Okuda, Tomoaki

写真a

Affiliation

Faculty of Science and Technology, Department of Applied Chemistry (Yagami)

Position

Professor

Related Websites

External Links
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Profile Summary 【 Display / hide 】

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

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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 】

  • 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

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Academic Degrees 【 Display / hide 】

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

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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

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Research Keywords 【 Display / hide 】

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

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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

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Papers 【 Display / hide 】

  • Numerical analysis of collision mechanism that causes particle tribocharging in dry powder inhaler

    Mitani R., Nor M.A.b.M., Iinuma T., Mori T., Okuda T.

    Asian Journal of Atmospheric Environment 19 ( 1 )  2025.12

    ISSN  19766912

    　View Summary

    Chronic obstructive pulmonary disease (COPD) is induced by inhalation of toxic substances such as cigarettes and air pollution. Dry powder inhalers (DPIs) are the primary treatment for these diseases. However, they have some problems, such as residuals in a capsule caused by electrostatic force before reaching the human lungs. This study investigated the particle tribocharging mechanism in a DPI using a tandem differential mobility analyzer (TDMA) and a combined discrete element method and computational fluid dynamics (DEM-CFD) approach. In the TDMA experiment, the charging state of the particles changed from negative to positive charge in the DPI device fabricated by the 3D printer. This is because tribocharging is caused by particle–particle collisions and particle–wall collisions. In the numerical simulation, particle–wall collisions occurred more frequently than particle–particle collisions. Therefore, the particle–wall collisions change the charging state of the particle in the DPI device. These results suggest that collisions between particles and walls of the device cause the particles to become charged, leading to a decrease in their deposition in the deeper regions of the lungs. Moreover, the large turbulence kinetic energy of the airflow in the DPI device caused particle–wall collisions because the particles were widely dispersed in the DPI device. These results suggest that optimum turbulence kinetic energy is necessary to reduce particle aggregation and improve the delivery efficiency of DPIs to the human lungs.

  • Variations in polycyclic aromatic hydrocarbons concentrations and their contribution to aerosol optical depth during the COVID-19 outbreak: A study in Yokohama using generalized additive model

    Jing W., Nakano K., Mitani R., Shen Z., Okuda T.

    Atmospheric Pollution Research 16 ( 8 )  2025.08

    ISSN  13091042

    　View Summary

    The severe social restrictions aiming at reducing the novel coronavirus disease (COVID-19) transmission during its outbreak significantly affected regional air quality. This study analyzed changes in polycyclic aromatic hydrocarbons (PAHs) concentrations in cyclone-collected powder form particulate matter (PM) samples collected in Yokohama, Japan, from 2018 to 2023. The annual mean ∑PAHs concentration decreased significantly from 20.7 ng/mg in 2019 to 13.2 ng/mg in 2020 after the outbreak. However, the main sources of PAHs remained stable and were dominated by incomplete fossil fuel combustion. A generalized additive model was utilized to analyze the statistical relationships of air pollutants, namely, aerosol particulate matter (PM<inf>2.5</inf>), ∑PAHs, ozone (O<inf>3</inf>), metal, and meteorological factors such as solar radiation and their impact on aerosol optical depth (AOD). AOD remote sensing data collected by the Terra/MODIS satellite reflects the degree of air turbidity and atmospheric aerosol loading. Despite the small sample size, the model fitting demonstrated a good fit and showed smoothing non-linear interaction effects among the target factors influencing secondary aerosol generation. In conclusion, intense solar radiation, high concentrations of oxidative gases, elevated levels of organic contaminants in aerosols, and the catalytic degradation of PAHs by transition metals contribute to increased atmospheric aerosol loads. This finding enhances the present understanding of the photochemical reaction processes of aerosol particles. However, longer-term observational studies are needed to confirm our findings due to the limited sample size in this study.

  • Mapping of friction, wear and particle emissions from high-speed train brakes

    Lyu Y., Zhang Q., Tanzeglock L., Tu M., Mo J., Okuda T., Pagels J., Wahlström J.

