Air pollution control has been conducted mainly against gas components such as SO_x, and NO_x, while recent epidemiological studies indicate that suspended particulate matters, especially ultrafine particles, are more hazardous for human health than gas components. Environmental air with high level PM₁₀ may increase the number of daily deaths in inhabitants especially in old peoples having chronic obstructive lung diseases, due to an aggravation of the disease and cardiac disorders. PM₁₀ level shows relation to the incidence of respiratory symptoms such as chronic cough or wheeze, and to hospital admission days of small children due to asthma or bronchitis in the polluted districts. Lung function measurement also indicated the decreased bronchial air flow in relation to increased particle concentration in the environmental air. Suspended particulate matter originate from various sources, and black smoke from oil combustion in the industrial and urban areas, being less than 2 μm in diameter in most, are now the central concern of researchers. However, PM₁₀ from steel mill industry, consists mainly of iron, also showed the same effects on inhabitant's health, indicating that any particulate matter may be hazardous in various degree for respitatory organ. A study on the long term effects of air pollution showed that a lower survival curve was expected in the inhabitants of the most polluted cities as compared with those of the least polluted cities, and the death rates were correlated with particulate and sulfate levels in the environmental air. Air control strategy should focus on not only gas phase pollutants but also particulate matter.

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It is necessary to collect chlorofluorocarbons (CFCs) and hydrochlorofluorocarbon (HCFC) from discarded equipments and to decompose them for protection of the ozone layer.
Twelve runs of decomposition experiments of CFC-11, 12, 113 and HCFC-22 at a feed rate of 20 kg/ h were carried out in an inductrial waste incineration facility with rotary kiln. Depomposition efficiencies of the CFCs/ HCFC were over 99.99%, and none of volatile organochlorine compounds were formed. The produced HC1 and HF with the decomposition of CFCs/ HCFC were removed completely by the existing treatment system. It was confirmed that the concentrations of PCDDs/ PCDFs in flue gas were low enough and their contribution to the concentration in atmosphere was estimated to be below 1%. Impairment of fire-proof brick pieces with the decomposition of CFCs was not observed for 2 weeks. Consequently, it was demonstrated that CFCs/ HCFC could be decomposed safely and reliably in an industrail waste incineration facility.

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In order to clarify oxidation behavior of NO to NO₂ immediately after emission into the atmosphere, a chemical reaction model involving oxidation of NO_x and methane has been developed. To examine its validity at atmospheric temperature, irradiation experiments have been conducted under various conditions, and calculated NO and NO₂ values were compared with experimental values. As for the validity of the model at high temperature, modeling calculation results were compared with flow tube reactor experiments conducted in the literature. As a result, it was shown that the reaction model should adequately describe the oxidation behavior of NO to NO₂ atatmospheric temperature and high temperature condition.
In addition, important reactions which may influence oxidation behavior of NO to NO₂ at 298K and 873K have been examined by conducting sensitivity calculation. As a result, at 298K under dry condition, eight inorganic reactions including reaction 2NO+ 0₂→2NO₂ were suggested to be important, while at 873K, oxidation to NO occurs not through reaction 2NO+O₂→2NO₂, but mainly through NO+ HO₂→NO₂+ OH during the process of the oxidation of CH₄, while the reaction path involving the oxidation of C₂H₆ produced by combination of CH₃ is not important under the reaction condition studied. It was also suggested that elementary reactions NO₂ + hν→N0+ O (³P), NO₂+ 0 (³P)→NO + 0₂ and NO + OH +M→HNO₂ + M are important for NO₂ reduction, as well as NO₂ + H→NO +OH.
Using the reaction model, reaction calculations were carried out, assuming constant temperature and volume, to calculate the time profiles of NO₂ within a short reaction time. As a result, it was suggested that, within the temperature range of 500-700°C, presence of CH₄ in exhaust gases causes prompt NO oxidation and that the conversion behavior of NO to NO₂ in the vicinity of the emission duct cannot be ignored.

