Detection of Sulfur Dioxide by Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS)
arXiv:2411.15601 · doi:10.3390/s22072626
Abstract
Sulfur dioxide () is an important precursor for the formation of atmospheric sulfate aerosol and acid rain. We present an instrument using Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) for the measurement of with a minimum limit of detection of 0.75 ppbv (3-) using the spectral range 305.5--312 nm and an averaging time of 5 min. The instrument consists of high-reflectivity mirrors (0.9985 at 310 nm) and a deep UV light source (Light Emitting Diode). The effective absorption path length of the instrument is 610 m with a 0.966 m base length. Published reference absorption cross sections were used to fit and retrieve the concentrations and were compared to fluorescence standard measurements for . The comparison was well correlated () with a correlation slope of 1.04. Interferences for fluorescence measurements were tested, and the BBCEAS showed no interference, while ambient measurements responded similarly to standard measurement techniques.