Reconciling plastic release: Comprehensive modeling of macro- and microplastic flows to the environment

Plastic pollution is a major environmental challenge of the 21st century. Addressing this issue requires a clear understanding of environmental emissions. Combining material flow analysis with release assessments provides an effective way to quantify plastic emissions from a life cycle perspective. This study integrates recent research on key emission pathways into a plastic release model based on probabilistic material flow analysis, offering a comprehensive quantification of macro- and microplastic emissions for seven polymers. Switzerland in 2022 was selected as the case study due to the availability of detailed data. Emission factors for 245 release flows were determined, enabling the quantification of emissions to soil and water for each polymer. We estimate that a total of 222 ± 50 g of plastic per capita per year were released into the environment, with PET accounting for 37 %, followed by PP at 22 %. Macroplastics represent 82 % of the total plastic release. Comparison with previous estimates shows considerable variation in per capita emissions, mainly due to differences in the inclusion of tyre wear and how littering is modeled. Total plastic release based on our model is substantially lower than in earlier studies, suggesting that in an industrialized country with effective waste management and high environmental awareness, plastic emissions are lower than previously assumed.