著者
西村 秀一 大野 誠司
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.37, no.4, pp.276-282, 2022-12-20 (Released:2022-12-20)
参考文献数
24

For coping with aerosol infection in indoor settings, continuous ventilation and high efficiency air filtration are recommended. For air filtration systems, the reduction efficiency of airborne viruses in an enclosed space is important. Air purifiers with the high efficiency particulate air (HEPA) filter has been generally accepted as the best system because of their highest performance in removing airborne particles. However, whether the HEPA filter is essential for airborne infection control or not is inconclusive because of the great loss of filtration volume per hour by its air resistance. The performance of air purifiers containing an HEPA filter or an efficient particulate air (EPA) filter, a slightly less efficient filter to the HEPA as per the European Standard EN1822, was compared in the 25 m3 and 130 m3 closed space with respect to removal of artificial airborne particles and the aerosol containing influenza A viruses. The latter showed a 15% and 10% higher reduction rates in particle counts and airborne virus titers, respectively, than the former, supporting our theoretical calculation that removal is not solely dependent on a high particulate removal efficiency of the filter, and thus, suggesting an advantage of EPA to HEPA in practical settings.
著者
岩坂 泰信 小林 史尚 皆巳 幸也
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.25, no.1, pp.4-12, 2010-03-20 (Released:2010-03-25)
参考文献数
24
被引用文献数
3

There has been interest in bioaerosols that have been linked to health hazards for humans, animals, and plants. Additionally, recently possible contributions of bioaerosols to atmospheric processes become a large concern from the view point of interaction between climate-weather and bioaerosol, especially the potential of micro organisms as ice nuclei. However knowledge on atmospheric bioaerosols is extremely poor due to the technical difficulty in measurement of bioaerosols in the atmosphere. Recently some investigators tried to collect atmospheric bioaerosols on high mountains and/or high tower to understand the transport processes, the environmental stress on micro biota in the atmosphere, the concentration and diversity of micro organisms in the atmosphere. Now the science of bioaerosols is world-widely accepted as large break-through in atmospheric science, aerosol science, environmental science, and others. The concentrations and diversity of bioaerosols in the atmosphere and the changes in their temporal-spatial are essential knowledge to clarify the long range transport of bioaerosols and the atmospheric processes affected by bioaerosols, and the environmental effects of micro organisms transported in long range. Balloon borne measurements were actively made in Kanazawa, Japan and Dunhuang, China in 2005-2009 suggesting that Kosa (Asian dust) particles were effective carriers of micro biota. Mixture states of Kosa and micro biota certainly suppress the environmental stress such as ultra-violet solar radiation, dryness and low temperature. The papers in this special issue of EAROZORU KENKYU are mainly based on these balloon borne measurements, and the newest information is described. Considering that the westerly wind frequently transports lots of Kosa particles from arid and semi-arid regions in China and Mongolia to downwind including Japan, the effect of Kosa bioaerosol mixture on environment, weather and health is of large concern in downwind areas. The paper by Kohshima (this issue) describes interesting and valuable topics in order to discuss the effects of Kosa bioaerosols on environment.
著者
諏訪 好英 藤井 修二
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.27, no.3, pp.292-305, 2012 (Released:2013-01-18)
参考文献数
45
被引用文献数
1

DSMC (Direct Simulation Monte Carlo) technique is a direct approach to solve the Boltzmann equation. To simulate small scale phenomena of gas mixture close to molecular size, such as behavior of nano-particles, particle formation from gas, etc., DSMC technique was extended to the rarefied gas mixture. This advanced technique was applied to the fundamental problems, such as Rayleigh’s problem, velocity distribution of gas molecules in equilibrium gas mixture, and time-dependent change of distribution of diffused gas molecules. Simulated results using DSMC technique extended to gas mixture showed a good agreement with theories and previous studies. Also, characteristics of Bird-scheme and Nanbu-scheme which have been widely applied to treat collisions between molecules in DSMC method were studied. Finally, a practical problem, the deposition of sputtered molecule, was simulated, and this technique was proved to be a powerful tool for solving this sort of problems.
著者
王 青躍 栗原 幸大 桐生 浩希 坂本 和彦 三輪 誠 内山 巌雄
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 = Journal of aerosol research (ISSN:09122834)
巻号頁・発行日
vol.23, no.2, pp.120-126, 2008-06-20
被引用文献数
3

