A mesoscale numerical model simulation using four-demensional data assimilation (FDDA) was conducted to quantitatively evaluate complex airflow over the Kanto region. The Colorado State University Mesoscale Model (CSUMM) was used in this study. Rawin sonde observation (aerological data), AMeDAS data and pilot-balloon observation data were used in the FDDA. The model results were validated using data from a special three-dimensional observation carried out from July 15 to 17, 1981 over the Kanto region.
Model simulation using only synoptic scale geostrophic winds (without FDDA) was unsuccessful in predicting the observed wind fields. However, model simulation with FDDA by using aerological data dramatically improved wind field prediction. Simulated wind speed and wind direction agreed well with observation, especially in daytime. In night time, the FDDA run using aerological and AMeDAS data simulated well typical sea breeze and land breeze alternation, however, it could not simulate observed wind changes precisely. The standard deviations of model wind and temperature fields were smaller than that of observed.
Examination of the spatial density and time interval of observation showed that model and observation agreement increased in proportional to the number of observation points, and that the effect of using FDDA was most significant in improving night time simulation.

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The relationship between sulfur dioxide (SO₂)-induced damages and ethylene production was examined in tomato plants fumigated with 1.0 ppm SO₂, to illustrate involvement of ethylene production in SO₂-induced injury of plants. Ethylene production in tomato was enhanced by 1h SO₂ fumigation and moreincreased by prolonged exposure to SO₂ up to 4h, as did the SO₂-induced injury.
Next, we examined the effect of aminoethoxyvinylglycine (AVG), an inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) synthase, on ethylene production and leaf injury caused by SO₂ fumigation. AVG treatment prior to SO₂ fumigation effectively suppressed ethylene production, suggesting that ethylene synthesis induced by SO₂ fumigation was by way of ACC pathway in the plants. SO₂ fumigation induced chlorophyll destruction and increase of ion leakage of tomato leaves. AVG treatment blocked completely the chlorophyll destruction, though the treatment had no effect on stomatal diffusive resistance, namely SO₂ absorption rate. The suppressive effect of AVG on plant damages caused by SO₂ fumigation was nullified by ethylene treatment after SO₂ fumigation. These results indicated that ethylene might play an important role in SO₂-induced plant injuries at relatively short terms of SO₂ fumigation, thought ethylene did not cause the leaf damages by itself.

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Anthropogenic emission of sulfur dioxide (SO₂) in China was investigated to establish an emission inventory on air pollutants in East Asia. Major objectives of the study were to establish the emission inventory having the most detailed emission categories and regional resolution comparing with previous works, and being expandable to other air pollutants. Under popularization of desulfurization, conventinal methodologies face to limitation of data quality, but in this work the contribution of SO₂ removal by recent installation of desulfurization units was also taken into account. China was selected as the first subjective country because China has the largest emission sources of SO₂ in East Asia, which contribute a significant portion of acid deposition in Japan.
By our estimation total amounts of 21 Tg of SO₂ were emitted in China in 1990. About 90% of the SO₂ came from coal combustion, and power and heat generation part was responsible for over 30% of the total discharge. The total amounts of the SO₂ emission were classified by provinces, major cities, and two grid systems such as 80×80 km square and 1°×1° resolution. Emissions in Sichian, Shandong and Jiangus provinces were ranked as the top three. Chongqing, Shanghai and Chengdu were selected to be major cities for the SO₂ emission.

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Concentrations and size distributions of suspended particulate matter in the air inlarge underground areas and the corresponding above-ground areas were measured.The average concentrations of ultrafine particles (0.003-0.3 μm in diameter) were 5.6×10 ⁴and 12.6×10 ⁴ particles per cm3 in the underground and above-ground air respectively.Particles in the nuclei mode were distinguishable in the size distributionsmeasured in the above-but not in the underground air. There were no significantdifferences in the approximate mass concentrations of suspended particulate matter, which were determined by a laser dust counter, between the above-and undergroundspaces. However, the size distribution of particles (0.3-5.0 μm in diameter) differedbetween both areas. That is, the percentage of 0.5-1.0 μm particles to the totalparticle number was significantly higher in the underground areas than in the abovegroundareas. On the other hand, the percentage of 1.0-5.0 μm particles to the totalparticle number was lower in the underground than in the above-ground areas. Thedeposition of particles in the human respiratory tract after inhalation was estimatedfrom the above size distributions and the previously reported lung model regardingdeposition of inhaled particles. The amount of particles deposited in the pulmonaryregion was calculated to be larger in the underground than in the above-ground

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Seven atmospheric halocarbons, Freon-11 (F-11), Freon-113 (F-113), chloroform, 1, 1, 1-trichloroethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene, were monitored from Dec. 2 to 16, 1992 in Osaka City by using an auto-thermal desorption cold trap injector (Auto-TCT) and gas chromatography/ mass spectrometry (GC/ MS). The relative standard deviations of the determined values were less than 3% at atmospheric levels of the halocarbons, and the detection limits (ratio of signal to noise) were at 10ppt levels.
The concentrations of carbon tetrachloride showed a normal distribution in the range 0.08-0.20ppb. This suggested that no emission sources were near or around the sampling site. The behavior of chloroform was like as one of carbon tetrachloride, and thus suggested that there were little emission sources nearby. The concentrations of the other five halocarbons belonged to logarithm normal distribution, and were remarkably affected by near emission sources.
The medians of the concentrations were 0.83ppb for F-11, 0.33ppb for F-113, 0.14ppb for chloroform, 4.31ppb for 1, 1, 1-trichloroethane, 0.14ppb for carbon tetrachloride, 0.48ppb for trichloroethylene, and 0.22 ppb for tetrachloroethylene in the monitoring period.

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For a municipal incinerator, it is crucial to perform combustion in view of mixing, reaction and heat transmission of combustion gas for reducing the generation of micropollutants such as dioxins, nitrogen oxides and so on. The purpose of this work, therefore, is to recognize the degree of effect of each factor influencing gaseous combustion by actual incinerator. For the tests, inspiring of secondary air into the furnace in addition to water spray into the furnace and exhaust gas circulation was performed, and the variation of CO and NO_x concentration was measured. As a result, CO and NO_x concentration was controlled at low level.

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