Browsing by Author "Bac, VT"

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    Accelerator based ion beam analysis techniques contribute to a better understanding of long range fine particle pollution in Asia
    (International Atomic Energy Agency, 2012-09-15) Cohen, DD; Stelcer, E; Crawford, J; Bac, VT
    Fine-particle pollution in large populated Asian cities can be very high compared with internationally accepted health goals. Much of this fine-particle pollution is produced by motor vehicles, fossil-fuel combustion, industrial processes and even windblown soils from desert regions. As part of a long term project in the Asian region with support from the IAEA, ANSTO has been using nuclear techniques not only to characterize fine-particle pollution, but also to quantify their sources and origins within Vietnam. © International Atomic Energy Agency
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    Characterisation and source apportionment of fine particulate sources at Hanoi from 2001 to 2008
    (Elsevier, 2010-01) Cohen, DD; Crawford, J; Stelcer, E; Bac, VT
    PM2.5 particulate matter has been collected on Teflon filters every Sunday and Wednesday at Hanoi, Vietnam for nearly eight years from April 2001 to December 2008. These filters have been analysed for over 21 different chemical species from hydrogen to lead by ion beam analysis techniques. This is the first long term PM2.5 dataset for this region. The average PM2.5 mass for the study period was (54 ± 33) μg m―3, well above the current US EPA health goal of 15 μg m―3. The average PM2.5 composition was found to be (29 ± 8)% ammonium sulfate, (8.9 ± 3.3)% soil, (28 ± 11)% organic matter, (0.6 ± 1.4)% salt and (9.2 ± 2.8)% black carbon. The remaining missing mass (25%) was mainly nitrates and absorbed water. Positive matrix factorisation techniques identified the major source contributions to the fine mass as automobiles and transport (40 ± 10)%, windblown soil (3.4 ± 2)%, secondary sulfates (7.8 ± 10)%, smoke from biomass burning (13 ± 6)%, ferrous and cement industries (19 ± 8)%, and coal combustion (17 ± 7)% during the 8 year study period. © 2010, Elsevier Ltd.
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    IBA techniques for fine particle pollution, source characterisation and quantification of long range transboundary smoke and soil events in the Asian region
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2009-11-25) Cohen, DD; Stelcer, E; Crawford, J; Bac, VT
    As the Australian Nuclear Science & Technology Organisation (ANSTO) we have been collecting fine particle filter papers from sampling units around Australia and throughout the Asian region for many years. Some sampling sites have been running every Wednesday and Sunday continuously for more than 15 years now. All these have been analysed using accelerator based ion beam analysis (IBA) techniques at ANSTO. Recent novel methods of Positive Matrix Factorisation (PMF) for source apportionment and for identifying source fetch regions using wind back trajectory information will be discussed. In particular, examples of large scale long range dust movements from the Gobi desert regions in China and Mongolia and their impacts on Korea, japan and possible industrial emissions from mainland China into places like Vietnam will be discussed. New data on Australian dust and smoke impacts on Indonesia will also be presented. © 2009 AINSE
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    Long range transport of fine particle windblown soils and coal fired power station emissions into Hanoi between 2001 to 2008.
    (Elsevier, 2010-10) Cohen, DD; Crawford, J; Stelcer, E; Bac, VT
    Fine particulate matter (PM2.5), source fingerprints and their contributions have been measured and reported previously at Hanoi, Vietnam, from 25 April 2001 to 31 December 2008. In this study back trajectories are used to identify long range transport into Hanoi for two of these sources, namely, windblown dust (Soil) from 12 major deserts in China and emissions from 33 coal fired power plants (Coal) in Vietnam and China. There were 28 days of extreme Soil events with concentrations greater than 6 μg m−3 and 25 days of extreme Coal with concentrations greater than 30 μg m−3 from a total of 748 sampling days during the study period. Through the use of back trajectories it was found that long range transport of soil from the Taklamakan and Gobi desert regions (more than 3000 km to the north west) accounted for 76% of the extreme events for Soil. The three local Vietnamese power stations contributed to 15% of the extreme Coal events, while four Chinese power stations between 300 km and 1700 km to the north-east of Hanoi contributed 50% of the total extreme Coal events measured at the Hanoi sampling site. © 2010, Elsevier Ltd.