Marine biogenic emissions of benzene and toluene and their contribution to secondary organic aerosols over the polar oceans

Reactive trace gas emissions from the polar oceans are poorly characterised, even though their effects on atmospheric chemistry and aerosol formation are crucial for assessing current and preindustrial aerosol forcing on climate. Here, authors present seawater and atmospheric measurements of benzene and toluene, two gases typically associated with pollution, in the remote Southern Ocean and the Arctic marginal ice zone. Their distribution in depth profiles and in surface seawater suggests a marine biogenic source. Authors find that these two gases are nearly consistently supersaturated during both cruises, resulting in net sea-to-air fluxes of both gases. Including our calculated average emissions in a chemistry-climate model increased secondary organic aerosol mass concentrations only by 0.1% over the Arctic but by 7.7% over the Southern Ocean, with transient episodes of up to 77.3%. Hence, climate models should consider the hitherto overlooked emissions of benzene and toluene from the polar oceans.

Reference: Wohl, C., Li, Q., Cuevas, C.A., et al., (2023). Marine biogenic emissions of benzene and toluene and their contribution to secondary organic aerosols over the polar oceans. Sci. Adv., 9(4), eadd90319. https://doi.org/10.1126/sciadv.add9031