Continuous measurements of methane emissions from an urban area

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H03362
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Osaka Prefecture University
• Principal Investigator: Ueyama Masahito 大阪府立大学, 生命環境科学研究科, 准教授 (60508373)
• Co-Investigator(Kenkyū-buntansha): 高橋 けんし 京都大学, 生存圏研究所, 准教授 (10303596)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: メタンフラックス / 一酸化炭素フラックス / 温室効果気体 / 渦相関法 / 都市 / 連続観測 / 移動観測

Outline of Final Research Achievements

For investigating CH4 emissions from urban area, we continuously measured CH4 flux at two urban landscapes in Sakai, based on the eddy covariance method. The spatial variabilities in CH4 concentrations were also measured within the city based on a mobile measurement for evaluating CH4 emission hotspots. Based on the three years study, we conclude that the urban areas are a significant CH4 source. The mobile measurements suggested several CH4 point sources: gas leaks from natural gas networks, sewage pipes, gas-powered air conditioners, and moats. Since the measured annual CH4 source was more than twice the expected source by the local government, indicating that there are large missing sources in the urban area.

Free Research Field

微気象学

Academic Significance and Societal Importance of the Research Achievements

都市域のCH4フラックスを直接的に測定した例は、世界的に見ても数例の報告しかない。3年にわたるデータを蓄積させ、都市内の点源から考えられていたよりも大きなCH4排出が生じていることを明らかにできた点が、本研究の学術的な意義である。行政による排出インベントリーが実際のCH4排出量を過小評価している可能性を示せた点は、温室効果ガス削減を社会目的に掲げる日本において社会的意義がある。