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This paper presents the results of performance tests of various kinds of adsorbents by static and dynamic adsorption methods to select the optimum deodorant (adsorbent) for Hydrogen sulfide gas (H₂S).
In the performance test by the static adsorption method, the amounts of H₂S adsorbed of 15 different kinds of adsorbents (physical or chemical adsorbents) were measured.
The amounts adsorbed by adsorbents with high adsorption ability were 0.042-0.043 g/g at 30°C and an equilibrium pressure of 50 mmHg. The equilibrium adsorption amount adsorbed by chemical adsorbents were not higher when compared to physical adsorbents. The type of H₂S adsorption isotherm in all of the adsorbents fit in Freundlich's adsorption isotherm. All of adsorbents may be used repeatedly when judged from the values of heat of adsorption. The relationships between the equilibrium adsorption amount and specific area, pore volume, mean pore radius, pH were studied, the slight correlation was observed between the mean pore radius and the equilibrium adsorption amount.
In the performance test of the dynamic adsorption method, we examined four kinds of adsorbents selected from the above-mentioned 15 kinds of adsorbents. The removal efficiency and the breakthrough time were used as the indexes.
In the removal efficiency performance test, the removal efficiency is related to the equilibrium adsorption amount measured by the static adsorption method.
However, in the 10% breakthrough time performance test (experimental conditions: inlet gas concentra-tion 100 ppm, bed height 7 cm, gas linear velocity 0.4 m/sec, contact time 0.147 sec, gas temperature 25°C, relative humidity 50%), the breakthrough time of the adsorbent, which was third in equilibrium adsorption amount (0.042g/g at 30°C, 50 mmHg), was only 34 min, while the breakthrough time of the adsorbent, which was eighth in equilibrium adsorption amount (0.034 g/g at 30°C, 50 mmHg), was 202 min, which was about 6 times longer than that for the first one.
These results suggest that the performance test only by the static adsorption method is insufficient and that the breakthrough time test by the dynamic adsorption method is important.

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The effects of Al and Mn, alone and in combination, on dry weight growth and nutrient status of 2-year-old red pine (Pinus densiflora Sieb. et Zucc.) seedlings grown in a nutrient culture solution were investigated. Al was added as aluminum chloride at 1, 10, 30 or 60 mg·kg^-1 (ppm), and Mn was added as manganese chloride at 1, 30 or 60 mg·kg^-1 to the nutrient culture solution. The pH of the solution was maintained at 4.0 by adding HC1 or NaOH solution. The seedlings were transplanted into the nutrient culture solution, then they were grown in a greenhouse for 90 days from May 8 to August 6, 1996.
The interactive effects of Al and Mn on the dry weight growth of the seedlings were not statistically significant, while there were additive effects of Al and Mn on the dry weight growth of the seedlings. There were single effects of Al or Mn on the dry weight growth and element concentrations of the seedlings. The treatment with Al of ≥10 ppm or that with Mn of 60 ppm induced a significant reduction in the dry weight growth of the seedlings, which indicates that the effect af Al on the dry weight growth is stronger than that of Mn. The chlorophyll content of needles was not affected by Al treatment, but was significantly reduced by treatment with Mn of 60 ppm. Furthermore, the treatment with Al of 60 ppm or that with Mn of ≥30ppm caused a significant reduction in the dark respiration rate of the roots. The net photosynthetic rate of the seedlings reduced with increasing the concentration of Al or Mn in the nutrient culture solution, which suggests that Al or Mn induced reductions in the RGR and NAR of the seedlings were mainly due to the inhibition of net photosynthesis.

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The purpose of this paper is to investigate odors at a fish meat cannery and examine the possibility of applying an absorption method for odor countermeasures which is a combination of a chemical absorption method and a chemical oxidation method.
The odors are generated mainly from cooker, soup separator and primary finishing processes. The odor concentration was 18, 000 for the cooker steam and 7, 500 for the primary finishing room. It smelt like strong boiled fish odor. It was seemed main odorants were trimethylamine and methylmercaptan for the cooker steam and was trimethylamine for the primary finishing room.
The odor concentration of the treated gas by the absorption method was 70-310, suggesting that this absorption method is applicable.

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