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Author: search.filters.author.Junyapoon, SuwanneeSubject: search.filters.subject.Size distribution

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    Size distribution, characterization and risk assessment of particle-bound polycyclic aromatic hydrocarbons during haze periods in Phayao Province, northern Thailand
    (2017-11-01)
    Pooltawee, Jaturaporn
    ;
    Pimpunchat, Busayamas
    ;
    Junyapoon, Suwannee
    This study aims to investigate the concentrations and distributions of particulate matters and particle-bound polycyclic aromatic hydrocarbons (p-PAHs) in different inhalable fractions during haze periods in Phayao Province, northern Thailand and identify their possible emission sources through the characteristic ratios of selected PAHs, then determine an estimate of the potential lung cancer risk. The particulate samples were collected during haze periods between February 18 and April 8, 2014 and non-haze period from June 17 to 22, 2014 using an eight-stage cascade impactor. Each filter sample was weighed, ultrasonically extracted with acetonitrile, and then analyzed by SIM-GC-MS to identify 16 PAHs. The experimental results show that the concentrations of ultrafine (d<inf>ae</inf> < 0.4 μm), fine (0.4 μm < d<inf>ae</inf> < 2.1 μm), and coarse (d<inf>ae</inf> > 2.1 μm) particles during haze periods were in the range of 14.98–26.52 μg m<sup>−3</sup>, 62.57–101.52 μg m<sup>−3</sup>, and 55.27–89.68 μg m<sup>−3</sup>, respectively; whereas, their concentrations of 16 PAHs were in the range of 7.82–36.06 ng m<sup>−3</sup>, 26.66–61.89 ng m<sup>−3</sup>, and 9.35–30.93 ng m<sup>−3</sup>, respectively. The p-PAH distribution profiles during the haze periods were bimodal in coarse and accumulation modes, which are closely related to their particle size distributions. The characteristic ratios of BaP/BgP and INP/(BgP+InP) adsorbed on ultrafine and fine particles were 0.81–0.88 and 0.38–0.86 and 0.54–0.57 and 0.44–0.52, respectively. The values of B[a]P<inf>eq</inf> observed during haze periods varied from 9.57 to 29.05 ng m<sup>−3</sup>. Estimated lifetime cancer risks during haze periods ranged from 8.324 to 25.27 additional cases per 10,000 people exposed, which is about 10 times higher than that during non-haze period.
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    Size distribution of atmospheric particulates and particulate-bound polycyclic aromatic hydrocarbons and characteristics of PAHs during haze period in Lampang Province, Northern Thailand
    (2013-06-01)
    Phoothiwut, Sawan
    ;
    Junyapoon, Suwannee
    Size distributions of atmospheric particulates and particulate-bound polycyclic aromatic hydrocarbons (p-PAHs) in different inhalable fractions (9.0-5.8, 5.8-4.7, 4.7-3.3, 3.3-2.1, 2.1-1.1, 1.1-0.7, 0.7-0.4, and <0.4 μm) were investigated during a haze period in Lampang Province, Northern Thailand. The particulate samples were collected using an eight-stage cascade impactor. The sample filter in each stage was weighed to determine concentration followed by ultrasonic extraction with acetonitrile and then analysis using selected ion monitoring-gas chromatograph-mass spectrophotometer to identify 16 PAHs. Similarly, smoke emission from burning rice straw in the rice field and air sample during non-burning period were also analyzed. In this study, the particle size fractions were classified into three different size ranges according to their mechanism of formation: ultrafine particles (nuclei mode, d <inf>ae</inf> < 0.4 μm), fine particles (accumulation mode, 0.4 μm < d <inf>ae</inf> < 2.1 μm) and coarse particles (d <inf>ae</inf> > 2.1 μm). Experimental results show that the average concentration of particulate matter less than 10 μm during the haze period was 3.5 times higher than that during the non-burning period. The atmospheric aerosols during the haze period contained the largest fraction of particles in nuclei mode while the emission during rice straw burning introduced the largest fraction of particles in accumulation mode. The size distributions of total PAHs during the haze period and rice straw burning were shifted towards the smaller particles relative to their particle size distribution. The size distributions of total PAHs were bimodal during the haze period and unimodal during rice straw burning. The fractions of five- and six-ring PAHs bound on the particles were predominantly detected during the haze period whilst those of three- and four-ring PAH compounds were mainly found in smoke emitted from rice straw burning. The ratio of carcinogenic and noncarcinogenic PAH compounds during the haze period was composed of more carcinogenic PAHs than that during rice straw burning. © 2013 Springer Science+Business Media Dordrecht.