Quartz‐Enhanced Photoacoustic Sensors for Detection of Eight Air Pollutants

A quartz‐enhanced photoacoustic spectroscopy sensor architecture capable of detecting eight different air pollutants (CH 4 , NO 2 , CO 2 , N 2 O, CO, NO, SO 2 , and NH 3 ) is reported. Each analyte is targeted using the same sensor components (acoustic detection module, quartz‐tuning fork, etc.) and a dedicated laser source. Both interband cascade lasers and quantum cascade lasers are employed to target a well‐resolved and isolated absorption feature from each investigated gas, in a wavelength ranging from 3.35 to 9.06 μm. The sensor is calibrated with certified concentrations of each gas species, in a wet nitrogen matrix. For each analyte, the optimal pressure is determined. Minimum detection limits of 40, 13, 800, 230, 450, 78, 18, and 5.8 ppb are obtained for CH 4 , NO 2 , CO 2 , N 2 O, CO, NO, SO 2 , and NH 3 , respectively, at 100 ms of integration time.