The objective of this study was to examine the association between prevalence of respiratory symptoms and particulate matter (PM) air pollution. PM is successively measured as suspended particulate matter with an aerodiameter of<or=10 microns (SPM) in Japan. The following two points were taken into account for this survey. First, Itabashi-site maximum for SPM, Ohme-site (minimum for SPM) and four other sites were selected from among 47 air pollution monitoring sites in Tokyo for this study. Next, the subjects in the survey were housewives with low occupational exposure effects living in areas within 300 meters from the sites. As air pollution levels observed in small areas resultin a arrow renge of levels this survey in small areas should lead to more accurate exposure estimates than other surveys. The subjects completed simplified ATS-DLD questionnaires on eight respiratory symptoms, seven past diseases, age, smoking habits and dwelling environment. Among the five age graups surveyed, women over sixty years were the verwhelming number. Therefore, the prevalence of many symptoms was higher in this study than other studies. The prevalence of cough, phlegm and shortness of breath was about 15 percent of those observed in other studies for elderly women living dwelling in cities. By logistic regression analysis, aging and smoking had significant correlation with some symptoms. SPM levels were significantly associated with the prevalence of cough, sputum, wheezing, chronic wheezing and asthma, but nitrogen dioxide (NO₂) levels were not significantly related with any of the symptoms.

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It is well known that soluble substances are influenced by the presence of fog through dissolution into fog droplets and subsequent aqueous phase reactions. However changes in the thermal structure due to the presence of fog may also affect the physical behavior of atmospheric pollutants through changes in the turbulent diffusion capability.
In this study, we investigated the influence of fog on the deposition of atmospheric pollutants to the ground surface by means of numerical simulations, which were composed of a meteorological model, a deposition model, and an aqueous phase chemical model. Target period was night time when fog formed frequently. The main results obtained are as follows.
(1) It was recognized that the atmospheric condition of layering was destabilized in the fog layer and stabilized just above the fog layer when it formed.
(2) The amount of deposition of even insoluble and inactive substances to the ground increased when fog was present owing to changes in the thermal structure.
(3) The amount of total sulfur deposition also increased when fog was present. Especially that of total sulfate deposition increased significantly by effects such as dissolution and aqueous phase chemical reactions and changes in the thermal structure.
The results suggest that we should take into account the deposition of fog droplets and the effect of changes in thermal structure of the atmosphere in the presence of fog when we calculate the amount of deposition of atmospheric polllutants.

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A three-dimensional urban aerosol model was developed that predicts concentrations of major components of Suspended Particulate Matter (SPM), including nitrate, chloride, sulfate, ammonium, elemental carbon (EC), organic carbon (OC), and water. The model utilizes the outputs of a meso-scale meteorological model off-line, and runs a dispersion model that includes emission, chemical reaction, and dry-deposition processes. The chemical reaction sub-model adopted the CBM-IV photochemical reaction scheme, and forms NH₄NO₃ and NH₄Cl aerosols by gas-aerosol equilibrium assuming that they exist in the external mixture state. Sulfate is formed only in the gas-phase reaction of SO₂ with OH radicals; aqueous-phase reaction is neglected. Secondary formed OC is expressed by a simple parameterization based on an analysis of observed/computed OC concentrations and ambient non-methane hydrocarbon concentration. The model was applied to simulate atmospheric conditions of an extremely severe SPM pollution episode during the December 23-25, 1994, when intensive measurements of SPM were conduced. The model reasonably predicted the concentrations of each component at the evaluation sites located in the central part of the Kanto Plain, except for chloride. At evaluation sites in suburbs or country side, the model predicted concentrations were significantly low compared to those measured, which suggested further improvements of emission source models and dispersion models are required.

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To obtain basic data for clarifying the relationships between environmental factors and forest decline, we investigated leaf phenological characteristics and leaf components of birch (Betula ermanii), and soil chemical properties at birch stands around Mt. Mae-Shirane, Oku-Nikko, Japan from June to October, 2000. The trees growing on the NW-facing slope were not declining, but those growing on the SE-facing slope were declining. In the summer, the leaves of the trees growing on the SE-facing slope showed severe grazing damages by leaf insects, as compared to the leaves of trees growing on the NW-facing slope. Individual leaf area and leaf number per tree growing on the SE-facing slope were less than those of trees growing on the NW-facing slope. The leaf yellowing, leaf fall, and reduction in the concentrations of chlorophyll, Rubisco and total soluble protein of the leaves occurred earlier in trees growing on the SE-facing slope compared to trees growing on the NW-facing slope. Soil pH on the SE-facing slope was significantly higher than that on the NW-facing slope. The deficiency of elements such as K, Ca and Mg, and accumulation of Mn and Al were not observed in the soil or leaves of trees growing on the SE-facing slope. In conclusion, decline of Betula ermanii growing on the SE-facing slope around Mt. Mae-Shirane cannot be explained by soil acidification and nutrient deficiency of soil and leaves.

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[in Japanese]

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