm; 0.5- 0.2 μm; and <0.2 μm) were collected during the June 2013 haze episode. PM2.5 concentrations were elevated (up to 329 μg/m(3)) during the haze episode, compared to those during the nonhaze period (11-21 μg/m(3)). Chemical fractionation of particulate-bound trace elements (B, Ca, K, Fe, Al, Ni, Zn, Mg, Se, Cu, Cr, As, Mn, Pb, Co, and Cd) was done using sequential extraction procedures. There was a 10-fold increase in the concentration of K, an inorganic tracer of biomass burning. A major fraction (>60%) of the elements was present in oxidizable and residual fractions while the bioavailable (exchangeable) fraction accounted for up to 20% for most of the elements except K and Mn. Deposition of inhaled potentially toxic trace elements in various regions of the human respiratory system was estimated using a Multiple-Path Particle Dosimetry model. The particle depositions in the respiratory system tend to be more severe during hazy days than those during nonhazy days. A prolonged exposure to finer particles can thus cause adverse health outcomes during hazy days. Health risk estimates revealed that the excessive lifetime carcinogenic risk to individuals exposed to biomass burning-impacted aerosols (18 ± 1 × 10(-6)) increased significantly (P < 0.05) compared to those who exposed to urban air (12 ± 2 × 10(-6)).
authors.affiliation: Department of Civil and Environmental Engineering, National University of Singapore (NUS) , 1 Engineering Drive 2, E1A-07-03, 117576 Singapore.
authors.forename: Raghu
authors.initials: R
authors.lastname: Betha
authors.forename: Sailesh N
authors.initials: SN
authors.lastname: Behera
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Balasubramanian
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification*; D000397:Air Pollution / Q000032:analysis*; D001210:Asia, Southeastern; D005591:Chemical Fractionation; D006262:Health; D006801:Humans; D006813:Humidity; D008970:Molecular Weight; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D012137:Respiratory System / Q000378:metabolism; D018570:Risk Assessment; D012307:Risk Factors; D012906:Smoke / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D012906:Smoke