KEIO RESEARCHERS INFORMATION SYSTEM

Profile Summary 【 Display / hide 】

Profile Summary 【 Display / hide 】

• Study on physical and chemical characteristics of atmospheric particulate matter (PM2.5) associated with health hazard

Career 【 Display / hide 】

Career 【 Display / hide 】

• 2020.04

  -

  Present

  理工学部応用化学科, 大学教授

• 2023.04

  -

  Present

  理工学研究科開放環境科学専攻環境エネルギー科学専修, 専修主任

• 2015.04

  -

  2020.03

  理工学部応用化学科, 大学准教授

• 2007.10

  -

  2008.09

  University of Wisconson-Madison, USA, Visiting Assistant Professor

• 2007.04

  -

  2015.03

  理工学部応用化学科, 大学専任講師

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Academic Background 【 Display / hide 】

Academic Background 【 Display / hide 】

• 1999.04

  -

  2002.03

  Tokyo University of Agriculture and Technology, Graduate School, Division of Agricltural Sciences

  Graduate School, Completed, Doctoral course

• 1997.04

  -

  1999.03

  Tokyo Metropolitan University, Graduate School, Division of Natural Science, Department of Chemistry

  Graduate School, Completed, Master's course

• 1993.04

  -

  1997.03

  Tokyo Metropolitan University, Faculty of Science, Department of Chemistry

  University, Graduated

Academic Degrees 【 Display / hide 】

Academic Degrees 【 Display / hide 】

• Doctor (Agricultural Science), Tokyo University of Agriculture and Technology, Coursework, 2002.03

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Environmental Science/Agriculture Science / Environmental dynamic analysis (Environmental Dynamic Analysis)

• Nanotechnology/Materials / Green sustainable chemistry and environmental chemistry (Environmental Chemistry)

• Natural Science / Space and planetary sciences (Earth Astrohemistry)

• Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Transport phenomena and unit operations

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• aerosol, PM2.5, fine particulate matter, physical and chemical characteristics, health impacts

Books 【 Display / hide 】

Books 【 Display / hide 】

• 環境化学

  OKUDA TOMOAKI, 日本有機地球化学会, 2014

  Scope: 日本地球化学会（監修）地球・環境有機分子質量分析マニュアル2014，第１部第５章

• Aerosol Pollution in China

  OKUDA TOMOAKI, TANAKA SHIGERU, HE KEBIN, MA YONGLIANG, 京都大学学術出版会、京都, 2007

  Scope: 24-32

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Ferruginous components of particulate matters in subway environments, α-Fe<inf>2</inf>O<inf>3</inf> or Fe<inf>3</inf>O<inf>4</inf>, exacerbates allergies

  Watanabe H., Honda A., Ichinose T., Ishikawa R., Miyasaka N., Nagao M., Wang Z., Owokoniran O.H., Qiu B., Higaki Y., Liu W., Okuda T., Matsuda T., Takano H.

  Environmental Pollution (Environmental Pollution)  355 2024.08

  ISSN  02697491

  　View Summary

  The respiratory effects of particulate matter (PM) in subway station platforms or tunnels have attracted considerable research attention. However, no studies have characterized the effects of subway PM on allergic immune responses. In this study, iron oxide (α-Fe2O3 and Fe3O4) particles—the main components of subway PM—were intratracheally administered to BALB/c mice where ovalbumin (OVA) induced allergic pulmonary inflammation. Iron oxide particles enhanced OVA-induced eosinophil recruitment around the bronchi and mucus production from airway epithelium. The concentrations of type 2 cytokines, namely, interleukin (IL)-5 and IL-13, in bronchial alveolar lavage fluids were increased by iron oxide particles. Iron oxide particles also increased the number of type 2 innate lymphoid cells and CD86+ cells in the lung. Moreover, phagocytosis of particles in lung cells was confirmed by Raman spectroscopy. In a subsequent in vitro study, bone marrow-derived antigen-presenting cells (APCs) isolated from NC/Nga mice were exposed to iron oxide particles and OVA. They were also exposed to outdoor ambient PM: Vehicle Exhaust Particulates (VEP) and Urban Aerosols (UA) as references. Iron oxide particles promoted the release of lactate dehydrogenase, C-X-C motif chemokine ligand 1 and IL-1α from APCs, which tended to be stronger than those of VEP. These results suggest that iron oxide particles enhance antigen presentation in the lungs, promoting allergic immune response in mice; iron oxide particles-induced death and inflammatory response of APCs can contribute to allergy exacerbation. Although iron oxide particles do not contain various compounds like VEP, iron oxide alone may have sufficient influence.

