Prediction of Atmospheric Diffusion in Complex Terrain (ADCOT) is one of the important factors to be stated in the environmental assessment since complex terrain happens to cause worse pollution than predicted. The prediction can be usually carried out with simulation of diffusion wind tunnel model testing and numerical diffusion model, and the present state and prospect of the ADCOT prediction technique of the wind tunnel testing is described.

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For evaluation of photochemical reactivities of mixed hydrocarbons in various emission sources, direct method by ultraviolet irradiation test and calculation method by photochemical reactivity index like OH radical reaction rate constant and hydrocarbon components were discussed. As emission sources, paint solvents, autoexhaust gas, gasoline vaper and so on, which had large hydrocarbon emission, were considered with environmental hydrocarbons. It was clarified that there were considerable differences of photochemical reactivities in each emission source, and calculation method by OH radical reaction rate constant was useful for evaluation of photochemical reactivities of mixed hydrocaebons.
The relation between initial (hydrocarbon)/(nitrogen oxides) concentration ratio of irradiation test and photochemical reactivity index like O_3max, and recent ambient methan concentration in Japan were also discussed.

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The Japanese Islands is one of the most volcanic regions in the world. Since it has been estimated that about one half of sulfur dioxide in Japan is emitted from volcanoes, more precise survey of the volcanic emissions should be made.
This paper is concerned with the contribution of volcanoes to the atmospheric sulfur budget and the role of volcanoes on the quality of air and precipitation. It also covers the progress made so far in the related studies on the long-range transport of sulfur in East Asia and discusses the task that lie ahead.

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Characteristics of various continuous analyzers for nitrogen oxides in flue gas (NO_x analyzers) were investigated in municipal incinerators. The investigated NO_x analyzers were non-dispersive infrared absorption (NDIR), chemiluminescence and ultraviolet absorption (UV), respectively.
There were slight differences among the observed values of the NO_x analyzers by NDIR, chemiluminescence and UV.
CO₂ and H₂O were expected to influence the observed values of the NO_x analyzers by NDIR and chemiluminescence. HCl and NH₃ were expected to influence the observed values of the NO_x analyzer by UV. However, HC1 and NH₃ were easily dissolved and removed in condensed water in the dryer in the sampling system, therefore those gases did not interfere with actual measurement.
It was estimated that the differences between the observed values of the NO_x analyzers were dependent on the imperfect correction of the influence of CO₂ or H₂O. It is required to minimize the influence of CO₂ as follows: NO and CO₂ concentrations in the span caliblation gas should be controlled at the average concentration in flue gas, or electrical correction should be added for the average CO₂ concentration at the average NO_x concentration, or the NOx analyzer with CO₂ compensating detecter should be used. It is strongly recommended to maintain the dryer condition perfectly to minimize the influence of H₂O in the sample gas.

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The carcinogenicity of a mixture of 1-nitropyrene and a small amount of 1, 3-, 1, 6-and 1, 8-dinitropyrenes (NP-mix) was examined in 266 (C57BL/ 6N×C3H/ HeN) F1 mice. Pregnant C57BL/ 6N mice were given a single intraperitoneal injection of NP-mix at a dose of 0, 20, 40, 50 or 100mg/kg body weight on the 15th day after gestation. Abortions were frequently observed in pregnant mice received injection of NP-mix. Offspring, B6C3F₁ mice, from pregnant mice administered 20 or 40mg/kg b. w. NP-mix significantly (p<0.05) induced pulmonary adenomas and adenocarcinomas at 18 months of age. The results suggest that the transplacental exposure to NP-mix causes lung tumorigenesis in B6C3F₁ mice.

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Chlorobenzenes and chlorophenols are considered as precursors of dioxin and related compounds. Monochlorobenzene and orthochlorophenol were chosen among chlorobenzenes and chlorophenols in this study. Monochlorobenzene and orthochlorophenol were decomposed by honeycomb catalyst. The parameters were reaction temperyture of 200-400°C and space velocity of 600-10000 hr^-1. The chlorides were evaporated from an evaporator, and maintained at 30°C for monochlorobenzene and at 40°C for orthochlorophenol.
The evaporated gas was carried by flowing air, and adsorbed for 10 minutes by XAD-2 resin at the inlet and outlet of a reactor. Then monochlorobenzene and orthochlorophenol were extracted from XAD-2 resin by benzene. The extracted liquid was concentrated by KD concentrator and N₂ gas, and analyzed. The decomposition efficiencies of monochlorobenzene and orthochlorophenol aquired in this experiment were in the range of 70-99% at the space velocity of 1200 hr^-1 and the reaction temperature of 400°C.

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The amounts of sulfur oxides absorbed on PbO₂-cylinder were measured from April 1974 through March 1990 at 8 locations in Yukuhashi City. The results showed that the amounts of sulfur oxides were decreased steadily at all locations year by year, except 1979 (the 2nd oil crisis), 1984 and 1985.
From the relationship between the amounts of sulfur oxides and the frequency of wind direction, it was found that the amounts of sulfur oxides in Yukuhashi City were increased by the wind from 3 directions, namely NE (Ube, Onoda), NW (Kitakyushu) and SE (Buzen, Nakatsu), in spring, summer and autumn.
In winter, the amounts of sulfur oxides in Yukuhashi City were increased by the wind from W-N-E.
Correlation coefficients between the data with the PbO₂ method at the location No.4 and those with SO₂ auto analyzer at the location No.9, were γ= 0.76 (n= 47) in winter, γ=0.64 (n= 44) in autumn, γ= 0.52 (n= 46) in spring and γ=0.28 (n=44) in summer.

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