Measurement of ambient aerosol and nitrogen dioxide (NO₂) is important as they are major pollutants from the burning of fossil fuel and biomass. In the present work, a differential photoacoustic spectrometer (D-PAS) was developed for simultaneous, online measurements of aerosol optical absorption and NO₂ concentration. A novel photoacoustic resonator was designed and employed in the D-PAS for controlling a large flow rate, improving response time, and keeping the flow noise at a low level. The detection limits of 1.0 Mm⁻¹ and 0.87 ppb for aerosol absorption and NO₂ concentration measurements were achieved with a lock-in amplifier time constant of 1 s. The D-PAS accuracy was demonstrated by performing a long-time, continuous measurement of aerosol, and NO₂ in ambient air. The measured results of NO₂ are consistent with the NOx analyzer and environmental monitoring station results.

测量环境气溶胶和二氧化氮（NO ₂）非常重要，因为它们是燃烧化石燃料和生物质的主要污染物。在本工作中，开发了一种差分光声光谱仪（D-PAS），用于同时在线测量气溶胶的光吸收和NO ₂浓度。设计了一种新颖的光声谐振器，并将其用于D-PAS中，以控制大流量，改善响应时间并将流噪声保持在较低水平。气溶胶吸收和NO ₂的检出限为1.0 Mm ^-1和0.87 ppb锁定放大器的时间常数为1 s，即可完成浓度测量。通过对环境空气中的气溶胶和NO ₂进行长时间连续测量，证明了D-PAS的准确性。NO ₂的测量结果与NOx分析仪和环境监测站的结果一致。