KEIO RESEARCHERS INFORMATION SYSTEM

Career 【 Display / hide 】

Career 【 Display / hide 】

• 2016.04

  -

  2017.03

  The University of Tokyo, Graduate School of Science, 日本学術振興会 特別研究員(DC2)

• 2017.04

  -

  2021.03

  Tokyo University of Science, Physics, Faculty of Science, Division 1, 嘱託助教

• 2021.04

  -

  2022.03

  The University of Tokyo, Department of Earth and Planetary Science, 特任助教

• 2021.04

  -

  Present

  Tokyo University of Science, 客員研究員

• 2022.04

  -

  Present

  Keio University, Faculty of Science and Technology Department of Applied Chemistry, Assistant professor

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Natural Science / Atmospheric and hydrospheric sciences

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• Aerosol, charging states, East Asia, Arctic, Health effect

Papers 【 Display / hide 】

Papers 【 Display / hide 】

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

  Ryosuke Mitani, Muhammad Aiman bin Mohd Nor, Takuto Iinuma, Tatsuhiro Mori, Tomoaki Okuda

  Asian Journal of Atmospheric Environment (Springer Science and Business Media LLC)  19 ( 1 )  2025.12

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  19766912

  　View Summary

  Abstract
  
  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.
  
  Graphical Abstract

  • Access to Document (DOI)

• Sensitivity of Wintertime Arctic Black Carbon to Removal Processes and Regional Alaskan Sources

  Ioannidis E., Law K.S., Raut J.C., Marelle L., Onishi T., Andrews E., Ohata S., Mori T., Morris S., Kondo Y., Sharma S., Eleftheriadis K., Klimont Z., Soulie A., Granier C., Quinn P.K., Pratt K.A.

  Journal of Geophysical Research Atmospheres 130 ( 7 )  2025.04

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  2169897X

  　View Summary

  Air pollutants are primarily transported from midlatitude emission regions in winter and early spring, leading to elevated concentrations of aerosols, including black carbon (BC), in the Arctic, a phenomenon known as Arctic haze. The Weather Research and Forecasting model coupled with chemistry is used to investigate potential causes of uncertainties in modeling Arctic BC for winter 2014. The model captures observed variability in BC at surface sites, reproducing BC concentrations at Zeppelin but showing a low bias at Tiksi, Alert, and Utqiaġvik/Barrow. The influence of removal processes on model BC biases is explored by switching off dry or wet deposition. Wet deposition, during transport in the North Atlantic storm track, and locally over Svalbard, dominates BC removal at Zeppelin, while wet removal in the Pacific storm track influences BC at Alert and Utqiaġvik/Barrow. Dry removal over Asian source regions and Alaska affects BC at Utqiaġvik/Barrow, and is larger than wet removal at Tiksi due to the proximity of local/regional anthropogenic sources. Regional runs over northern Alaska in late January show improved simulated BC compared to observations at Utqiaġvik/Barrow, in part, due to better resolution of removal processes, and local/regional emissions. Sensitivity runs also show that regional Alaskan sources, notably from the North Slope of Alaska oil fields, may be contributing 30%–50%, on average, to observed BC at Utqiaġvik/Barrow in January and February 2014, with the remainder from outside the region. These findings highlight the importance of local Arctic emissions, and the need for improved emission inventories in the Arctic.

  • Access to Document (DOI)

• Aircraft‐Based Observation of Mineral Dust Particles Over the Western North Pacific in Summer Using a Complex Amplitude Sensor

  S. Ohata, N. Moteki, K. Adachi, Y. Tobo, H. Matsui, K. Kita, T. Mori, M. Koike

  Journal of Geophysical Research: Atmospheres  2025.03

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted

  • Access to Document (DOI)

• High-resolution analyses of concentrations and sizes of refractory black carbon particles deposited in northwestern Greenland over the past 350 years - Part 2: Seasonal and temporal trends in refractory black carbon originated from fossil fuel combustion and biomass burning

  Goto-Azuma K., Ogawa-Tsukagawa Y., Fukuda K., Fujita K., Hirabayashi M., Dallmayr R., Ogata J., Moteki N., Mori T., Ohata S., Kondo Y., Koike M., Matoba S., Kadota M., Tsushima A., Nagatsuka N., Aoki T.

