A Quantum Cascade Laser-Based Optical Sensor for Continuous Monitoring of Environmental Methane in Dunkirk (France)

Rabih Maamary (1) , Xiaojuan Cui (2) , Éric Fertein (1) , Patrick Augustin (1) , Marc Fourmentin (1) , Dorothée Dewaele (3) , Fabrice Cazier (3) , Laurence Guinet (4) , Weidong Chen (1)

1 LPCA - Laboratoire de Physico-Chimie de l'Atmosphère
2 Anhui Institute of Optics and Fine Mechanics
3 CCM-ULCO - Centre commun de mesures
4 ONERA - The French Aerospace Lab [Palaiseau]

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.

Mots clés: QCL-BASED SENSOR; ENVIRONMENTAL METHANE; CAMPAIGN MEASUREMENT

Domaines: Ingénierie de l'environnement; Chimie analytique

Rabih Maamary, Xiaojuan Cui, Éric Fertein, Patrick Augustin, Marc Fourmentin, et al.. A Quantum Cascade Laser-Based Optical Sensor for Continuous Monitoring of Environmental Methane in Dunkirk (France). Sensors, 2016, 16 (2), pp.224. ⟨10.3390/s16020224⟩. ⟨hal-01728945⟩