China's PFOS and PFOA emissions drop sharply, but hotspots persist

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are persistent organic pollutants regulated under the Stockholm Convention. However, consecutive annual changes in PFOS and PFOA emissions across the Chinese mainland, their distribution among environmental media, and their spatial variation have not yet been systematically quantified. A new study develops a bottom-up, consecutive 0.1° × 0.1° inventory tracking PFOS and PFOA releases to air, water and soil across China from 2016 to 2021. The work quantifies sharp national declines alongside persistent localized hotspots and identifies a structural shift in emission sources from dispersed pesticide and industrial uses toward concentrated firefighting and manufacturing sites. It provides a spatially and temporally resolved basis for understanding multimedia release patterns and priority control areas.

Per- and polyfluoroalkyl substances (PFAS) have been widely used since the mid-20th century and are ubiquitous in water, air, soil and biota. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) can accumulate in the human body and have been linked to immunotoxicity, endocrine disruption, developmental effects and certain cancers. China has introduced measures including the PFOS Priority Sectors Reduction and Phase-Out Project and restrictions on sulfuramid, but existing inventories often cover single years or selected regions and lack consecutive annual trends, medium-specific releases and national spatial detail. Given these challenges, in-depth research is needed on the consecutive annual, multimedia emission dynamics and priority control areas for PFOS and PFOA across China.

Researchers from Peking University, Shanghai Jiao Tong University and Southern University of Science and Technology published (DOI: 10.1016/j.ese.2026.100785) the study in Environmental Science and Ecotechnology, available online 29 October 2026. The team built a bottom-up multimedia emission inventory for the Chinese mainland at 0.1° × 0.1° resolution from 2016 to 2021, combining source-specific activity data, literature-derived emission factors and Monte Carlo uncertainty analysis. The inventory covers releases to air, water and soil across five PFOS and four PFOA source categories.

The inventory shows that PFOS emissions fell by about 89% and PFOA emissions by more than 99% over the study period. These reductions coincided with regulatory restrictions and technological transitions in fluoropolymer manufacturing, metal plating, aqueous film-forming foams (AFFFs) and sulfuramid pesticides. PFOS emissions were dominated by use-related releases in 2016, while PFOA emissions were overwhelmingly production-related; by 2021, AFFFs dominated residual PFOS and nearly all residual PFOA emissions. The decline also reshaped the spatial structure of releases, shifting the emission profile from geographically dispersed pesticide and industrial uses toward localized clusters at industrial and firefighting sites. 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), overlapping with dense populations in eastern and southeastern industrial zones. Grid-level emission densities contracted sharply, yet relative spatial heterogeneity remained substantial. A population-weighted emission index further identified the YRD and PRD as priority areas where residual sources coincide with dense populations. The authors used source-specific downscaling proxies, including land-use data for sulfuramid and fire statistics combined with facility locations for AFFF use.

The authors said the sharp declines reflect a structural transformation in China's emission profile for legacy C8 (eight-carbon) PFAS, driven by source-directed regulation and industrial transition. They said residual emissions are now increasingly concentrated in industrialized and densely populated regions, and targeted control should prioritize remaining metal-plating and firefighting-related sources. They added that the inventory offers spatially and temporally resolved source terms for multimedia fate modeling and policy evaluation, while cautioning that replacement PFAS were not included because consistent national activity data and process-specific emission factors remain unavailable.

The inventory provides a quantitative basis for multimedia fate modeling, hotspot mitigation and policy evaluation. It offers spatially explicit source terms for exposure assessment and environmental monitoring, particularly in the YRD and PRD where residual sources coincide with dense populations. 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.

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References

DOI

10.1016/j.ese.2026.100785

Original Source URL

https://doi.org/10.1016/j.ese.2026.100785

Funding information

National Natural Science Foundation of China (42521004, 42477455 and 41991310); Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China (JYB2025XDXM909); High-Performance Computing Platform of the Center for Life Sciences, Peking University (computing support).

About Environmental Science and Ecotechnology

Environmental Science and Ecotechnology (ISSN 2666-4984) is an international, peer-reviewed, and open-access journal published by Elsevier. The journal publishes significant views and research across the full spectrum of ecology and environmental sciences, such as climate change, sustainability, biodiversity conservation, environment & health, green catalysis/processing for pollution control, and AI-driven environmental engineering. The latest impact factor of ESE is 14.3, according to the Journal Citation ReportsTM 2024.