In this study, we focus on the investigation of the airborne behavior of respirable particulate matters containing Japanese cedar pollen allergen Cry j 1 exfoliated from the Ubisch bodies on the pollen surfaces and Cry j 2 comprised in the starch granules within the pollen. The airborne Japanese cedar pollens were counted, and at the same time, the Cry j 1 and Cry j 2 particles were collected and determined in different particle sizes at the urban site (Cooperative Research Center of Saitama University) during daily sampling periods of the most severe pollination season of FY 2005 in Saitama, Japan.<BR>Morphological observation of Ubisch bodies exfoliated from pollen and ruptured pollens was performed with a scanning electron microscope. Moreover, the existing evidences of visualized Cry j 1 and Cry j 2 allergen particles below 1.1&mu;m were also sensitively found by an immunofluorescence technique with a fluorescence microscope. Simultaneously, the high concentrations of Cry j 1 and/or Cry j 2 were determined in the fine particle sizes below 1.1&mu;m. It was suggested that airborne respirable particulate matters containing Cry j 1 and Cry j 2 play a key role in the increasing incidence of asthma in the lower respiratory tract. Furthermore, although the release mechanisms of Cry j 1 and a Cry j 2 particles may be differed, the daily variation delays in the peaks of Cry j 1 (or Cry j 2) concentrations compared to the peaks of airborne pollen counts were observed since the fine particles were suspended in the atmosphere over a longer period of time after released. It is important to observe and determine the size distribution of airborne Japanese cedar pollen allergen particles in the long-term sampling research continually, and to elucidate the allergen particle release mechanisms. In the future, we should investigate the chemical, physical and biomedical combination effects on Japanese cedar pollen allergens, and have to consider proposing a new forecast informational system of the Japanese cedar pollen and their allergen particle variations.
著者
折笠 成宏 村上 正隆 斎藤 篤思
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.30, no.1, pp.24-31, 2015-03-20 (Released:2015-04-16)
参考文献数
9
被引用文献数
1

As one of the physical evaluation techniques of seeding effects, cloud seeding experiments were conducted utilizing an instrumented aircraft, with the use of dry-ice pellets in cold clouds and hygroscopic flares and salt micro-powders in warm clouds as a seeding agent. We demonstrated from the in-situ measurements that dry-ice pellet seeding of mixed-phase orographic clouds were effective, based on the comparison of estimated radar reflectivity factor, ice water content, or precipitation intensity from the 2D images of ice particles between seeded portions and their surroundings. The observational results we obtained so far showed that hygroscopic seeding of warm clouds might be effective under limited conditions.
著者
太田 幸雄
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.6, no.2, pp.98-105, 1991-06-20 (Released:2011-06-09)
参考文献数
13
被引用文献数
2
著者
中串 孝志 古川 邦之 山本 博基 大西 将徳 飯澤 功 酒井 敏
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 = Journal of aerosol research (ISSN:09122834)
巻号頁・発行日
vol.22, no.2, pp.107-112, 2007-06-20

Planetary aerosol laboratory experiments for science education were carried out in a curriculum of Kyoto University. Our goal is to reproduce "the blue sunset" on Mars which are reported from NASA's Mars Pathfinder. In reproducing the rays scattered by Martian atmosphere (dust storm) in a laboratory, the number density of scattering particles has to be as large as possible. Three experiments were conducted in the air and water. Although we were not able to reproduce Martian blue sunset, we elucidated its spectrum. Converting this spectrum to a color in the RGB system, we obtained R = 114, G = 122, B = 192. Though the experiment, we proved that planetary aerosol laboratory experiments are significantly fruitful for science education as well as for science studies. We propose that researchers and lecturers should make active use of planetary aerosol laboratory experiments for science education.
著者
北園 孝成 上田 佳代 吾郷 哲朗 新田 裕史 鴨打 正浩
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.29, no.S1, pp.s207-s211, 2014-02-20 (Released:2014-04-01)
参考文献数
16

The underlying risk factors for stroke, such as hypertension, diabetes, dyslipidemia, and atrial fibrillation, have been established. However, the factors that trigger stroke in patients at high risk are still uncertain. Recent epidemiological studies have documented the possibility that Asian dust may be related to diseases and health conditions. Recently, utilizing data from the Fukuoka Stroke Registry(FSR), we have shown that Asian dust exposure is associated with the incidence of atherothrombotic brain infarction, a subtype of ischemic stroke. Several studies have reported small but statistically significant associations between short-term particulate matter (PM) exposure and incidence of ischemic stroke. Several biological pathways responsible for PM-associated cardiovascular diseases have been explored, including endothelial dysfunction, production of oxygen species, hypercoagulability, induction of arrhythmia, and systemic inflammation. Because the concentrations of PM were higher in the periods with Asian dust than those in the periods without Asian dust, PM may contribute, at least in part, to the occurrence of atherothrombotic infarction in response to Asian dust exposure. Further studies are needed to elucidate the precise mechanisms.
著者
松井 康人
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.32, no.3, pp.157-161, 2017-09-20 (Released:2017-10-05)
参考文献数
10

