We have recently demonstrated new techniques for sensitive measurements of nitrogen dioxide (NO2) and black carbon. Both techniques are based on cantilever-enhanced photoacoustic detection:
J. Karhu et al., "", ACS Sensors 6, 9, 3303–3307 (2021)
J. Karhu et al., "," Aerosol Science and Technology 56, 1, 92-100 (2022)