Micro- and nano-plastics (MNPs) in urban air: polymer composition, interactions and inhalation risk

Airborne micro- and nano-plastics (MNPs) represent a long-time underestimated threat to the urban environment, directly challenging Sustainable Development Goal 3 (Good Health and Well-Being). This study characterizes the concentration and polymer composition of atmospheric MNPs in urban air by analyzing size-fractionated aerosol samples using Pyrolysis-Gas Chromatography-Mass Spectrometry. Total PM₁₀MNPs concentrations averaged 0.6 ± 0.2 µg/m³, with fine microplastics and coarse microplastics contributing equally. Tire wear particles were dominant, constituting approximately 65% of total MNPs, and car tire tread particles were consistently abundant across all studied size fractions. The identified polymers were strongly correlated with carbonaceous aerosol markers, indicating complex atmospheric interactions. An estimated inhalation of 2.1 µg/day of airborne MNPs, combined with polymer-specific hazard index, may increase the relative risk of cardiopulmonary mortality by up to 9% and lung cancer-related mortality by up to 13%. By integrating exposure, risk assessment, and analytical data, these findings highlight the need for global policy action, emphasizing the value of region-specific research for air quality and public health initiatives.