In 2022, it was found that levels of at least four perfluoroalkyl acids (PFAAs) in rainwater worldwide ubiquitously and often greatly exceeded the EPA's lifetime drinking water health advisories as well as comparable Danish, Dutch, and European Union safety standards, leading to the conclusion that "the global spread of these four PFAAs in the atmosphere has led to the planetary boundary for chemical pollution being exceeded". There are some moves to restrict and replace their use.