An investigation led by researchers at the Yale School of Public Health has identified potential health hazards in settled dust.Per- and polyfluoroalkyl substances (PFAS) have been used for decades to create stain-resistant carpeting, waterproof packaging, non-stick cookware and other consumer products. But while the strong carbon and fluorine bonds found in PFAS compounds have proven useful in these applications, their resistance to degradation also means they can linger in the environment long afterward, contaminating drinking water and hampering air quality.These so-called “forever chemicals” are dangerous at certain concentrations, studies have shown. Exposure to PFAS has been linked to delayed brain development in children, thyroid cancers and liver and kidney damage. And, according to some researchers, PFAS compounds can accumulate in settled dust in indoor spaces, where toddlers face an even greater risk of inhaling or ingesting them.The new YSPH study, published Jan. 5 in Current Environmental Health Reports, increases researchers’ understanding of the specific PFAS compounds often found in dust and where they may come from, as well as their potential implications for human health.“Dust collected from on the top of doorframes or windows or from carpets can be used to capture a person’s exposure to pollutants in the air,” said Krystal Pollitt, an assistant professor of epidemiology (Environmental Health Sciences) at YSPH and senior author of the study. “Settled dust is especially relevant for infants and children that spend extended periods on the ground where they may inhale or ingest the dust.”For the paper, Pollitt’s team compiled a list of some of the sources potentially contributing to the presence of PFAS in settled dust, as identified by other scientists. The list is long: rugs and carpets, food packaging, cosmetics, paper products, clothing, insecticides and more.“So many children's products, like foam play mats or clothing that is stain- or water-resistant, likely contain PFAS,” Pollitt said. Cookware, too. “PFAS are applied to many household items to achieve the non-stick surface,” she said.There are steps individuals can take to try and avoid potentially hazardous compounds in dust, Pollitt said, including frequent cleaning and having greater awareness of the chemicals household products contain.Settled dust is especially relevant for infants and children that spend extended periods on the ground where they may inhale or ingest the dust.Krystal Pollitt“It is important to prevent exposure from the onset,” she said. “There are a growing number of companies that are committed to not using PFAS in their products.”PFAS research is an active area of science, but also one that has many challenges and limitations. While scientists can identify new sources of PFAS exposure, they are currently unable to gauge which types of environments, products and locations may have the highest concentrations.Measuring and tracking different sources of PFAS exposure is difficult because the family of chemicals is so large. Methodologies that can account for the extensive variety and diversity of compounds can be costly and time-consuming. That means that studies looking for certain compounds in specific settings can completely overlook hundreds of others, greatly complicating the research.Further research can help to address this missing link, Pollitt said. Her team is developing software that can predict the structures of new compounds, which could allow scientists to be more specific with their identification efforts. Biological samples taken from pregnant women and newborns, for instance, are helping scientists measure the levels at which these harmful chemicals can reach the womb, potentially causing pediatric cancers.Wearable air samplers that Pollitt’s team recently developed are also being used to study children’s exposure to PFAS.All of these different efforts contribute to what Pollitt said is a “very active area” of research — and one that could have major implications for maternal and child health.Her team’s work “has many applications to better understand our exposures in a more comprehensive manner,” she said. For instance, the current study’s findings will help public health officials and other researchers take new steps toward addressing the link between PFAS exposure and potential health impacts, especially in children.