This paper introduces the study on structure of atmospheric boundary layer, data analysis and air quality modeling for urban air pollution such a photochemical smog in the Kanto and other areas, and numerical modeling of regional and transboundary air pollution and development of emission inventory in East Asia. Additionally, the tasks for study on the transboundary air pollution in East Asia are summarized and the future direction of atmospheric environmental research in the mid- and long-term are discussed.

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Groundwater contamination by nitrate-nitrogen has become one of the most serious environmental problems in the Gunma Prefecture of Japan. This study examined the effects of atmospheric nitrogen deposition on groundwater contamination. To estimate the amount of dry deposition of nitrogen compounds, we determined the concentrations of atmospheric nitrogen compounds at four sites in areas of different land use. By using the inferential method, we estimated the amount of dry deposition of nitrogen compounds to be 0.46 t-N/km²/yr, with nitric acid (HNO₃-N) and ammonia (NH₃-N) accounting for 47% and 21%, respectively. We previously estimated the amount of wet deposition of nitrogen compounds to be 1.68 t-N/km²/yr. Consequently, the total amount of atmospheric nitrogen deposition was estimated to be 2.14 t-N/km²/yr. This accounts for 24% of the total nitrogen load (including agriculture, livestock, industry sewage, and domestic sewage) in the groundwater.

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We investigated the monitoring of dust and PM_2.5 using the non-sampling and light scattering Dust Density Meter (DDM-HAL2) recently developed for small-scale chimney facilities. We first selected seven types of samples: fly ash (types 5 and 10), Kanto loam (types 7, 8 and 11), and talc (types 4 and 9) as test particles (JIS Z 8901), and evaluated the performance of the DDM-HAL2. The results showed that the DDM-HAL2 has a good response to the change in the test particle concentration, smooth handling of particulate matter and excellent reproducibility in performance tests, as well as a high correlation of greater than R = 0.9 with manual measuring methods of dust and PM_2.5 concentration. Furthermore, we conducted in-situ verification tests on two types of boilers. Based on the results, we found that DDM-HAL2 has high correlations (R = 0.977 and 0.983) between the indication value of the DDM-HAL2 and concentration value of dust and PM_2.5 over wide ranges from 0.04 g/m³_N to 1.5 g/m³_N against particles of average diameter from 0.5 μm to 0.8 μm, and that the DDM-HAL2 has long-term indication value and zero point stabilities, and high detectabilities of extremely low concentrations and rapid concentration changes of dust and PM_2.5 for long-term monitoring.

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To provide direction for the management of soil contamination by radioactive matter polluted from the Fukushima Daiichi nuclear power station, I summarized the previous reports related to the adsorption of soil contaminants with charcoal. In this review, I discussed 5 topics;1.e, the adsorption mechanism by charcoal, variations in adsorption by charcoal, form of ¹³⁷Cs in soil, specific ways for charcoal use in the field, and combinational utilization between charcoal and phytoremediation. Based on this survey, we discussed the possibilities that charcoal can be utilized to adsorb ¹³⁷Cs and remove it from soils. In combination with the addition of KCl and organic matter to the soil, removal of ¹³⁷Cs by charcoal was supposed to efficiently occur. As a source of charcoal, utilization of unused bio-resources such like thinned woods or bamboo stems can attain the large scale production of charcoal which has an efficient adsorption capacity. Not only the way to apply the charcoal to the soil, but also the way to retrieve the charcoal from the soil with adsorbed ¹³⁷Cs was discussed for the actual use of charcoal.

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As a stationary source survey of Suspended Particulate Matter (SPM) and Particulate Matter 2.5 (PM_2.5), dusts were collected at the inlet of the bag filters (BFs) and stacks in four municipal solid waste incineration facilities by particle size. The average of total dust concentrations was 1,300 ~ 2,000 mg/Nm³ in the flue gas at the inlet of the BFs at four facilities and their average was 0.007 ~ 0.31 mg/Nm³ in the flue gas at the stacks. The average total dust concentration in the flue gas at the stacks decreased to 1/200 or less than the concentration of the past study conducted for same facilities with an electrostatic precipitator (EP) in 1998. This is because the EP was replaced with the BF introduced for dioxin control at these facilities. The frequent distributions of dust show two peaks around 1μm and 10μm at the inlet of the BFs at four facilities, the same result as from the past study, however, they show a different pattern in the stacks. The SPM and PM_2.5 concentrations in the stacks of facility A are less than the Japanese air quality standards of SPM (0.10mg/m³) and PM_2.5 (15μg/m³). The collection efficiency of total dust is greater than 99.9% at all the facilities; this value is higher than that of past facilities with an EP. The collection efficiency of PM_2.5 is greater than 99.9%. The frequent distributions of fine particle dust show one peak around 30nm in the flue gas at the outlet of the BFs. The emission of SPM and PM_2.5 as primary particles is estimated to be very low from a state-of-the-art municipal solid waste incineration facility.

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