  • Access to Document (DOI)

• Atmospheric Aerosol and Gas Measurements at the Westernmost Large City, Fukuoka, Japan—Transboundary/Local Air Pollution and Health Effects—

  Takashima H., Hara K., Nishita-Hara C., Shiraishi K., Hayashi M., Irei S., Kaneyasu N., Ko R., Kobayashi H., Marumoto K., Okuda T., Osada K., Otobe N., Takami A., Uchio E., Ueda K., Yamazaki A., Yoshino A.

  Earozoru Kenkyu (Earozoru Kenkyu)  39 ( 2 ) 129 - 144 2024.06

  ISSN  09122834

  　View Summary

  Long-term observations of atmospheric aerosols and gaseous species have been conducted in Fukuoka, located in westernmost Japan, to understand the atmospheric environment of the region and to elucidate their health effects. Fukuoka represents an ideal site for studying interaction between urban air pollution originating from local urban areas in Japan and transboundary air masses from the Asian continent. Fukuoka air quality is strongly affected by transboundary transport from the Asian continent. Diurnal variations of atmospheric composition in Fukuoka are also affected by local emissions, atmospheric reactions, and local circulation. The health effects of aerosols have been investigated through epidemiological and toxicological studies. This report presents comprehensive summary of research findings obtained from studies conducted in the Fukuoka region.

  • Access to Document (DOI)

• Seasonal charge distributions of submicron atmospheric particles in Yokohama, Japan

  Mori T., Ishii Y., Iwata A., Okuda T.

  Atmospheric Environment (Atmospheric Environment)  324 2024.05

  ISSN  13522310

  　View Summary

  Charge distribution measurements are required to understand the spatiotemporal distribution of the number concentrations of submicron atmospheric particles that affect radiative forcing and particle deposition in human airways. The number concentrations of non-charged and charged particles within the 0.3–0.5 μm diameter (D) range were measured at Keio University in Yokohama, Japan, from June 2022 to January 2023 by combining a parallel-pate particle separator and optical particle counters to investigate critical parameters controlling the charging state of submicron atmospheric particles. The measurement uncertainties in the average charge number per particle (pave) and the standard deviation (1σ), derived from the charge distribution of the submicron particles, were within 15%. The monthly median values of 1σ increased in summer and decreased in winter and correlated with the water vapor amount and wind speed. The 1σ values in summer and winter, derived from the seasonally averaged charge distributions of particles, were close to those from the theoretically calculated charge distribution of particles within 0.387–0.5 μm D range and with D = 0.3 μm, respectively, suggesting that the observed particle charge distributions approached the stationary charge distribution for the effective D. In summer, the frequent transport of water molecules and ions from the Pacific Ocean causes efficient collisions between multiple ions and submicron particles with a larger effective D, which may expand the charge distribution of particles. The polarity ratio, the concentration of positively charged particles relative to that of negatively charged particles, was almost unity, indicating the well-balanced charge polarity of the submicron atmospheric particles. The polarity ratio and pave changed significantly during lightning events, indicating that the atmospheric particle charge balance broke. Our findings show that the charge distribution of submicron atmospheric particles can be partly controlled by meteorological parameters (e.g., absolute humidity) and the microphysical properties of the particles.

  • Access to Document (DOI)

• Key Factors Controlling Number Concentrations of Non-charged Particles: An Experimental Study

  Mori T., Iwata A., Tabata R., Okuda T.

  Aerosol and Air Quality Research (Aerosol and Air Quality Research)  24 ( 4 )  2024.04

