title: A Quantum Cascade Laser-Based Optical Sensor for Continuous Monitoring of Environmental Methane in Dunkirk (France).
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 9th to 22nd 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.
authors: Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque 59140, France. rabih.maamary.physique@gmail.com.
authors: Rabih
authors: R
authors: Maamary
authors: Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
authors: Xiaojuan
authors: X
authors: Cui
authors: Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque 59140, France. fertein@univ-littoral.fr.
authors: Eric
authors: E
authors: Fertein
authors: Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque 59140, France. augustin@univ-littoral.fr.
authors: Patrick
authors: P
authors: Augustin
authors: Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque 59140, France. fourment@univ-littoral.fr.
authors: Marc
authors: M
authors: Fourmentin
authors: Centre Commun de Mesures, Université du Littoral Côte d'Opale, Dunkerque 59140, France. Dorothee.Dewaele@univ-littoral.fr.
authors: Dorothée
authors: D
authors: Dewaele
authors: Centre Commun de Mesures, Université du Littoral Côte d'Opale, Dunkerque 59140, France. cazier@univ-littoral.fr.
authors: Fabrice
authors: F
authors: Cazier
authors: ONERA, DOTA, BP 80100, Palaiseau cedex 91123, France. Laurence.Guinet@univ-littoral.fr.
authors: Laurence
authors: L
authors: Guinet
authors: Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, Dunkerque 59140, France. chen@univ-littoral.fr.
authors: Weidong
authors: W
authors: Chen
mesh_terms: D000388:Air / Q000032:analysis*; D004784:Environmental Monitoring; D005602:France; D006801:Humans; D054023:Lasers, Semiconductor; D008697:Methane / Q000302:isolation & purification* / Q000633:toxicity
chemical_list: D008697:Methane
keywords: QCL-based sensor; campaign measurement; environmental methane