Expert and non-expert perceptions of ‘forever chemicals’:identifying commonalties and differences to inform PFASrisk communication

Per- and polyfluoroalkyl substances (PFAS), also known as ‘forever chemicals’, are a large class of synthetic chemicals with consumer benefits, including waterproofing, stain prevention and non-stick properties. However, some PFAS have been identified as toxic to human health, being linked to cancer, lowered fertility, and developmental issues. Concern is high because PFAS can persist for long periods in the environment, accumulate in animals and humans, and are easily transported by water. Both scientific experts and the public (non-experts) are key actors who can support a reduction in PFAS pollution, but we lack data on public PFAS awareness and what actions they will support to reduce pollution. Combining quantitative and qualitative data in a mental models approach, we systematically compare expert and non-expert perceptions of PFAS and related issues, including the essentiality of consumer items that can contain PFAS. While we find knowledge gaps, such as a non-expert tendency to focus on direct chemical exposure routes during the use phase and to underestimate exposure through indirect routes, we also find commonalities: Both experts and non-experts understand the benefits chemicals provide alongside the risks and are aware of the greater risks posed by chemicals like PFAS to vulnerable groups. Moreover, experts and non-experts tend to view similar kinds of products and the functions they serve as most or least essential. Commonalities can provide routes to reducing PFAS use by highlighting cases where the majority agree a level of performance afforded by PFAS is not necessary. Finally, we provide suggestions for developing effective risk communications about PFAS with the public.