The oxidation of S (N) ion in rain water containing Fe³⁺ and Mn²⁺ was investigated in test solutions, and rain water samples. The rate of oxidation reaction of S (IV) ion both in test solutions and rain water was of the first order. The rate of oxidation of S (N) ion was 0.12-1.6×10^-6s^-1 without the catalyst, while it became larger, 1.7-16×10^-4 s^-1, by the order of 2 to 4 by the existence of Fe³⁺ and Mn²⁺. Therefore, Fe³⁺ and Mn²⁺ strongly contribute as catalysts for the oxidation of S (IV), and the positive correlationship was found between the concentrations of Fe³⁺ and/or Mn²⁺ and the oxidation rate. The increase of the oxidation rate at lower pH of solution was also found at pH4 to 6. This could be due to the change of chemical form of each catalytic ion by the pH of solution. As the results of these experiments, catalytic oxidation reaction of S (IV) ion was expressed as a function of concentrations of Fe³⁺ and Mn²⁺ and pH of solution.
The oxidation rate of S (N) ion in 11 rain water samples collected at Hiyoshi, Yokohama, May through November, 1985 was 3.4-92×10^-5 s^-1. These measured values were almost agreed with the values, 3.5-140×10^-5 s^-1, calculated by the experimental equation.

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In order to clarify the relationship between the alteration of collagen-metabolism in lungs and lung fibrosis, rats were exposed acutely and chronically to NO2, and the changes of lipid peroxides, and collagen-metabolizing factors in lungs, serum and urine were examined.
In the acute experiment with rats exposed to 10 ppm NO₂ for 2 weeks, the contents of hydroxyproline in lungs and serum were significantly increased from 4 to 10 days by NO₂ exposure. Collagenolytic enzyme activity in lungs at 4-10 days was higher than the control level. A significant relationship between collagenolytic enzyme activity in lungs and hydroxyproline contents in serum was observed. The activities of collagenase inhibitors in lungs and serum were decreased significantly at 1-4 days, and then the activities showed a tendency to increase over the control level from 7 to 10 days. And a significant relationship between the activities of collagenase inhibitors and the contents of lipid peroxides in lungs was observed. This result suggests that collagenase inhibitors are inactivated by lipid peroxides. Thickening of the wall of alveolar duct and ad jacent alveoli, and slight development of fibrosis were also observed microscopically at 7 and 14 days, but the degree of their changes at 14 days was less than that at 7 days. These morphological observations corresponded well with the changes of biochemical collagen-metabolizing factors in lungs, serum and urine.
In the chronic experiment with the rats exposed to 0.4, 1. 2 and 4ppm NO₂ for 18 months, the dosedependent decrease of collagenolytic enzyme activity in lungs was most characteristic change. On the other hand, the activity of collagenolytic enzyme in serum was increased dose-dependently. These evidences suggest that the activity of collagenolytic enzyme in lungs might be related to that in serum, and that the decrease of collagenolytic enzyme activity in lungs might be a major mechanism of lung fibrosis observed in the morphological examination reported previously (6).

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Motions of a particle after it starts to move on a wall surface may be classified as sliding/creeping on the surface, saltation from the surface, and suspension in the fluid body. Among these three motions, suspension is considered to be the most important mechanism from the view point of air pollution. Initiation of suspension is mainly due to either detachment by collision after creeping motion, or detachment by lift-up. In order to simulate these phenomena, systematic models which incorporate these two initiation mechanisms and Lagrangian diffusion were developed and evaluated. Lagrangian velocity which affects on the motion of particle is expressed by the first order Markov process in the models. Only viscosity term and gravity term are included in the equations of motion for spherical particle. A set of hypothetical physical characteristics of a particle were assumed for the investigation.
It was shown by comparing numerical solutions of the Lagrangian diffusion model with analytical solutions for concentration distribution expressing diffusion in shear flow that the Lagrangian diffusion model is rationally representative of characteristics of particle suspension.
The two models for initiation mechanisms of particle detachment from wall surface were investigated by utilizing experimental data obtained from particle suspension experiment conducted with a pile of coal because wind speed data and total estimated amount of particles suspended were available. The bound detachment model was found to show better agreement with the experimental data than the lift-up detachment model. This result appears to be rational because repellent detachment phenomenon was expected to be predominant in the experiments due to relatively large sizes of coal particle.

