Henry's law constants of HCHO, CH₃CHO and H₂O₂ were determined with bubbling and transpiration methods at 12 C. The constants are HCHO: 3500, CH₃CHO: 11.5 and H₂O₂: 1.8×10⁵ (moll^-1 atm^-1). The application of the constant for H₂O₂ to the calculation of liquid phase production of H₂SO₄ by the reaction of SO₂ and H₂O₂ shows that the reaction is a relatively rapid process.

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Nitration behavior of polynuclear aromatic hydrocarbons (PAH) was investigated by mutagenicity and chemical analysis. PAHs was applied uniformly to a Teflon-coated glass fiber filter and/or to diesel particles which were collected on a Teflon-coated glass fiber filter. PAHs used were pyrene (Py), benzo (a) pyrene (Bap), chrysene (Chry), benzo (ghi) perylene (BghiP), benzo (b) fluoranthene (BbF) and perylene (Pery). These PAHs samples were exposed for 4 or 8 hours to a diluted exhaust gas which prepared by diluting original diesel exhaust from a heavy duty diesel engine with fresh air in the ratio 1: 10, and by eliminating particles in the diluted exhaust by filtration, successively. Mutagenic activity of the exposed sample was measured by the pie-incubation method using Salmonella typhimurium TA98 strain without S-9mix. Chemical analysis was carried out by a fused silica capillary column gas chromatography with a nitrogen-phosphorus detector.
Five out of 6 PAHs tested produced direct mutagens by the exposure to diesel exhaust gas. BbF did not produced direct mutagen in the both tests, filter-PAH test and the diesel particle-PAH test. Mutagenic activity produced by the filter-PAH test was in the order of Py, BaP, Chry, Pery and BghiP samples. In the case of the diesel particle-PAH test, the direct mutagenic activity was in the order of Py, Pery, Bap, BghiP and Chry samples. The activity in the diesel particle-PAH test was higher than those in the filter-PAH test. In the both tests, mutagenic activity was increased with the increase of exposure time.
Gas chromatographic analysis showed the formation of l-nitropyrene from the Py sample, 3 kinds of mononitroBaP including 6-nitroBaP from the Bap samples. A nitre derivative produced from peryrene was suggested to be 3-nitroperylene. The amounts of the nitre compounds were increased with the increase of the exposure time in the both tests, and the amounts of these compounds produced in the diesel particle-PAH test were higher than those in the filter-PAH test like the results in the mutagenic activity measurement.

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Dogs are good models for studying the relation between air pollution and lung cancer. One thousand dogs with recorded life histories in Kawasaki city were autopsied. As results of histopathological studies, their degrees of lung contamination and findings of pathological changes were evaluated.
The degree of lung contamination increased with age: 43.0% of the old dogs from the industrial zone had highly contaminated lungs, as opposed to only 20.6% of the dogs of the same age group from the residential zone in Kawasaki city.
Emphysema observed among the dogs was of the centrilobular-type and was seen Particulary in the older dogs with highly contaminated lungs.
Epithelial proliferation around the thrombotic scar caused by Dirofilaria immitis was also seen, but there was no difference as regards the zone.
There were 14 lung tumor cases: 7 were benign (2 bronchial papillomas, 5 adenomas) and 7 malignant (6adenocarcinomas, 1 epidermoid carcinoma), without undifferentiated carcinomas (so-called oat cell type). There were 3 cases of multiple carcinoma. All 7 malignant cases located in midzonal and in the peripheral area of the lungs. Four cases were from the industrial zone, from the commercial zone, and 2 from the residential zone; all dogs were older than age of 8.
Therefore, air pollution is recognized to give a strong influence on the incidence of both lung contamination and lung cancer.