  Atmospheric Chemistry and Physics 25 ( 1 ) 657 - 683 2025.01

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  16807316

  　View Summary

  The roles and impacts of refractory black carbon (rBC), an important aerosol species affecting Earth's radiation budget, are not well understood owing to a lack of accurate long-term observations. To study the temporal changes in rBC since the pre-industrial period, we analyzed rBC in an ice core drilled in northwestern Greenland. Using an improved technique for rBC measurement and a continuous flow analysis (CFA) system, we obtained accurate and high-temporal-resolution records of rBC particle size and mass/number concentrations for the past 350 years. Number and mass concentrations, which both started to increase in the 1870s associated with the inflow of anthropogenically derived rBC, reached their maxima in the 1910s-1920s and then subsequently decreased. Backward-trajectory analyses suggest that North America was likely the dominant source region of the anthropogenic rBC in the ice core. The increase in anthropogenic rBC shifted the annual concentration peaks of rBC from summer to winter-early spring. After rBC concentrations diminished to pre-industrial levels, the annual peak concentration of rBC returned to the summer. We found that anthropogenic rBC particles were larger than biomass burning rBC particles. By separating the rBC in winter and summer, we reconstructed the temporal variations in rBC that originated from biomass burning, including the period with large anthropogenic input. The rBC that originated from biomass burning showed no trend in increase until the early 2000s. Finally, possible albedo reductions due to rBC are discussed. Our new data provide key information for validating aerosol and climate models, thereby supporting improved projections of future climate and environment.

  • Access to Document (DOI)

• Studies of atmospheric climate forcers in the Arctic during the ArCS II project

  Koike M., Takigawa M., Morimoto S., Adachi K., Aizawa T., Chandra N., Fujita R., Goto D., Ishidoya S., Ishijima K., Ito A., Kawai K., Kanaya Y., Kim Y., Kinase T., Kondo Y., Machida T., Matsui H., Miyakawa T., Mochida M., Mori T., Moteki N., Murayama S., Ohata S., Oshima N., Patra P.K., Taketani F., Tobo Y., Tohjima Y., Toyoda S., Tsuboi K., Rui O.C., Yahara K., Yamaji K., Yoshida A., Zhu C.

  Polar Science  2025

  Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted,  ISSN  18739652

  　View Summary

  This paper reviews studies of atmospheric climate forcers, namely, greenhouse gases (GHGs) and aerosols, and their impacts on radiation and clouds in the Arctic during the Arctic Challenge for Sustainability II (ArCS II) project conducted between 2020 and 2024. In GHG research, we measured atmospheric mixing ratios of CO<inf>2</inf>, CH<inf>4</inf>, and N<inf>2</inf>O and their isotope ratios, as well as O<inf>2</inf>/N<inf>2</inf> ratios from the ground, ship (research vessel Mirai), and commercial aircraft over the northern high latitudes. We showed that the rapid increase of CH<inf>4</inf> mixing ratios after ∼2018 could be attributed to elevated microbial CH<inf>4</inf> emissions. The increase of N<inf>2</inf>O after ∼2011 was attributable to an increase of N<inf>2</inf>O emissions from soil treated with chemical fertilizer. In aerosol research, we provided a scientific basis for constructing unified black carbon (BC) datasets in the Arctic and estimated the contributions to Arctic BC from biomass-burning and anthropogenic sources in various regions. We showed the abundance of highly active ice nucleating particles (INPs) increased with rising surface temperatures above 0 °C and evaluated impacts of Arctic dust that serve as INP on clouds. We found that marine biota were likely the sources of cloud condensation nuclei and INPs over the remote Arctic Ocean during periods of high biological activity.

