An open global registry of primary-aluminium smelters and a derived gridded spatial prior for CF₄ (PFC-14) emissions

Abstract. CF₄ (PFC-14, tetrafluoromethane) is a long-lived greenhouse gas with a 100-year global warming potential of 7,380 and an atmospheric lifetime of 50,000 years (IPCC AR6 WG1, Table 7.SM.7); its dominant anthropogenic source is the anode effect in primary-aluminium smelting. The smelters are a finite, public, mappable set of industrial facilities, yet the gridded inventories used as inversion priors distribute CF₄ spatially by population and built-up-area proxies. This paper describes an open registry of the world's primary-aluminium smelters operating in 2020 — 94 facilities across 36 countries (95 registry rows), with coordinates, nameplate capacity, operating status, and per-row source notes — and a set of gridded relative-weight fields derived from it: capacity-weighted, presence-only, and production-rescaled variants at 1° globally and 0.1° over Europe, formatted for use as the aluminium-sector component of a CF₄ prior in atmospheric inversions and inventory disaggregation. Registry capacity tracks USGS national production within roughly 25% in every listed producing country except China, where 12 registered cluster-anchor plants stand for a fleet of roughly 120 and the production-rescaled variant rescales the national total (not the within-country placement). Evaluated against an observation-driven, flat-prior ICOS 2020 European CF₄ posterior ensemble, the smelter field correlates with the posterior better than the EDGAR v8.0 baseline in Iceland — 0.25 versus 0.00, significant under spatial tests in both (single-system, RHIME) ensemble members that cover Iceland — and directionally in five of six members over the pooled smelter countries, while France significantly favours the baseline in the same two members and Norway, Spain, and the UK are EDGAR-favoured; EDGAR assigns exactly zero CF₄ to 15 of the 22 European smelter cells in the analysis domain. The fields are relative weights for one sector, not emissions estimates, and Sect. 6 states the workflow and cautions required to use them. The dataset is archived at https://doi.org/10.5281/zenodo.20673973 (Dissington, 2026) under CC-BY-4.0.