Health effects of particulate substances in the environmental air, especially those of diesel exhaust particles and asbestos fibers, were reviewed. In contrast to toxic gas which demonstrates acute and transitory effect on human airway, particulates deposit in the lung show chronic and long-standing hazard to human health, resulting in different diseases.
Diesel exhaust particles reveal mutagenicity in vitro experiments, and nitropyren is now considered to be diesel-characteristic, mutagenic hydrocarbon. Epithelial DNA damage, hyperplastic foci of the airway epithelia and adenomas or carcinomas of the lung were produced around the particle deposition in animal experiments. It is reported that suspended particulate matter in the air along automobile roads consists of diesel exhuast, in over 30%, and the roles of which on human lung cancer formation are to be clarified in future.
Short asbestos fibers are suspended in the environmental air of industrialized society, are inhaled and deposited in the lungs of urban residents, and are calculated to be over 10/ in number for the whole lung. Occupational exposure to asbestos increases incidences of malignant pleural mesothelioma and lung cancer, especially among smokers in the latter, and the results of animal experiments coincide with those of humans. In vitro studies revealed prominent absorption of chemicals by the fiber, and suggested accelerated uptake of carinogenic substances into nuclei due to cell membrane disturbance by the fibers, however, co-carcinogenicity of asbestos may be the more important factor for pathogeneis of lung cancer in humans.

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Optimum design and quantative evaluation of parameters of dispersion model are proposed by experimental regression analysis with orthogonal array table and Signal-Noise ratio (SN ratio). The advantages of this method are as follows.
1) The same effect as is obtained by calculations of all combinations of parameters can be obtained by much less calculations.
2) The effectiveness of each parameter can be evaluated quantatively by Analasis of Variance (ANOVA).
3) The precision of prediction by dispersion model can be evaluated quantatively by SN ratio.
The proposed method is applied to the dispersion experiment in Garfield area by using the prediction system of pollutant dispersion in complex terrain proposed by the authors and is found to be applicable.

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Stabilities of pH, electric conductivity and main components of rainwater were investigated under various conditions by using rainwaters collected in Kobe area, to find a suitable sampling and preservation method.
When the rainwater was stored in a polyethylene bottle in the dark at 4°C, concentrations of most components were kept constant for more than five years, but the concentration of NO₃^-was slightly increased due to the unknown cause.
The concentrations of the main components in the rainwater stored in a glass vessel were stable on standing in a room for 10-30 days, but on longer standing in a room (about one year), pH value of the rainwater was increased gradually.
Some rainwaters were exceptional and exhibited the changes in both pH value and ammonium concentration, irrespectively of the storage condition.

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High oxidant concentrations are generally measured in the springtime in rural regions in Japan as well as in Niigata area. The possible origin is the downward transport of stratospheric ozone or the phtochemical production near the ground. If the intrusion of stratospheric ozone is the main origin, increased concentrations of beryllium-7 that is the radioactive isotope formed in stratosphere by cosmic rays will also be observed at the same time. From this point of view, beryllium-7 concentrations in the springtime were measured for 3 years from 1983 through 1985, compairing with the ozone concentrations measured at a rural point in Niigata area.
The concentration peaks of beryllium-7 were found on the backside of high pressure systems in well agreement with the ozone's. Significant correlations wcre obtained between beryllium-7 and ozone concentration for each year. This indicates downward transport of stratspheric air markedly influence to ground-level ozone concentration. But, the concentration variation of ozone and beryllium-7 were not always the same in details because of their differences of physical form and origin.

