2005 Fiscal Year Final Research Report Summary
Temporal variation of nano-particle, elemental carbon and organic carbon in the urban atmosphere
| Project/Area Number |
16310003
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOMAZAKI Yuichi The University of Tokyo, Research Center for Advanced Science and Technology, Specially Appointed Associate Professor, 先端科学技術研究センター, 科学技術振興特任教員(特任助教授) (80286640)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Yutaka The University of Tokyo, Research Center for Advanced Science and Technology, Professor, 先端科学技術研究センター, 教授 (20110752)
TAKEGAWA Nobuyuki The University of Tokyo, Research Center for Advanced Science and Technology, Associate Professor, 先端科学技術研究センター, 助教授 (00324369)
KOIKE Makoto The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (00225343)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Environmental behavior / Urban atmophere / Nano-particle / Elemental carbon / Organic carbon / Carbon monoxide |
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| Research Abstract |
EC comprises a significant portion of nano-particles, which are harmful to human health. EC has also been identified as making important contributions to the radiative heating of the atmosphere. Mass concentrations of EC in fine mode and CO were measured in Tokyo. EC were measured using a semi-continuous thermal-optical analyzer. The mass concentrations of non-volatile fine-particle measured by the calibrated SMPS combined with a heated inlet agreed with the independent EC measurements, demonstrating that the mass concentrations of non-volatile particle well those for EC. EC mass concentration was in volume equivalent diameters between 50-200 nm, peaking at around 130 nm. The correlation of EC and CO was generally compact throughout the measurement period. The slope of the EC-CO correlation (ΔEC/ΔCO) is therefore a useful parameter in validating EC emission inventories. The EC concentration and ΔEC/ΔCO showed distinct diurnal variation. On weekdays, EC and ΔEC/ΔCO reached maximum values, respectively, in the early morning, when the traffic density of heavy-duty trucks with diesel engines was highest. In addition, these values were lower by a factor of 2 on Sundays. The heavy truck traffic showed similar diurnal and weekday/weekend variations, indicating that exhaust from diesel engines is an important source of EC. Monthly mean ΔEC/ΔCO showed a seasonal variation, reaching broad maximum values in spring-autumn and reaching minimum values in midwinter. More stringent regulation of emissions of particles from diesel cars started in the Tokyo metropolitan area in October 2003. The ΔEC/ΔCO values did not change significantly (10%) after one year from the start of the new regulations, when the temperature dependence is taken into account. This indicates that the regulation of particle emissions in the Tokyo Metropolitan Area was not effective in reducing the EC concentrations after one year.
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