Oxidation reactions of atmospheric sulfur and nitrogen compounds dissolved in aqueous solutions are reviewed. Important viewpoints were summarized in a matrix-like form for evaluating chemical reactions in the aqueous systems. Recent progresses are addressed for kinetics and mechanisms of the oxidation of major chemical species such as SO₂, NO₂, and H₂S by H₂O₂, O₃, and free radicals. Much of the informationis potentially applicable as well as to lake and ocean surface waters which compose the interface of the atmosphere.
Among the conclusions are the following:(1) Rate laws and rate constants are established for S (IV)-0₃ and S (IV)-H₂O₂ systems.(2) Reactions with OH and SO₄^- radicals are shown to be very important.(3) Reliable mechanisms are presented for the Fe (III)-catalyzed autoxidation of S (IV).(5) Accommodation coefficients are precisely determined for SO₂, H₂O₂, and 0₃.

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A determination was studied for acidic gases (HCl, HNO₃, SO₂) and particulate matter (Cl^-, NO₃^-, SO₄^2-) in the atmosphere.
The investigation revealed the following points:
1. Combination of the polyamide filter collection system provided with diffusion denuder tubes and the polyamide filter plus alkaline filter collection system enabled to collect acidic gases and particulate matters separately. Furthermore, these compounds could be determined rapidly by using Ion chromatography.
2. If an aqueous solution of 5% potassium carbonate and 2% glycerol is used for coating the inside of the tube, more than 97% collection efficiency and more than 95% penetration efficiency were achieved for acidic gases and particulate matter, respectively, at a flow rate of 12l/min (1l/min per piece).
3. Acidic gases and particulate matter in the atmosphere were separately determined in March 1985 by the method. HCl 0.4-5.8ppb, Cl^-0.6-4.5 μg/m³, HNO₃ 0.4-2.9 ppb, NO₃^- 2.2-8.5 μg/m³, SO₂ 2.0-11.4 ppb and SO₄^2-;4.1-4.7 μg/m³.
The limit of detection of this method (sample air volume: 720 liters) are HCl 0.18 ppb, Cl-0.28 μg/m³, HNO₃ 0.08 ppb, NO₃^- 0.20 μg/m³, SO₂ 0.08 ppb and SO₄^2- 0.34 μg/m³.

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When the source of air pollutants is isolated on shore, high concentrated pollutants originated in the formation of the internal boundary layer are often observed (fumigation phenomena). In the present report, we developed the simple diffusion model which includes the fumigation effect, in order to support concerning the assessment. The model is tested by the data of experiments at Tokai village Ibaraki prefecture in summer 1982 and 1983 which were carried out by many members in Japan Atomic Energy Research Institute. It is found that the proposed model agrees well with the experimental results (the maximum concentration, etc.) compared to the usual plume models.

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The final purpose of this study is to establish the evaluating model of complex odors based on the selective recepting characteristics of odorous compounds in the sense of smell and the existing of the fundamental odor.
At first, therefore, in this paper the fundamental odor was estimated by the psychometrical method, such as the factor analysis and the cluster analysis, and the method of applying the sensory cross-adaptation of olfaction.
As a result of the qualitative classification by each method, 1, 8 cineole, 1, 2 dichloroethane, dimethyl disulfide, geraniol, methylamine, pentadecanolactone and isovaleric acid were selected as fundamental odors.

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In this study, based on the conception of the selective recepting and the fundamental odors, the estimating model of the sensory odor intensity and odor quality were established newly. And it was examined whether the model had an agreement with the experimental data in the complex odor samples composed of 2 or 3 odorous components, or not.
Namely, the human recognition system of the odor intensity was divided the physiological intensity from the sensory intensity, and the estimating model for each intensity and that for complex odor qualities were presented. The models were based on the similarity profiles for the seven fundamental odors.
As a result of the comparison estimated values with measured values, it was confirmed that the estimating model for physiological intensity had the accuracy in the range of ±10% for 80% of all odor pairs. And it was confirmed, based on the corresponding relationship between the pattern similarity rate of the estimated profile and that of the measured profile, between the pattern similarity rate and the sensory similarity, that the estimating model were applicable for the estimate of the complex odor quality.

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The effect of a passage of land breeze front as a meteorological factor upon high concentration of NO_x was analyzed based on the observation data conducted during January, 1983 at Shinjuku Imperial Garden. At the passage of land breeze front, NO_x showed high concentration from the surface to a height of several hundred meter, and the region of this high concentration coincides with the head of land breeze. At surface level, NO_x concentration also shows quite similar pattern. However, NO₂ does not show a significant increase compared with NO_x, O_x concentration inside the land-breeze head was almost zero due to the reaction with NO. On the other hand, concentration of O_x above the level of 200 m showed several ten ppb, and the downward transport of O_x may be important at the upper boundary of land breeze head. The occurrence of high concentration of NO_x was correlated with the passage of the land breeze front, and the appearance time of peaks in NO_x inversely correlated to the N-S distance from the Tokyo Bay area.

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Aerosol size distribution were determined in Chiba City by Andersen sampler from April 1987 to March 1988 for the major ionic species (H⁺, NH₄⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, SO₄^2-, NO₃^- and Cl^-) and TSP (Total Suspended Particles). The seasonal variations in concentrations and size distributions have been investigated.
The size distributions of TSP and each of the ionic species were bimodal throughout the year. The size distribution of these ions were divided into four patterns, one variant pattern with season and three variant ones throughout the year:
(1) fine-mode dominant in the summer and coarse-mode dominant in the winter for NO₃^- and Cl^-.(2) fine-mode dominant for SO₄^2-, NH₄, K⁺ and H⁺.(3) coarse-mode dominant for Na⁺, Ca²⁺, and Mg²⁺.(4) both-mode dominant for TSP.
There was no seasonal variation in concentration for SO₄^2-, K⁺. But the concentration of Na⁺ increased in the summer and those of NO₃^-, Cl^-, NH₄⁺, Ca²⁺, Mg²⁺ and H⁺ increased in the winter.
In the fine-mode the sum of ionic species (neq/m³) increased in the winter and decreased in the summer, but in the coarse-mode the seasonal variation was not observed.

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In this study, a pattern recognition technique which can calculate such various molecular properties as a molecular weight, a molecular surface area, a sigma charge, a moment of inertia, a molecular refraction and so on, was used together with the sensory experimental data presented by Amoore which contain the values of odorous similarity of 97 compounds to ethereal, camphoric, musky, floral, pepperminty, pungent and putrid odor.
The relationships between molecular properties and the odor quality were investigated using a multiple regression analysis. Five regression formulas with 5 descriptors were formulated for 5 odors, that is ethereal, camphoric, musky, floral and pepperminty odor. The high correlation was found between experimental similarity of ethereal odor and calculated ones. These formulas were employed to predict the odor quality of 27 ethereal odorants and 44 musky odorants, previously unused, and the results were satisfactory.

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To clarify the air pollutants distribution aloft over the Tokyo districts an Airship observation was conducted on 27 March 1989. NO/NO_x, O₃, nonmethan-hydrocarbon concentration and meteorological parameters were observed. NO_x profile and NO₂ ratio for NO_x along with the trajectory line were analyzed. In neglecting the photochemical reaction processes NO₂ emission ratio from Tokyo city area was estimated.

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