Emissions of two regulated persistent organic pollutants—perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)—fell dramatically across the Chinese mainland between 2016 and 2021, according to a new bottom-up inventory published in Environmental Science and Ecotechnology. PFOS emissions dropped by about 89%, while PFOA emissions plunged more than 99%, the study found. However, the research also identifies persistent localized hotspots and a structural shift in emission sources, with significant implications for environmental monitoring and public health in China’s most industrialized regions.
The study, conducted by researchers from Peking University, Shanghai Jiao Tong University and Southern University of Science and Technology, constructed a consecutive 0.1° × 0.1° multimedia emission inventory covering releases to air, water and soil from 2016 to 2021. It used source-specific activity data, literature-derived emission factors and Monte Carlo uncertainty analysis to track five PFOS and four PFOA source categories. The work was published online on October 29, 2026, and is available via DOI 10.1016/j.ese.2026.100785.
The sharp declines coincide with regulatory restrictions and technological transitions in fluoropolymer manufacturing, metal plating, aqueous film-forming foams (AFFFs) and sulfuramid pesticides. In 2016, PFOS emissions were dominated by use-related releases, while PFOA emissions were overwhelmingly production-related. By 2021, AFFFs dominated residual PFOS emissions and nearly all residual PFOA emissions. This shift—from dispersed pesticide and industrial uses to concentrated firefighting and manufacturing sites—has reshaped the spatial structure of releases, creating localized clusters that pose ongoing risks.
Water remained the principal receiving medium for both compounds. Residual hotspots persisted in the Bohai Rim, Yangtze River Delta (YRD) and Pearl River Delta (PRD), areas that overlap with dense populations in eastern and southeastern industrial zones. A population-weighted emission index identified the YRD and PRD as priority areas where residual sources coincide with large populations. The authors note that while grid-level emission densities contracted sharply, relative spatial heterogeneity remained substantial, meaning hotspots are increasingly isolated but intense.
“The sharp declines reflect a structural transformation in China’s emission profile for legacy C8 PFAS, driven by source-directed regulation and industrial transition,” the authors said. They emphasized that residual emissions are now concentrated in industrialized and densely populated regions, and targeted control should prioritize remaining metal-plating and firefighting-related sources. The inventory offers spatially and temporally resolved source terms for multimedia fate modeling and policy evaluation, but the authors caution that replacement PFAS were not included due to unavailable consistent national activity data and process-specific emission factors.
The implications for readers and industry are significant. PFOS and PFOA can accumulate in the human body and have been linked to immunotoxicity, endocrine disruption, developmental effects and certain cancers. The study provides a quantitative basis for hotspot mitigation and exposure assessment, particularly in the YRD and PRD. The authors recommend prioritizing monitoring of PFOS sources linked to metal plating and firefighting, and PFOA hotspots near fluoropolymer facilities. They also call for facility-level mass-balance measurements and China-specific process-level emission factors to improve future inventories, and for expanding compound coverage to replacement PFAS as nationally consistent activity data become available. Such work could help assess the health benefits of source-control strategies and inform future regulatory priorities.
