Methane emissions in Kuwait: Plume identification, isotopic characterisation and inventory verification
Methane emissions in Kuwait: Plume identification, isotopic characterisation and inventory verification
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DOI：
10.1016/j.atmosenv.2021.118763
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发表时间：
2021-10-16
影响因子：
5
通讯作者：
France, J. L.
中科院分区：
文献类型：
--
作者：
Al-Shalan, A.;Lowry, D.;France, J. L.
通过移动车辆测量甲烷摩尔分数和在来源收集空气样本进行随后的同位素分析，绘制了科威特甲烷源的分布。流动烟柱识别和同位素分析表明，迄今为止，科威特观测到的最大甲烷来源来自垃圾填埋场（δ C-13（CH4）为-58‰），化石燃料工业（-50‰）、废水处理（-49‰）和反刍动物（羊-64‰，牛-62‰，骆驼-60‰）的贡献较小。两年多来，每周定期从科威特的三个地点收集空气样本，一个在城市西北部，一个在城市东南部，一个在城市的科威特科学学院的屋顶。与较高的摩尔分数相关的是甲烷C-13的持续耗竭，这表明全国的碳-13（CH4）混合源为-55.9‰。这与使用EDGAR v.5清单的计算结果有很大不同，后者表明源混合为52.8‰。从城市地区进行的昼夜运动证实，城市地区及其周围的来源主要是生物来源（-59至-56千分之一）。EDGAR 5.0清单表明，科威特甲烷的主要来源是天然气燃烧和化石燃料分配的泄漏，垃圾填埋场、污水（废水）处理和反刍动物的排放量较小，但近几十年来，相对于化石燃料排放，废物成分有所增加。2015年和2016年期间的测量表明，除了该国最南部和西南部以外的所有地区（这些地区不在固定地点或移动测量的气象足迹范围内），主要的废物来源是化石燃料活动，所观察到的比例要小得多。该研究在科威特首次证明，连续移动测量与使用CF-GC-IRMS（连续流气相色谱-同位素比质谱）的高精度同位素分析相结合，是识别甲烷来源并了解其相对贡献的有效方法。要明确量化相对贡献，将需要进一步的工作，特别是在该国的西南地区，利用飞机和/或卫星检索。本研究的结果将有助于了解这一研究较少的地区的甲烷收支。
The distribution of methane sources in Kuwait was mapped through mobile vehicle surveying of methane mole fraction, and by collection of air samples at source for subsequent isotopic analysis. Mobile plume identification and isotopic analysis, reveals that by far the largest observed source of methane in Kuwait is from landfill sites (delta C-13(CH4) of -58 parts per thousand), with smaller contributions from fossil fuel industry (-50 parts per thousand), wastewater treatment (-49 parts per thousand) and ruminant animals (sheep-64 parts per thousand, cows, -62 parts per thousand, camels-60 parts per thousand).Regular weekly air samples were collected over two years from three sites in Kuwait, one NW of the city, one to the SE and one in the city from the rooftop of the Kuwait College of Science. Associated with higher mole fraction is a consistent depletion in C-13 of methane, pointing to a national source mix with delta C-13(CH4) of -55.9 parts per thousand. This is significantly different from calculations using EDGAR v.5 inventory that suggest a source mix of-52.8 parts per thousand. Diurnal campaigns from a city location confirm that the sources are dominantly biogenic (-59 to -56 parts per thousand) in and around the urban areas.The EDGAR 5.0 inventory suggests that the dominant sources of methane in Kuwait are leaks from gas flaring and fossil fuel distribution, with additional smaller emissions from landfills, sewage (wastewater) treatment and ruminant animals, but with a waste component increasing relative to fossil fuel emissions in recent decades. Measurements during 2015 and 2016 suggest that for all but the far south and SW of the country which is not in the meteorological footprint of fixed site or mobile measurement, there is a dominant waste source and much smaller observed proportion from fossil fuel activities.This research demonstrates for the first time in Kuwait that continuous mobile measurements for plume identification coupled with high-precision isotopic analysis using CF-GC-IRMS (Continuous Flow Gas Chromatography-Isotope Ratio Mass Spectrometry) is an effective way of identifying methane sources and understanding their relative contributions. To unambiguously quantify relative contributions will require further work, particularly in the SW region of the country, utilizing aircraft and/or satellite retrievals. The results of this research will contribute to understanding the methane budget of this poorly studied region.