Positive interference of nitrous acid in the determination of gaseous HNO3 by the NOx chemiluminescence-nylon cartridge method: Applications to measurements of ppb levels of HONO in air

Abstract Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an absolute method, differential optical absorption spectroscopy, and by a nylon cartridge-chemiluminescence NO x technique originally developed by Spicer and co-workers for gaseous HNO 3 . In the absence of HNO 3 , the latter technique proved to be a simple and accurate method for measuring ppb levels of HONO in air. However, the positive interference by HONO in the nylon cartridge-chemiluminescence technique may have important ramifications due to possible artifacts in measurements of gaseous HNO 3 by removal on nylon surfaces. Thus, previous observations in night-time atmospheres or environmental chambers attributed entirely to gaseous HNO 3 may have been, at least in part, due to the presence of gaseous HONO.