Detectionof trace gas (water vapour) using quantum cascade laser open - path system (qclops) version 2 sensor and the analysis of smoke from some selected wood species

Abstract

A Quantum Cascade Laser Open-Path System (QCLOPS) version 2 sensor has been set-up and used to measure water vapour in the troposphere. The QCLOPS version 2 sensor was compared with a commercial humidity sensor. A positive correlation of 71.46 % was established between the coefficient of variation of the version 2 sensor and the mass concentration of the commercial humidity sensor. Ten different wood species namely Kroma, Dwindwinaba, Esia,Yaya, Konkroma, Emire, Mango, Esakoko, Cocoa and Aborday were studied to ascertain the chemical compounds emitted during combustion. Volatile organic compounds (VOCs) such as Acetone, Acrolein, 2-Butanone and Benzene were found in these wood species with gas concentrations ranging between 65.2898 - 20.6254, 131.9121 - 9.4528, 20.6529 - 5.6554 and 1.8760 - 0.3982 respectively. Semi-volatile organic compounds (SVOCs) such as Benzyl alcohol and 2-Methylphenol were also found in these wood species with gas concentrations ranging between 119.7127 - 10.9159 and 5.3206 - 0.2796 ppm respectively. Finally, direct absorption method and Fourier Transform Infrared (FT-IR) Spectrometer were used to measure Benzyl alcohol and 2- Methylphenol in the laboratory. The infrared absorption spectra of Benzyl alcohol and 2-Methylphenol showed absorption at 1020, 1036, 1080 and 1108, 1176 cm-1respectively. This compares well with the Know-it-All infra-red database. The results show the capability of a future sensor to measure these gases in the field.