Minnesota officials say their state’s landmark effort to control levels of per- and polyfluoroalkyl substances (PFAS) in ambient air, one of the first such programs in the country, could mirror earlier efforts to address mercury, which, like PFAS, was spread through the air and deposited onto waterbodies where it contaminated fish. “Right now, it looks almost like PFAS and air could be similar to mercury, in the sense that there's sort of a global atmospheric reservoir of mercury that kind...