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Actual conditions and annual variation in pollution from metals on airborne particles were determined on the basis of the metal content in the lungs of dogs. Also, the effects of air pollution on the respiratory system are described. The stage of lung contamination (the stage of carbonic dust deposits), pulmonary emphysema, epitherial proliferation and lung tumor (malignant and benign) in about 500 lungs of dogs living in Kawasaki city and of known age and residence were exmained. The presence of 13 different metals (Cr, Ni, Cd, Pb, Co, Cu, Zn, Mg, Fe, Ca, Sn, Ti and Be) was found by atomic absorption spectrometry. The relationship of age, residence, stage of lung contamination, pathological findings and metal content in lungs is discussed.
The following results were obtained.
1) The lungs of dog living in industrial areas exhibited significantly greater concentration of Cr, Ni, Cd, Pb and Co than those living in commercial and residential areas. The concentration of these metals was usually greater in older dogs.
2) Cr, Ni, Cd, Pb and Co content in lungs significantly increased with advancing stage of lung contamination. There was a tendency towards pulmonary accumulation of these metals in all areas but most prominently in industrial areas.
3) No relationship among pulmonary emphysema, epitherial proliferation, tumor and various metals content in lungs could be recognized.
4) A relationship between the kind of dust deposit (black, brown and combination of these) and various metals content in lungs could not be recognized.
5) A high chromium content in the lungs (over 5 μg/g dry tissue) of dogs in industrial areas suggests that the cause is related to a stationary source, but the contribution to lung contamination from a mobile source is comparatively low.
Author's findings clearly indicate that Cr, Ni, Cd, Pb and Co content in lungs, especially Cr and secondarily Ni result from air pollution. By determination of metal content in the lungs of some dogs for which other sources of exposure (smoking, occupational and etc.) may be ignored, the actual conditions and annual variation in pollution from metals on airborne particles could be adequately determined.

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Ozone disappears when in contact with silica gel as reported in the previous paper. The disappearance of ozone on metal (M) oxides was extensively studied with regard to reactions on air borne particulates (M=Ag, Co, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn). Ozonized oxygen was allowed to pass through packed beds of metal oxides at 25°C. The concentration of ozone decreases after passing through metal oxide layers. The rate of disappearance of ozone (r) gradually decays. log (r) is linearly related to log (contact time). Initial rate of ozone disappearance (r₁) was defined as the value obtained by extrapolation of the log (r) vs log (time) straight line to l min. Metal oxides are grouped into highly active ones andmoderate ones in accordance with ri. Highly active metal oxides, Ag₂O, PbO, CuO and Fe₂O₃, show 1-0.1 cm/s for r₁; moderate ones, V₂O₅ and TiO₂, 10^-3-10^-4 cm/s. Linear correlation is found between r_i and free energy of formation of metal oxides per gram atom of oxygen.

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The recent development of environmental problems has been requesting the detail information of the distribution of air pollutants in local area. For these needs, a simple oxidant monitor for measurement of oxidantin ambient air has been designed and constructed.
The sensing part of the oxidant monitor is a sheet of paper soaked with 10% neutral-buffered potassium iodine solution (10% NBKI) or 10% NBKI containing triethanolamine solution (TEA+10% NBKI).
In the oxidant monitor containing 10% NBKI, the determined amount of iodine decreases with temperature raising and increases with humidity raising. On the other hand, in the oxidant minitor containing TEA+10% NBKI, the determined amount of iodine was not so remarkable affected by variation of temperature and humidity.

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The pulmonary function of schoolboys was followed by checking PFR value of each boy for about ytwo ears, and the prevalence of the SO₂ susceptible schoolboys was studied. This study was based on the data which were obtained by examining the PFR value of schoolboys in T, M and O areas in Osaka City during the period from 1963 to 1968.
1. In M area, the SO₂ concentration in the air was low in each season, and the difference of PFR value of M schoolboys between the warm and the cold season was not clear.
2. In T area, the SO₂ concentration in the air was low level in the warm season and became high level in the cold season. The prevalence of the SO₂ susceptible boys who had low PFR value in the cold season and whose PFR value returned within normal limit in the warm season during 2 years, was 20% in 46 subjects.
3. In O area, the SO₂ concentration in the air was high level through the years. The prevalence of the SO₂ susceptible boys, whose PFR value changed following to daily change of SO₂ level in the month when the SO₂ concentration increased not following to the decrease of the temperature in the atmosphere during 2 years, was 19% in 26 subjects. The mean of PFR value of SO₂ susceptible boys was lower than that of nonsusceptible boys.

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A systematic method of analysis of nitrogen-containing cyclic compounds (NCCC) by high performance liquid chromatography (HPLC) and thin layer chromatography (TLC) was investigated for motor bike exhaust gases.
Exhaust gases (about 1 m³) were collected in a liquid oxygen trap. After the NCCC in the collection trap was extracted with methanol, the extract was concentrated to 2 ml of final volume under reduced pressure at 20°C. NCCC was separated with a methanol-water mixture by HPLC, and determined by the comparison of reten tion time and UV spectrum. NCCC was also identified by two-dimensional TLC. HPLC conditions for the determination of NCCC were studied with 16 kinds of standard NCCCs, and the following conditions were found to be optimum for the analysis of NCCC in the motor bike exhaust gases; stationary phase: Zorbax-SIL (6.2 mm i.d.×250mm), mobile phase: methanol-water mixture, flow rate: 1.2ml/min, column temperature: 53°C, wavelength of UV monitor: 254 and 230nm. Indole and g-acridone were detected and identified in the exhaust gas of motor bike, and their concentrations were 17 and 2.9μg/m³, respectively, for examined samples.

