Direct observations of Biogenic Volatile Organic Compound (BVOC) Air-Sea Exchange in the remote North Atlantic from the High-Wind Gas-Exchange Study (HiWinGS)

Biogenic Volatile Organic Compounds (BVOC) are highly reactive trace gases that can significantly alter the atmosphere's oxidative capacity and the production rate and hygroscopicity of secondary organic aerosol (SOA). While terrestrial BVOC fluxes are well studied, marine fluxes remain poorly characterized. Here, we report direct measurements of monoterpene and isoprene air-sea exchange via eddy covariance. A chemical-ionization time-of-flight mass spectrometer (CI-ToF-MS) utilizing benzene cations was deployed as part of the High Wind Gas Exchange Study (HiWinGs) to quantify monoterpenes, isoprene and dimethylsulfide fluxes in the remote North Atlantic. We report dimethylsulfide concentrations and vertical fluxes that are in strong agreement with those determined by the University of Hawaii's atmospheric pressure ionization mass-spectrometer. In the remote marine boundary layer, positive monoterpene fluxes (emission) were observed while isoprene levels rarely exceeded the detection limit. We discuss the potential for simultaneous detection of a suite of chemically varied trace gases in helping to untangle chemical, biological, and physical controls of trace gas air –sea exchange.