Sensitivities of emission sources and transboundary transport on pollutant concentrations were calculated by 3-D air quality simulation. The sensitivity of transboundary transport on O₃ was exclusively high. The sensitivities of vehicles and other anthropogenic sources on yearly or monthly O₃ were negative throughout a year. Transboundary transport had a certain sensitivity on SPM and even on NO₂ because NO₂ production via the reaction of NO and O₃ is O₃-sensitive under high NO conditions like urban areas. The sensitivities of sources and the transboundary transport on individual components of SPM were affected by various nonlinear processes like photochemical reactions involving O₃ and VOC, and the equilibrium between particles and gas in the atmosphere, as well as the direct contribution of emissions and transboundary transport.
It was implied that tranboundary transport and complex and nonlinear processes in the atmosphere, as well as the direct emission of pollutants, must be taken into account in order to consider effective strategies to improve air quality.

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Global warming is one of the most anxious worldwide environmental problems. Emission of CO₂, one of green house gases, from road vehicles should be reduced for anti-global warming after improving fuel consumption in road vehicles. Since a fair wind way of one way 4 lanes was aerodynamically shown useful for energy savings due to aerodynamic drag reduction in vehicles, energy savings, fuel savings and CO₂ reduction on a fair way of one way 3 lanes with a new cross sectional area of 157 m² and two sky tunnels, each 5 km long, are here studied to be about 9 GJ/h (energy saving rate of 35%), at least about 350L/h (fuel saving rate of more than 15%) and at least about 900kg-CO₂/h (CO₂ reduction rate of more than 15%), respectively, for a traffic flow of 2500 veh./h and a large motor mixing ratio of 20%.

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To evaluate the effect of trans-boundary and regional air pollution regarding precipitation, we collected precipitation from April 2000 through March 2001 in Yasaka, which has long-range transported air pollution, and Yahata which has regional air pollution from southern Kyoto prefecture and the Osaka plain. From the concentrations of water soluble ionic components, metal components, the ratio of metal concentrations and the lead isotope ratio, we evaluated the effect of anthropogenic pollutants and soil elements to chemical constituents in precipitation, based on the backward trajectory analysis. The ion balance of anion and cation was good in both Yasaka and Yahata; however, the total ion equivalent concentrations were higher in Yasaka than in Yahata. The effect of sea salt was more prominent in Yasaka than in Yahata which is located inland. As for metals of anthropogenic origin, the concentration levels and concentration variations were quite different in both sampling sites. From the analysis conducted of Pb/Zn, Sr/Mn, Pb/Cd and V/Mn in the precipitation, it was found that the ratios increased for long-range transported air pollution. In Yahata, a relatively similar metal concentration ratio was observed between aerosol in the urban area and in the precipitation. A high ²⁰⁷ Pb/²⁰⁶ Pb ratio was observed when the air mass travelled over central China and the Korean peninsula; on the other hand, a low ²⁰⁷ Pb/²⁰⁶Pb ratio was observed in Yahata regarding regional air pollution. The validity of the metal concentration ratios, as well as the lead isotope ratio, for the index of long-range transported and regional air pollution were clarified.

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We propose herein a new principle to measure atmospheric NO using an NO₂ detector. We tested this method to determine whether precise measurements are achievable or not when using a laser induced fluorescence detector for NO₂. To convert NO to NO₂, O₃ is added to the sample air. When adding O₃, not all of the NO is used in the generation of NO₂: some of the NO does not react with the O₃ and some of the formed NO₂ reacts with O₃.Using a box model we simulated the time evolution of the NO₂ concentration after the addition of the O₃. We found the optimum condition of reaction time and O₃ concentration by both calculation and experiment. To verify the usefulness of ambient air measurements using this technique, observations were conducted. NO concentrations obtained by this system were compared with those of the chemiluminescence technique and resulted in excellent agreement.

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An inside stack sampler (type-1 stack sampler), which is not significantly influenced by the partial pressure and the temperature difference between the inside and outside of the flue, has been developed for the measurement of sublimable boron compound gas. An alkaline solution (potassium carbonate) impregnation filter paper was used as the absorbent.
However, the previously developed outside stack sampler with collection bottles (type-2 stack sampler) was susceptible to both the partial pressure and the temperature difference for the measurement of sublimable compounds. Comparing both samplers, it can be concluded that the type-1 stack sampler is superior to the typ-2 because the former is not influenced by sublimation due to the inside stack sampling.

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