Three groups of female mice (Jcl: ICR) were raised in the exposure chambers set atthe roadside in Osaka City. One group was exposed to ambient air, and the other one to filtered ambient air (dust free), and the control group to purified air. The results obtained by hematological and histopathological examinations during exposure for two years were as follows.
The findings observed only in the ambient air group were, the appearance of free large dust cells in the bronchial and alveolar cavity, the deposition of black dusts in the lung tissue, and sometimes foreign body polynuclear cells and a small number of granulomatous change of the lung.
The findings observed common to the ambient air and the filtered air groups were the increase of goblet cells in nasal mucosa, the proliferation of tracheal mucous glands, the hyperplasia of bronchiolar epithelium, edematous thickening of alveolar wall, and minimal signs of red blood cell anemia.
Any significant differences were not found among body weight change and half survival time of three groups.
The mean levels of ambient air pollutants during the experimental period at the exposure site were, also presented in parenthesis the percentage of inside-chamber pollutants to ambient air, 97.6 μg/m³ (68%) of suspended particulate matter, 18 ppb (100%) of sulfur dioxide, 51 ppb (77%) of nitrogen dioxide, 0.2 ppm (82%) of nitrogen monoxide, and 8.4 ppm (93%) of carbon monoxide.

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Every other year since 1971, the Osaka Prefectural Medical Association has conducted a series of investigations regarding sub jective symptoms resulting from air pollution.
The investigation were conducted on all public school children in Osaka Prefectureby the use of a specific questionnaire. In 1979 the fifth investigation was conducted. The total number of schools and students studied between 1971 and 1979 has reached 4, 173 and 3, 648, 550 respectively. In the Osaka area, the sulfur dioxide concentration and the quantity of suspended particulate matter decreased each year, and the nitrogen dioxide showed little change.
1) Osaka was divided into five regeons, according to the level of sulfur oxides. Every series studied illustrated that the more heavily the air was polluted, the higher the prevalence rate of cough as a complaint, and at the same time, the more markedly it decreased year by year. On the other hand, the frequency of cough as a complaint remained almost constant in the non-polluted area.
2) In schools near 9 monitoring stations where the nitrogen dioxide concentration remained at the same level, a decrease in the cough complaint was observed as well as a decrease in sulfur dioxide concentration. Based on these results, we could obtain a model equation showing the prevalence rate of cough and its relationship to the nitrogen dioxide concentration and sulfur dioxide concentration.

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Selenium and sulfur concentration ratios in snow sample, distribution, enrichment factor and size distribution of selenium in aerosol samples were investigated to study sources of selenium pollution in the atmosphere.
The analytical results showed that the average values of the snow samples were O. 13 μg/l for selenium and 1.2 mg/l for sulfur averaging the concentration ratio, Se/S to 1× 10^-4. The average selenium to sulfur concentration ratio in snow samples was found to be in the same order of magnitude as those of fuel oils and rubber products. There was also a significant relationship between selenium and vanadium concentrations in the atmospheric aerosol samples. The enrichment factor of atmospheric selenium to crustal abundance varied from 530 to 2000. According to the enrichment factor of selenium, it is assumed that the crustal contribution to the atmospheric selenium levels is negligibly small. The fine to coarse ratio of selenium in the particle size distribution was much higher than that of aluminium, and the variation of selenium to sulfur ratios with increasing selenium concentration differed was large in the fine particles, leaving that in coarse particles constant. This result suggested that selenium in the fine particles was originated from chemical processes, while selenium in the coarse particles seems to be originated from mechanical process. Therefore, it must be concluded that emission sources of selenium in aerosol samples were mainly combustion processes, especially in urban air.

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NO₂^--impregnated filter (12-1500μgNO₂^-/a filter) was prepared, statically, by adding NaNO₂ methanol solution to quartz filter.[NO₂^-]-decrease rate on the filter was investigated by air-flow through the filter under various conditions, as well as on standing in the desiccator with known relative humidity (RH) controlled by isopiestic method.
It was proved that O₂-H₂O and O₃ (-H₂O) in the air were main substances to decrease the [NO₂^-]. NO₂^- on the filter reacts with O₂-H₂O by the following equation: 3HNO₂=HNO₃+2NO+H₂O and HNO₂+1/20₂→ HNO₃, as in NO₂^- aqueous solution and with O₃ (-H₂O) by the follow: NO₂^-+O₃=NO₃^-+O₂.
In the O₂-H₂O system, [NO₂^-]-decrease rate was increased with an increase of RH in the air, but the rate near RH= 100% became slow. The behavior near RH= 100% was concluded that the surface/volume ratio of particulate NO₂^- was reduced at the RH, making O₂ attack to the NO₂^- difficult.

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A study of the prevalence of respiratory symptoms and pulmonary functions in inhabitants living at the clean air area was done from November 1978 to September 1979. Sub jects of the study were 826 inhabitants from 30 to 49 years of age at clean air areas, Yonezawa and Higashine in Yamagata Prefecture.
The following results were obtained.
1.%VC was 103.4% in males and 107.2% in females. FEV 1.0% was 82.0% in males and 84.9% in females. These values were higher than those of another rural area. Pulmonary obstructive and restrictive incompetency were found to be 5% at the most, and mixed incompetency was zero.
2. V750/Ht was 4.4l/sec in males and 3.7l/sec in females.V725/Ht was 1.6l/sec in males and 1.4l/sec in females. And, V.50/V25 was 2.8 in both males and females. Those values were much the same as those of another roural area. An abnormal rate of V50/V25 was 3.8% found in both males and females. This rate was less than in another rural area.
3. Persisent cough (grade 1) was found in 1.8% of the males and 0.2% of the females and persisent phlegm (grade 1) in 3.3% of the males, 1.3% of the females. These rates were lower than those of another rural area (Sakai Gun) in Fukui Prefecture. And “Persisent cough, phlegm” and “Chronic bronchial symptom” were found rarer than in another area.
4. “stridor” was found in 1.8% of the males and 1.1% of the females. These rates were extremely low level, similar to the lowest cough and phlegm level area in Japan.

