Abstract Since 1850 the atmospheric mixing ratio of methane (CH4), a potent greenhouse gas, has doubled. This increase is directly linked to an escalation in emissions from anthropogenic sources. An inexpensive means to identify and monitor CH4 emission sources and evaluate the efficacy of mitigation strategies is essential. However, sourcing reliable, low-cost, easy-to-calibrate sensors that are fit for purpose is challenging. A recent study showed that CH4 mixing ratio data from a low-power, low-cost CH4 sensor (Figaro TGS2600) agreed well with CH4 mixing ratios measured by a high precision sensor at mixing ratios between 1.85 ppm and 2 ppm. To investigate, as a proof of concept, if this low-cost sensor could be used to measure typical ambient CH4 mixing ratios, we operated a TGS2600 in conjunction with a Los Gatos Ultra-portable Greenhouse Gas Analyzer (UGGA) in controlled laboratory conditions. We then explored the sensor's long-term reliability by deploying the TGS2600 near an onshore gas terminal to calculate emissions from May to July 2018. Our initial studies showed that previously published linear algorithms could not convert TGS2600 output to CH4 mixing ratios measured by the UGGA. However, we derived a non-linear empirical relationship that could be used to reliably convert the output of a TGS2600 unit to CH4 mixing ratios over a range of 1.85–5.85 ppm that agree to a high-precision instrument output to ±0.01 ppm. Our study showed that the TGS2600 could be used to continuously measure variability in CH4 mixing ratios from 1.82 to 5.40 ppm for three months downwind of the gas terminal. Using a simplified Gaussian Plume approach, these mixing ratios correspond to an emission flux range of 0–238 g CH4 s−1, with average emission of 9.6 g CH4 s−1 from the currently active North Terminal and 1.6 g CH4 s−1 from the decommissioned South Terminal. Our work here demonstrates the feasibility of utilizing a low-cost sensor to detect methane leakage at concentrations close to ambient background levels, as long as the device is routinely calibrated with an accurate reference instrument. Having a widely deployed network of such low-cost CH4 sensors would allow improved identification, monitoring and mitigation of a variety of CH4 emissions.

中文翻译：

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低成本甲烷传感器的校准和部署

摘要 自 1850 年以来，强效温室气体甲烷 (CH4) 的大气混合比翻了一番。这种增加与人为源排放量的增加直接相关。一种用于识别和监测 CH4 排放源以及评估缓解策略效力的廉价方法是必不可少的。然而，寻找适合用途的可靠、低成本、易于校准的传感器具有挑战性。最近的一项研究表明，来自低功耗、低成本 CH4 传感器 (Figaro TGS2600) 的 CH4 混合比数据与高精度传感器在 1.85 ppm 和 2 ppm 之间的混合比下测量的 CH4 混合比数据非常吻合。作为概念验证，为了研究这种低成本传感器是否可用于测量典型的环境 CH4 混合比，我们在受控实验室条件下将 TGS2600 与 Los Gatos 超便携式温室气体分析仪 (UGGA) 结合使用。然后，我们通过在陆上天然气终端附近部署 TGS2600 来计算 2018 年 5 月至 7 月的排放量来探索传感器的长期可靠性。我们的初步研究表明，先前发布的线性算法无法将 TGS2600 输出转换为 UGGA 测量的 CH4 混合比。然而，我们得出了一个非线性经验关系，可用于将 TGS2600 装置的输出可靠地转换为 CH4 混合比，范围为 1.85–5.85 ppm，这与高精度仪器输出一致至 ±0.01 ppm。我们的研究表明，TGS2600 可用于连续测量天然气终端顺风处三个月内 CH4 混合比的变化，从 1.82 到 5.40 ppm。使用简化的高斯羽流方法，这些混合比率对应于 0–238 g CH4 s-1 的排放通量范围，平均排放量为 9.6 g CH4 s-1，来自当前活跃的北终端和 1.6 g CH4 s-1已退役的南航站楼。我们在这里的工作证明了利用低成本传感器检测浓度接近环境背景水平的甲烷泄漏的可行性，只要该设备使用准确的参考仪器进行常规校准。拥有广泛部署的此类低成本 CH4 传感器网络将有助于改进对各种 CH4 排放的识别、监测和缓解。6 g CH4 s-1 来自退役的南航站楼。我们在这里的工作证明了利用低成本传感器检测浓度接近环境背景水平的甲烷泄漏的可行性，只要该设备使用准确的参考仪器进行常规校准。拥有广泛部署的此类低成本 CH4 传感器网络将有助于改进对各种 CH4 排放的识别、监测和缓解。6 g CH4 s-1 来自退役的南航站楼。我们在这里的工作证明了利用低成本传感器检测浓度接近环境背景水平的甲烷泄漏的可行性，只要该设备使用准确的参考仪器进行常规校准。拥有广泛部署的此类低成本 CH4 传感器网络将有助于改进对各种 CH4 排放的识别、监测和缓解。