Nitros-ylhemoglobin (Hb-NO), prepared in a gas-tight syringe anaerobically, was reacted with dissolved oxygen (O₂) in phosphate buffered saline at pH 7.4 and 37°C. The reaction process was monitored by measuring (i) O₂ concentration in the medium by O₂ electrode, continuously, (ii) Hb-NO and methemoglobin (Met Hb) concentrations by EPR spectroscopy and (iii) NO₂^- and NO₃^- concentrations by chemical analyses.
(1) Hb-NO was quantitatively converted to Met Hb by consuming dissolved O₂, and NO₃^- was produced.The reaction process consisted of branched, successive reactions:(i) The dissociation of Hb-NO was rate-limiting step, yielding deoxyhemoglobin (deoxy Hb) and NO; NO in solution changed to NO₂^-.(ii) At higher O₂concentration, oxyhemoglobin (Hb-O₂) was transiently formed, and reacted with NO₂^-, yielding Met Hb and NO₃^-.(iii) At lower O₂ concentration, deoxy Hb reacted with NO₂^-. yielding Hb-NO, Met Hb and NO₃^-.(iv) NO₃^- production from NO₂^- and O₂ was catalyzed by Met Hb. The following scheme was proposed.
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(2) As proceeding the Met Hb formation from Hb-NO, the ratio of α-NO to β-NO in Hb-NO augumented and the alteration of α-NO was found, as judged from ESR spectra.
(3) The reaction between Hb-NO in erythrocytes and dissolved O₂ was qualitatively interpreted by the proposed scheme.

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Effect of air pollution on the mortality for respiratory diseases except tuberculosis and neoplasm was studied in a city located in a cold district with two big iron and steel industries as air pollution sources.
Population studied was the residents of two districts; different with respect to air pollution level and same in the socioeconomic level, and aged 50 years and over.
Mortality rate was calculated for three 5-years periods between 1963 and 1977.
In the first 5-years period, when air polluion was most severe, the mortality rate for respiratory diseases except tuberculosis and neoplasm in the cold season of the high-pollueted district was higher than that in the warm season and that in the cold seaosn of the low-polluted district. Especially in the case of the female, these differences were statistically significant.
The mortality rate for selected respiratory diseases (bronchitis, emphysema and asthma) showed also the same tendency in the first 5-years period.
In the middle and last 5-years period, these high mortality rate, especially of the female, tended to decrease Its causal factors were considered to be mainly the improvement of air pollution and in some part of the change of host factor due to removal of residents susceptible for air pollutants from the polluted area.

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An attempt was made to determine the factors influencing personal exposure levels of NO₂ for housewives living in urban area in two seasons, winter and summer.
NO₂ was measured with small passive sampler containing triethanolamine, and samplers were set for 24 hours at three points, they are: near the collar of volunteers (personal exposure level), near the TV in living room (in-door level) and near the porch of their houses (outdoor level).
The subjects recorded the times of spending cooking using gas appliances, using kitchen ventilator and unvented oil or gas heater, total of minutes of opening window, going out of home and so on.
There was an apparent increase in personal exposure level in case of unvented heater, although it did not marked increase by using cooking gas appliance.
Through these observations, we concluded that personal exposure lev el of NO₂ was strongly related to indoor NO₂ level, and factors influencing indoor NO₂ level seemed different between in winter and in summer, the biggest one was indoor pollution in the former and in the latter that was the level of outdoor environment.

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Relative value (Rc=o) of infrared absorption of carbonyl stretching vibration (-1720cm^-1) to that of methylene asymmetric stretching vibration (-2920 cm^-1) was defined. Its utility to investigate chemistry of aerosols was illustrated by dependence of R_c=0 of organic components in airborne particulate matter on concentration of ozone.

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Diurnal variations of relative values (R_c=0 and RoNo₂) or νOc=o absorption (-1720 cm^-1) and νONO₂ absorption (-1280cm^-1) to νCH₂ absorption (-2920 cm^-1) in infrared spectra of organic components in airborne particulate samples, which were collected over a sampling time as short as 2 or 3 hours, were studied. It was found a similarity on diurnal variations between the former and ambient ozone concentration as well as between the latter and inorganic nitrate concentration. A possible origin of the similarity was discussed.

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This paper presents a comparison of four idealized line source dispersion models which include the EPA-HIWAY model, GM line source model, Tokyo Government model and Japan Environmental Agency's model. Each model validation was obtained by the regression analysis. In the analysis the model predictions were compared to measured NO_x concentrations.
The result of the model validation analysis shows that the EPA-HIWAY model has a tendency of over-estimated, but among the others, there are no large differences for the statistical evaluations.

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