  ISSN  16808584

  　View Summary

  The charging state of submicron particles strongly affects the number of particles deposited on the inner surface of human airways during inhalation, and an increase in this number leads to adverse effects on human health. However, the key factors controlling the charging state of particles are poorly understood because of the limited measurements of the number concentrations of charged submicron particles. In order to experimentally investigate the key factors controlling the number concentration of charged particles, the technique for accurately measuring the number concentration of non-charged particles (Nnon-charge) was improved based on a system consisting of optical particle counters and a parallel-plate particle separator to which a high voltage (1.0–1.5 kV) was applied. The ratio of the Nnon-charge to the total number concentration of particles (Ntotal), with diameters 0.3–0.5 µm, was used as a metric of the number fraction of non-charged particles. A decrease in the Nnon-charge/Ntotal ratio with an increase in the negative ion concentration (nion–) and the nion–/Ntotal ratio under stable meteorological conditions showed an increase in the number of charged particles by collisions between aerosols and ions. Under fluctuating humidity conditions, the Nnon-charge/Ntotal ratio also decreased with an increase in the nion– and the nion–/Ntotal ratio. Particularly, the decrease rate in the Nnon-charge/Ntotal ratio was greater at higher nion– and nion–/Ntotal ratio values than that under stable meteorological conditions. This suggests that the generation of water vapor drives an increase in ion concentration, leading to frequent collisions between excessive negative ions and aerosols. A quantitative understanding of the changes in the number fraction of charged particles with increasing humidity and nion– can assist in estimating the number of particles deposited on the inner surface of human airways.

  • Access to Document (DOI)

• Characteristic Fe and Cu Compounds in Particulate Matter from Subway Premises in Japan and their Potential Biological Effects

  Okamoto T., Iwata A., Yamanaka H., Ogane K., Mori T., Honda A., Takano H., Okuda T.

  Aerosol and Air Quality Research (Aerosol and Air Quality Research)  24 ( 3 )  2024.03

  ISSN  16808584

  　View Summary

  Suspended particulate matter (PM) in subway premises contain high concentrations of metal components and distinctive compounds owing to their unique emission processes. However, little is known regarding the detailed chemical states of airborne PM and their biological effects. Therefore, to demonstrate the unique chemical states of the PM collected from subway premises and outdoors, this study compared the chemical speciation of iron (Fe) and copper (Cu) components using X-ray absorption fine structure analysis. The potential biological effects of these chemical states on humans were also investigated in vitro by assessing cell damage and its pathways in cells after exposure to several compounds. Compared with a reference outdoor PM sample, Fe was enhanced by at least 10 times in subway PM and the concentrations of several metal components, including Cu, contained in railway bodies, rail, overhead wires, and tunnel walls, also increased. In these chemical speciations, the compounds derived from wear processes with relatively high-temperature oxidation (Fe3O4, γ-Fe2O3, and monovalent Cu compounds) were detected among the Fe and Cu components in subway PM. Our cell-based bioassay suggested that the contribution of the Fe component to cell damage can be enhanced by the predominance of Fe3O4 in subway PM. In contrast to typical bivalent Cu compounds in the atmosphere, monovalent Cu compounds, which are characteristically identified in subway PM, exacerbate cell damage via different cell death pathways. Our results indicate that the chemical states of the distinctive compounds in the PM of subway premises differ from those in the typical atmosphere, thus exerting different biological effects. These findings suggest that the detailed chemical speciation is an important factor in accurately understanding their PM toxicities.

  • Access to Document (DOI)

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Social implementation of medical assistive devices to remove surgical smoke

  Okuda, Tomoaki

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2021

• Development of medical assistive devices for surgical smoke reduction

  Okuda, Tomoaki

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2020

• High-volume collection of aerosols in India and China using the originally developed cyclone sampler and evaluation of their health impacts

  Okuda, Tomoaki

  科学研究費補助金研究成果報告書 2019

• Elucidation of the electrostatic charging state of ambient aerosols and evaluation of its effect on deposition to body tissue

  Okuda, Tomoaki

  科学研究費補助金研究成果報告書 2019

• Evaluation of health impact of transboundary air pollution by an intensive observation of the concentrations of aerosol surface area and chemical constituents

  Okuda, Tomoaki

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2017

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Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• 環境大気エアロゾルの帯電状態測定の現状と展望

  奥田 知明

  クリーンテクノロジー 27 ( 4 ) 37 - 40 2017.06

  Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work

• 連載 エアロゾル基礎講座 ―計測― 6. 分級②：慣性運動や遠心力を用いた分級

  奥田知明, 榎原研正, 飯田健次郎

  エアロゾル研究 (日本エアロゾル学会)  32 ( 4 ) 276 - 288 2017.12

  Article, review, commentary, editorial, etc. (scientific journal), Joint Work

• A simple air–liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation

  Kono M., Takaishi M., Okuda T., Fujihara M., Noguchi S., Ishihara Y.

