The extensive use of natural gas (NG) in urban areas for heating and cooking and as a vehicular fuel is associated with potentially significant emissions of methane (CH₄) to the atmosphere. Methane, a potent greenhouse gas that influences the chemistry of the atmosphere, can be emitted from different sources including leakage from NG infrastructure, transportation activities, end-use uncombusted NG, landfills and livestock. Although significant CH₄ leakage associated with aging local NG distribution systems in the U.S. has been reported, further investigation is required to study the role of this infrastructure component and other NG-related sources in atmospheric CH₄ enhancements in urban centers. In this study, neighborhood-scale mobile-based monitoring of potential CH₄ emissions associated with NG in the Greater Houston area (GHA) is reported. A novel dual-gas 3.337 μm interband cascade laser-based sensor system was developed and mobile-mode deployed for simultaneous CH₄ and ethane (C₂H₆) monitoring during a period of over 14 days, corresponding to ∼ 90 h of effective data collection during summer 2016. The sampling campaign covered ∼250 exclusive road miles and was primarily concentrated on eight residential zones with distinct infrastructure age and NG usage levels. A moderate number of elevated CH₄ concentration events (37 episodes) with mixing ratios not exceeding 3.60 ppmv and associated with atmospheric background enhancements below 1.21 ppmv were observed during the field campaign. Source discrimination analyses based on the covariance between CH₄ and C₂H₆ levels indicated the predominance of thermogenic sources (e.g., NG) in the elevated CH₄ concentration episodes. The volumetric fraction of C₂H₆ in the sources associated with the thermogenic CH₄ spikes varied between 2.7 and 5.9%, concurring with the C₂H₆ content in NG distributed in the GHA. Isolated CH₄ peak events with significantly higher C₂H₆ enhancements (∼11%) were observed at industrial areas and locations with high density of petroleum and gas pipelines in the GHA, indicating potential variability in Houston's thermogenic CH₄ sources.

在城市地区广泛使用天然气（NG）进行取暖和烹饪以及作为车辆燃料与向大气中排放大量甲烷（CH ₄）有关。甲烷是一种有力的温室气体，会影响大气的化学性质，可从各种来源排放，包括天然气基础设施的泄漏，运输活动，未使用的天然气的最终用途，垃圾填埋场和牲畜。尽管据报道，在美国，与当地天然气分配系统老化相关的大量CH ₄泄漏，但仍需要进一步研究以研究该基础设施组件和其他与NG相关的源在大气CH _{4中的作用。}城市中心的改善。在这项研究中，报告了大休斯顿地区（GHA）与邻域相关的潜在CH ₄排放的基于邻域规模的移动监测。开发了新型的基于双气体3.337μm的带间级联激光的传感器系统，并在14天以上的时间内部署了移动模式，用于同时监测CH ₄和乙烷（C ₂ H ₆），相当于约90小时的有效数据2016年夏季进行了采集。采样活动覆盖了约250英里的专属公路里程，并且主要集中在具有不同基础设施年龄和天然气使用水平的八个住宅区。中等数量的CH ₄升高在野战期间观察到混合比不超过3.60 ppmv的浓度事件（37次），且与大气本底增强低于1.21 ppmv有关。基于CH ₄和C ₂ H ₆水平之间的协方差的源判别分析表明，在CH ₄浓度升高事件中，热源（例如NG）占主导地位。与热源CH ₄峰相关的源中C ₂ H ₆的体积分数在2.7％至5.9％之间变化，这与GHA中分布的NG中的C ₂ H ₆含量一致。隔离CH ₄在工业区和GHA中油气管道密度高的工业地区和地点，观察到C ₂ H ₆浓度显着升高的峰值事件（约11％），表明休斯敦的热成因CH ₄来源具有潜在的可变性。