The air we breathe in our homes, schools, and workplaces can be polluted with harmful PFAS chemicals, according to a study published today in Environmental Science & Technology Letters. A new measurement technique developed by the research team detected PFAS chemicals in the air of kindergarten classrooms, university offices and laboratories, and a home—some with levels as high as those measured at an outdoor clothing company and carpet stores selling PFAS-treated products. The results suggest indoor air is an underestimated and potentially important source of exposure to PFAS, particularly for children.