The findings, published by the University of Rhode Island and Green Science Policy Institute, provide worrying evidence for a third way humans are at risk of exposure to PFAS, with food and water already known to be major sources, according to the study’s authors.
Rainer Lohmann, senior author of the study and professor of oceanography at the University of Rhode Island, said: “Our study shows that indoor air, including dust, is another source of exposure to potentially harmful forever chemicals.
“In fact, for children in homes or schools with old PFAS-treated carpets, inhalation may be even more important than dust as an exposure pathway to volatile PFAS that eventually could biotransform to more persistent and harmful PFAS.”
Well-studied PFAS have been associated with a wide range of serious health harms, from cancer to infertility to immune system problems. Research has also suggested an impact on the development of foetal brain tissue and low birth weight.
The researchers developed a new measurement technique whereby polyethylene sheet samplers were affixed to ceilings inside homes, classrooms, shops and offices.
The scientists measured volatile PFAS chemicals in the air of nine carpeted kindergarten classrooms, one home, and the storage room of an outdoor clothing store in California. They also measured the chemicals in two laboratories, five offices, one classroom, one storage room, and one elevator at the University of Rhode Island; and two carpet stores, also in Rhode Island. PFAS were detected in the air at nearly every location.
Several kindergarten classrooms and rooms at the university had higher indoor air concentrations of PFAS than the storage room of the outdoor clothing store, which was full of jackets and gear treated with PFAS. The highest concentrations were found in the two carpet stores.
“PFAS were formerly used as stain and water repellents in most carpets,” according to the paper’s lead author Maya Morales-McDevitt.
The authors of the paper said their findings were particularly important given that humans spend typically 90% of their time indoors.
Until now the focus has been on PFAS exposure from food and water.
An analysis by ENDS revealed in December that in the UK high levels of the substances had been found in treated wastewater effluent which is then either pumped into rivers or spread onto farmland as fertiliser.