In order to evaluate the effects of short or long term exposure to ozone on cardiovascular systems, we developed the technique to continuously record electrocardiogram, blood pressure and electroencephalogram. Acute exposure to 1 ppm ozone induced marked decreases in heart rate and blood pressure. No significant difference in the variation of heart rate during exposure to 0.2 ppm ozone was noted between elastase induced emphysematous rats and normal rats, however, normal rats were more tolerant of challenge exposure to ozone than emphysematous rats. It is suggested that these observations result from enhanced activity of cardiac parasympathetic nerves.
The method of health risk assessment for hazardous air pollutants becomes popular in environmental policy. We carried out study on perceived carcinogenic lifetime tolerable risk level in Tokyo metropolitan residents in 1997 to 1999. One in 10, 000 lifetime risk from exposure to chemicals in the ambient air was most frequent choice as their tolerable risk level. It is suggested that lifetime risk level for air quality standard is not so different from the perceived level (one in 100, 000) in Japanese citizens.

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We conducted wind tunnel experiments, using a 1: 300 scale model of an actual built-up area in Kamiuma, Setagaya-ku, Tokyo, to study the flow and distribution of air pollution arounda heavily trafficked roadway and the lid effect of an elevated road on pollution flow and distribution at grade.
Ground-level pollution concentrations were greatly influenced by nearby buildings. In general, they increased when buildings on both sides of the road (especially the windward side) were high, and decreased when roadside buildings were lower or absent.
The lid effect of the elevated road, which was perpendicular to the prevailing wind direction, caused a slight increase in ground-level pollution. When no large buildings were present near the roadway, the flat elevated road suppressed vertical diffusion instead of blocking the flow around the roadway. Therefore, pollution under the elevated road was carried out of the road at grade more efficiently than when there was no elevated road. Pollution concentrations downwind from the main road increased when an elevated road was present.
Ground-level concentrations were lower when an emission source was placed on the elevated road than when an equivalent emission source was placed on the road at grade. We concluded that high pollution concentrations at ground level can be reduced by routing through traffic over an elevated road.
In the wind tunnel experiment using model building blocks, the concentration distribution pattern, normalized by the average concentration of the street canyon cross section, did not change greatly, even with changes in the road configuration and atmospheric stability. In the actual street canyon, the concentration distribution patterns were very similar to those generated by the block models.
Our improved SRI street canyon model reasonably estimated concentrations in the street canyon.

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A deodorizing system by combustion of fermentation gas from chicken droppings was developed, and the deodorizing effect was investigated. The reaction of NH₃/N0_x in the combustion system was also studied. The odor concentration of exhaust from this system was less than 10³ and the odor removal at 650°C and 780°C of the furnace temperature was 92 and 98%, respectively. The NO_X concentration in the exhaust was less than 140 ppm, though the concentration of NH₃ in the fermentation gas was over 1000 ppm. It was assumed that NO_X generated by combustion reacted noncatalytically with NH₃ in inflow gas and formed N₂ in the combustion furnace. The excess of 0₂ was favorable in the reduction of NO_X from the results of the NH₃/NO_X reaction in an electric furnace. The generation of NO_X at high temperature was restrained in the excess of NH₃.

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In Saitama Prefecture, monitoring of halocarbons has continued since 1990 as a part of the measures for ozone layer protection. Sample airs were obtained from two urban sites, a suburb site and a mountain site twice every month, and chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbon and other chlorinated organic compounds were analyzed. The samples were obtained also from the sky and vertical distribution was determined.
Although the atmospheric concentrations of chlorofluorocarbons were clearly high in 1991 as compared with background areas, the concentrations decreased and the features of their variations changed around the time of complete phase-out of chlorofluorocarbon production in 1995. Especially the concentration of 1, 1, 1-trichloroethane decreased rapidly to 1/30 of the peak time, and the influence ofnearby sources decreased. These changes were considered to be the result of regulations on ozone depleting substances, and it was noted that the effect of measures appeared in urban environmental concentrations earlier and more notably than background areas. However, decreased concentration of dichlorodifluoromethane (CFC12) was slight even in urban areas, and it is suggested owing to its concentration characteristics that discharge of CFC12 to the atmosphere has also occurred recently. Further surveillance and measures are needed. The conver sion of these substances was carried out in response to regulations. Concentration rises and large concentration variations of hydrochlorofluorocarbons and hydrofluorocarbon because discharge to the atmosphere were seen, and it was considered that the increase in alternative use of trichloroethylene caused the concentration rise in washing solvent fireld. Although the environmental influence of trichloroethylene was feared, the concentration decreased after 1998.

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On estimation of growth of the thermal internal boundary layer (TIBL) in flatcoastal regions, the theoritical formulation by Garratt (1992) and the simple empirical formulationof a parabolic growth type (h= aX^0.5) were applied to the observational data from TOKAI 1982-83 83 in Tokai-village, Ibaraki-Prefecture by Kakuta et al.(1986, 1987) and cmpared to aircraft observations from KASHIMA 1972-77 in the Kashima coastal industrial zone by Gamo (1981) and the OCD-model by DiCristfaro et al.(1989), where h (unit: m) is the TIBL depth, X (unit: m) is the distance toward inland perpendicular to the coastal line, and a is the proportional coefficient. The observational areas TOKAI and KASHIMA are relatively flat terrains on the east coast of the Kanto region.
As a result of this study, it is found that the accuracy of the theoritical TIBL depth formulation by Garratt (1992) is facter 2, the coefficient a of the above-mentioned empirical TIBL depth formulation varies from 1 to 8, the mean values of the TIBL growth observations are close to the calculated value by the empirical formula of the case of a=4 in the case of TOKAI and the calculated value by the OCD-model. Moreover it is found that most data of the TIBL depth from KASHIMA are included within the spread of the data from TOKAI.

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