China PFOS, PFOA emissions fall sharply as hotspots persist

By Rebecca Stone

PFOS emissions across mainland China fell about 89% from 2016 to 2021, while PFOA emissions dropped by more than 99%, according to a multimedia inventory published in Environmental Science and Ecotechnology.

The study, available online on 29 October 2026 under DOI 10.1016/j.ese.2026.100785, was produced by researchers at Peking University, Shanghai Jiao Tong University and Southern University of Science and Technology. It covers releases to air, water and soil across five PFOS and four PFOA source categories.

How was the inventory built?

The researchers constructed a bottom-up inventory for the Chinese mainland at 0.1° × 0.1° resolution, covering 2016 through 2021. They combined source-specific activity data, emission factors derived from published literature and Monte Carlo uncertainty analysis.

Source-specific downscaling proxies included land-use data for sulfuramid pesticides and fire statistics combined with facility locations for aqueous film-forming foam, or AFFF, use. These inputs supported the inventory’s sector-by-sector distribution of releases across the grid.

What changed across the source sectors?

The authors said the sharp reductions coincided with regulatory restrictions and technological transitions in four sectors:

• fluoropolymer manufacturing;
• metal plating;
• aqueous film-forming foams; and
• sulfuramid pesticides.

The sector mix changed as those restrictions took effect. In 2016, PFOS releases were dominated by use-related sources, while PFOA releases were overwhelmingly production-related. By 2021, AFFFs dominated residual PFOS emissions and nearly all residual PFOA emissions.

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.

Where did residual emissions concentrate?

The decline moved China’s 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 across the inventory period.

Residual hotspots persisted in the Bohai Rim, Yangtze River Delta and Pearl River Delta, overlapping dense populations in eastern and southeastern industrial zones. Grid-level emission densities contracted sharply, yet relative spatial heterogeneity remained substantial. Local concentrations remained.

A population-weighted emission index identified the Yangtze River Delta and Pearl River Delta as priority areas because residual sources coincide with dense populations. The lower national totals therefore did not produce an even geographic pattern of remaining releases.

What can the inventory support?

The researchers say the dataset provides spatially and temporally resolved source terms for multimedia fate modeling, hotspot mitigation and policy evaluation. Its spatial detail can also support exposure assessment and environmental monitoring, particularly in the Yangtze River Delta and Pearl River Delta.

Which sources need tighter control?

The authors recommend prioritizing monitoring of:

• PFOS sources linked to metal plating and firefighting; and
• PFOA hotspots near fluoropolymer facilities.

They also say residual emissions are increasingly concentrated in industrialized and densely populated regions. Their recommendation directs targeted controls toward the remaining metal-plating and firefighting-related sources despite the large national declines.

What must improve before the next inventory?

The study does not include replacement PFAS. The authors cautioned that “replacement PFAS were not included because consistent national activity data and process-specific emission factors remain unavailable.”

To improve future inventories, they call for:

• facility-level mass-balance measurements;
• China-specific process-level emission factors; and
• expanded compound coverage as nationally consistent activity data become available.

Those steps could help quantify the health benefits of source-control strategies, refine estimates of remaining PFOS and PFOA releases and inform future regulatory priorities. They would also connect the national totals with the industrial, firefighting and fluoropolymer-related sources identified at grid level.

The next regulatory milestone is the availability of nationally consistent activity data and process-specific emission factors for replacement PFAS. Until those data exist, the study cannot be extended to those compounds. Once available, they could support evaluation of source controls and future regulatory priorities across a wider set of PFAS.