In this review, I summarized the development and application of evaluation methodology for atmospheric environment in Niigata Prefecture as a main investigation field, along with the establishment of acid deposition monitoring methodology in East Asia region. In regarding with the former, I described emission sources and its ambient environmental air pollution problems, general atmospheric environmental issues, regional assessment method focused on mercury in the atmospheric environment, and acid deposition as a wider regional environmental issue. Concerning the latter, the establishment of acid deposition monitoring methodology in East Asia region, I described the outlines of establishment process of the acid deposition network in East Asia (EANET), technical documents for EANET, quality assurance and quality control (QA/QC) activities, and studies on acid deposition monitoring methodologies.

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It is important to determine “the annual average concentration” of volatile organic compounds (VOCs) and semi-, and non-volatile organic compounds (SNVOCs) like dioxins and polycyclic aromatic hydrocarbons (PAHs) which influence human health at low concentrations and over long periods of exposure. However, it is difficult to measure these compounds frequently because of the cost and labor necessary. We have investigated the error ranges of annual arithmetic means of “annual average concentration data” in various sampling terms or annual measuring numbers. Since continuous measurement data were necessary for statistical analysis, non-methane hydrocarbons (NMHC) and suspended particulate matter (SPM) were examined as representatives of VOCs and SNVOCs, respectively.
The error ranges in stratified sampling for daily average concentrations varied little among monitoring stations. The error ranges for measurements every two months or once a month by 24h sampling of NMHC were estimated at±20%-±32% or±13-±23%, respectively. The error ranges for measurements every half year or every season by 24h sampling of SPM were estimated at±47%-±62%or±32%-±45%, respectively.
The error ranges for 7 day samplings were about half of the error ranges of 24 h samplings with the same measurement number. Seasonal measurements of 7 day samplings were most efficient, and error ranges of these sampling schemes of NMHC and SPM were estimated to be±16% and±18%, respectively. These error ranges were less than those for measurements each month by 24 h samplings commonly performed in Japan. It has been shown that long term sampling, especially 7 day sampling was effective for improved accuracy of annual average concentration in the evaluation of health effects caused by long periods of exposure.

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The concentrations of 9 organophosphorus pesticides (dichlorvos, diazinon, dichlofenthion, chlorpyrifosmethyl, methyl parathion, chlorpyrifos, fenitrothion, malathion and pyridaphenthion) were measured in indoor and outdoor air. The air samples were collected from 96 rooms of 48 houses, 46 offices of 23 buildings and 34 outdoor points in Tokyo during the summer and winter seasons between July 2000 and March 2001.
Since dichlovos and fenitrothion were detected frequently in outdoor air samples, it was revealed that outdoor air was widely polluted with these pesticides. The compounds detected in indoor air were dichlorvos, diazinon, chlorpyrifos and fenitrothion. The concentrations of the detected pesticides except chlorpyrifos were higher in offices than in houses. The ranges (median) of dichlorvos concentration in houses, offices and outdoor air were <0.50-18.1 (1.4) ng/m³, 0.64-130 (4.0) ng/m³ and <0.50-14.2 (3.1) ng/m³, respectively. The dichlorvos concentration in houses was found to correlate with the dichlorvos concentration outdoors (r=0.892, p<0.01). Diazinon was detected in 17% of offices compared to 2% of houses. The maximum level of diazinon observed in offices was 52.3 ng/m3, which was 16 times higher than that observed in houses. The concentrations of fenitorothion in houses, offices and outdoors were found in the range of <1.0-51.3ng/m³, <1.0-1, 480 ng/m³ and < 1.0-6.0ng/m³, respectively. The maximum level of fenitrotion in offices was 2 orders of magnitude above the maximum level outdoors. Chlorpyrifos was detected only in 15% of detached houses in the range of <1.0 to 12.4ng/m³.

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To collect individual snow crystals a particular method for the snow crystal replication was newly applied using collodion (nitrocellulose) film. Samplings of snow crystals were carried out at the Kyoto University Uji Campus during snowfall events in January 2001. Individual snow crystals, which were unagglomerated and maintained their original shapes such as hexagonal and dendritic plates ranged from 120 pm to 2.5 mm, were replicated on thin collodion film (130±10μm). Particle induced X-ray emission (PIXE) and micro-PIXE analytical methods were uniqucly applied to the analysis of individual snow crystals to investigate their particle scavenging properties and chemical characteristics including chemical inner-structure and elemental mixing state. It was possible to resolve the elemental peaks corresponding to channel number of PIXE spectra without filter rupture or film blank concentrations. Several elements, most of which became incorporated into the snow crystals by impaction scavenging of soluble and insoluble aerosol particles, were successfully analyzed. These elemental masses showed the strong size dependence of snow crystal. Almost all of the components were distributed at the rim portion of snow crystals. Every component retained in and/or on individual snow crystals existed as a mixed state of soil and anthropogenic components including sulfur. These detailed results such as the crystal size dependence of elemental mass, chemical inner-structure, and mixed elemental state in individual snow crystals obtained from this study should be helpful to better understand the ice-nucleation and scavenging processes of pollutants by snow.

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An ADMER (Atmospheric Dispersion Model for Exposure and Risk Assessment), has been developed and tested in the real environment. The ADMER was designed to estimate the long-term average spatiotemporal distribution of the concentrations and depositions of chemicals in comparatively wide areas such as the Kanto region of Japan. The concentrations for a 5×5 km square grid spatial resolution of 6 time zones (i. e., 4 hours average) for a month is available. The model has been well verified. The results of the ADMER in the Kanto region of Japan fit well with the measured data for nitrogen oxides (NO_x) and tetrachloroethylene, as determined in cases of sufficient measurable data. The ADMER includes some useful functions for calculations and for exposure and risk assessment, used for compiling meteorological data and making up gridded emission data for simulations, and for analyzing calculated results visually using several kind of maps, charts and graphs, and estimating the size and location of populations exposed to chemicals.
The ADMER has an MS-Windows graphic user interface which may help not only experts of simulation models, but also risk assessors in government or industry performing simulations. The ADMER will be useful for those risk assessments in which spatiotemporal distributions must be considered.

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