Study on atmospheric environmental problems in megacities that consider the surface of paved roads as a new reaction field

• Project/Area Number: 18K19858
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 63:Environmental analyses and evaluation and related fields
• Research Institution: University of the Ryukyus (2020); Waseda University (2018-2019)
• Principal Investigator: Shimada Kojiro 琉球大学, 理学部, 助教 (70707190)
• Co-Investigator(Kenkyū-buntansha): 茶谷 聡 国立研究開発法人国立環境研究所, 地域環境研究センター, 主任研究員 (40394837)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2018: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: 不均一反応 / 光分解 / 有機エアロゾル / VOC / メガシティー / オゾン / シミュレーションモデル / 寄与率 / 大気環境問題 / 反応場 / 舗装道路 / 揮発性有機物質

Outline of Final Research Achievements

In megacities around the world, atmospheric environmental problems are being addressed in both developed and developing countries.Among them, even Tokyo, which is one of the most regulated megacities, has not been able to solve the atmospheric environmental problem of photochemical oxidants (ozone).In this study, we changed the "reaction field" of VOCs generated by photolysis of organic aerosol from the atmosphere to paved roads, instead of the overlooked "source" of VOCs required for ozone generation. As a result, it was discovered that the organic aerosol deposited on the paved road was photodecomposed to release VOCs. VOC emissions were high, and it was found that the current simulation model underestimated VOC emissions by more than three times.

Academic Significance and Societal Importance of the Research Achievements

本研究成果の学術的意義は、VOC生成の新しい反応場を発見したことにより、研究の発展が見込まれることにある。舗装道路だけでなく、建築物の屋上、壁面などを考慮すると東京都23区の土地面積に対して、大気汚染物質の沈着面積は土地面積よりも広い面積に沈着する。
そのため、これまでシミュレーションモデルで評価しきれていないVOCの発生量をおぎなえる可能性が高い。シミュレーションモデルが改良されれば、社会的意義としてオゾンの環境問題の解決に近づくことが予想される。このVOCの反応場は世界中に存在するため、東京だけでなく、世界中のメガシティーにおけるVOCのシミュレーションをすることが可能となる。

Research Products

• [Int'l Joint Research] 香港理工大学(中国)
• [Int'l Joint Research] 香港/香港理工大学(その他の国・地域)
• [Journal Article] Degradation of PAHs during long range transport based on simultaneous measurements at Tuoji Island, China, and at Fukue Island and Cape Hedo, Japan (2020)
  • Author(s): Shimada K, Nohchi M, Yang X, Sugiyama T, Miura K, Takami A, Sato K, Chen X, Kato S, Kajii Y, Meng F, Hatakeyama S
  • Journal Title: Environmental Pollution Volume: 260 Pages: 113906-113906
  • DOI: 10.1016/j.envpol.2019.113906
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Estimation of background PM2.5 concentrations for an air-polluted environment (2020)
  • Author(s): Wang S-H, Hung R-Y, Lin N-H, Gómez-Losada Á, Pires J. C.M., Shimada K, Hatakeyama S, Takami A
  • Journal Title: Atmospheric Research Volume: 231 Pages: 104636-104636
  • DOI: 10.1016/j.atmosres.2019.104636
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Seasonal and annual changes in PAHs transported from East Asia to Cape Hedo, Okinawa (2019)
  • Author(s): Miura K., Shimada K, Sugiyama T, Sato K, Takami A, Chan K. C, Kim P. Y, Lin N-H, Hatakeyama S
  • Journal Title: Scientific Reports Volume: 9 Issue: 1 Pages: 12591-12591
  • DOI: 10.1038/s41598-019-47409-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Sources of High Sulfate Aerosol Concentration Observed at Cape Hedo in Spring 2012 (2019)
  • Author(s): Itahashi S, Hatakeyama S, Shimada K, Takami A
  • Journal Title: Aerosol and Air Quality Research Volume: 19 Issue: 3 Pages: 587-600
  • DOI: 10.4209/aaqr.2018.09.0350
  • Peer Reviewed / Open Access
• [Presentation] Degradation of PAHs during long range transport based on simultaneous measurements at Tuoji Island, China, and at Fukue Island and Cape Hedo, Japan (2019)
  • Author(s): Shimada K, Nohchi1 M, Yang X, Sugiyama T, Miura K, Takami A, Sato K, Chen X, Meng F, Hatakeyama S
  • Organizer: AAC meeting (2019/5).
  • Int'l Joint Research
• [Presentation] The Impact of Particulate Matters on the Formation and Chemistry of Tropical Heavy Rain Accompanied by Squall (2019)
  • Author(s): Kajikawa T, Okochi H, Nakano T, Shimada K
  • Organizer: AAC meeting
  • Int'l Joint Research
• [Presentation] , The Impact of Particulate Matters on the Formation and Chemistry of Tropical Heavy Rain Accompanied by Squall (2019)
  • Author(s): Kajikawa T, Okochi H, Nakano T, Shimada K, Uchida E, Nakagawa T, Matsui T, Ishizuka M, Arai T, Lay P, Hang P
  • Organizer: The 28th Symposium on Environmental Chemistry
  • Int'l Joint Research
• [Presentation] Observation of Cloud Water Chemistry in the Free Troposphere and the Atmospheric Boundary Layer on Mt. Fuji (6) (2019)
  • Author(s): Okochi H, Dairiki M, Nakamura M, Tahara D, Takemura N, Nakano T, Shimada K, Katumi N, Minami Y, Takeuchi M, Toda K, Kato S, Wada R, Miura K, Nonemochi S, Hatakeyama S, Dokiya Y
  • Organizer: IFDA2019, 8th International Conference on Fog, Fog Collection and Dew
  • Int'l Joint Research
• [Presentation] Air pollution and its impact of rain- and dew-water chemistry in Siem Reap-Angkor region of Cambodia (2019)
  • Author(s): Kajikawa T, Okochi H, Shimada K, Nakano T, Uchida E, Ishizuka M, Nakagawa T, Matsui T, Lay P, Hang P
  • Organizer: IFDA2019, 8th International Conference on Fog, Fog Collection and Dew
  • Int'l Joint Research
• [Presentation] Observation of Cloud Water Chemistry in the Free Troposphere and the Atmospheric Boundary Layer on Mt. Fuji (5) (2019)
  • Author(s): Dairiki M, Okochi H, Nakamura M, Tahara D, Takemura N, Nakano T, Shimada K, Katumi N, Minami Y, Takeuchi M, Toda K, Kato S, Wada R, Miura K, Yonemochi S, Hatakeyama S, Dokiya Y,
  • Organizer: IFDA2019, 8th International Conference on Fog, Fog Collection and Dew
  • Int'l Joint Research
• [Presentation] 沖縄県辺戸岬において2012年春季に見られた高濃度硫酸塩の発生源寄与評価 (2019)
  • Author(s): 板橋秀一，畠山史郎，島田幸治郎，高見昭憲
  • Organizer: 日本地球惑星科学連合2019年大会