Global geographical redistribution and source dynamics of selected semi-volatile organic compounds in the marine air boundary layer.

The semi-volatile organic compounds (SVOCs), various priority pollutants of the marine air boundary layer (MABL), continue to elude full comprehension, creating substantial uncertainties about their global transport dynamics. We investigated 39 individual SVOCs during 3 large-scale Arctic and Antarctic expedition cruises. Our findings illuminate a discernable global gradient in their concentrations, with low molecular weight polycyclic aromatic hydrocarbons (PAHs) dominating. Interestingly, currently used pesticides (CUPs) have surpassed legacy organochlorine pesticides (OCPs) as primary pollutants. Despite international efforts to reduce emissions, SVOC mass inventories in polar regions have risen and are now identified as a significant source. The Westerlies disrupt SVOCs' global transport pathways, resulting in the "Westerly Wind Wall Block" effect, substantially influencing their redistribution in the Southern Hemisphere (SH). Our analysis ultimately underscores the pivotal roles of air-seawater exchange mechanisms and oceanic currents in the global transport dynamics of SVOCs within the MABL.