Development of a novel method for determination of branching ratios between reaction paths in HOx cycle by selective detection of HOx radicals

• Project/Area Number: 18K18179
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Kyoto University
• Principal Investigator: KOHNO Nanase 京都大学, 地球環境学堂, 特別研究員(RPD) (40736766)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: HOxサイクル / OHラジカル / HO2ラジカル / RO2ラジカル / 大気化学 / 化学反応 / 反応経路分岐比 / ラジカル反応 / エアロゾル / レーザー分光法 / 同位体

Outline of Final Research Achievements

In this study, we conducted experiments for the quantitative evaluation of the HOx cycle, which is one of the most important chain reactions in atmospheric chemistry. First, we improved the combination system of laser-induced fluorescence (LIF) and chemical conversion methods to detect each HOx (OH, HO2, RO2) radical selectively. Furthermore, heavy water was used to generate OD radicals, and detect the branching ratio between generation HO2 radicals and generation RO2 radicals using sample gases and real atmospheric air.

Academic Significance and Societal Importance of the Research Achievements

本研究で構築したRO2検出手法を用いることにより，これまで困難であった各HOxラジカルを1つの装置で室温・大気圧条件下で選択的に観測することが可能となった。さらに，重水を用いてHOxラジカルの反応経路分岐比決定手法を構築したことで，これまで複雑であった対流圏化学反応の包括的な定量評価が可能となりつつある。本成果により，大気反応シミュレーションの精度向上，あるいは新規な大気反応経路の発見や光化学オキシダント削減へ向けた新たな取り組み立案など，学術的発展を期待することが出来る。

Research Products

• [Journal Article] Total hydroxyl radical reactivity measurements in a suburban area during AQUAS-Tsukuba campaign in summer 2017 (2020)
  • Author(s): Li Jiaru、Sakamoto Yosuke、Kohno Nanase、Fujii Tomihide、Matsuoka Kohei、Takemura Marina、Zhou Jun、Nakagawa Maho、Murano Kentaro、Sadanaga Yasuhiro、Nakashima Yoshihiro、Sato Kei、Takami Akinori、Yoshino Ayako、Nakayama Tomoki、Kato Shungo、Kajii Yoshizumi
  • Journal Title: Science of The Total Environment Volume: 740 Pages: 139897-139897
  • DOI: 10.1016/j.scitotenv.2020.139897
  • Peer Reviewed
• [Journal Article] Rate constants of CH3O2 + NO2 CH3O2NO2 and C2H5O2 + NO2 C2H5O2NO2 reactions under atmospheric conditions (2020)
  • Author(s): Kohno Nanase、Li Jiaru、Sakamoto Yosuke、Kajii Yoshizumi
  • Journal Title: International Journal of Chemical Kinetics Volume: 53 Issue: 5 Pages: 571-582
  • DOI: 10.1002/kin.21466
  • Peer Reviewed
• [Journal Article] Real-time quantification of the total HO2 reactivity of ambient air and HO2 uptake kinetics onto ambient aerosols in Kyoto (Japan) (2020)
  • Author(s): Jun Zhou, Kentaro Murano, Nanase Kohno, Yosuke Sakamoto and Yoshizumi Kajii
  • Journal Title: Atmospheric Environment Volume: 223 Pages: 117189-117189
  • DOI: 10.1016/j.atmosenv.2019.117189
  • Peer Reviewed
• [Journal Article] Relative and Absolute Sensitivity Analysis on Ozone Production in Tsukuba, a City in Japan (2019)
  • Author(s): Yosuke Sakamoto, Yasuhiro Sadanaga, Jiaru Li, Kohei Matsuoka, Marina Takemura, Tomihide Fujii, Maho Nakagawa, Nanase Kohno, Yoshihiro Nakashima, Kei Sato, Tomoki Nakayama, Shungo Kato, Akinori Takami, Ayako Yoshino, Kentaro Murano and Yoshizumi Kajii
  • Journal Title: Environmental Science & Technology Volume: 53 Issue: 23 Pages: 13629-13635
  • DOI: 10.1021/acs.est.9b03542
  • Peer Reviewed
• [Journal Article] Kinetics Study of OH Uptake onto Deliquesced NaCl Particles by Combining Laser Photolysis and Laser-Induced Fluorescence (2018)
  • Author(s): Sakamoto Yosuke、Zhou Jun、Kohno Nanase、Nakagawa Maho、Hirokawa Jun、Kajii Yoshizumi
  • Journal Title: The Journal of Physical Chemistry Letters Volume: 9 Issue: 14 Pages: 4115-4119
  • DOI: 10.1021/acs.jpclett.8b01725
  • Peer Reviewed
• [Presentation] 大気中におけるHOxラジカル反応性観測および揮発性炭化水素との反応経路の定量的評価手法の開発 (2020)
  • Author(s): 河野 七瀬，Jiaru Li，Jun Zhou，坂本 陽介，梶井 克純
  • Organizer: 第61回大気環境学会年会, 特別集会
• [Presentation] FAGE-LIF法を用いたRO2ラジカルの検出およびNO2との反応速度定数の決定 (2020)
  • Author(s): 河野 七瀬, Jiaru Li, 坂本 陽介, 梶井 克純
  • Organizer: 第61回大気環境学会年会, 一般発表
• [Presentation] Impact of aerosol uptake on HOx cycle (2019)
  • Author(s): Nanase Kohno
  • Organizer: The 5th International Workshop on Heterogeneous Kinetics Related to Atmospheric Aerosols
  • Int'l Joint Research / Invited
• [Presentation] Development of a new method for selective detection of ROx radicals and determination of radical yields (2019)
  • Author(s): Nanase Kohno, Jiaru Li, Jun Zhou, Kentaro Murano, Yosuke Sakamoto, Yoshizumi Kajii
  • Organizer: 35th Symposium on Chemical Kinetics and Dynamics
  • Int'l Joint Research
• [Presentation] オゾン生成に対するOHラジカル未知反応性およびエアロゾルのHOxラジカル取り込みの影響 (2019)
  • Author(s): 河野 七瀬, Jiaru Li, Jun Zhou, 坂本 陽介, 梶井 克純
  • Organizer: 第24回大気化学討論会
• [Presentation] 大気中のHOxサイクルの重要性と研究状況 (2019)
  • Author(s): 河野 七瀬, Jiaru Li, Jun Zhou, 坂本 陽介, 梶井 克純
  • Organizer: 第60回大気環境学会年会
• [Presentation] Development of a new method for selective detection of ROx radicals and determination of radical yields (2019)
  • Author(s): 河野 七瀬
  • Organizer: 第35回化学反応討論会
  • Int'l Joint Research
• [Presentation] ポンプ-プローブ法を用いたHOxラジカル反応性観測における新展開 ---スモッグチャンバーを利用したVOCのOH酸化過程の観測--- (2018)
  • Author(s): 河野 七瀬
  • Organizer: 第59回大気環境学会年会