The effect of cupric ion on the corrosion of copper in a dilute sulfuric acid solution was studied by using polarization conductance.
The square root of the concentration of cupric ion was found to be proportional to the corrosion rate.
The corrosion rate also increased with pH, when the solution included cupric ion.
These results were successfully explained with the reaction mechanism having proposed by the authors in the previous papers.
It was estimated that the increase in corrosion rate with time would continue as long as the active dissolution proceeded.

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Personal exposure to nitrogen dioxide for urban office workers in the central area of Tokyo were examined in two seasons, fall and winter. Indoor and outdoor levels in the office and in the home of the participants were simultaneously measured with small passive sampler for 24 hours. Each participant kept a diary of his activities, those are, time spent indoors at home and office, during commuting and staying another places. NO₂ exposure level predicted from a time-weighted activity model were compared with the measured value by sampler.
It suggested that the model provided a good prediction of personal exposure level of nitrogen dioxide.

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To estimate precisely an average SO₂ concentration in the atmosphere with the lead peroxide method, the actual kinetic expression for SO₂-PbO₂ reaction system are investigated by regarding the reaction system as a noncatalytic reaction of solid particle with surrounding gas. The reaction models used are progressve-conversion model and unreacted-core model. The experimental research to examine the effect of the atmospheric conditions such as wind velocity, humidity, solute gas concentration, and temperature on the reaction has been performed with the cylindrical PbO₂ pellet. The values for the gas film mass transfer coefficient, the effective diffusivity in porous solid, and reaction rate constant are estimated according to the reaction model and experimental data and the rate controlling resistance for the actual kinetic is discussed on the basis of various properties estimated.

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For the precise evaluation of SO₂ concentration measured with the lead peroxide method, the effect of nitrogen dioxide on the method is studied experimentally. The experiment has been carried out with a cylindrical PbO₂ pellet and SO₂-NO₂-N₂ gas mixture. The selectivity to produce the solid product and the transfer mechanism for gaseous reactant in the porous solid are discussed according to the dataobtained in this experiment.

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Concentrations of sulfur dioxide in the environmental air at Minma and Yoneizumi regions in Kanazawa city was measured with the lead peroxide method every ten days over sixty days. The two shelters made with polyvinyl chloride plate were set at each measuring point to investigate the effect of light energy hν on the measured values. One was covered with thin aluminum film and the other was not treated. For the purpose of comparing the values obtained at different measuring points absolutely, the semi-theoretical equation is derived by using the characteristic parameter ψ due to the difference in the environmental conditions at measuring points and the effects of several gaseous substances coexisting with sulfur dioxide and sunrays on reaction.

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We observed NO₂ concentration in the vicinity of an intersection. NO₂ concentrations are always higher on the intersection (12 pphm) than on neigh by roads (5 pphm). Numerical model was developed to calculate NO₂ concentrations around the intersection. This model is the two dimensional diffusion model for continuous constant multiple point sources. This simulation show that the most important factor is advection and the calculaton agree favorably with measurements.

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The purpose of this study is to observe the histological changes of the lungs of male Wistar rats exposed continuously to 20 ppm NO₂ for 20 hours and to 0.5 ppm NO₂ for 19 months.
After the interuption of exposure of high concentration of NO₂, blebbing of the Type I cells was observed at the 1st day. 15 to 30 days later, the alveolar intermediate type cells appeared, which represent the transformation of Type II cells to Type I cells.
The number of the Type I and Type II cells was countered. The ratio of the Type II cells to Type I cells increased on the 5 th day, reached the maximum on the 15 th day, and then returned to normal on the 30 th day. The alveolar intermediate type cells were remarkable in this period.
The pinocytotic vesicles of capillary endothelial cells became remarkable at an early stage. And then the pulmonary interstitial tissue became edematous, while no histological changes of junction of endothelial cells was found out during the experiment in each stage. And the disappearance of edema of interstitial connective tissue needed for about 30 days.
The changes in alveolus after the long term exposure to low concentration of NO₂ were as follows. After the exposure for 2 months, hypertrophy and increase of Type II cells and the increasing permeability of capillary endothelial cells were observed. And after exposure for 4 months, the edema of pulmonary interstitial connective tissue was observed. These changes had been continuously increasing for 19 months. These changes of the lung after the long term exposure to low concentration of NO₂ resemble to the progressive changes of it after the exposure of high concentration of NO₂.

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Present studies were performed to compare the quantitative and qualitative aspects of pharyngeal flora and the concentrations and ratios of immunoglobulins in saliva of students at elementary and junior high schools exposed to heavily polluted air with those exposed to lightly polluted air. Two hundred forty school children from three elementary schools and 100 students from two junior high schools were examined for bacterial growth in pharyngeal mucus. Ninety-eight students from two junior high schools were examined for the presence of immunoglobulins and albumin in their saliva. The authors obtained the following results. 1. The rate of detection of gram negative bacilli in pharyngeal mucus was higher in subjects exposed to heavily polluted air than in those exposed to lightly polluted air. 2. The ratio of Ig A in saliva was lower in subjects exposed to heavily polluted air than in those exposed to lightly polluted air. These results suggest that a low concentration of Ig A enhances the ability of gram negative bacilli to survive in the upper respiratory tract.

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Heavy metals such as Cd, Pb, Zn, Sn, and Hg were discharged together with smoke and dust when municipal solid waste were incinerated. The emissions of these five metals were given as following.
(1) The emissions of Cd, Pb, Zn, and Sn in the soot and dust have positive correlation with the disposal quantity of the waste plastics (especially chlorine plastics) in refuse.
(2) In the case that the proportion of the waste plastcis were from 7 to 13%, electrostatic precipitators have proved efficiently clearing up the emissions of Cd, Pb, Zn, and Sn. However, when the disposal quantity of the waste plastics were much, it had been not sufficient to clear up the emissions of these heavy metals because of the insufficiency of dust-collecting capacity in electrostatic precipitators.
(3) The emission of Hg was supposed to come from a kind of dry cell, a thermometer, and a fluoresent light contained in the refuse.
Therefore, separation of the these stuffs from the municipal solid waste by separate collection prior to incineration should reduse the emissions of Cd, Pb, Zn, Sn, and Hg.

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