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Volume 47 (2012)
- Issue 6 Pages 241-
- Issue 5 Pages 195-
- Issue 4 Pages 137-
- Issue 3 Pages 105-
- Issue 2 Pages 75-
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Volume 47, Issue 6
Displaying 1-7 of 7 articles from this issue
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Blue Sky
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Shinji Wakamatsu2012 Volume 47 Issue 6 Pages pref1
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSDownload PDF (229K)
Original Paper
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Hiroyuki Ueno, Hisashi Yokota, Koichiro Ishii, Kaoru Akiyama, Yuta U ...2012 Volume 47 Issue 6 Pages 241-251
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSA rapid and simple analytical method of low molecular dicarboxylic acids and levoglucosan in PM2.5 by in-situ silylation thermal desorption GC/MS has been developed. The optimum thermal desorption conditions for the derivatization were as follows: the primary desorption temperature : 320 ℃, helium flow: 20 mL/min, the reaction time: 10 min, and the amount of the reagent (BSTFA+TMCS(99:1) :pyridine 9:1): 10μL. Standard recovery tests using PM2.5 samples showed that an excess amount of the samples caused deterioration of the peak shapes of the derivatives. The sample amount of PM2.5 should be limited. Nonpolar compounds; i. e., n-alkanes, hopane, and PAHs, can be analyzed by the same system, although a bsimultaneous analysis is difficult due to the deference in the appropriate sample amount. Application of this method to PM2.5 ambient samples in Tokyo showed that the composition of the organic matters was different between summer and winter and the composition of the n-alkanes may be varied due to emissions from different sources. This method may be an effective tool for the investigation of organic aerosols.View full abstractDownload PDF (2520K) -
Takayuki Miyake, Osamu Nagafuchi, Kenshi Tetsuka, Kuriko Yokota, Seiic ...2012 Volume 47 Issue 6 Pages 252-260
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSWe continuously measured surface ozone (O3) concentrations on Yakushima Island, a remote site in southwest Japan, during July 2009-July 2011 to investigate the long-range transport of air pollutants from highly polluted areas of East Asia. The mean O3 concentration during the observation period was 32.0±17.3 ppbv, and the O3 concentrations showed a clear seasonal variation with higher values during spring and fall, and lower values during summer. Back trajectory analysis results showed that the air masses with higher O3 concentrations observed on Yakushima Island during October-May were of significant terrestrial origin and contained high concentrations of air pollutants from anthropogenic sources. In contrast, the lower values observed during June-September were associated with air masses of mainly oceanic origin. We discussed the effect of O3 exposure on the vegetation of Yakushima Island by the AOT40 index. For April-September 2010, the AOT40 was 8122.4 ppb·h, for April-November 2010, it was 17922.3 ppb·h, and for April-July 2011, it was 5750.1 ppb·h. A further study of plant O3 sensitivity and the complex influence of acidic deposition on plants, especially Pinus armandii var. amamiana, an endangered species on Yakushima Island, is needed to evaluate the influence of air pollutants on the island's biota. Nevertheless, a comparison of our results with the critical AOT40 level showed that the observed O3 concentrations did not immediately adversely affect the island vegetation.View full abstractDownload PDF (1459K) -
-Applications of numerical model to high stacks-Koichi Sada, Ayumu Sato, Takenobu Michioka, Yoichi Ichikawa2012 Volume 47 Issue 6 Pages 261-269
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSA three-dimensional computational fluid model is applied to the atmospheric diffusion evaluation of stack gas emitted from thermal power plants under complex terrain conditions for environmental assessment in Japan. Recently, the construction of many low stacks has been attempted instead of high stacks, due to the improvements in the thermal power plants facilities and the decrease in pollutant gas levels with the selection of high-quality fuels. In this study, a numerical simulation model of the diffusion of gas emitted from low stacks near the ground surface was developed using the nonhydrostatic formulation for flow, which takes into consideration the effects of terrain near the ground surface. Prior to the application of the developed numerical model to low stacks near the ground surface, the diffusion of gas emitted from high stacks, such as those of conventional thermal power stations, was simulated in this study. The surface concentrations of the stack gas were simulated and compared to those obtained in wind tunnel experiments. Furthermore, the ratios of the maximum concentration and its observed distance to those obtained under flat-plate conditions were also compared with other calculation results (Ichikawa and Sada, 2002) and wind tunnel experimental results. It was apparent that almost the same ratios could be obtained using the numerical simulation model developed in this study.View full abstractDownload PDF (2714K)
