Airborne micro- and nanoplastics: hidden vectors for human infection?

Airborne micro- and nanoplastics (MNPs) are an emerging component of human exposure. Yet, whether and how they influence respiratory virus transmission remains poorly understood. This commentary synthesizes evidence on the plausibility of MNPs as viral carriers, drawing on their high abundance in the air, their physicochemical properties that may enhance viral persistence, and parallels with particulate matter and plastic-surface studies. Key uncertainties persist, however, regarding the viral loads MNPs can sustain, the environmental conditions under which infectivity is maintained, and their relative role compared to other particulate matter constituents. To address these gaps, we call for coordinated experimental and epidemiological studies that integrate ecotoxicology, microbiology, and atmospheric science. Collectively, such efforts are essential to determine whether MNPs act not only as pollutants but also as hidden vectors of respiratory disease.