Seminar

Abstract

Reactions occurring at atmospheric, aqueous interfaces can serve to catalyze reaction pathways that are energetically unfavorable in the gas phase. The reactive uptake of N₂O₅, a primary nocturnal nitrogen oxide (NOx) reservoir, serves as both an efficient NOx removal mechanism and regionally significant halogen activation process through the production of photo-labile ClNO₂. Both the reaction rate and ClNO₂ product yield are a complex function of the chemical composition of the reactive surface. To date, analysis of the impact of N₂O5 chemistry on oxidant loadings in the marine boundary layer has been limited to reactions occurring on aerosol particles, with little attention paid to reactions occurring at the air-sea interface. Here, we report the first direct measurements of the air-sea flux of N₂O₅ and ClNO₂ made via eddy covariance in the polluted marine boundary layer. The results are combined with in situ determinations of the N₂O5 loss rates to aerosol particles and interpreted within a time-dependent coupled atmosphere-ocean model.