Anthropogenic methane plume detection from point sources in the Paris megacity area and characterization of their δ13C signature
Anthropogenic methane plume detection from point sources in the Paris megacity area and characterization of their δ13C signature
复制标题
巴黎大城市地区点源的人为甲烷羽流检测及其 δ13C 特征表征
DOI：
10.1016/j.atmosenv.2019.117055
复制
发表时间：
2020
影响因子：
5
通讯作者：
E. Nisbet
中科院分区：
文献类型：
--
作者：
I. Xueref;G. Zazzeri;F. Bréon;F. Vogel;P. Ciais;D. Lowry;E. Nisbet
减少人为甲烷排放是实现《巴黎协定》近期目标的可用工具之一。需要确定这些来源排放的甲烷羽流的同位素特征，以改进区域范围内甲烷来源的量化。城市化和工业化地区，如巴黎大都市，是更好地表征人为甲烷源的关键地点。在本研究中，我们展示了巴黎地区首次移动的调查结果，评估了来自10个垃圾填埋场（在区域清单中，这些垃圾填埋场是该地区甲烷的主要排放部门）、5个气体储存点（供应）的甲烷点源。巴黎）和1个废水处理（WWT）设施（欧洲最大，全球第二）。对源羽流中局部大气甲烷浓度（或混合比）的增强进行了量化，并表征了其CH4中的δ 13 C（进一步标记为δ 13 CH4）特征。在10个采样的垃圾填埋场中，我们在其中6个填埋场检测到大气甲烷局部增强，范围为百万分之0.8至8.5（ppm），δ 13 CH4特征在−63.7 ± 0.3 permils（‰）至−58.2 ± 0.3‰之间。在调查的5个储气库中，我们可以观察到其中3个正在泄漏甲烷，局部甲烷浓度增加范围为0.8至8.1 ppm，δ 13 CH4特征范围为−43.4 ± 0.5‰至−33.8 ± 0.4‰。荷兰气的δ 13CH4特征为−33.8 ± 0.4‰（典型的热成因气）也可能被发现。污水处理厂排放的局部甲烷浓度高达4.0 ppm。在这个地点，两个δ 13 CH4特征被确定为−51.9 ± 0.2‰和−55.3 ± 0.1‰，这是典型的生物成因。在巴黎市还检测到大约40个甲烷羽流，导致当地浓度增加，由于其同位素组成，在两种情况下，其来源被解释为天然气泄漏。然而，这种改进远不如北美城市普遍。需要进行更多的同位素调查，以区分这种城市甲烷的增加是否来自天然气管道泄漏和下水道网络排放。此外，我们的研究结果使我们得出这样的结论，即区域排放清单可能低估了污水处理行业的甲烷排放量。需要开展进一步的活动，以评估污染源及其同位素特征的可变性和季节性，并使用独立于清单的方法估计其排放量。
Mitigating anthropogenic methane emissions is one of the available tools for reaching the near term objectives of the Paris Agreement. Characterizing the isotopic signature of the methane plumes emitted by these sources is needed to improve the quantification of methane sources at the regional scale. Urbanized and industrialized regions such as the Paris megacity are key places to better characterize anthropogenic methane sources. In this study, we present the results of the first mobile surveys in the Paris region, assessing methane point sources from 10 landfills (which in the regional inventory are the main emission sector of methane in the region), 5 gas storage sites (supplying Paris) and 1 waste water treatment (WWT) facility (Europe's largest, second worldwide). Local atmospheric methane concentration (or mixing ratio) enhancements in the source plumes were quantified and their δ13C in CH4(further noted δ13CH4) signature characterized. Among the 10 landfills sampled, at 6 of them we detected atmospheric methane local enhancements ranging from 0.8 to 8.5 parts per million (ppm) with δ13CH4signatures between −63.7 ± 0.3 permils (‰) to −58.2 ± 0.3‰. Among the 5 gas storage sites surveyed, we could observe that 3 of them were leaking methane with local methane concentration enhancements ranging from 0.8 to 8.1 ppm and δ13CH4signatures spanning from −43.4 ± 0.5‰ to −33.8 ± 0.4‰. Dutch gas with a δ13CH4signature of −33.8 ± 0.4‰ (typical of thermogenic gas) was also likely identified. The WWT site emitted local methane enhancements up to 4.0 ppm. For this site, two δ13CH4signatures were determined as −51.9 ± 0.2‰ and −55.3 ± 0.1‰, typical of a biogenic origin. About forty methane plumes were also detected in the Paris city, leading to local concentration enhancements whose origin was in two cases interpreted as natural gas leaks thanks to their isotopic composition. However, such enhancements were much less common than in cities of North America. More isotopic surveys are needed to discriminate whether such urban methane enhancements are outcoming from gas line leaks and sewer network emanations. Furthermore, our results lead us to the conclusion that the regional emissions inventory could underestimate methane emissions from the WWT sector. Further campaigns are needed to assess the variability and seasonality of the sources and of their isotopic signature, and to estimate their emissions using methods independent of the inventory.