POPE: a Global Gridded Emission Inventory for PFAS 1950–2020

Abstract. This study presents a global multi compartment Persistent Organic Pollutant Emissions model and inventory: POPE. The model computes temporally and spatially resolved model ready emissions for 23 of the most widely used Per- and Polyfluoroalkyl Substances (PFAS) distinguishing between emissions to air and emissions to water covering the time span from the first industrial scale production in 1950 up until 2020 on an annual basis on a grid with 0.5° resolution.

The POPE model distributes estimated total PFAS emissions in space and time based on several data sets such as the E-PRTR, NACE and US-EPA FRS in combination with socio-economic data as population and GDP complemented by estimates for individual point sources, such as industrial sites and airports, whereby the source activity is dependent on regional changes in production volumes, usage quotas, and recapturing efficiency over time. It includes emissions by industrial production, diffuse emissions through usage and disposal of consumer products, secondary emissions from the reaction of precursors, and emissions by firefighting exercises on airports using Aqueous Film Forming Foams.

It is demonstrated that the POPE emission inventory is compatible with current global emission estimates, and temporal and spatial variability of the emissions is explored. A comparison of independent measurements with modelled river concentrations based on the POPE emission inventory is provided. The POPE emission inventory is meant to be used as input for atmospheric and marine chemistry transport models, eventually allowing to assess the environmental fate of PFAS. POPE can be used to create hypothetical future emission scenarios, enabling model based predictions which can inform policy decisions. This is important given that even with a theoretical global fade-out of PFAS production, significant legacy pollution is still to be expected.