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Anesthetized, tracheotomized, artificially ventilated rabbits were exposed to 1.5 ppm and 4.1 ppm of formaldehyde for 3 hours. During the exposure, respiratory machenics, quasi-static volume-pressure curve of lung and flow-volume curve were successively measured. The exposure to the both concentrations of formaldehyde resulted in no noticeable change in all the parameters measured except that the increase in pulmonary flow resistance was suggested in the rabbits exposed to the higher concentration of formaldehyde. A comparison of these results with the respiratory effects of acute exposure to ozone suggests that formaldehyde produces less deleterious effects on ventilatory functions than does ozone, when these gaseous pollutants are entering the lower airways.

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Anesthetized, tracheotomized, artificially ventilated rabbits were exposed to 1.5 ppm and 3.6 ppm of nitrobutene vapor for 3 hours. During the exposure, respiratory mechanics, quasi-static volume-pressure curve of lung and flow-volume curve were successively measured. No significant change in ventilatory functions was observed in the exposure to the lower concentration. The exposure to 3.6 ppm of nitro-butene vapor resulted in a stimulation of the airway secretion and a significant reduction in peak flow and maximum flow at 50% vital capacity on the flow-volume curve without any noticeable changes in other functional parameters. This result suggests that nitro-butene vapor affects the rigidity of the airways thus producing decreased flow during forced expiration.

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Photocatalytic oxidation of SO₂ and/or cis-2-butene with TiO₂ (anatase) was studied in connection with photochemical air pollution. The following results were obtained;(1) Most of cis-2-butene was oxidized to CO₂ with O₂ in the presence of TiO₂ under photoirradiation with a high pressure mercury lamp.(2) SO₂ was also oxidized to SO₃ photocatalytically.(3) The presence of SO₂ reduced the photocatalytic effect of TiO₂ on the oxidation of cis-2-butene.

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In epidemiological studies, the information of exposure and dose for exposed population is insufficient, and we can not usually make a definite judgment as to the specific cause of the observed effects. Controlled human exposure studies have provided considerable information of high scientific reliability for evaluating air pollution risks, since they can clearly demonstrate the relationships between specific pollutants exposure and short-term health effects by controlling confounding factors included in epidemiological studies. Epidemiological and controlled human exposure studies play an important part in evaluating the lowest exposure level including probable adverse health effect. However, a great and clear discrepancy is generally observed between both studies. The available data of controlled human exposure studies do not support positively the results of epidemiological studies. A brief summary and future problems of clinical human exposure studies of air pollutants are presented.

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During the period from Oct. 1 to Nov. 30, 1982, rain water samples was collected in two rural hinterland areas close to an urban area, Nara city and a hillside of Mt. Ikoma, by sequentially sampling of every 1 mm and 5 mm rainfall, respectively. And pH, electric conductivity (E. G.) and concentrations of nine dissolved ions (NH₄⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, SO₄^2-, NO₃^-, Cl^-, F^-) were measured and the property of the rain water was investigated.
Concentrations of the dissolved ions, pH and E. C. in the rain water decreased with the elapse of rainfall and became practically constant after 6 mm rainfall. Thus, the rain water was divided into two groups, the early rain water (1-5 mm rainfall amount) and the succeeding rain water (6mm-rainfall amount).
The maximum frequencies of pH in the rain water in the two sampling sites were concentrated at 4.5-5.0 for both the early rain water and the succeeding rain water. On the assumption that the acid rain water was defined by the rain water with a pH of less than 5.6, 90% of the early rain water and 100% of the succeeding rain water were found to be the acid rain water at the two sampling sites.
The dissolved ions in the rain water at the two sites were mainly consisted of the six cations and four anions determined in this study. On the equivalence basis, the cations and anions in the whole rain water were found in the order of decreasing concentration NH₄⁺, H⁺, Na⁺, Ca²⁺, K⁺, Mg²⁺, and SO₄^2-, Cl^-, NO₃^-, F^-, respectively, in Nara city, while Na⁺, H⁺, Ca²⁺, NH₄⁺, Mg²⁺, K⁺, and Cl^-, SO₄^2-, NO₃^-, F^-, respectively, at a hillside of Mt. Ikoma.
Contribution of sea salt to the dissolved ions in the rain water at a hillside of Mt. Ikoma near the seacoast relative to Nara city was speculated.

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