A great deal of volatile halocarbons are used as solvents in various fields of industries and may be emitted to the ambient air. Some of the compounds are recognized or suspected to be mutagenic and/or carcinogenic. In recent years, a number of reports have been published concerning analytical methods and field research for the volatile halocarbons in the atmosphere. This review covers mainly for recent 5 years of the works in the area of sampling and determination of atmospheric volatile halocarbons, and their distribution in a global scale. The article includes scientific papers, books, some oral presentations and other published materials. Emphasis has been on problems, such as sampling error, collection efficiency, analytical sensitivity and effects of interfering substances, which could occur in determination of traces of the compounds in the atmosphere. A brief discussion is given to the determined data of the compounds in atmospheric boundary layers in a global scale.

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An effort to undersatnd the relationship between the measurement conditions (filter media, exhaust gas temperature, etc.) and the emission rates of certain vaporous metals (Cd, Pb, Zn, Cu, As) were performed at the refuse incinerator. The results may be summarized as follows:
(1) In the case that silica filters (thimble and circle filter) and silica wool were used to collect particle-form metals, the emission rates of vaporous cadmium and lead measured by silica wool (low in collection efficiency) were higher than those of silica filters (high in collection efficiency).
(2) In the case that sampling was performed in using of filters, the emission rates of vaporous cadmium, lead, and zinc were about 10% at the municipal refuse incinerator. But, the vaporous copper was not detected.
(3) The emission rate of vaporous cadmium from the refuse incinerator substantially increased as the exhaust gas temperature of measuring site increased from 240°C to 650°C.
(4) The vaporous arsenic was not detected (<0.01 mg/N³) in all the municipal refuse incinerators (8 facilities) aimed at this investigation.

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In order to grasp the actual state of working environment, the variation of pollutant concentration in the area of laboratory waste treatment plant was investigated.
Mercury vapour concentrations captured by a gold-amalgam method from indoor and outdoor of laboratorywaste treatment plant were determined with a flameless atomic absorption spectrophotometer.
This plant was established in 1980 and actually, mercury containing wastewater started to treat since 1982. When various kinds of wastewater with no mercury were treated before 1982, mercuryvapour concentrations were 0.006-0.092μg/m³ in the air at this plant, and the average concentration was 0.029μg/m³.
On the other hand, while mercury containing wastewater were treated after 1982, mercury vapour concentrations in the air at this plant were -0.3 μg/m³ and the average concentration was approximately 10 times as much as prior average of mercury vapour concentration.
As mercury vapour concentrations in the area of this plant have a tendency to rise every year, so that the air in this plant have to be kept clean and mercury containing wastewater have to be stored up tightly.

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1, 6-Dinitropyrene (1, 6-DNP) is a strong mutagen and carcinogen. This compound coexists with polynuclear aromatic hydrocarbons (PAHs) in the environment. Then, we studied the effect of PAHs on the mutagenic activity of 1, 6-DNP by the pre-incubation method using Salmonella typhymurium TA98 with and without S-9 mix.
The direct-acting mutagenicity of 1, 6-DNP was reduced by the coexistence of PAHs which did not show any activity in the test condition without S-9 mix. The reducing effect of PAHs was in the following order; benzo-(e) pyrene, benzo (a) pyrene (5 ring PAHs), benz (a) anthracene, chrysene, pyrene, fluoranthene (4 ring PAHs), anthracene, phenanthrene and acenaphthene (3 ring PAHs). On the other hand, the promutagenic activity of 1, 6-DNP was enhanced by the coexistence of PAHs in the test system. The enhancement effect of PAHs was generally in the same order in the case of reducing effect for direct-acting mutagenicity. That is, higher PAH in molecular size gave larger effect for the both mutagenic activity of 1, 6-DNP.
1, 6-DNP is an electron acceptor and PAHs are generally electron donnor. Then, charge-transfer complex may be formed in the mixture of 1, 6-DNP and PAH. High molecular PAH can more easily form the complex, because electron donnating activity increases generally with the increase of molecular size of PAH. These facts suggest strongly that the effect of PAHs on the mutagenic activity of 1, 6-DNP may be mainly due to the complex formation.

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A comparison between the carcinogenicity of N-Nitrosodiethylamine (NDEA) and of benzo (a) pyrene [B (a) P] was carried out using male Syrian golden hamsters which were administered a total dose of 7.5 mg by means of intratracheal instillation once a week for 15 weeks. At the same time, a control group of hamsters were treated with a phosphate buffer solution. During their total life span, tumor incidence rates of the respiratory organs in the NDEA and B (a) P groups were 100% and 69% respectively, while in the control group it was 8%. With these results, it can be concluded that the carcinogenic potency of NDEA in the respiratory organs of Syrian golden hamsters is much higher than that of B (a) P.