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Desorption introduction of volatile organic air pollutants collected on polymer beads adsorbent was investigated for a capillary gas chromatograph. When carrier gas is used to introduce a desorbed sample to a capillary column by split method, a large portion of the sample is purged from the split vent together with splitted carrier gas, and so analysis of less amount components in the sample are not suitable for split capillary column gas chromatograph, although separation ability of a capillary column is better than that of a packed column. For this reason, splitless introduction method is required for desorption analysis of trace amount of organic air pollutants.
In this paper, a splitter with a stop valve before the split gas exit was used for splitless introduction of desorbed sample from Tenax GC collectors. When the stop valve is closed and the head pressure of the column is raised to about 4kg/cm², splitless desorption introduction is carried out under a condition of 20ml/min flow rate and-40°C column temperature, and then the stop valve is opened to recover the optimum column flow rate (3.4ml/min for 0.31mm i.d. column) and elution is started by raising the column temperature. In this method desorption is almost complete and column flow rate is optimized, and the column efficiency is relatively high.

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Effective method for extracting mutagens in engine oils was investigated in order to determination emission level of mutagens from gasoline and diesel cars, mutagenic activity in engine oil was attended and a effective method for extracting chemicals was investigated. Engine oils were collected from 12 gasoline which were driving in Tokyo, and 7 diesel cars which were driving outside of Tokyo. Engine oils from mileage were also collected for every 1, 000 km after filling with new oils. The pre-incubation modified method of Ames original method was used for estimating mutagenicity using Saimonella typhimurium strains TA100 and TA98 with and without S9mix.
The combination of the reflux methanol extraction and liquid-liquid extraction using isopentane and acetonitrile was effective for detecting mutagens in both gasoline and diesel engine oils. Relationship between the mutagenicity and the mileage was observed towards both types of cars. Mutagenic activities of gasoline engine oils showed generally higher values than those of diesel engine oils. Mutagenicities of gasoline engine oils from longer distance driving cars more than 30, 000km were also higher values than shoter distance driving cars.

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According to the direction and distance from Mt. Sakurajima, thirty-nine local communities in the surrounding area of this volcano were classified into four regional groups, in which the week-to-week variations in mortality covering a 3-year period 1982 to 1984 were investigated in relation to volcanic air pollution. Mumber of cruption times of the volcano and atmospheric concentration of sulfur dioxide were used as the indices for correlation with volcanic air pollution.
In every regional group, the variations of weekly deaths showed a seasonality with the highest in winter and the lowest in summer seasons though there were some additional irregular short-term fluctuations. When the week-to-week variation in mortality was reviewed for the increase or decrease of deaths on the basis of consecutive two weeks, the number of deaths for the week following an abrupt rise in the atmospheric concentrations of sulfur dioxide was found to increase as compared with those for the preceding week without exception in the two regional groups within 20km north-west and within 30km south-east from the volcano's summit. Such increase was not evident for the other two regional groups more than 20 to 30km distant from the volcano. The weekly maximum of hourly sulfur dioxide concentrations at and above which significant association occurred with an increase in mortality was 0.2ppm. Since this measurement was obtained at a single point in the study area, however, it should be presumed that a relatively wide range of values around this level actually contributed to the increased deaths. For every regional group, there were no examples given where number of volcanic eruptions appeared to be related to increased mortality.
From the above, it is suggested that excess mortality as an “iceberg” of acute health effects can be detectable in large population, if the atmospheric concentrations of sulfur dioxide rise abruptly to the level at or above 0.2ppm in the presence of volcanic ash.

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The well-known bivariate Gaussian Plume model (GP model) is very widely used for the prediction of diffusion from a continuous point source in the atmosphere and yields the Gaussian concentration distribution (shape exponent n=2) both in the horizontal and vertical directions. However, an application of the GP model to diffusion from a source near the ground level in the atmospheric surface layer frequently results in prediction errors of the concentrations mainly because of the shear affected non-Gaussian concentration distribution (n≠2) in the vertical direction near the ground level. Thus, one of the authors previously proposed a new non-Gaussian plume model (NTI model), taking the non-Gaussian vertical distribution into consideration by the mathematical improvement of the conventional GP model.
This time, the diffusion experiment of varied source heights has been carried out in a simulated turbulent boundary layer in our wind tunnel to study the experimental validation of the NTI model.
The results showed that ground level concentrations between the measurements and the NTI model agreed fairly well and it was concluded that the proposed NTI model might be of practical use for diffusion prediction near the ground level.

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