エアロゾル研究
Online ISSN : 1881-543X
Print ISSN : 0912-2834
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29 巻 , 4 号
選択された号の論文の9件中1~9を表示しています
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特集「未来を切り開くスプレーテクノロジー」
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  • 奥田 知明
    29 巻 (2014) 4 号 p. 263-271
    公開日: 2014/12/27
    ジャーナル フリー
    This paper focuses on the long-term trend and current status of air pollution in China. In particular, fine particulate matter (PM2.5) in Beijing city was introduced. The annual number of scientific journal publications regarding PM2.5 in China has been increased from zero before 2000 to more than 100 in the past two years. The concentrations of PM10 in Beijing have been decreased from 169±94 µg/m3 in 2001 to 109±73 µg/m3 in 2012. Researchers should note that Beijing is not a representative city of China because it was uniquely developed due to the hosting of the 2008 Summer Olympic Games. The concentrations of PM2.5 in Beijing have almost been constant at a level of 100 µg/m3 from April 2010 to October 2013 except in January 2013, showing remarkably high monthly average PM2.5 concentrations (200 µg/m3). This highly polluted situation was probably due to a tentative meteorological condition in that period, and this did not cause any elevation of PM2.5 concentration in Japan. The chemical composition of PM2.5 in 2010 was similar to that in 2000, however, the content of carbonaceous species in PM2.5 was likely to have decreased from 2000 to 2010 when compared to water-soluble ionic species. The concentrations of air pollutants decreased by up to 50% in the summer of 2008 due to Olympic Game related environmental control measures, but they increased again in 2009. It seems difficult for many Chinese cities to satisfy the ambient air quality standard for PM2.5 even though the standard is not strict when compared to other countries. Since the status of atmospheric environment in China changes abruptly, the continuous monitoring is mandatory.
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  • Yoshiki OKADA, Shintaro MIYAZAKI, Takashi OTSUKI, Satoshi KUDOH
    29 巻 (2014) 4 号 p. 272-277
    公開日: 2014/12/27
    ジャーナル フリー
    We describe the improvement in the sensitivity of an aerosol spectrometer that simultaneously measures the size-dependent concentration and chemical composition of particulate organic matter.The spectrometer studied in the present work consists of a differential mobility analyzer (DMA) for the size classification and a gas chromatography mass spectrometer (GC-MS) for the composition analysis.Size-classified particles of hydrocarbons were directly introduced into a thermal desorption (TD) tube packed with absorbent. Hydrocarbon molecules thermally desorbed from the TD tube were then introduced into the GC-MS. We improved the vacuum level in the ion source section of the GC-MS by changing the GC-MS carrier gas, and increased the velocity of carrier gas that expelled the hydrocarbon vapor from the TD tube into the GC-MS by reducing the size of the pipe. For a particle size of 330 nm, the detection sensitivity of the spectrometer for nonylbenzene particles was approximately 30 times as high as that of the spectrometer developed in our previous work (Okada et al., 2012). From the results of our investigation of the adsorption and desorption efficiency of the TD tube and the lower detection limit of the GC-MS using nonylbenzene vapor as a sample, we found that nonylbenzene weighing more than 6.6×10-2 ng could be measured with our spectrometer, i.e., the lower detection limit.
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