  Journal of Toxicological Sciences (Journal of Toxicological Sciences)  49 ( 2 ) 61 - 68 2024

  ISSN  03881350

  　View Summary

  Particulate matter (PM) is among the major air pollutants suspended in the atmosphere. PM2.5 has a particle size of 2.5 µm; it is known to cause inflammation, especially in the respiratory tract and skin. Since the skin acts a primary barrier against harmful environmental substances that may enter the body, it is highly exposed to PM2.5 present in the environment. However, the adverse health effects of PM2.5 exposure on human skin have not been accurately examined due to the lack of a system that expos-es human epidermal tissue to the actual environmental concentration of PM2.5. In this study, we developed an air–liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation. PM2.5 suspension was nebulized in an acrylic chamber, and the resulting mist was pumped through a diffusion dryer into a glass exposure chamber. A particle counter was connected to the exposure chamber to continuously measure the spatial mass concentration of PM. Human 3D epidermis was cultured in the exposure chamber. Exposure of the human 3D epidermis to PM aerosol increased interleukin-8 release into the media around 50 µg/m3. Mass concentrations above 100 µg/m3 caused cell death. Furthermore, a human corneal model showed similar responses against PM2.5 exposure as 3D epidermis. The air–liquid interface exposure system developed in this study is considered useful for evaluating the health effects induced by environmental PM2.5 and can be used as an alternative to experiments involving actual human or animals.

  • Access to Document (DOI)

• 環境大気中PM2.5の比表面積の測定

  奥田知明

  クリーンテクノロジー (日本工業出版(株))  25 ( 6 ) 23 - 26 2015.06

  Article, review, commentary, editorial, etc. (scientific journal), Single Work

• 東アジアにおけるエアロゾルのフィールド観測および分析法の開発

  奥田知明

  大気環境学会誌 (（公社）大気環境学会)  50 ( 1 ) 1 - 8 2015.01

  Article, review, commentary, editorial, etc. (scientific journal), Single Work

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Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• PM2.5の物理化学特性の解明と曝露実験による生体有害性評価

  奥田知明

  第88回日本衛生学会 (東京工科大学蒲田キャンパス、東京都大田区) , 

  2018.03

  , 

  Oral presentation (invited, special), 日本衛生学会

• Development of measurement techniques of physical and chemical characteristics of atmospheric aerosols related to their adverse health effect

  Okuda, T.

  Frontiers of Atmospheric Aerosol Studies: Toward the Understanding of Their Health and Climatic Effects (Nagoya, Japan) , 

  2018.01

  , 

  Oral presentation (invited, special)

• Numerical simulation of a parallel plate particle separator for measurement of charging state of PM2.5

  Yonemichi, T., Fukagata, K., Fujioka, K., Okuda, T.

  9th JSME-KSME Thermal and Fluids Engineering Conference (Okinawa, Japan) , 

  2017.10

  , 

  Poster presentation, JSME

• PM2.5を集めて測る ～捕集と特性解明の技術～

  奥田知明

  第7回CSJ化学フェスタ (タワーホール船堀、東京都江戸川区) , 

  2017.10

  , 

  Oral presentation (invited, special), 日本化学会

• 黄砂・PM2.5の健康乳幼児の目・鼻・呼吸器症状への影響 - エコチル調査追加調査『黄砂と子どもの健康調査（パート２）』より -

  金谷久美子、亀田貴之、大久保綾乃、森育子、増本年男、黒沢洋一、大西一成、奥田知明、中山健夫

  第58回大気環境学会年会 (兵庫医療大学、兵庫県神戸市) , 

  2017.09

  , 

  Poster presentation, 大気環境学会

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• Establishment of a new environmental chemical analysis method for endotoxin as a key parameter to elucidate the toxicity of aerosol particles

  2024.04

  -

  2027.03

  基盤研究(B), Principal investigator

• Development of a Health Effect Evaluation System for Particulate Matter Characteristics for the Central Asian Region

  2023.09

  -

  2027.03

  国際共同研究加速基金（海外連携研究）, Principal investigator

• Development and practical application of a new filter to promote collaboration between the chemical and biological research fields of aerosol toxicity assessment

  2022.06

  -

  2025.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, 挑戦的研究（萌芽）, Principal investigator

• Evaluation of the influence of charging state of atmospheric aerosol on particle deposition on human body and ground surface

