This paper presents the results of performance tests of various kinds of adsorbents by static and dynamic adsorption methods to select the optimum deodrant (adsorbent) for ammonia gas (NH₃).
In the peformance test of the static adsorption method, the amounts of NH₃ adsorbed by 21 kinds of adsorbents including physical and chemical adsorbents were measured.
The amounts adsorbed physical adsorbent No.6, chemical adsorbents No.18, No.19 and No.20 which showed higher adsorption ability were 0.0160g/g, 0.0284g/g, 0.0250g/g, 0.0249g/g respectively at 30°C under equilibrium preasure of 50mmHg. All of the adsorbent showed in Freundlich's adsorption isotherm for NH3. Although the correlation between specific area, pore volume, mean pore radius, pH each adsorbent and the amount of adsorbed were tried, the correlation between the pH and the amount of NH₃ adsorbed was significant. This suggests that the pH is a proper criterion for selection for adsorbents.
The performance test of the dynamic adsorption method, was conducted for adsorbents No.6, 18, 19 and 20 above-mentined. The 10% breakthrough time was compared as the performance index. The breakthrough time of the adsorbent whith the amount adsorbed was large was long but the breakthrough time was not proportional to the amount adsorbed.
These results suggest that the perfoemance test only by the static adsorption method is insufficient and that the breakthrough time test by the dynamic adsorption method is essential.

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Activated carbon is utilized as one of the most popular odor control measures. In designing an activated carbon bed, adsorption capacity and removal rate are very important factors. These factors are influenced by temperature and humidity.
The effects of temperature and humidity on hydrogen sulfide removal were therefore investigated in laboratory experiments. Removal of hydrogen sulfide by activated carbon involves not only physical adsoprtion but also oxidation. A higher temperature decreases adsorption capacity, but it increases the oxidation rate of hydrogen sulfide. Humidity in flow gas increases removal capacity. The removal rate depends on the concentration of hydrogen sulfide. It is believed that odor removal with an activated carbon bed can be performed more effectively based on information about thesefactors.

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Seedlings of two coniferous tree species: Japanesse cedar (Cryptomeria japonica), Nikko fir (Abis homolepis) and two deciduous broad-leaved tree species: Japanese white birch (Betula platyphylla var. Japonica), Japanese zelkova (Zelkova serrata) were exposed to ozone and simulated acid rain, alone or in combination, for 20 weeks. Ozone exposure was conducted daily in four environment-controlled greenhouses. The ozone treatments consisted of four simulated profiles with diurnal fluctuation: 0.4 (×0.4), 1.0 (×1.0), 2.0 (×2.0) and 3.0 (×3.0) times of the average profile of ozone concentration in ambient air in 1991 and 1992. Exposure to simulated acid rain was conducted three times per week in the nighttime. The rain pHs were 5.6 and 3.0.
Two deciduous broad-leaved tree species showed white fleck leaf injeries followed by yellowing and defoliation in their early stages at ×2.0 and ×3.0 of ozone. Rain treatment at pH3.0 caused necrotic spots on the leaves of Japanese zelkova. Any visible injury symptoms induced by rain treatments were not observed in the leaves of Japanese white birch and not in two conifers by ozone and rain treatmens. After 20 weeks of exposure, dry weights of leaf, stem, root and total plant per seedling of Japanese cedar and two broad-leaved trees significantly decreased linearly with increasing the level of ozone. The root dry weight of Nikko fir was decreased linearly with increasing the level of ozone. On the other hand, the leaf and total dry weights of fir and zelkova exposed to the rain at pH 3.0 significantly decreased.
Net photosynthetic rates of Japanese cedar and two broad-leaved trees, and carboxylation efficiencies (initial linear slope of A/Ci curves) of two broad-leaved trees decreased linearly with increasing the level of ozone. Dark respiration rates of fr increased linearly with increasing the level of ozone. Moreover, rain at pH 3.0 caused an increase in the dark respiration rates in fir and zelkova. Significant interactive effects of ozone and simulated acid rain were observed in the ratio of top dry weight to root (T/R) in all tree species. The T/R of two conifers and birch increased linearly with increasing the level of ozone when they were exposed to the rain at pH3.0. The T/R of zelkova increased linearly with increasing the level of ozone, and the slope of regression line at the rain of pH3.0 was greater than that at the rain of pH 5.6.

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Deposition velocities of O₃ (K_O3) and CO₂ (K_co2) were measured by the Bowen-ratio technique in a maize fi eld (LAI: 5.7; daytime mean net radiation: 557 Wm^-2) during the summer of 1995 in Fuchu, Tokyo. The K_O3, K_CO2 and deposition velocities of NO₂ (K_NO2) were also measured in an oat field (LAI: 3.8; daytime mean net radiation: 296 Wm-2) during the autumn of 1995. The ratios of deposition velocities of O₃ and NO₂ to CO₂ (RK_O3 and RK_NO2) were calculated from the IC_O3, K_NO2 and K_CO2 measured under the field conditions.
The RK_O3 for maize was 2.2 and that of oat was 5.1. The difference in the RK_O3 between the two species was mainly caused by the difference in K_CO2 rather than K_O3. In the oat field, the RK_NO2 and RK_O3 were 3.8 and 5.1, respectively.

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Chloroform, carbon tetrachloride, 1, 1, 1-trichloroethane, trichloroethylene and tetrachloroethylene in the urban atmosphere were measured during four or five years from 1992 to 1997 at two sites in Sapporo by using adsorbent collection/solvent extraction/GC/ECD. The most of chlorinated hydrocarbons at both sites showed peak tops in summer and peak valleys in winter.
The concentrations of carbon tetrachloride and 1, 1, 1-trichloroethane have been increasing. On the other hand the concentrations of trichloroethylene, chloroform and tetrachloroethylene have been decreasing during the period.
The concentrations of chlorinated hydrocarbons in the area near the center of city (site A) is higher than those in Makomanai area (site B) where is 8 km distant from the center of city. Chloroform and tetrachloroethylene, more reactive species in the atmosphere, showed large differences of their concentration between both areas because of emission sources. Carbon tetrachloride and 1, 1, 1-trichloroethane, less reactive species, showed small differences of their concentrations between both areas because of their long stay in atmosphere.
According to the consideration of wind velocity and wind direction, it is suggested that the chlorinated hydrocarbons in Makomanai are area-wide pollutants.

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The distributions of acid rain with the annual mean pH of rainfalls and acid rain frequency of yearly precipitation in South China are described for the period of 1991-1995. The areas suffering from heavy acid rain were the Sichuan Basin, Guizhou, Hunan and Jiangxi (SGHJ) where is the center of South China. Some climate features in SGHJ are summarized about cloud, precipitation, and wind. The formation reasons of acid rain are discussed. The lowest annual mean pH of rainfalls was 3.8, and the acid rain frequency of yearly precipitation exceeded 90% in several cities. The most fl ourishing districts where the energy consusmption is greatest is not in SGHJ but in the coastal area. The climate characters in SGHJ such as cloudy, moist and weak wind, must be the important factors for the acid rainfall, although SO₂ emission is the original cause. The maximum annual mean of total cloudiness canopies the main part of Sichuan-Guizhou where the acid rain originated in China and is a part of acid rain region all along. The annual rainfall amount in SGHJ is large but slightly less than that of the southeast cast. However, its annual mean of rainy days is higher than that of the coast. The prevailing wind speeds, directions and frequencies in SGHJ, and its geographical features, are unfavorable to diffusion.

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