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Behaviors of sulfate, nitrate and other pollutants in long-range transport of airpollutants were investigated using the cooperative field observation data. The observation was conducted during 26-30 July 1983 in the wide area from the coastal region around Tokyo Bay to the northeastern part of Nagano prefecture which located in central mountainous region.
In the inland area, SO₄^2-, NO₃^- and NH₄⁺ in aerosol and gaseous HNO3concentrations increased notably by transport of the polluted air mass. Usually the ion balance in aerosol using SO₄^2-, NO₃^-, Cl^-, NH₄⁺, Na⁺, K⁺, Ca₂⁺ and Mg₂⁺ was in good in inland area, but when the polluted air mass was transported, the ion balance leaned toward anion side. From this, existence of the droplet of H₂SO₄ or NH₄HSO₄was suggested.
It was observed that the gaseous HNO₃ converted into the aerosol phase according o the equilibrium relationship between gaseous HNO₃, NH₃ and NH₄NO₃ which depended on temperature and relative humidity, when the polluted air mass transported to the central mountainous region in the late afternoon.
It was considered that the oxidation of NOR to HNO₃ or NO₃^- proceeded almost at the same time of generation of oxidants, but oxidation of SO₂ to SO₄^2- proceeded more slowly than that of NO_x.

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Long-range transport of air pollutants occurs frequently in summer which causes high concentration oxidants in Nagano Prefecture more than 100 km inland from the large emission sources along Tokyo Bay. Basing upon hydrocarbon concentration data obtained in the co-operative field observation in July 26-30, 1983, characteristics of the hydrocarbon concentrations and their composition were investigated, as well as photochemical reactions of hydrocarbons.
When long-range transport was supposed to occur in Takasaki and Karuizawa, high oxidants concentration was accompanied by high concentration of toluene, particularly its fraction in the total amount of hydrocarbons becoming twice, and the hydrocarbon compositions were very similar to that along Tokyo Bay. These facts support concretely the occurrence of the long-range transport.
During the long-range transport, as a result of photochemical reactions, the ratios of hydrocarbon component to acetylene decreased, and the decreasing rates were higher for more reactive components. From the observed rates in this rural area, OH radical concentration was estimated to be (1.5±0.2)×10^-7 ppm. The value was well compared with that in the urban area.

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A major concern when considering respiratory disorders that harm the health of the city dweller is the concentration of air pollutants in his living environments and the amount of time he spends there. The proportion of time he spends indoor in a 24-hour day has risen to 80-90%, so it is especially important to know how much of the pollutants that are generated indoors he is exposed to.
It was from these viewpoints that I investigated the actual conditions of air pollution in buildings and houses and the indoor/outdoor ratio of pollutants generated.
The results were as follows: The amount of dust was higher in buildings than outdoors. The contribution made by tobacco smokers was also high. The concentration of NO₂ was lower in office buildings than outdoors but higher in restaurant kitchens and underground rooms. The concentration of NO₂ and NO in houses was higher than outdoors, due to the use of winter heating equipment.
The concentration of HCHO was higher in both buildings and houses than outdoors. It was especially high in newly-constructed houses, which show the high exposure that housewives are subjected to.

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Using a continuous mercury monitor Mercury AM-1 model of Nippon Instruments Co. Ltd. which consisted of the collection by gold amalgamization and analysis by cold flameless atomic absorption spectroscopy, a atmospheric mercury concentration at Mt. Ohdaigahara, a clear area was measured and its behavior was investigated.
The atmospheric mercury concentration at Mt. Ohdaigahara ranged from 0.91 to 4.38 ng/m³, and the mean value and standard deviation was 1.58±0.54 ng/m³ (n=435).
The behavior of the atmospheric -mercury was similar to that of SO₂, NO₂, NO and CO and moreover, the correlation between concentrations of the atmospheric mercury and other species showed high correlation coefficients (r=0.599-0.673; SO₂: n=234, NO₂, NO_x, CO: n=235). Therefore, it became apparent that even at Mt. Ohdaigahara the atnospheric mercury showed similar behavior of the air pollutants generated from combustion sources.
Accordingly, the atmospheric mercury concentration was able to regard of very sensitive index of air pollution.
On the other hand, as to meteorological conditions, the atmospheric mercury was not correlated with temperature and humidity but it was correlated with wind velocity. From correlation with wind direction, the correlation coefficient was maximum when the wind direction was ESE direction and the transport of the atmospheric mercury from Owase city was considered.
The hourly variation of the atmospheric mercury concentration at Mt. Ohdaigahara showed high in night and low in day. Such a behavior was estimated to affect of geographical factors that was the transport of air from Owase city.

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