  • Access to Document (DOI)

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

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

• Observational studies on behaviors of the charged black carbon particles in the air with a new technique for measuring of the charge distribution of black carbon

  Mori, Tatsuhiro

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2022

Reviews, Commentaries, etc. 【 Display / hide 】

Reviews, Commentaries, etc. 【 Display / hide 】

• Long-term variation in atmospheric aerosol particles over the central Tokyo and the summit of Mt. Fuji

  三浦和彦, 三浦和彦, 森樹大, 森樹大, 岩本洋子, 岩本洋子, 上田紗也子, 上田紗也子, 五十嵐博己, 桃井裕広, 桃井裕広, 青木一真, 青木一真, 齋藤天眞, 齋藤天眞, 伊藤佳樹, 伊藤佳樹, 大河内博, 加藤俊吾, 和田龍一

  日本地球惑星科学連合大会予稿集(Web) 2022 2022

  Lead author, Corresponding author

• 東京におけるエアロゾル・雲相互作用のレジーム分類

  三隅良平, 宇治靖, 當房豊, 三浦和彦, 森樹大, 岩本洋子

  日本気象学会大会講演予稿集(CD-ROM)  ( 120 )  2021

  Lead author, Corresponding author

• 東京スカイツリーにおける降水経験の有無によるエアロゾル粒子の吸湿性の違い

  田柳紗英, 森樹大, 三浦和彦, 岩本洋子, 速水洋, 三隅良平, 宇治靖, 當房豊

  大気電気学会誌(Web) 15 ( 1 )  2021

  Lead author, Corresponding author,  ISSN  1882-0549

• 2016-2018年の東京スカイツリーで観測された新粒子生成

  佐藤丈徳, 前田麻人, 森樹大, 桃井裕広, 五十嵐博己, 三浦和彦, 三隅良平, 宇治靖, 當房豊, 岩本洋子

  大気電気学会誌 13 ( 1 )  2020

  Lead author, Corresponding author,  ISSN  1882-0549

• Evaluation of surface condition on non-hygroscopic soot particles in urban

  上田紗也子, 森樹大, 岩本洋子, 丑久保裕太, 丑久保裕太, 三浦和彦

  エアロゾル科学・技術研究討論会(CD-ROM) 37th 2020

  Lead author, Corresponding author

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Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• 能登における粒子の帯電状態と大気電場との関係

  森樹大, 奥田知明, 松木篤, 岩田歩, 鴨川仁

  日本大気電気学会第103回研究発表会, 

  2025.01

  , 

  Oral presentation (general)

• 横浜と能登における粒子の帯電分布の変動要因

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  第65回大気環境学会年会, 

  2024.09

  , 

  Poster presentation

• 能登における帯電粒子の季節変化と変動要因の解明

  森樹大, 松木篤, 岩田歩, 鴨川仁, 奥田知明

  第41回日本エアロゾル科学・技術研究討論会, 

  2024.08

• Igor Pro 実践編

  森樹大

  第19回エアロゾル学会若手フォーラム 若手研究者・技術スキルアップセミナー「粒子のデータ解析・可視化に使われるソフトウェア講習会」, 

  2024.01

  , 

  Oral presentation (general)

• 都市域における帯電粒子の数濃度分布の季節変化

  森樹大, 石井悠人, 岩田歩, 奥田知明

  第64回大気環境学会年会, 

  2023.09

  , 

  Oral presentation (general)

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

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

• 東アジアにおけるブラックカーボンの長期変動と気候への影響

  2025.04

  -

  2028.03

  Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  　View Summary

  ブラックカーボン（BC）は大きな正の放射強制力を持つ。BC排出量が世界最大である東アジアはBCの発生源として最も重要な地域である。我々は22°Nの台湾から44°Nに位置する北海道までの5つの観測所で長期にわたりBC濃度を高精度で観測してきた。
  本研究ではこれまで得たデータを解析し、BCの空間分布と時間変動を明らかにする。また解析されたデータを地球システムモデル(MRI-ESM2)と比較しモデルの精度を評価する。精度評価されたモデルを用いて、アジアにおけるBCの時空間変動の要因を解明する。またBCの放射効果・気候影響とその時間的推移を明らかにする。

• ブラックカーボンの帯電状態の測定法の開発とその変動要因の観測的解明

  2024.04

  -

  2027.03

  日本学術振興会, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

  　View Summary

  実環境大気中の微小粒子状物質の電荷数を推算する測定技術と、ブラックカーボン（BC）粒子の大きさごとの数・質量濃度を測定する装置を組み合わせることで、BC 粒子の帯電状態を高い時間分解能で観測可能な、新たな手法の確立を目指す。さらに、本測定手法を実大気観測に適用することで、実環境大気中のBCの帯電状態の変動要因を明らかにする。本研究の遂行により、数値モデルで表現されるエアロゾルの帯電メカニズムの表現を適切に精緻化することで、生体内に沈着する BC の粒子数の予測精度が一層向上すると期待される。

