The dose-response relationship in asbestos exposure and provoked malignancies inhumans has been reported during the last 10 years. however, the slope of the correlation equation varied widely among the authors. In order to clarify the reasons for the variation, 17 reports in the world were analysed focusing on the background factors which may influence the calculated risk.
The duration of follow up and the rate/number of workers dieing the follow up period, as well as the total number of subjects, are the most influential factors, and accuracy of measurement of exposed fiber concentration and of diagnosis of mesothelioma, may be the other significant factors. Different kinds of work seemed to correlate with the different physical or chemical nature of the fibers and to the resulting risks.
The 17 reports were scored according to each factor, and each report was evaluated by total score. Considering EPA re-calculation value in each report, it was concluded that in average, a 1% increase of lung cancer per 1 fiber·Eyear/m1 can be used as the risk coefficient in occupational asbestos exposure.
When this figure was applied to the population, and yearly lung cancer death by age in Japan, lifetime lung cancer risk due to ordinal asbestos concentration in environmental air was calculated to be 2-8×10^-5 (male and female, smoker and non-smoker), and the annual risk to be 0.2-1.0×10^-6. Lifetime risk of mesothelioma was also calculated, by using an average K_M of 1.9, to be 11-53×10^-4, and annual risk, 1-7×10-6, which is nearly the same as the annual death rate of the disease in Japan.

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In order to observe the health effects of diesel exhaust, long-term inhalation experiments were carried out on F344 rats. The inhalation experiments consisted of a carcinogenicity test with emphasis on the respiratory system and a long-term inhalation test in which the health effects of diesel exhausts on rats were evaluated every six months from the start of inhalation.
LD and HD diesel engines were used in these tests and the engines were operated at a constant speed.
Experimental animals used for these tests were Fischer 344 rats (SPF), 5 weeks old. For the carcinogenicity and long-term inhalation tests, five experimental groups were used in the LD (2.3, 1.1, 0.4, 0.1 and 0 mg/m³) and HD (3.7, 1.8, 1.0, 0.5 and 0mg/m³) series, respectively. Each experimental group of rats consisted of 120 males and 95 females. The inhalations were carried out 16 hours a day, 6 days a week for 30 months at the longest. The living environments in the barrier were strictly controlled from the microbiological standpoint in order to protect animals from infection and other diseases. As the result, the average number of airborne bacteria in the barrier was less than 3 colonies per plate during the experimental period. Antibody-titers of specific pathogens were not detected at all. The results obtained from these experiments as follows:
(1) The survival rates of both sexes in all experimental groups after 30 months inhalation were in the range of 30%-40%.
(2) Diesel particles were histologically observed to be deposited mainly in the alveolar cavities in short duration and low particle concentration groups, but the degree of interstitial deposition increased gradually, with inhaled duration and particle concentration.
(3) The swelling of type II alveolar epithelium and the extension of respiratory bronchiole epithelium toward the alveolar ducts were caused by the anthracosis.
These hyperplastic lesions have a tendency to increase in relation to the particle concentrations and inhalation time, particularly, the focus of adenomatous hyperplasia which fused the each lesions observed in the high concentration and longer duration groups.
(4) All primary lung tumors observed in this test were epithelial tumors; nonepithelial tumors did not occur. Histological types of the carcinomas showed no particular tendencies.
(5) The incidence of lung tumors was low and showed a significant difference (P-0.05) between the 3.7mg/m³ group and the control group in the HD series.
(6) No remarkable changes were seen in the trachea, the bronchi, the bronchial gland or the nasal cavity.Leukemia, breast tumors and other tumors were not significantly increased in the experimental groups compared with the control group after 30 months inhalation.

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Content of mercury in Parmelia tinctorum Nyl. was relatively high among the eighteen epiphytic lichens investigated.
Mercury content in P. tinctorum was well correlated to the atmospheric mercury concentration in the area where the sources of mercury could not be specified.
And the mercury content in P. tinctorum was positively correlated to the sulphur content in P. tinctorum and negatively correlated to 1AP value (Index of Atmospheric Purity) calculated from the distribution and coverage of epiphytic lichens.
Mercury content in P. tinctorum collected at 190 points in Hyogo Prefecture were analyzed and the distribution of mercury content was mapped over the Hyogo Precefture except for the area along the coast of the Sea of Japan.

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In order to obtain some basic knowledge on the toxicity of apparently long-lived and highly reactive gas-phase radicals from cigarette smoke, its possibility to initiate of autoxidation of polyunsaturated fatty acid methyl ester (PUFA), which are model compound of lipid, one of the most principle constituent of biomembrane, has been studied using UV-absorption method and oxygen absorption method.
As the result it is that gas-phase radicals in cigarette smoke can principally initiate autoxidation of PUFA and subsequently form toxic PUFA-hydroperoxisides.

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In order to determine nitrogen oxides below 50 ppm by hydrazine-NEDA method, which conditions for nitrate-to-nitrite reduction were improved.
The reduction by hydrazine sulfate is influenced by many parameters in reducing procedures: concentration of alkaline, concentration of hydrazine sulfate, temperature, time of reduction, added amount of catalysis, shape of reactor, volume of reactive solution, and mixing conditions. These parameters were evaluated by use of L₁₆ type orthogonal array table. The results showed that alkalinity was most effective, and the combination effects of temperature and hydrazine sulfate concentration were affected significantly the reduction efficiency. Improved procedures of hydrazine-NEDA method were made up by a combination of optimum conditions of parameters for the reduction. The advantage of the proposed method is as follows:
1) Reduction efficiency was more than 93%.
2) The reproducibility was better than 99.9% for standard sample on repeated runs.
3) The proposed procedure considerably shortens the length of time for measuring nitrogen oxides.
For determination of nitrogen oxides in stack gas, a combination of the proposed method with the common grab sampling procedure provides a supreior method to the official zinc-NEDA method.

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Atmospheric and precipitation chemistry data derived from a sampling network operated in the Northwestern Kyushu during the period from June 1986 to May 1987 are used as a basis for discussing the scavenging ratio of sulfate around the coastal region. Frequency distribution, seasonal variation and relationship between scavenging ratio and precipitatiin amount are discussed. In-cloud and below cloud scavenging of sea salt sulfate and excess or not of sea salt sulfate during the cold season are also covered.

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