November 16, 2023

Researchers in the Department of Environmental Sciences and Engineering at the UNC Gillings School of Global Public Health published a new study about the effects of the toxic chemicals, per- and polyfluoroalkyl substances (PFAS), in residential indoor air and cloth material. 

Doctoral candidate Clara Eichler, first author and principal designer of the Indoor PFAS Assessment (IPA) Campaign, and Barbara Turpin, PhD, professor in the Department of Environmental Sciences and Engineering, conducted a measurement campaign to better understand the mechanisms that govern PFAS behavior, exposure, and transport indoors. 

Clara Eichler

Doctoral candidate Clara Eichler

The IPA campaign was designed to provide answers to questions that had not previously been addressed: 

  • Which neutral PFAS can be measured in indoor air and at what concentrations in North Carolina (N.C.) homes? 
  • Does clean, PFAS-free cotton cloth accumulate PFAS over time? How long does it take to do so and does the storage method (folded in a dresser vs. hanging in a closet) make a difference? 

PFAS contamination has continually been a concern in soil and waterways in N.C., but identification and exposure to PFAS compounds in residential indoor air had not been studied until Eichler and Turpin’s research team created the IPA campaign. 

Other researchers involved in the study were doctoral candidate Naomi Chang and Master of Science student Daniel Amparo. Along with Eichler, Chang and Amparo started the IPA campaign by sampling homes in the Chapel Hill and Durham, N.C., area in the summer of 2021. 

The IPA Campaign included 11 single-family, nonsmoking detached homes, which were visited, sampled and surveyed over the course of several months. Air samplers and cloth samplers (clean cloth strips) were placed in each home over the course of the study. 

The clean cloth strips were left hanging in study participants’ closets and placed in dresser drawers and then analyzed for PFAS in the Turpin lab.

Dr. Barbara Turpin

Dr. Barbara Turpin

The results of the assessment showed that methyl- and ethylperfluorooctane sulfonamidoethanol (MeFOSE and EtFOSE), which are PFAS used for manufacturing other PFAS, had accumulated over the duration of three to six months in the cloth strips hanging in the closets, and the amount that accumulated in the cloth was directly proportional to the concentrations of these PFAS in indoor air. 

Hanging in the closet, MeFOSE and EtFOSE were the most common species of PFAS to be found in the cloth, and those two species contributed most to the total neutral PFAS concentration in the cloth. 

However, the folded cloth stored in the dresser drawers accumulated more and higher concentrations of fluorotelomer alcohols (FTOHS) — another type of PFAS — meaning that the storage method and location of the cloth really matters in terms of which neutral PFAS accumulate in the cloth. 

The study indicates that PFAS are present in indoor air in N.C. homes. This suggests that indoor exposure, especially inhalation of indoor air, should be considered to get a complete picture of human exposure to PFAS.  

In addition, clothing and fabric present in homes can accumulate PFAS over time. This means that PFAS can remain in the home for an extended period of time, stored in the fabric, and in turn, fabric that is now PFAS-contaminated can become a secondary source of exposure, even though it had been initially PFAS-free.  
This can lead to prolonged and potentially increased exposure, by inhalation and by skin contact with the clothing. 

The associated health effects with PFAS exposure are due to chronic, low-level exposures. As with most exposures of this kind, it is difficult to point a finger at one particular type of exposure or chemical when negative health impacts occur many years later.  

PFAS have been used in consumer products since the 1940s, meaning that most Americans have been exposed to them in some way for most or all their lives. The National Health and Nutrition Survey shows that more than 95% of Americans have PFAS in their blood and tissue.  

Therefore, people should be made aware about PFAS because the chemicals are truly “forever chemicals.. Most importantly, there are still many unknowns about many PFAS.  

“We are hoping to further increase awareness of the importance of indoor environments to human exposure to PFAS,” says Eichler. “There are certainly other exposures that may be of greater concern for some populations, for example because of occupational exposures or contaminated water sources, but for the general population, residential indoor exposure is likely to play a significant role.”  

Eichler continues, “We as exposure scientists still need more data to put numbers to the contribution of indoor exposure to total exposure for the general population, but our study and subsequent publications based on the IPA campaign data will help to close this knowledge gap.” 

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