Ocean waves crashing on the world’s shores emit more PFAS into the air than the world’s industrial polluters, new research has found, raising concerns about environmental contamination and human exposure along coastlines. The study measured levels of PFAS released from the bubbles that burst when waves crash, spraying aerosols into the air. It found sea spray levels were hundreds of thousands times higher than levels in the water. The contaminated spray likely affects groundwater, surface water, vegetation, and agricultural products near coastlines that are far from industrial sources of PFAS, said Ian Cousins, a Stockholm University researcher and the study’s lead author. “There is evidence that the ocean can be an important source [of PFAS air emissions],” Cousins said. “It is definitely impacting the coastline.”

The Stockholm researchers several years ago found that PFAS from ocean waves crashing are released into the air around shorelines, then can travel thousands of kilometers through the atmosphere before the chemicals return to land. The new research looked at levels in the sea spray as waves crash by testing ocean samples between Southampton in the UK and Chile. The chemicals’ levels were higher in the northern hemisphere in general because it is more industrialized and there is not much mixing of water across the equator, Cousins said. It is unclear what the findings mean for human exposure. Inhalation of PFAS is an issue, but how much of the chemicals are breathed in, and air concentrations further from the waves, is still unknown.