Using a choice experiment which is one of the stated preference methods, we examine the residents' preference towards the policy for reducing NOx-PM and evaluated its social effects. As object of choices, we choose situations buying condominiums. This allows respondents to easily understand the hypothetical situation posed in the questionnaire. We collect data from samples of citizens around Kobe and Yokohama city, and analyze it with the conditional multinomial logit model. The result of the simple model which shows that the marginal willingness to pay for a level of improvement in NOx-PM pollution is from 1, 910, 000 yen to 2, 150, 000 yen (from 66, 000 yen to 74, 000 yen by annualized value). A benefit function transfer adjusted by individual characteristicsshows that the percent error is smaller than the result with simple model. The result is applied to an environmental accounting of a carrier company. Comparing the effect of NOx reduction by the company in 2002, the benefit is 619, 780, 000 yen around Tokyo, which overwhelmed the cost.

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The elution test of chemical substances in active carbon produced from scrap tires with water or organic solvent was performed and was compared with those of reagent active carbon and raw scrap tires. While alkanes (0.076-7.6 mg/kg), alkenes, benzenes (0.047-6.1 mg/kg) and phthalates (0.037-3.2 mg/kg) were detected in the elution test for active carbon produced from scrap tires with acetone, no GC/MS peak was observed in the test with water . On the other hand, alkanes (0.29-10μg/l), alkenes, phthalates (0.91-1.2μg/l), styrene, phenols, bisphenols, ketones, amines, amides, caprolactam, isocyanates, pyridines, quinolines, pyrimidines, imidazoles, triadins, imides, isoindoles, isothiocyanates, benzothiazolone, benzothiazoles, organophosphonic acids and silica compounds were eluted from raw scrap tires even with water in the high concentration level. Many kinds of organic substances in raw scrap tires were pyrolyzed and removed from the active carbon produced by carbonization and steam activation.

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Recently, the number of lead contaminated site is increasing in Japan, and the countermeasure costs of contaminated soil are burden to landowner . Now, the human health risk by direct ingestion of the lead contaminated soil is judged by which lead content in soil exceed soil content standard for lead (SCSL) (150mg/kg) or not . SCSL which established by Soil Contamination Countermeasures Law is a uniformly value regardless of land use. But the amount of lead ingestion via contaminated soil varies with land use, so human health risk varies with land use, too. In this research, the problem of way to set up SCSL is arranged, and the management target values (MTV) for several land use are computed by the detailed risk assessment and the countermeasure cost reduction rate by application of MTV is evaluated . Consequently, the maximum MTV is 5, 100mg/kg by an industrial use which is 34 times as SCSL. The cost reduction rate measured by MTV is 96% by an industrial use . In conclusion, it is possible that the greater part of countermeasure costs cut down byintroducing MTV, if land use industrial purpose. However, we need to be careful that we ignored the groundwater drinking pathway in the risk assessment.

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The atmospheric concentrations of gaseous and particulate Hg (Hg(p)) and the Hg wet deposition flux at Matsue City located in a region facing the Sea of Japan were measured from December 1998 to November 2001. Observations of 14 chemical components (Al, Ca, Cd, Fe, K, Mg, Mn, Na, Pb, Zn, Cl^-, NO₃^-, 5SO₄^2-, NH₄⁺) and Pb isotope ratios (²⁰⁷Pb/²⁰⁶pb, ²⁰⁸Pb/²⁰⁶Pb) were also conducted to obtain useful information on the sources of atmospheric Hg including long range transport from the Asian continent. The Hg(p) concentration and the Hg wet deposition flux during winter and spring were higher than those during summer. Especially during spring, their increase was accompanied with an increase in atmospheric concentrations and wet deposition fluxes of Al, Fe, non-sea-salt (nss-) Ca and Mn, major components of soil. This suggests the large contribution of the Kosa phenomenon, which frequently occurred during this season. During winter and the Kosa periods, the Pb/Zn concentration ratio and Pb isotope ratios in air and precipitation observed in Matsue were close to those in the Asian continent. Also, the Hg(p) concentrations during thisseason were significantly correlated (P <0.001) with the concentrations of Pb and nss-SO₄^2-, which are known to be primarily transported from the Asian Continent . In addition, analysis using the enrichment factor of Hg(p) based on elemental composition of crust and the scavenging ratio of Hg between airborne particulate matters and precipitation showed that the large portion of Hg in precipitation during winter originated from Hg(p) but not gaseous Hg. These indicate that during winter in Matsue, long-range transport of Hg(p) from the Asian continent contributes primarily to the Hg wet deposition. In contrast, Hg wet deposition flux during summer is dominated by the precipitation scavenging of gaseous Hg (i.e., Hg²⁺) via the oxidation of Hg⁰ by O₃ and so on.

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Technological progress is one of the means available for reduction of energy usage and carbon dioxide (CO₂) emissions. However, this improvement will cause a reduction in the real per unit cost of energy services and result in an increase in the demand for energy services. Therefore, the potential CO₂ emissions reduction caused by technological improvement may be offset partially in response to this cost reduction. In previous studies this effect was referred to as the "rebound effect." In order to measure the degree of the rebound effect, we estimate a demand model of Japanese households and conduct a simulation study, assuming an exogenous energy improvement. Based on the results of our empirical analysis, there is a rebound effect that declines as the replacement cost increases. However, even if the replacement cost in our simulation is high, the rebound will be about 37% when a 20% improvement in energy efficiency occurs. That is, an actual saving effect of only 12.6% can be attained. Therefore, the Japanese Government needs to combine the existing energy saving policy and other policies that reduce the magnitude of the rebound effect.

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