Technical Report
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Keiko Shibata, Nobuhiro Yanagisawa, Kenji Enya, Kazuhiko Sakamoto2012 Volume 47 Issue 6 Pages 270-277
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSThere was a theory about the evaporation of ultrafine-mode particles (< 0.1 μm) collected by a low-pressure impactor (LPI), but the atmospheric-pressure impactor (Nanosampler) had not been commercially available; therefore, these instruments were not compared. In this study, we obtained the Nanosampler, then, the size-segregated amount of diesel particles and chemical constituents on the low-pressure stages were evaluated and compared between these two samplers. As a result, the collected amount of organic carbon (volatilizing at about 120℃)in the ultrafine-mode particles by the Nanosampler was about 370 times more than the LPI. Moreover, the lost amounts of benz(a)anthracene (BaA), chrysene (CHR), benzo(b)fluoranthene (BbF) and benzo(k)fluoranthene (BkF) of the polycyclic aromatic hydrocarbon (PAH) by the LPI were about 3 times on the < 0.1 μm stage compared to the Nanosampler. It was suggested that for the degree of influence of loss and volatility with the chemical constituents in the diesel ultrafine-mode particles, the Nanosampler is a more suitable instrument than the LPI for diesel ultrafine-mode particle collection.View full abstractDownload PDF (2281K) -
Renqiu Cao, Kuniyoshi Makino, Susumu Tohno, Kouhei Yamamoto2012 Volume 47 Issue 6 Pages 278-284
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSA few studies have reported the concentrations of nitrate and sulfate because the continuous measurements of both substances are not typically easy. Since we could use continuous analyzers, we surveyed the concentrations of nitrate and sulfate for almost a year in Uji, Kyoto Prefecture , and then analyzed the seasonal variation and diurnal variation of the concentrations. The concentrations of PM particles(PM1, PM2.5, PM10)were low in the winter. The concentrations of nitrate in the PM1 and PM10 decreased in the summer. In contrast, the concentrations of sulfate increased in the spring. It is considered that these concentration variations are influenced by the gasification of nitrate in the summer and blowing of yellow sand in the spring. The peak time of the nitrate concentrations was typically observed between 8 a. m. and 9 a. m. in the diurnal variation in relation to the increased concentration by increased traffic volume and decreased concentration by a warmer temperature. In addition, the peak time of the sulfate concentrations was observed about 2 p. m. when the amount of UV increased. By comparing the concentrations among the main wind directions, both the concentrations of nitrate and sulfate were appreciated to be found by the wind from the direction of Osaka City.View full abstractDownload PDF (1915K) -
Naoki Kaneyasu, Nobuo Sugimoto, Atsushi Shimizu, Shigekazu Yamamoto, ...2012 Volume 47 Issue 6 Pages 285-291
Published: November 10, 2012
Released on J-STAGE: March 12, 2013
JOURNAL FREE ACCESSIn several epidemiological studies, the arrival of an Asian Dust event has recently been evaluated using the Dust extinction coefficient derived from the NIES Mie Lidar network. We analyzed the relation between the NIES Dust extinction coefficient and surface aerosol measurement in the northern part of Kyushu, Japan. Although a good correlation was observed between the Dust extinction coefficients at a lower height and [SPM] - [PM2.5] in Nagasaki, a better correlation was found between the Dust extinction coefficients at Nagasaki and Fe concentration in PM2.5 collected at Fukuoka in spite of their geographical separation of 100 km. The arrival of Asian Dust can be clearly identified when the Dust extinction coefficient> 0.1 km-1 using the Fe concentration as an indicator. In the prominent Asian Dust events, the ratio [SPM] / [PM2.5] ratio characteristically showed the value of 3, which presumably reflects the typical characteristics of the Asian Dust size distribution that has experienced the long-range transports.View full abstractDownload PDF (1014K)
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