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A simple and rapid method for analysing polynuclear aromatic hydrocarbons (PAHs) in airborne particulates was devised.
This method consists of following 3 procedures; ultrasonic extraction of PAHs from airborne particulates, separation of PAHs into their components by high performance liquid chromatography (HPLC), and identification and determination of PAHs by spectrofluorometry. By this method, 3 PAHs, that is benzo-(a) pyrene (BaP), benzo (k) fluoranthene (BkF) and benzo (ghi) perylene (BghiP) in airborne particles can analysed routinely.
PAHs in airborne particles were extracted into benzene by ultrasonic extraction method. The extracted solution was dried under a reduced pressure at 40°C and the residue was dissolved in a small amount of dimethylsulfoxide. 3 PAHs stated above were analysed HPLC under the following condition. That is, column used was Finesil-C₁₈-10 (4. 6 mm i. d.×250 mm). Mobile phase was acetonitrile-water mixture (80: 20, v/v) and flow rate 2.0ml/min. Column temperature was maintained at 5°C, and the excitation and emission wavelengths of the detector was set at 370 nm and 410 nm, respectively. It was proved that this method could determine accurately the 3 PAHs in airborne particles in about 30 min.
This method was applied to the analysis of 3 PAHs in airborne particles in Tokyo air. About 90% or more of the 3 PAHs are in the respirable particles. The concentrations of these PAHs are larger in the winter than in the summer, and also larger in the nighttime than in the daytime.

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A study was made of the characteristics of diffusion parameters which are closely related to the lateral diffusion of pollutants in the atmospheric surface layer. In general, lateral turbulence magnitude and its scale, which are both important parameters in diffusion process, can not adequately be explained by the similarity theory of Monin and Obukhov. In stable air, lateral turbulence magnitude δv depends on Richardson number Ri, while in unstable air the relation between δv/u_* (u_*: friction velocity) and Ri depends also on height above the ground surface. In addition, sampling duration is equally an important parameter related to turbulence magnitude. On the other hand, regarding turbulence scale, dimensionless spectral peak frequency (fm) v depends on Ri and height in stable air, while in unstable air peak wavelength (λm) v seems to be dependent on the depth of the convective layer zi. Using these relationships on turbulent magnitude and scale, we find that the ratio of lateral to vertical diffusivity Ky/Kz decreases with the increase of unstability in unstable air and in stable air this ratio increases with the increase of stability.

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Treatment of trace chlorine in the exhaust gas from a hypochlorite deodorization process was investigated with sodium thiosulfate aqueous solution. The optimum conditions for treating 10 ppm of chlorine at normal temperature were clarified as follows; gas flow rate: 35 kg/h (superficial gas velocity: 1.5 m/s), liquid flow rate: 54 kg/h (liquid/gas ratio: 2l/m³), pH value of the absorption solution: 8-9, sodium thiosulfate concentration in the absorption solution: 500 ppm (w/v, molor ratio of Na₂S₂O₃/Cl₂: around 15). Under these conditions chlorine (0.1-0.2 ppm) in the exhaust gas was proved to be treated completely.

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Sulfate emission from a direct injection type diesel engine, 3.6 1 of displacement, was measured on an engine dynamometer using a dilution tunnel. Emission values, about 2-13 mg/m³ and 20-50 mg/km, were obtained on the basis of concentration and mass, respectively, which are considered to contribute to ambient air quality along a road considerably. Sulfate conversion was found to be 1-2% of sulfur in fuel, showing the maximum value at about 2.2 of excess air ratio. The measurement in this study seem to be reasonable by taking relatively high sulfur content (0.466 wt%) in used fuel into consideration.

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The distributions and chemical compositions of acidic aerosol in OSAKA City were investigated. Samples were collected at five sites in OSAKA City during June to September in 1979. Acidic aerosol was determined by acid-base titration method and then sulfate ion was determined by barium chloride turbidimetry, nitrate ion by xylenol method and chloride ion by mercury thiocyanate method respectively. The concentrations of acidic aerosol at five sites were ranging from 7.7μg/m³ to 10.0μg/m³, but mean concentration of residential area was slightly higher than that of industrial area.
When acidic aerosol concentration were compaired with other strong acidic ions, SO₄^2-, NO₃^- and Clconcentration, it was shown significant correlations between acidic aerosol and SO₄^2-. The sum of each ion equivalents (sulfate ion+ nitrate ion+chloride ion) showed good correlation with the acidic aerosol equivalent during whole periods.

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A mathematical model of diffusion by analytical solution was designed by a simple method to compute the pollutants concentration near a point source sited above the ground surface. The other models were surveyed to compare with the proposed model. The following matters are main features of the model.(1) The model satisfies the condition that wind profile may be represented by the power law as a function for the height from the ground surface.(2) The model consists with the Ukeguchi-Ide's model in the condition of emission height=0, of which the diffusion coefficients are represented by specific functions. But it is not necessary to relate diffusion coefficients to parameters in the model.(3) Roberts's model and other models are correspond to the solution of the model under the specific conditions. The relation between diffusion paramers in the model and air current conditions are under consideration by using the results of field tracer experiment near roadway.

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