    Wear 572-573 2025.07

    ISSN  00431648

    　View Summary

    This study reports contact pressure-sliding speed maps for friction, wear and particle emissions from high-speed train brakes. Two particle spectrometers measured the airborne wear particles generated with a pin-on-disc tribometer. Particles were characterized with transmission electron microscopy and energy dispersive X-ray fluorescence. The results indicate that both the friction and wear of brake pads and discs gradually decreased as sliding speed increased, which showed less dependence on contact pressure. Particle concentrations gradually increased with increasing sliding speed. Low contact pressure and sliding speed tended to generate particles smaller than 2.5 μm. The train brake emitted particles had higher average geometric mean diameters than the car brake emitted particles, which were primarily composed of iron, copper and chromium and were oxidized.

  • Complement system is activated in acute inflammatory response to environmental particulates in the lungs

    Zhang K., Honda A., Sagawa T., Miyasaka N., Qiu B., Ishikawa R., Okuda T., Kameda T., Sadakane K., Ichinose T., Takano H.

    Ecotoxicology and Environmental Safety 297 2025.06

    ISSN  01476513

    　View Summary

    Short-term exposure (typically ranging from a few hours to 7 days) to particulate matter (PM) elicits acute inflammatory responses with significant activation of complement component C5. However, the relationship between PM-induced complement system activation, acute inflammation, and the contributing factors remains unclear. In this study, we aimed to investigate the intensity of acute inflammatory responses, as well as the activation levels of complement C5 and its related products, C5aR1 and C5b-9, following exposure to different types of PM. Acute inflammatory responses and complement activation were assessed in mice intratracheally administered four types of PM: titanium dioxide (TiO₂), diesel exhaust particles (DEP), Asian sand dust (ASD), and ambient PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5). Complement system and inflammatory markers were evaluated by analyzing increased C5 protein levels, C5b-9 deposition, and C5aR1 expression. Additionally, dark-field microscopy and Raman microscopy were used to detect PM components adjacent to infiltrating neutrophils, and elemental composition was quantified using ICP-MS and EDXRF. ASD, DEP, and PM2.5 exposure significantly increased C5b-9 deposition in lung tissues. All PM-exposed groups exhibited substantial upregulation of C5aR1 expression, primarily in neutrophils. Raman spectroscopic analysis revealed Si, K, Mg, Al, and Fe adjacent to infiltrating neutrophils in ASD-exposed lungs. Furthermore, elemental analysis identified Si, Mg, Al, and K as the most potent contributors to complement activation and inflammatory responses. Of the four types of PM, ASD induced the most severe acute inflammatory response and complement system activation. Therefore, ASD-induced complement system activation, driven at least partly by its mineral components, may play a critical role in neutrophil activation and acute pulmonary inflammation. These findings highlight the differential impact of PM types on complement system activation and underscore the importance of PM composition in the evaluation of air pollution-related health risks, particularly acute pulmonary inflammation.

  • Effects of inbound attendees of a mass gathering event on the COVID-19 epidemic using individual-based simulations

    Saito M.M., Katayama K., Naruse A., Ruan P., Murakami M., Okuda T., Ysutaka T., Naito W., Tsubokura M., Imoto S.

    Plos One 20 ( 4 April )  2025.04

    ISSN  1932-6203

    　View Summary

    Given that mass gathering events involve heterogeneous and time-varying contact between residents and visitors, we sought to identify possible measures to prevent the potential acceleration of the outbreak of an emerging infectious disease induced by such events. An individual-based simulator was built based on a description of the reproduction rate among people infected with the infectious disease in a hypothetical city. Three different scenarios were assessed using our simulator, in which controls aimed at reduced contact were assumed to be carried out only in the main event venue or at subsequent additional events, or in which behavior restrictions were carried out among the visitors to the main event. The simulation results indicated that the increase in the number of patients with COVID-19 could possibly be suppressed to a level equivalent to that if the event were not being held so long as the prevalence among visitors was only slightly higher than that among domestic residents and strict requirements were applied to the activities of visitors.

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

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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.

  • 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 】

  • 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 】

  • 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 】

  • 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

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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 】

  • SEMINAR IN APPLIED CHEMISTRY

    2025

  • PROJECT FOR MULTIDISCIPLINARY AND INTERDISCIPLINARY KNOWLEDGE (SUSTAINABLE ENVIRONMENT)

    2025

  • OFF-CAMPUS WORK-STUDY PROGRAM

    2025

  • LABORATORIES IN APPLIED CHEMISTRY C

    2025

  • INTRODUCTION OF ENVIRONMENTAL CHEMISTRY

    2025

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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 】

  • 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 】

  • 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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