A simple mathematical model of air pollution is developed. This model is based on the finite difference solution of mass conservation equation. An airshed is divided into manyboxes. The size of each box is 2 km square, and the depth changes with time due to variation of the mixing depth. The wind components of each box are calculated by weighted average interpolating scheme from observed winp data at several meteorological stations.
The initial application of this model is the calculation of carbon monoxide concentration which is considered as the unreactive contaminant. The calculated values and observations are in good agreement.

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The purpose of this paper is to develop the multi-box model which is described in Part I, in order to simulate the photochemical air pollution. The pollutant concentrations are calculated by the kinetic model of photochemical reactions proposed by Friedlander and Seinfeld.
This model is applied to the estimation of nitric oxide, nitrogen dioxide, hydrocarbon and ozone concentrations in Tokyo metropolitan area.

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In this study, automobile exhaust gases, one of the main air pollution causes in urban areas, is basically investigated by operating a conventional engine on an engine dynamometer. It was shown that balancing the carbon atoms of supplied fuel and of exhaust gas is useful to make clear the reliability of measured values in the CVS system. The relative reliability of the exhaust gas analyzers was made sure by comparing measured values of direct exhaust gas with those of diluted exhaust gas under a hundred sorts of engine conditions.
The behavior of exhaust gas releasing and some characteristics of engine parameters were tested in various engine steady states. In addition, the effect of the slow system of the carburetor on the exhaust gas was studied. The equivalence ratio, one of the important combution factors, was calculated also from direct gas concentrations, and it was shown that this method was available in the case of the conventional engine.

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The airborne particulate matters were collected using Andersen impactors before and after an air filter placed on the 27th floor of a building at downtown Yokohama. Filtration characteristics of the filters were obtained by measuring the particle size distributions on weight basis, and simultaneously, neutron activation analysis method was applied to determine the size distributions for trace elements.
The size distribution curve of the particulates has two peaks: one of “coarse particles” at 4μm and the other of “fine particles” at smaller than 0.5μm. On the other hand, the size distribution curves for elements were classified to three typical patterns. The coarse particles ware removed by the hi-efficiency filter, but the fine particles were little removed. The fine particles were remoed about half by the charcoal filter.
Removal efficiency of trace element by the air filter depends on the size distribution of each element. Almost all of the coarse particles which could be originated from the ground can be ramoved by the filter, but the fine particles probably originated from combustion sources are hardly removed.

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The diffusion parameters which have been most widely used hitherto in making practical estimates of the distribution of ground-level concentration are those developed by Sutton, Pasquill and Turner. However, for predicting absolute values of concentration so as to be agreeable with the observed concentration over a wide range of meteorological conditions, those parameters are notalways satisfactory, mainly due to difficulties in evaluating reliably each value of parameters according to respective meteorological conditions.
In this report, instead of selecting appropriate values of parameters which weretabulated by meteorological properties of the atmosphere, the optimum values of parameters could bedetermined by a mathematical method so that the estimated concentration might closely agree withthe observed concentration. It was also found that in determining the optimum values of parameters, the gradient method was very useful. The estimated optimum values of parameters were applied to the diffusion formulae of the so-called plume model and the distribution of ground-level concentration was practically evaluated in the urban area where many small continuous sources caused low level air pollution.
The principal component analysis was also performed among the meteorological factors available and further it was tried to carry out the multiple regression analysis the to discuss the correlation between from first to forth principal components of meterological factors and the estimated optimum parameters. As a result, it was confirmed that the coefficient of correlation was 0.8 in case where the wind direction observed at a given point well represented thore of neighboring area.
Even though the correlation did not exist between the available meteorological factors and the estimated optimum parameters, in predicting the distribution of ground-level concentrationwith optimum values of parameters, colose agreement could be obtained between the observed concentration and the estimated concentration. Thus, in any cose, the optimum values of parameters which could be determined by the gradient method was available to a sufficient accuracy for making practical estimates of the distribution of ground-level concentration and also it was proved that this gradient method migh be applied to a variety of other practical uses in the atmospheric dispersion computation.

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Effect of ozone on viability of alveolar macrophages were studied. Rabbits were exposed to 1.0 ppm or 2.7 ppm of ozone for 3 hours, or 1.0 ppm of ozone for 3 hours a day for 7 days.Then alveolar macrophages were harvested and cultured in vitro. The viability of alveolar macrophageswas determined using cell growth and mitotic index.
Cell growth and mitotic index were decreased by the exposure to ozone but no difference between acute exposure (1.0 ppm for 3 hours) and repeated exposure (1.0 ppm for 3 hoursa day for 7 days) was found.

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This paper describes a simple and rapid analysis of polynuclear aromatic hydrocarbons (PAH) in gasoline. The metnod consists of the following procedures. PAH in gasoline is directly separated with one-dimensional dual band thin-layer chromatography [Thin-layer plate; Kieselguhr G (5×20, cm).-(26% Acetylated cellulose +Cellulose D-O) (95: 5, w/w, 15×20, cm), Developer; Ethanol-Ether-Water (4: 4: 1, v/v) for the 1st development, Methanol-Ether-Water (4: 4: 1, v/v) for the 2nd development]. Each PAH spot separated on the thin-layer is scraped off into a small centrifugal-tube. After adding 4 ml of dimethyl sulfoxide (DMSO) into the tube, ultra sonic extraction is carried out for 10 minutes in order to dissolve PAH completely into the solvent. The DMSO solution is then centrifuged for 5 minutes. Each PAH in the supernatant is identified by comparison of its fluorescence and excitation spectra with those of standard PAH solution and determined spectrofluorometrically by means of a narrow base line method.
The analysis of PAH in 8 segular and 8 premium gasolines was carried out by the method mentimed above. Ten PAH were identified by spectrofluorometrical analysis, namely, pyrene, fluoranthene, chrysene, benz (a) anthracene, benzo (b) fluoranthene, anthanthrene, benzo (a) pyrene, benzo (k) fluoranthene, perylene and benzo (ghi) perylene. The identified PAH except benzo (b) fluoranthene were also determined quantitatively. Reporducibility of PAH determination in the present method was high and stable. PAH content in gasoline was in the order of pyrene>fluoranthene>benzo (ghi) perylene>chrysene>benz (a) anthracene >benzo (a) pyrene>benzo (k) fluoranthene>anthanthrene>perylene Benzo (a) pyrene contents were ranged from 0.05 to 0.32μg/g for regular gasolines and 0.06 to 0.56μg/g for premium gasolines. PAH contents in premium gasolines were about 1.8 times higher than that in regular gasolines.

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