Intercomparison of the DOAS and LOPAP techniques for the detection of nitrous acid (HONO)

摘要

Recent studies have demonstrated that nitrous acid (HONO) is a source of hydroxyl radicals (OH) in the boundary layer not only early in the morning but also throughout the day. Despite its importance, all known instruments to detect HONO in the atmosphere suffer either from the great experimental effort necessary or from the possibility of significant interferences. In addition, only a few instruments are sensitive enough to detect low HONO concentrations during daytime. Accordingly, validated and sensitive measurements of nitrous acid are of paramount importance to describe the oxidation capacity of the atmosphere. Up to now, in intercomparisons of these chemical detectors with the well accepted DOAS technique significantly higher concentrations have been detected during the day with the chemical detectors, the discrepancy being attributed to interferences.