Near‐ultraviolet Incoherent Broadband Cavity Enhanced Absorption Spectroscopy for OClO and $CH2O$ in Cl‐initiated Photooxidation Experiment

Chlorine dioxide (OClO) is an important indicator for Cl‐activation. The monitoring of OClO appears to be crucial for understanding the chemistry of Cl‐initialed oxidation and its impact on air quality in polluted coastal regions and industrialized areas. We report the development of a Xe arc lamp based near‐ultraviolet (335–375 nm) incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) spectrometer for quantitative assessment of OClO in an atmospheric simulation chamber. The important intermediate compound $CH2O$⁠, and other key atmospheric trace species (⁠$NO2$⁠) were also simultaneously measured. The instrumental performance shows a strong potential of this kind of IBBCEAS instrument for field and laboratory studies of atmospheric halogen chemistry.