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Volume 48, Issue 1
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Blue Sky
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Hiroshi Ohkochi2013 Volume 48 Issue 1 Pages Pref01_1-Pref01_2
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSDownload PDF (316K)
Original Paper
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Takao Miyoshi, Akinori Takami, Akio Shimono, Shiro Hatakeyama2013 Volume 48 Issue 1 Pages 1-11
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSWe used an Aerodyne aerosol mass spectrometer to measure the chemical composition (ammonium, nitrate, sulfate, chloride and organics) and size distribution of ambient aerosols at Cape Hedo, Okinawa, from October 2003 through July 2004. Sulfate was the dominant component of the aerosol mass throughout the observation period, contributing 3.8 µg m-3 on average. The distributions of the vacuum aerodynamic diameter were very similar for all species; the modes were around 500 - 600 nm. Using back trajectory analyses, we classified the data according to the 10 regions (the Pacific, Japan, Korea, northern China, southern China and their boundary areas) through which the air masses mainly traveled en route to Cape Hedo, and into five seasons (fall, winter, spring, early summer and late summer). The total mass concentrations were high (the concentrations ranged between 5.0 and 10.9 µg m-3, the sum of the mass concentrations of all the aerosol components) in the air masses from the continent and low(2.5µgm-3)in theair masses from the Pacific. The seasonal variation in each aerosol component was also studied. The correlations between the aerosol chemical compositions and transport time from the source areas and relative humidity were investigated in the air masses from northern China in the winter. The ratios of the transformation of SO2 to sulfate were 1.6%h-1 (relative humidity<50%) and 6.5% h-1 (relative humidity≧75%). This result showed that the transformation smoothly proceeded under a high relative humidity, presumably reflecting the effects of a heterogeneous and liquid phase reaction with cloud, fog and rain water droplets.View full abstractDownload PDF (1846K) -
Shin-ichi Fujita2013 Volume 48 Issue 1 Pages 12-19
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSThe nitrate to non-sea-salt sulfate ratio (NO3-/nssSO42- ) in precipitation is a useful factor in evaluating the relative contributions of H2SO4 and HNO3 to the acidity of precipitation. Based on the wet deposition monitoring data collected in Japan between 1976 and 2011, I analyzed (i) the long-term trends and seasonal variations of the NO3-/nssSO42- ratio in precipitation at Ryori, Komae, and Goto; (ii) changes in the horizontal distribution and temporal variation of the NO3-/nssSO42- ratio in recent years; and (iii) the influence of the east-Asian NOx/SO2 emission ratio on the NO3-/nssSO42- ratio in precipitation over the Japanese Archipelago. The NO3-/nssSO42- ratio in precipitation significantly increased during the 1980s and 1990s, while no significant variation was observed in the 2000s at Ryori, Komae, or Goto. Since the summer of 2000, the eruption of the Miyakejima volcano has impacted the NO3-/nssSO42- ratio at Ryori and Komae. The average annual rate of change of the NO3-/nssSO42- ratio during the 1980s and 1990s at Ryori and Goto was similar to that of the east-Asian NOx/SO2 emission ratio. The average annual rate of change of the NO3-/nssSO42- ratio at Komae, however, was greater than those of Ryori or Goto, and indicated the importance of HNO3 in the metropolitan atmosphere. The NO3-/nssSO42- ratio in precipitation in central Japan, including the Sea of Japan and Pacific Ocean coastal regions, was greater than those in northeastern and southwestern Japan. The NO3-/nssSO42- ratio in precipitation showed no significant variation through the middle of the 2000s, but it has clearly increased since the late 2000s. This tendency was observed across a large area of Japan, particularly on the Sea of Japan side of western Japan. If the increases in the NO3-/nssSO42- ratio in precipitation in western Japan reflect changes in emissions in the region, increases in the NOx emissions and/or decreases in the SO2 emissions would be expected. A recent analysis of the source contributions to sulfate and nitrate in Japan suggests that increases in the SO2 emissions from mainland China are not relevant to the increases in the NO3-/nssSO42- ratio in precipitation of western Japan.View full abstractDownload PDF (1996K) -
Akiyoshi Kannari, Kazuo Kokuryo2013 Volume 48 Issue 1 Pages 20-34