• 電荷数ごとの粒子数濃度を高精度・高時間分解能で計測する手法の開発

  2023.11

  -

  2024.10

  公益財団法人天野工業技術研究所, Principal investigator

• 光吸収性粒子の帯電分布の測定法の開発と実大気観測

  2023.10

  -

  2025.11

  公益財団法人鉄鋼環境基金, 若手研究助成, Principal investigator

• 北極気候に関わるエアロゾルの長期的変化の把握と放射・気候影響評価

  2023.04

  -

  2026.03

  環境再生保全機構, 環境省環境研究総合推進費, Principal investigator

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Awards 【 Display / hide 】

Awards 【 Display / hide 】

• 第103回研究発表会 学生発表表彰

  寺坂桃, 森樹大, 奥田知明, 2025.03, 日本大気電気学会, 開閉平行板型帯電分級装置の開発と大気中帯電粒子の化学成分分析

• Paper Award

  速水洋, 伊賀悠太, 三浦和彦, 森樹大, 櫻井達也, 2023.09, 大気環境学会(AJAE部門), Detection of Ship Fuel Sulfur Contents in Exhaust Plumes at the Kanmon Straits, Japan, before and after the Global Sulfur Limit 2020

• 第98回研究発表会 学生発表表彰

  五十嵐博己, 森樹大, 三浦和彦, 岩本洋子, 和田龍一, 加藤俊吾, 大河内博, 2021.01, 日本大気電気学会, 富士山頂における日中と夜間の新粒子生成イベントの長期観測

• 第97回研究発表会 学生発表表彰

  横山慎太郎, 永野勝裕, 三浦和彦, 櫻井達也, 森樹大, 2020.01, 日本大気電気学会, 富士山におけるラドン濃度変動と気塊由来の関係

• 第96回研究発表会 学生発表表彰

  佐藤丈徳, 三浦和彦, 森樹大, 三隅良平, 宇治靖, 當房豊, 岩本洋子, 2019.01, 日本大気電気学会, 2016-2017年の東京スカイツリーで観測された新粒子生成の季節変化

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• LABORATORY IN SCIENCE

  2025

• LABORATORIES IN APPLIED CHEMISTRY C

  2025

• LABORATORY IN SCIENCE

  2024

• LABORATORIES IN APPLIED CHEMISTRY C

  2024

• LABORATORY IN SCIENCE

  2023

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Courses Previously Taught 【 Display / hide 】

Courses Previously Taught 【 Display / hide 】

• 応用化学実験C

  慶應義塾大学

  2022.04

  -

  Present

  , 

  Full academic year, Laboratory work/practical work/exercise

• 自然科学実験

  慶應義塾大学

  2022.04

  -

  Present

  , 

  Full academic year, Laboratory work/practical work/exercise

• 物理学実験

  東京理科大学

  2017.04

  -

  2021.03

  , 

  Full academic year, Laboratory work/practical work/exercise

• 物理数学演習

  東京理科大学

  2017.04

  -

  2021.03

  , 

  Full academic year, Laboratory work/practical work/exercise

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• Society of Atmospheric Electricity of Japan, 

  2024.04

  -

  Present

• 大気環境学会, 

  2023.04

  -

  Present

• 富士山測候所を活用する会, 

  2017.04

• 日本大気化学会, 

  2014

  -

  Present

• 日本エアロゾル学会, 

  2013

  -

  Present

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Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2024.09

  -

  Present

  実行委員会, 第42回日本エアロゾル学会

• 2024.09

  -

  Present

  若手会 代表, 日本エアロゾル学会

• 2023.09

  -

  Present

  若手会 副代表, 日本エアロゾル学会

• 2023.04

  -

  2024.09

  会場委員会委員長, 第65回大気環境学会年会

• 2022.09

  -

  Present

  大気環境学会AJAE委員

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