State-level material flow analysis suggests the need to reconsider current monitoring practice and mitigation policies for poly- and perfluoroalkyl substances in carpet

The use of per-- and polyfluoroalkyl substances (PFAS) in consumer products are under scrutiny due to persistence and toxicity concerns, and large-scale monitoring is being implemented to better estimate and manage the associated risks. However, current monitoring efforts are often conducted independently from regional material flow analysis (MFA), leaving missed opportunities for monitoring to generate data more compatible with MFA, and to benefit from the insights that can be generated by MFA. This study aims to bridge the gap by quantitatively evaluating the sensitivity of state-level PFAS emissions from carpet to two emission models and seven input parameters. While this exercise is theoretical in nature, it demonstrates the synergies from connecting the often disparate monitoring efforts and regional MFA. Most notably, this study finds that the widely-followed linear emission reporting would suggest that current mitigation policies (e.g., regulating the PFAS use in carpet production) are ineffective at reducing PFAS emissions from in-use and landfilled carpet - defeating one of the key purposes, but the hypothetical first-order emission model would suggest the opposite. The contrast points out the need for future monitoring efforts to prioritize the confirmation of the "true" emission models, including but not limited to the ones examined herein, which will improve the usability of PFAS monitoring in MFA, risk assessment and policy design, and vice versa.