Currently used and legacy pesticides in the marine atmosphere from Patagonia to Europe

Pesticides can enter the atmosphere upon application due to spray drift, volatilization, or wind erosion. Subsequently, certain pesticides undergo atmospheric transport to non-target areas, where they deposit. To investigate their potential long-range transport, 329 pesticides were analyzed in air samples collected on a south-north Atlantic Ocean transect between South America and Europe in 2023. In total, twelve currently used pesticides (CUPs) and one transformation product (TP) were quantified in concentrations ranging from 1.6 to 420 pg/m³. Additionally, nine pesticides (three CUPs, three TPs and three legacy pesticides) were detected in the air samples but could not be quantified as the method performance acceptability criteria were not met for these compounds. All CUPs and TPs were found in the marine atmosphere across the Atlantic Ocean for the first time. Higher pesticide concentrations were observed in the atmosphere of the northern hemisphere, while the number of pesticides per sample was comparable between the northern and southern hemisphere. Air mass back trajectories showed a high marine influence for the majority of samples, indicating a potential long-range transport of the found pesticides. This research provides the first empirical evidence for the long-range transport potential of 12 CUPs and 4 TPs to the remote atmospheric environment of the Atlantic Ocean. The calculated atmospheric half-lives of less than two days for these compounds indicate the importance to complement the model predictions with measurements of airborne pesticides in remote areas to assess their long-range atmospheric transport potential.