Studies on the wintertime photochemical air pollution, which was merely a hypothesis 10 years ago and now is taken for granted in the numerical studies, are reviewed. The phenomenon was first assumed in the analysis of severe NO₂ pollution episodes in early winter, which was unable to explain by a conventional photostationary state concept. Subsequently, the existence of wintertime photochemical air pollution was confirmed by field studies. Severe NO₂ pollution episodes caused by such mechanism was then reproduced by more detailed numerical study. On the basis of these studies, an urban aerosol model which built-in the NO₃^- formation scheme is under development. Although studies in European countries have generally neglected the photochemical reactions as a source of high winter NO₂, some studies in the United States regarded it as a source of NO₃^- in urban aerosol pollution. It suggests that the wintertime photochemical air pollution could be a common phenomenon at metropolitan cites in the mid-latitude zone.

View full abstract

Influences of fluoride exhausted from electrolytic factory of alumina on physiology of paddy rice and yield were investigated. As the results; it was recognized that the more paddy rice was injured, the more total nitrogen content in leaf blade was increased. In addition, calcium content in leaf blade was decreased and silicon content in straw was increased in the area. From the fact that the more fluoride content in straw, the more fluoride content in rice bran, it was recognized that fluoride is accumulated in rice bran. Accordingly, it was presumed that a portion of fluoride taken in rice plant was translocated through rice plant with nutriment or water.
In visual injury of fluorine to paddy rice, leaf blade tended to hang down at ligule, and also colors of tip and marginal of leaf blade faded from green to greyish green. These symptoms spread gradually over the whole leaf blade, which was resulted in browning and withering. It was also recognized that injured paddy rice was low in height, number of the culm decreased, the heading stage delayed and the amount of accumulated starch in leaf sheath decreased. At the harvest time it was observed that the more paddy rice was injured, the more a number of paddy per ear tended to decrease. Accordingly, it was presumed that paddy rice was injured by fluoride at spikelet differentiation stage. It appeared extremely that hydrogen fl uoride in the ambient air had an effect on the decrease of yield. The fluoride content for the border of leaf injury was assumed to be nearly 70μg/g in leaf blade.
Considering the relation between amount of fluoride accumulation derived from data of lime filter papermethod and fluoride content in leaf blade of paddy rice, it was presumed that the absorption coefficient of hydrogen fluoride into leaf blade was 0.051. Accordingly, it was supposed that the concentration of hydrogen fl uoride in the ambient air might be nearly 0.04ppm at the severely injured point, when the paddy rice was injured by hydrogen fluoride in 1968.

View full abstract

Concerning citrus Unshu, growing around electrolytic factory of alumina, relation between the distance from source of emitting fluoride and the accumulation of fluoride inside leaves was studied.
Fluoride content in citrus leaves gradually increased immediately after a growth of leaf. The increase almost stopped after about eight months. The increase of fluoride content in citrus leaves continued on and after eight months at the near region where the paddy rice was vigorously injured by fluoride in 1968, therefore it was presumed that the increase of fluoride content was due to fluoride in the ambient air.
Significant correlation was recognized between the distance from the source of emitting fluoride and the fl uoride content in citrus leaves, but in cource of time the reciprocal relation gradually became more close.
As for the relation between the content of fluoride and that of another inorganic component in citrus leaves, it was appeared that none of Ca, Mg, K, Zn, Fe, Mn is related to fluoride. Accordingly, it was presumed that fluoride hardly promote the deficiency diseases of Mg, Mn, Zn.
Concerning the fall of leaves, an investigation was carried from 1969 to 1970. As the result, significant positive correlation was recognized between the fluoride content in living leaves and the fallen leaves, and the fluoride content in citrus leaves tended to decrease. Under higher hydrogen fluoride in ambient air, more fl uoride was inevitably accumulated in living leaves.

View full abstract

A simultaneous determination method by gradient ion chromatography was developed for tormic, acetic and oxalic acids with other anions in precipitation samples. Fifty-five precipitation samples were collected in suburbs of Niigata City. The concentrations and wet deposition amounts of the organic acids were measured by the developed method. The seasonal variations in concentrations and in wet depositions of the organic acids, and in the ratio of organic acids to total acidic components were shown to be higher in spring to summer and lower in autumn to winter. There were high correlations among these organic acids.

View full abstract