Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi
Online ISSN : 2185-4335
Print ISSN : 1341-4178
ISSN-L : 1341-4178
Volume 34, Issue 5
Displaying 1-5 of 5 articles from this issue
  • Characteristics of Concentration Fluctuation with Low Concentration Threshold
    Kouichi SADA, Ayumu SATO
    1999 Volume 34 Issue 5 Pages 337-351
    Published: September 10, 1999
    Released on J-STAGE: November 08, 2011
    JOURNAL FREE ACCESS
    Wind tunnel experiments were conducted to study concentration fluctuation within a gas plume, considering the characteristics of plume dispersion in the atmosphere. Tracer gas was continuously released from an elevated point source located in a simulated atmospheric boundary layer and concentration fluctuation was measured using fast-response flame ionization detectors. The threshold concentration was determined by noise effects of the concentration measurement.
    Almost constant values were observed not only for the conditional ratio of RMS values to mean concentration, estimated using the threshold value within the plume, but also for the skewness and flatness factors of concentration fluctuation. These constant values were obtained at allthe threshold values used in this study. Probability distribution functions of concentration fluctuation were approximated by those of clipped normal distribution at near-by regions, and exponential and lognormaldistributions at regions far from the tracer gas release point. Concentration ratios at maximum 1% values were almost constant within the plume, and showed nearly the same values as those of lognormal and exponential distributions.
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  • Hiroaki MORI, Toshihiro KITADA
    1999 Volume 34 Issue 5 Pages 352-375
    Published: September 10, 1999
    Released on J-STAGE: November 08, 2011
    JOURNAL FREE ACCESS
    In order to obtain knowledge for urban and regional planning suitable for the prevention of air pollution, meteorological conditions for high concentrations of air pollutants were statistically investigated, using hourly NO2, NOx, Oxidant (Ox), SO2 and SPM concentration data measured at 73 monitoring stations in Nohbi Plain, for the period from April 1985 to March 1987.
    First, daily-averaged and daily-maximum concentrations of air pollutants were computed for each year. Secondly, by using these concentrations, “high concentration” days were selected in 6 areas for April 1985 -March 1986 and for April 1986-March 1987. The “high concentration” days stand for those concentrations which fall within the highest thirties, in over 70% of all monitoring stations, or stand for the days more than 2 areas over 50% of all stations fall within the highest thirties, for daily average of daily maximum concentrations. Thirdly, for those selected days, the diurnal variations of pollutants and meteorological factors, such as wind speed, wind direction and atmospheric stability, were analyzed. Fourthly, vertical structure of atmospheric temperature, wind direction and wind speed were compared among the two types of “high concentration” day (i. e. good weather with weak wind or bad weather with weak wind), using rawinsonde soundings in South Nagoya from 28 November to 7 December 1990.
    Obtained results are as follows: in monthly variations, most high concentration days appeared during the cool period (i. e. from October to March) except for Ox Especially, NOx showed that tendency clearly. The main meteorological conditions for the high NO2 days were “bad weather with weak wind” and “good weather with weak wind”, while high Ox days appeared with “extended land and sea breezes”. Thus, a relationship was shown between high Ox and the sea breeze blowing from the southern industrial area along Ise Bay. However, high Ox days selected by daily average also occurred with “good weather with northwestern wind”. In the latter case, high Ox depended on ozone supply from the stratosphere by a travelling anticyclone.
    Though the high SO2 and SPM concentrations days appeared mainly with “good weather with weak wind” or “bad weather with weak wind” in cool periods, sometimes they occurred with “land and sea breezes” in warm periods. These results showed that the high SO2 and SPM days in warm periods depended on advection of pollutants from coastal area.
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  • Kazuhiko SAKAMOTO, Mie UETA, Toyohiko NEZU, Misa TSUBOTA, Katsunori KI ...
    1999 Volume 34 Issue 5 Pages 376-385
    Published: September 10, 1999
    Released on J-STAGE: November 08, 2011
    JOURNAL FREE ACCESS
    A method for determination of α, ω-dicarboxylic acids (succinic acid, glutaric acid, and adipic acid) in an atmospheric aerosol collected on a quartz filter has been developed by means of pyrolysis of alkylating reagent-methylation-gas chromatography (PyMe-GC) equipped with a flame ionization detector. Simultaneous pyrolysis of tetramethylammonium hydroxide (TMAH)-methylation of dicarboxylic acids was achieved at 386°C using a Curie-point pyrolyzer. Under optimized analytical conditions, conversion ratios of these diacids to the corresponding diesters were found to be 95.5-103%. The pyrolysis of alkylating reagent-methylation method with direct addition of TMAH methanol solution to the quartz filter made possible direct determination of dicarboxylic acid concentrations in an atmospheric aerosol collected on a quartz filter without any pretreatments, extraction, concentration, or derivatization.
