Abstract: The present invention relates to a photoacoustic sensor system for detecting target molecules in air samples or compressed air samples. The photoacoustic sensor system comprises an acoustic resonator forming a cylindrical resonant cavity and an air or compressed air sampling system configured for directing a flow of air or compressed air through the cylindrical resonant cavity. The photoacoustic sensor system comprises first and second microphones for generating first and second photoacoustic signals in response to absorption of modulated light within the cylindrical resonant cavity. A light source is configured to direct a modulated light beam through the cylindrical resonant cavity of the photoacoustic spectroscopy cell.