Strength in numbers: How citizen science can upscale assessment of human exposure to plastic pollution

Plastic pollution is ubiquitous, and the presence of plastic particles available for human uptake is documented, for example, in air, foodstuffs, and drinking water. Meanwhile, researchers, organizations, and policy agencies call for large-scale analyses of plastic pollution exposure. Doing precisely this in neighboring research fields, we argue that citizen science (CS) can contribute to close knowledge gaps for human exposure. We reviewed the recent literature (2019-present) on the assessment of human exposure to plastic pollution using CS to document the state-of-the-art and only found a single study. We discuss the strength of citizen-generated evidence regarding the most prominent exposure routes, and we present an example of a future, large-scale CS project assessing plastic exposure via drinking water.