From the viewpoint of evaluating the inhabitants' risk by air pollution, it is one of the important purposes imposed on air pollution monitoring system to evaluate the degree of air pollution in the living space and population exposure. To clarify the possibility of evaluating the air pollution in the living space by means of monitoring system, the information on the spatio-temporal variation of air pollutant's concentration in the city is essential. In order to evaluate the spatio-temporal variations of NO2 concentration in a residential area with trunk roads, daily average concentration was measured by using passive samplers in an area of 3 km in east and west and 4 km in north and sourth around Setagaya Ward Office of Tokyo. The survey was carried out during a period of 5 days in March 1989. Sampling sites were located in two kinds: sites at the grid points with about 1 km intervals (3×4=12 sites) and sites between the Ward Office and the No.7 loop road (15 sites). The latter sites were grouped according to the distances from the No.7 loop road. Analysis of variance of a two way classification with main effects for days and sites confirmed the previous result that the variances due to days were extremely large. Further analyses showed the following results:(1) the variations of 1 km scale revealed variances between sampling sites and those due to day/site interaction were the same as or smaller than the previous results, (2) the concentration near the No.7 loop reduced much in case some structures exist between road and site, and the concentration decreased with the distance from the road, (3) variance between days within each group did not depend much on the distance of the group of sites from the road in the area within 350 m from road, (4) the variances between sites and day/site interaction terms were large in the group of sites facing the road with no structures between roads and sites and extremely small in other groups of sites, (5) the daily change patterns of concentration did not depend much on the distances from the road in the area within 350 m from road, and (6) the concentrations of the group at 400 m to 700 m away from No.7 loop road showed higher than those of groups nearer to No.7 loop road, and the magnitudes of the daily variation, the site variation and day/site intercation showed larger than those of groups closer to No.7 loop road, which suggests the existence of the pollution effects of other local roads than No.7 loop road.

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An experimental apparatus for exposure of sulfuric acid aerosol to animals was developed for the present study. Changes of lipid peroxides and their related-factors in lungs of rats and changes of superoxide (O₂^-) production ability in alveolar macrophages of rats exposed intermittently to 10 mg/m3 of sulfuric acid aerosol (mass mediandiameter=0.7μm) using the newly developed apparatus were examined.
Lipid peroxide levels in lungs of rats exposed to sulfuric acid aerosol were decreased significantly. On the other hand, activities of glutathione peroxidases and glutathione S-transferase in rat lungs were increased. Nonprotein sulfhydryl levels in rat lungs were increased significantly, although vitamins C and E levels did not increase. Superoxide dismutase (SOD) activity in rat lungs was increased significantly. This increment suggests that the O₂^- production in rat lungs was increased by the exposure. But, the ability of O₂^- production by alveolar macrophages of rats was decreased significantly.
These results suggest that the sulfuric acid may concern in the decrements of resistance to lung infections.

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Methods of measurement and phenomena on dry deposition within acid deposition have not been understood, and not been established enough until lately. In this study, measurements by surrogate sampling method using bottle, which is one of the measuring methods of dry deposition, were performed, and discussed. The effect of water addition in sampling periods of dry deposition was significant, and the amounts of all species in collected dry deposition were higher than those at no addition of water and especially, easily water soluble components such as SO₄^2- and NO₃^- were more collected by a factor of two or more. Another effect of water addition was that Ca₂⁺, which is the major component of atmospheric giant particle, was collected much more than other components in many cases. Regional distribution of dry deposition components showed that SO₄^2- and sea salt components such as Na⁺ and Cl^- decreased inversely proportional to the distance from the sea coast. But, NO₃^- and NH₄⁺, which were transformed secondary in atmospheric air, were highest in middle inland region such as Fussa. Comparing to the amounts of wet deposition components, dry deposition amount of Ca₂⁺ was about same with that in wet deposition, and dry deposition amounts of SO₄^2- and NO₃^- were about half of those in wet deposition.

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Radish and bush bean plants were exposed to sulfuric acid solution of pH 2.0, 3.0 or 4.0 diluted with deionized water of pH 5.8 for 4 or 6 weeks. Adaxial surfaces of radish and bush bean leaves on the specimen holder of cryo-scanning electron microscope (Cryo-SEM) were rapidly frozen by liquid nitrogen without any fixation and dehydration processes and leaf surface perturbations were observed.
The treatment with sulfuric acid solution at pH 2.0 induced many necrotic lesions in both plants. Cryo-SEM revealed that individual surface cells in the necrotic lesions were flaccid and indistinguishable. However, lesions were distinguishable from the healthy epidermal cells. Necrosis randomly developed without any linkage with the distribution of stomata, trichomes, or glandular hairs.
Crystalline substances in the necrotic lesion and/ or on the healthy epidermal surface were observed. Energy dispersive qualitative X-ray analysis revealed that pillar or needle shaped crystalline substances had major two peaks of S and Ca. Calcium contents of leaves exposed to sulfuric acid solution at pH 2.0 and 3.0 were greater than that of the control 5 to 6 weeks after the initiation of exposure. These results suggest that leaf Ca was leached by the sulfuric acid solution and was crystallized as Ca-S compounds on the adaxial leaf surface.

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Field observations of wintertime photochemical pollution have been conducted in order to investigate the cause of severe NO₂ pollution that often occurs in early winter in the Kanto Plain, Japan. Intensive measurements of secondary photochemical products were carried out on November 26 and 27 and December 6 and 7, 1991, when high concentrations of NO₂ (>90 ppb) were observed. Sampling sites were located in the Metropolitan Tokyo area, as well as four sites at inland of the Kanto Plain, and a site at the top of Mt. Tsukuba (800 m height, 50 km northeast of Tokyo). During the intensive measurement period, daily maximum concentrations of peroxyacetylnitrate (PAN) were 3.9-11.7 ppb on the coast at Tokyo Bay; diurnal variation was similar to that of [PO (=NO₂+0₃) NO₂^Prime (primarily emitted NO₂)]. The diurnal variation of total inorganic nitrates concentrations showed a daytime maximum except on December 7; it reached an extremely high value (59 μg m^-3) on December 6. Acetaldehyde/CO ratio also showed remarkable daytime maxima on December 6 and 7. The behavior of photochemical products indicates that the NO_x-hydrocarbons system photochemical reactions were dominant during this period. In addition, shipboard measurements in Tokyo Bay suggested that PO is predominantly in the form of O₃ above Tokyo Bay, which is contrary to land-based measurements. The results of this study further suggest that the photochemical formation of nitrate is one of the causes of suspended particulate matter (SPM) pollution, which is often accompanied by high concentrations of NO₂.

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Enzyme fluorometry using p-hydroxyphenylacetic acid and peroxidase has become a well-established continuous monitoring method for hydrogen peroxide, and provided important field data mainly in North America and Europe. We have built an automatic analyzer based on the method for continuous field measurements at remote sites and on board of research vessels that was successfully used during several compaigns. The system consists of air scrubbers, multichannel flow system and dual channel fluorometer. This technical note describes the principle, construction, installation, operation, calibration and maintenance of the enzyme fluorometric hydrogen peroxide analyzer. Emphasis is placed on how to avoid troubles with the sensitive instrument to help disseminate the method, and obtain a larger data base about peroxides in East Asia.

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