Here we present benzene and toluene measurements in seawater and ambient air in the open Southern Ocean and the Arctic marginal sea ice zone. Our novel seawater measurements from both polar oceans include high-resolution surface underway measurements and depth profiles, which are compared to chlorophyll fluorescence and density profiles to explore the possible marine sources of benzene and toluene. The high-resolution measurements at both sides of the airsea interface are used to calculate the oceanic saturation and the net fluxes at high resolution using the two-layer bulk flux method. These oceanic emission fluxes are incorporated in a global chemistry-climate model, the Community Atmospheric Model with Chemistry (CAM-Chem (39)), to assess the atmospheric implications of ocean benzene and toluene outgassing over the polar oceans. We find that benzene and toluene emission fluxes significantly increase the modelled SOA, especially over the remote Southern Ocean.