Novel Broadband Cavity-Enhanced Absorption Spectrometer for Simultaneous Measurements of NO₂ and Particulate Matter

A novel instrument based on broadband cavity-enhanced absorption spectroscopy has been developed using a supercontinuum broadband light source, which showcases its ability in simultaneous measurements of the concentration of NO2 and the extinction of particulate matter. Side-by-side intercomparison was carried out with the reference NOx analyzer for NO2 and OPC-N2 particle counter for particulate matter, which shows a good linear correlation with r2 > 0.90. The measurement limits (1σ) of the developed instrument were experimentally determined to be 230 pptv in 40 s for NO2 and 1.24 Mm–1 for the extinction of particulate matter in 15 s. This work provides a promising method in simultaneously monitoring atmospheric gaseous compounds and particulate matter, which would further advance our understanding on gas–particle heterogeneous interactions in the context of climate change and air quality