Simultaneous measurement of NO and NO2 by dual-channel cavity photoacoustic spectroscopy technique

•The dual-channel cavity photoacoustic spectroscopy instrument can be applied to simultaneous measurement of NO2 and NO.•In order to confirm the reliability of the PAS instrument in the field atmosphere. Continuous measurement was conducted and the stability of the instrument was shown. When comparing the PAS instrument for NO2 measurement with a CRDS instrument in the field, the results both showed a good correlation between these techniques.•In order to reduce the local noise of the system, the optimized design and test of the buffer cavity are carried out. Minimum detection limits of NO2 and NOx were estimated to be 1.47 ppb and 1.50 ppb at an average time of 60 s with the sensitivity of 0.040 μv/ppb and 0.039 μv/ppb.•As a result, the instrument can be seen as a low-cost, simple, reliable method for the measurement NO2 and NOx directly with good sensitivity and good time resolution in the field. The instruments developed could lead to the wider application for ambient air quality monitoring and will be useful to investigate photochemistry in the atmosphere more precisely.