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A lot of measures which evaluate the performance of diffusion model have been suggested. It has not clalified what characteristics of the model these measures evaluate and the similarity among these measures.
It is necessary, however, to select the proper measures which suit the objectives of diffusion models and to judge the model in accordance with the quantitative standard.
In this paper, first the evaluation measures and correlation coefficients among them were derived based on the observed and the calculated concentrations using diffusion model which was applied to the Kashima areas. It was clear that the correlation coefficients among some measures were high value.
Next principal component analysis was introduced in order to make clear the characteristics of these evaluation measures toward the model. As a result, these measures were diveded into four groups, and then it was possible to evaluate easily the different ability of the diffusion model by means of the different four measures which were selected from each group.

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This report presents the lung clearance of the rats measured by the technique of “the magnetopneumography”in order to evaluate effects of the xposure to air pollutants on the small animals.
Ferrimagnetic Fe₃0₄particles (1 pm diam.) of 0.3mg/100 g body wt which was suspended into 0.4 ml of sterile physiological saline was transorally instilled into trachea of anesthetized male Wistar rats (12 weeks old, N=9). Rats were exposed to magnetic field of 800 Gauss for periods of 30 seconds to magnetize the particles and then transferred into the shields made of double cylinders of Permalloy. The remanent field from the lungs was measured by a flux gate magnetometer, which probe was installed inside the cylinder.
A gradual decrease was observed in the remanent magnetic field and called “relaxation phenomenon”. The first one minute of the relaxation curve was fitted to the exponential function, Y=ae^-bX, where “X” is the time (sec) after the external magnetic field was turned off, “Y” is the field strength at timeX, “a” (initial field strength, obtained by extrapolation) is the field strength at timeX=0, and “b” is the relaxation rate for the first one minute. The above measurements were carried out every during the first 4 days and then every one or two week up to the 9th week after the particle instillation. The normalized clearance curve which was drawn using the time-“a” relation were shown to have two components, the first one decreased rapidly during the first 2 weeks (T_1/2= 16.2 days) and the second one decreased more gradually (T_1/2= 52.3 days). Nine weeks after the instillation, 65% of the particles in the lungs had been cleared.
The relaxation rate for the first 30 seconds period increased the most rapidly the forth day after the instillation.
The clearance curve estimated by this technique was similar to that of well-characterized radiologicaldetection method and this relatively inexpensive and noninvasive technique was suggested to be suitable for studying the efffects of the exposure to air pollutants on the lung clearance of small animals.