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSThe total emissions of NOx, PM, SO2, CO, NMHC, NH3 and CO2 from road vehicles in Japan were estimated for the period of 1980 - 2010. The applied emission model consisted of hot running exhaust emissions, cold start exhaust emissions and evaporative NMHC emissions. The estimated historical changes in the emissions are affected by various historical changes such as changing traffics, increasing number of diesel buses and trucks, temporary prevailing diesel passenger cars, retirement of two reduced stroke minicars, step-by-step reinforcing of emission regulations and corresponding renovations of countermeasures, and sulfur content and lowering of the Reid vapor pressure in fuels. This information about the historical changes in atmospheric emissions is thought to be useful for the data analysis of environmental concentrations, reproduction of the concentrations by simulation models and/or evaluation of its sociological history.View full abstractDownload PDF (1941K) -
Jun Matsumoto2013 Volume 48 Issue 1 Pages 35-42
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSTo evaluate theatmospheric photochemical oxidant (OX) on a second time scale, we propose a modification of a fast-response NO2 analyzer based on the laser-induced fluorescence (LIF) technique. In this study, we tested the combination of the conversion of O3 to NO2 by adding NO to the sample air and the following quantification of NO2. The direct measurement of ‘potential ozone (PO)', which was defined as the sum of O3 and NO2, was examined. Through the validation experiments for a standard gas mixture, the conditions of the NO addition were optimized and a nearly complete conversion of O3 to NO2 was achieved. To explore the applicability of the analyzer to atmospheric observations, a preliminary observation test was conducted in a suburb of Tokyo. Consequently, the O3 concentrations observed by this analyzer well agreed with those by a commercial-based UV-O3 analyzer. The reasonability of the PO analyzer was experimentally confirmed. From the acquired relationship among the 1-s data of NO, the NO2, and O3, NO2 fraction was estimated as 12 % of the emitted NOX.View full abstractDownload PDF (1471K)
Note
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Yusuke Maejima, Kiyoshi Matsumoto, Koichiro Ishii, Takehiro Ishika ...2013 Volume 48 Issue 1 Pages 43-48
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSPatients with hay fever caused by Japanese cedar pollen have increased in the urban regions of Japan, and air pollution might exacerbate their symptoms. We collected fresh and airborne cedar pollen particles and analyzed them for Cry j 1 and the attached aerosol component. The concentration of the cedar pollen allergen, Cry j 1, in the aerosol was found to increase with an increase in the cedar pollen concentration in the air, although the Cry j 1 concentration significantly varied due to unknown factors. We quantitatively determined the attached aerosol component by a microbeam scanning particle induced X-ray emission analysis. The concentrations of the elements deposited on the cedar pollen surfaces were found to correlate well with those of the aerosol in the atmosphere. The air pollutant might be attached to the pollen in the polluted air and the Cry j 1 distribution varied during the transport.View full abstractDownload PDF (2110K)
Technical report
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Seiichi Toriyama, Toshiaki Mizoguchi, Takayuki Kondo, Mizuka Kido, Nor ...2013 Volume 48 Issue 1 Pages 49-64
Published: January 10, 2013
Released on J-STAGE: April 22, 2013
JOURNAL FREE ACCESSThirty VOC ingredients have been measured and analyzed in the air samples collected from Tateyama Murodo (2,450 m a. s. l. ) and Tateyama Gondola (1,180 m a. s. l. ) in the Mt. Tateyama area from the middle of August to the end of October 2009, from the beginning of May to the end of October 2010, and from the beginning of May to the end of October 2011. Air samples were collected 165 times and 171 times, from both areas respectively. The annual average values of the VOCs30 ingredients showed a dereasing tendency from 2009 to 2011. The environment appears to be inproving. Among the VOCs30 ingredients, benzene, toluene, ethylbenzene, and p-dichlorobenzene showed high concentrations. We have classified a source area according to a back trajectory analysis. An East Asia source was repponsible for 64% at Tateyama Murodo and 38% at Tateyama Gondola. Based on monthly variations, the concentration of benzene was low in the summer and the tendency for the East Asia source to decrease was seen during the same season. It is thought that the benzene concentration is dependent on the East Asia origin. The concentrations of all the VOCs in both areas were lower than those inurban areas except for chloroform being equivalent, and almost equivalent to those at Cape Hedo in Okinawa. We have compared the concentrations with those obtained in a mountain area. The concentrations of benzene and toluene at both points were slightly higher than those at Jungfraujoch in Switzerland. The benzene/toluene ratio indicates that the index of the East Asia origin was confirmed based on the data from these three years at both areas.View full abstractDownload PDF (3820K)
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