Plastic Airprint: The Atmospheric and Environmental Cost of Polyethylene Plastic Degradation.

Petroleum-sourced plastics, while indispensable to modern societies, impose environmental costs beyond visible residues. Research has mainly addressed solid fragments, while gaseous byproducts remain overlooked. Here, environmentally relevant abiotic aging under UVC radiation and mechanical stress shows that polyethylene plastics release a diverse mixture of volatile organic compounds (VOCs) and carbon dioxide (CO2). Multiscale analyses (ATR-FTIR, DSC, PTR-MS, and μGC-MS) link VOC emissions to chemical transformations within the polymer matrix. Life cycle assessment demonstrates that, despite trace-level concentrations, toxic VOCs such as acrolein dominate the human health and ecosystem damages. When extrapolated to global oceanic HDPE stocks (44.71 Mt), these emissions correspond to more than 5.4 × 1011 μPoints and 1.32 × 107 kg CO2eq in environmental impact. These findings uncover a neglected atmospheric dimension of plastic degradation, showing that volatile emissions represent a significant pathway of carbon release with implications for climate policy, risk assessment, and global plastic governance.