In the semiconductor industry, many chemicals such as silane, arsine, and phosphine are used and most of them are highly toxic and hazardous. Therefore, it is imperative that special cares must be taken in handling these gases.
This paper is briefly described on the following contents:(1) the current trends, in the U. S. A., with respect to the safeguard and regulations, (2) the features, practical storage, and transportation of highly reactive, decomposable and toxic gases, and (3) the analytical methods and typical application results (GC, GC-MS, and FT-IR).

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A simple and simultaneous measurement method of sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) concentration in the atmosphere was examined.
The method was as follows; a paper cylindrical filter treated with 30%(v/v) triethanolamine solution (TEA-CF) set in a shelter was exposed to adsorb SO₂ and NO₂ in the atmosphere. SO₄^2- and NO₂-in an aquous extract of the TEA-CF were analyzed with a ion chromatograph. It became evident that this method was a rapid determination and an effective simple measurement of SO₂ and NO₂ concentration in the atmosphere for the month long term.
Influences of meteorological factors (temperature, relative humidity and wind velocity) on this method was not noticed for measurement of SO₂. But, influences of temperature on this method described below was noticed for measurement of NO₂; the nitration rate (adsorption quantity of NO₂-to TEA-CF per 1 ppb of NO₂ concentration a day, μgNO₂/day/100 cm²/ppb NO₂) was caused 18% increase owing to 10°C rise of temperature for measurement of NO₂.
By comparing data sets gained with this method to those with automated SO₂ and NO₂ analyzers, the correlation coefficients (r) and the sample numbers (n) were r=0.69 (n=200) for SO₂ and r=0.79 (n=226) for NO₂ in such case temperature correction were performed, and hence the correlation were recognized at 1% significant level. The confidence ranges of data gained with this method were ±28% for SO₂ and ±22% for NO₂ with respect to data reduced to ppb unit.

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The cytogenetic effect of in vivo exposure to diesel exhaust or cigarette smoke was investigated in mice by the micronucleus test. Exposure of diesel exhaust to mice for more than 12 months induced about a 2-fold increase in micronucleated polychromatic erythrocytes (MNPCEs) in bone-marrow. Mice exposed to the exhaust from their newborn age, also showed a positive response. A single exposure to mice of two different streams of cigarette smoke (mainstream and sidestream) showed slight increases in MNPCEs in the smoke-exposed mice as compared with the non-exposed controls. Repeated exposure to the sidestream of smoke resulted in a significant increase (p<O.05) of MNPCEs.
The results obtained in the present study suggest that diesel exhaust or cigarette smoke may act as a factor relating to human respiratory carcinogenesis.

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The turbulence structure of the nocturnal urban boundary layer (UBL) and accompanying high concentration of air pollutants at Sapporo, Japan, were analyzed experimentally. A strong, elevated inversion formed over the Sapporo urban area. Its base height was approximately 40-60m, which corresponded to twice the average building height. Velocity fluctuations σ_u, σ_W and Reynolds stress -u'w' had nearly uniform profiles within the nocturnal UBL and decreased with height above the UBL. On the other hand, heat flux -w'θ' had a large negative peak at the inversion base. Thus, the mechanism of UBL formation was found to be controlled by the downward transport of sensible heat from elevated inversion which was caused by mechanically-generated turbulence. Analysis based on the entire data of November 1984 showed that the nocturnal UBL was created when the averaged surface wind speed over the city was less than approximately 1.8m/s. Under such conditions, air pollutants showed very high concentration within the UBL and NO/NO_x ratio showed the inverse correlation with O₃ concentration. The existence of nocturnal UBL prevented the development of thermal convective layer in the next morning and worked to increase the level of ground base concentration. These facts are very important to understand the formation mechanism of the high air pollution occurring in the large cities.

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Long-range transport of air pollutants occurs very frequently in summer which causes high ozone concentration in the mountainous region more than 100 km inland from the large emission sources along Tokyo Bay in the Central Japan. Behavior of lower fatty acids along with the other pollutants was investigated in the co-operative field observation from 26 July to 2 August, 1986.
The fatty acids were collected on beads which were coated by 1 wt% strontium hydroxide and packed in a sampling tube. The collected fatty acids were regenerated by formic acid and measured by GC-FID. The concentrations of acetic, propionic and n-butyric acids increased to 4-8 ppb, 0.3-0.7 ppb and 0.1-0.3 ppb, respectively in the daytime, in particular, when the transported air mass was arrived at the sampling sites, and decreased at night. These diurnal variations were very similar to that of ozone, thus having a strong correlation with the concentration of ozone, while they were not correlated with the concentration of hydrocarbon attributable to motor exhausts.
Of the fatty acids more than 60% were estimated to be produced by photochemical reaction in the daytime. Moreover, it corresponded to about 10% of hydrocarbons transformed. Thus, it was concluded that most of the fatty acids in the atmosphere were produced by the photochemical oxidation of anthropogenic compounds during the long-range transport.

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A highly sensitive umu test for mutagenicity assay is developed. This method consists of the following procedures. Salmonella typhimurium TA1535/pSK1002 solution (9.7 μl) is added to dimethylsulfoxide solution (0.33 μl) and incubated at 37°C for 2 hrs in order to produce β-galactosidase in proportion with the mutagenic activity of the test chemical added. Cell walls of the bacteria are broken by a vigorous shaking with a voltex mixer for 10 sec after adding Z-buffer solution (100 μl), SDS solution (10 μl) and chloroform (10 μl) to the incubated 50μl of the solution, mixed with 100μl of 4-methylumbelliferone-β-D-galactosidase, and incubated at 37°C for 10 min, and finally added 4 ml of Scrensen buffer solution. Activity of β-galactosidase is measured from the fluorescence intensity of 4-methylumbelliferone produced in the above incubation, in the measurement conditions of 355 nm for excitation wavelength and 480 nm for emission wavelength.
Reproducibility and sensitivity of the test method was tested with 4-nitroquinoline-N-oxide. It was found that the reproducibility was fairly good (coefficient of variation: 5. 6% to 8. 9% for 0 to 6.6 ng of the test chemical), and the sensitivity was about 300 times higher than that of the ordinary umu test.

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