    This method was applied sucessfully to the determination of C4, C5, C6 α, ω-dicarboxylic acids in the urban aerosol samples collected at Saitama University, Urawa in summer, 1993. The observed ambientconcentrations were 116-669, ca. 16-131, and ca. 7-61ng m-3 for succinic acid, glutaric acid, and adipic acid, respectively.
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  • Kiyoshi SAKAI, Naomi HISANAGA, Eiji SHIBATA, Yasuhiro TAKEUCHI
    1999 Volume 34 Issue 5 Pages 386-397
    Published: September 10, 1999
    Released on J-STAGE: November 08, 2011
    JOURNAL FREE ACCESS
    The objectives of this study were to determine the concentrations and types of both asbestos and nonasbestos fibers in an urban atmosphere during a five year period and to evaluate annual and seasonal variations. The air samples were collected monthly from August 1992 to July 1997 at a fixed point in Nagoya City. Asbestos and non-asbestos fibers in the air were analyzed by direct transfer-analytical transmission electron microscopy. Identification of asbestos, classification of non-asbestos fibers based on their main elements, and quantification of mineral fibers were carried out.
    Geometric mean concentrations (range) of asbestos and non-asbestos fibers were 2.0 (<0.5-21.5) fibers/liter and 86.5 (15.8-912) fibers/litter, respectively. There were no significant differences among the annual and seasonal geometric means of either asbestos or non-asbestos fiber concentrations. No definite annual or seasonal trends concerning ambient concentrations of asbestos or non-asbestos fibers were found during the five years. Asbestos concentration was significantly correlated with non-asbestos fiber concentrations (p<0.01). There was no significant correlation between total fiber and total dust concentrations.
    The mean (range) of percentage of asbestos to total fiber concentration was 2.4 (0.0-7.1)%. The majority of asbestos types was chrysotile (91%). The predominant types of non-asbestos fibers (mean percentage of non-asbestos to total fibers) were mainly fibers composed of S and Ca (44.6%), Al and Si (21.2%), Na and S (7.7%), Mg and S (5.4%), S (3.8%), Si only (3.5%) and Fe only (2.3%).
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  • Susumu KATO, Masayoshi KITABATAKE, Feng Y. PIAO, Toru YAMAUCHI
    1999 Volume 34 Issue 5 Pages 398-406
    Published: September 10, 1999
    Released on J-STAGE: November 08, 2011
    JOURNAL FREE ACCESS
    In March of 1996, measurement of spirometric lung function and ATS-DLD (American Thoracic Society Division of Lung Disease) questionnaire survey of 11 years old school children, free from chronic symptoms, were conducted in a heavily polluted (annual average SO2: 79ppb) and a control (annual average SO2: 24ppb) area of the northeast industrial city, Shenyang, China. The prevalence of persistent cough in heavily polluted area was 8.9% and was significantly higher than 2.8% in the control area by ATS-DLD questionnaire. The same tendencies were observed except for persistent sputum. The prevalence of respiratory symptoms among schoolchildren, who had been living for more than 6 years in same place and who lived in brick homes with wooden window flames in the polluted area, was significantly higher than that in the control area. But there was no significant difference of lung function between the areas. The average personal exposure concentration (24 ppb) of SO2 measured by a passive sampler in the heavily polluted area was lower than that (47ppb) of ambient conditions in March, 1995. Also, the personal average exposure concentration (39±21 ppb) among boy children with one positive answer on ATS-DLD questionnaire (persistent cough, persistent sputum, asthmatic-like symptoms and wheezing) in the heavily polluted area was significantly higher than 27±11 ppb in the negative group who gave all negative answers. Moreover, V50%(flow volume on expiring 50%) of both boy and girl children in the heavily polluted and control areas were 53.2±12.9% and 74.9±18.3% with one positive answer on ATS-DLD, respectively. In contrast, V50% in the negative group was 57.8±14.4%(boys) and 81.7±15.5%(girls), and were significantly lower than those in the positive group. V50%(How volume on expiring 75%) among children also showed the same results.
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