AMT Atmospheric Measurement Techniques AMT Atmos. Meas. Tech. 1867-8548 Copernicus Publications Göttingen, Germany 10.5194/amt-5-1925-2012 Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies Eugster W. 1 Kling G. W. 2 ETH Zurich, Institute of Agricultural Sciences, Universitätsstrasse 2, 8092 Zurich, Switzerland University of Michigan, Department of Ecology & Evolutionary Biology, Ann Arbor, MI 48109-1048, USA 13 08 2012 5 8 1925 1934 Copyright: © 2012 W. Eugster 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://amt.copernicus.org/articles/5/1925/2012/amt-5-1925-2012.html The full text article is available as a PDF file from https://amt.copernicus.org/articles/5/1925/2012/amt-5-1925-2012.pdf

Methane is the second most important greenhouse gas after CO<sub>2</sub> and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH<sub>4</sub> concentrations can help identify and locate these methane hotspots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH<sub>4</sub> even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong sensitivities for temperature and relative humidity. Correcting for this sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH<sub>4</sub> concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hotspots.

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