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Epidemiological studies have been conducted from 1980 to 1984 to investigate health effect of air pollution in 53 areas whithin Japan showing different degrees of ais pollution (average NO₂value of three years before the investigation was 5-43 ppb).
Self-admistrated questionnaires based upon the ATS-DLD standard were prepared by Research Team for Air Pollution Effect on Human Health in Japan Environment Agency and were distributed to 125. 728 school-children (boy: 64.218 girl: 61.510) in surveyed areas.
Effective collected questionnaires numbered 123.536 with response rate of 98.2%.
98. 965 cases from the responded who had been resided in the surveyed areas for more than three yearswere analyzed for further examination and following results were obtained:
1. Prevalences of respiratosy symptom of surveyed areas were:
Persistant cough...boy 1.8% girl 1.3%
Persistent congestion and/or phlegm...boy 1.2% girl 0.9%
Asthma-like symptom (existing)...boy 4.6% girl 2.9%
Wheezing...boy 6. 3% girl 5. 3%
Prevalence of each item showed higher for boy than girl.
Clear difference was found among the areas concerning the prevalence of asthma-like symptom (existing) and wheezing, i. e.
Asthma-like symptom (existing)...boy 2. 9% (min.) 8. 7% (max.)
girl 1. 4% (min.)-6. 9% (max.)
Wheezing...boy 3. 9% (min.)-9. 9% (max.)
girl 2. 9% (min.) 9. 0% (min.)
Prevalences of persistent cough and persistent congestion and/or phlegm were low enough so that difference among the areas decreased.
2. Concerning various factors relating to asthma-like symptom and whcezing, i. e. allergic disposition, medical anamnesis, infantile nutrition, smoking within family, dwelling condition, heating apparatus, all of which could be obtained from the questionnaires, were analyzed and result was as follows:
Concerning cases having medical anamnesis of allergic disease (nettle rash, allergic coryza, eczema, ) and cases having family history of asthma and/or allergic coryza, higher prevalence was revealed than the cases which had no such medical anamnesis and family history.
Influence of smoking whithin family could be seen a little in wheezing prevalence but it could not be found in the prevalence of asthma-like symptom.
Prevalence of asthma-like symptom (existing) showed a little higher tendency for the cases who used heating apparatus whithout ventiduct in reinforced concrete houses (air-tight structural house) than those who used heating apparatus with ventiduct in wooden houses with wooden sash (non-air-tight house). But this difference was not significant.
Allergic dispostion and medical anamnesis of allergic disease were found influential to prevalence but this did not explain the difference among the surveyed areas.
3. The surveyed areas were classified into four groups according to NO₂concentration, i. e. under 10 ppb, 21-30 ppb, over 31 ppb. The higher was NO₂value, the higher was the prevalence of each symptom (asthma-like, wheezing, persistent cough, persistent congestion and/or phlegm).
Such tendency was found in the cases having allergic dispostion and medical anamnesis of allergic disease mentioned above. Nevertheless as to the cases without said allergic dispostion and medical anamnesis of allergic disese, only girl cases showed higher increased.
Correlation coefficients between prvalence of asthma-like symptom (existing) and average NO₂value of three years befor the investigation were significant for both sexes.
This investigation were cross sctional study mainly for respiratory symptoms and therefore other relating factors of asthma such as social, economical, or psychoanalystic factors have been left untouched.

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In U.S.A., as developing programs of the Air Pollution, it was controlled by thelaw of the Clean Air Act. And the Mobile Source Air Pollution Controll program has developed a system of primary gas standards which permits commercial gas blend to be named within 2% of true values and traceability relationship of each gas to NBS's SRM.
And then the measuring method of CO, NOx and HC in motor vehicles exhaust gases was specified by the regulation of the control of Air Pollution from new motor vehicles and new motor vehicle engines.
According to it regulations, it was enacted that calibration gases shall be traceability to within 1% of NBS gas standards or other gas standards which have been approved by the administrator, and more, span gases shall be accurate within 2% of true concentration, where true concentration refers to NBS gas standards or other gas standards which have been approved by the administrator.
In Japan, the traceability of reference gases have been established with the inspection system of them by CITI under the guidance of MITI (ministry of International Trade and Industry).
Therefore, in order to make the international agreement of concentration of reference gases, we performed the round robin test between NBS, EPA, BOC, VSL and AL about the each concentration of samples of some reference standard gases which were prepared by gravimetric method.
It is concluded that the reference gases of the participating countries agreed well in the concentration and most of their difference between the countries were within 1% except the following data; 5 ppm CO-N, (NBS and EPA), 1200 ppm C3H8-N₂ (NBS), 5 ppm and 20 ppm NO-N₂ (AL, CITI) and 500 ppm, 100 ppm and 50 ppm 5O₃-N₂ (BOC, NBS).

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