  2020.04

  -

  2024.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A) , Principal investigator

• Multidisciplinary Analysis of Airborne Particle Surface Area as a New Indicator of Adverse Health Effect of PM2.5

  2018.06

  -

  2021.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory) , Principal investigator

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Intellectual Property Rights, etc. 【 Display / hide 】

Intellectual Property Rights, etc. 【 Display / hide 】

• 微小粒子の捕集装置

  Date applied： 特願2017-132547  2017.07 

  Date announced： 特開2018-023970  2018.02 

  Patent, Joint

• 自動オープンクロマトグラフィー装置

  Date applied：   2007.07 

  Date announced：   2007.09 

  Date issued： 3135990 

  Utility model, Joint

Awards 【 Display / hide 】

Awards 【 Display / hide 】

• 2015 Asian Young Aerosol Scientist Award

  Tomoaki OKUDA, 2015.06, The Asian Aerosol Research Assembly, Outstanding contribution to aerosol science and technology in Asia

  Type of Award： International academic award (Japan or overseas)

• 2023 Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology

  Tomoaki OKUDA, and 4 other members, 2023.04, Ministry of Education, Culture, Sports, Science and Technology , Contributions to the mass-gathering event under the COVID-19 pandemic

  Type of Award： International academic award (Japan or overseas)

• Best Paper Award, Japan Society for Atmospheric Environment

  Tomoaki OKUDA, Masanobu SAKAIDE, Ayumi IWATA, Motoi FUJIWARA, 2020.09, Japan Society for Atmospheric Environment, Investigation of the Characteristics of Particulate Matter Suspended in a Subway Station Platform

  Type of Award： Award from Japanese society, conference, symposium, etc.

• Incentive Award 2015, Japan Association of Aerosol Science and Technology

  Tomoaki OKUDA, 2015.06, Japan Association of Aerosol Science and Technology, Elucidation of physical and chemical characteristics of atmospheric aerosols related to their adverse health effect

• Creative Work Award for Young Scientists, Japan Society for Atmospheric Environment

  Tomoaki OKUDA, 2014.09, Japan Society for Atmospheric Environment, Outstanding Works for Field Study on Aerosols in East Asia

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• SEMINAR IN APPLIED CHEMISTRY

  2024

• PROJECT FOR MULTIDISCIPLINARY AND INTERDISCIPLINARY KNOWLEDGE (SUSTAINABLE ENVIRONMENT)

  2024

• LABORATORIES IN APPLIED CHEMISTRY C

  2024

• INTRODUCTION OF ENVIRONMENTAL CHEMISTRY

  2024

• INDEPENDENT STUDY ON SCIENCE FOR OPEN AND ENVIRONMENTAL SYSTEMS

  2024

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Courses Previously Taught 【 Display / hide 】

Courses Previously Taught 【 Display / hide 】

• 自然科学実験（化学）

  Keio University

  2018.04

  -

  2019.03

  , 

  Spring Semester, Laboratory work/practical work/exercise, Within own ｆaculty

• 大気環境科学

  Keio University

  2018.04

  -

  2019.03

  , 

  Autumn Semester, Lecture

• 化学B

  Keio University

  2018.04

  -

  2019.03

  , 

  Autumn Semester, Lecture

• 環境化学２

  Keio University

  2018.04

  -

  2019.03

  , 

  Autumn Semester, Lecture

• 応用化学実験CD

  Keio University

  2018.04

  -

  2019.03

  , 

  Autumn Semester, Laboratory work/practical work/exercise, Within own ｆaculty

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Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• The Chemical Society of Japan, 

  2015.06

  -

  Present

• Japan Association of Aerosol Science and Technology, 

  2006.04

  -

  Present

• The Japan Society for Analytical Chemistry, 

  2004.04

  -

  Present

• 日本大気化学会, 

  2002.04

  -

  Present

• Japan Society for Atmospheric Environment, 

  2002.04

  -

  Present

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Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2022.08

  -

  Present

  常任理事, 日本エアロゾル学会

• 2020.09

  -

  Present

  常任理事, 大気環境学会

• 2020.06

  -

  2021.03

  新型コロナウイルス対策専門家会議委員, 内閣府

• 2019.04

  -

  Present

  環境安全推進委員会委員長, 日本化学会

• 2019.04

  -

  2020.03

  PM2.5対策総合推進委員会委員, 環境省

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