Abstract
A room-temperature continuous-wave (CW) quantum cascade laser (QCL)-based methane (CH4) sensor operating in the mid-infrared near 8 μm was developed for continuous measurement of CH4 concentrations in ambient air. The well-isolated absorption line (7F2,4 ← 8F1,2) of the ν4 fundamental band of CH4 located at 1255.0004 cm−1 was used for optical measurement of CH4 concentration by direct absorption in a White-type multipass cell with an effective path-length of 175 m. A 1σ (SNR = 1) detection limit of 33.3 ppb in 218 s was achieved with a measurement precision of 1.13%. The developed sensor was deployed in a campaign of measurements of time series CH4 concentration on a site near a suburban traffic road in Dunkirk (France) from 9 to 22 January 2013. An episode of high CH4 concentration of up to ~3 ppm has been observed and analyzed with the help of meteorological parameters combined with back trajectory calculation using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model of NOAA.
Highlights
Methane (CH4 ), as the second most important greenhouse gas after carbon dioxide (CO2 ), contributes to the increase in global warming with a lifetime of about 12 years [1,2]
We report on the development and deployment of a continuous-wave (CW)
The objective of the present work is to develop an optical sensor based on direct multipass absorption spectroscopy capable of performing in situ continuous measurement of CH4 absolute concentration in the environment, which could provide a local background reference of CH4 emission level prior to the installation of a new liquefied natural gas (LNG) terminal in Dunkirk in 2016
Summary
Methane (CH4 ), as the second most important greenhouse gas after carbon dioxide (CO2 ), contributes to the increase in global warming with a lifetime of about 12 years [1,2]. Its concentration in the atmosphere has increased since the pre-industrial time from 700 ppb (parts per billion) to 1810 ppb [3]. Methane is produced naturally by anaerobic decomposition of organic materials as well as emissions from anthropogenic sources like ruminants, rice agriculture, biomass burning, fossil fuels and landfills [4,5]. Methane oxidation in the tropospheric and stratospheric layers is a key-reaction that affects the atmospheric concentration of the hydroxyl (OH). A liquefied natural gas (LNG) terminal located in Dunkirk (France) will be in operation in 2016.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