Risks of Nanoparticle should be assessed comprehensively by their physicochemical characteristics. However, such assessment has not been conducted because various physicochemical parameters and end points are involved. The relationship between one characteristic and the specific effect has to be analyzed in order to conduct sufficient risk assessment of nanomaterials. In this study, it was found that there was the quantitative relationship between the specific surface modification/size of nanoparticle and the endocytic uptake of alveolar epithelial cells. The results indicate that the amount of cellular uptake of nanoparticles is independent of the surface modification, but it depends on the particle size. The uptake rate is high in the order of COOH>NH2>plain on the surface modification and faster as the particle size increases. It was suggested that uptake rate depends on the surface potential and the hydrophilicity.
著者
上島 寉也
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.4, no.4, pp.265-277, 1989-12-20 (Released:2011-06-23)
参考文献数
16
著者
谷村 泰宏
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.18, no.1, pp.20-26, 2003-03-20 (Released:2007-11-27)
参考文献数
24
被引用文献数
2
著者
脇坂 昭弘
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.26, no.1, pp.24-29, 2011 (Released:2011-04-12)
参考文献数
11

When mist particles are generated from ethanol-water mixtures by ultrasonic atomization at a low temperature, ethanol is concentrated in the atomized mist particles. This paper explains the mechanisms of ethanol thickning in atomized droplets based on the cluster-level structures analysed by the mass spectrometry. When ultrasonic atomization of equimolar ethanol-water mixture is carried out at a lower temperature, e.g. 10°C, small clusters composed of only ethanol molecules can transfer from the liquid phase to the gas phase, while the large clusters consisting of both ethanol and water molecules cannot move across the interface. This leads to the thickning of ethanol in the atomized mist particles. The cluster-level structures of ethanol-water mixture, which varies with the ethanol concentration and the liquid temperature, directly determines the characteristics of ultrasonic atomization of ethanol aqueous solution.
著者
山内 俊幸 須田 洋 松井 康訓
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.22, no.1, pp.5-10, 2007-03-20 (Released:2007-03-20)
参考文献数
6
被引用文献数
2

A device which cools a discharge electrode to cause condensation and then electrostatically atomize the condensed moisture by applying high voltage to the discharge electrode has been developed. The electrostatic particulate water generated through the electrostatic atomization by this device has been confirmed to have a peak particle diameter of approximately 20 nm. In addition, simultaneous formation of radicals was verified by ESR analysis. It has been confirmed that this electrostatic particulate water has the effects of deodorization by adsorbing/absorbing odors and deactivation of pollen or mite antigens. An air cleaner equipped with this electrostatic atomization device has been developed. Further, when this device was employed on a hair dryer, it was found to have the effects of increasing the moisture-holding power of hair, giving hair softness and increasing the tensile breaking strength of hair. This is presumed to be due to the abundant moisture given to hair compared to negative ion devices.
著者
足立 光司
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.32, no.4, pp.255-260, 2017-12-20 (Released:2018-01-12)
参考文献数
17

Insoluble radioactive particles emitted from the Fukushima nuclear accident have been found from the samples collected in various environments. This manuscript summarizes the studies that characterized such particles using electron microscopy and synchrotron radiation analyses. The shapes and compositions of 33 radioactive particles from aerosol particles, soil, plant tissues, non-woven fabric cloth, and masks have been identified. These radioactive particles contained radioactive Cs ranging from 0.5 to 109 becquerel per particle. Diameters of spherical particles ranged from 0.8 to 4 μm, and those of non-spherical particles were from 1.4 to 250 μm. They consisted of silicate glass with Cs, Zn, and Fe as well as many minor elements (in total, 33 elements were detected). These particles tended to have more Cs on their surface than the core and contained nano-crystals consisting of, for example, Cu-Zn-Mo, Ag-Te, CaSO4, FeCr2O4, Sn-Te, Ag-Sb, and iron oxides. Such crystalline structures will be important to understand the formation and degradation processes.
著者
京野 洋子
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.11, no.3, pp.211-217, 1996-09-20 (Released:2010-07-08)
参考文献数
37
著者
江見 準
出版者
日本エアロゾル学会
雑誌
エアロゾル研究 (ISSN:09122834)
巻号頁・発行日
vol.4, no.4, pp.246-255, 1989-12-20 (Released:2011-06-23)
参考文献数
40
被引用文献数
3