Analysis methodology, distribution, and health risk assessment of size-segregated airborne micro(nano)plastics

The objective of this study is to investigate airborne micro(nano)plastics (MNPs) that were collected from industrial, rural, and urban areas using a high-volume size-segregated sampler. A sample pretreatment and the optimization of the sampling parameters (a flow rate of 40 cfm for eight hours) were conducted, and the slotted Teflon filter, which was placed in both the five-stage and the glass fiber in the nano-fraction stage, was analyzed without pretreatment by particle (μ-Raman and SEM-EDX) and mass-based analysis (Pyr-GC/MS). The distribution of MNPs was found to vary according to geographical location, with concentrations observed in the industrial (1.8±3.1 μg/m³), urban (2.2±4.4 μg/m³), and rural/suburban (1.5±2.4μg/m³) regions. The majority of these particles (approximately 95%) were found to be in the form of fragments, while the remaining 5% were classified as fibers with a chemical identity of carbon black in particle-based analysis. Of the polymers analyzed by the mass-based approach (i.e., PE, PET, PP, PVC, PS, PC, SBR, and NR), results revealed that tire-derived rubbers (SBR, NR), along with PE, were the predominant polymers, with urban areas exhibiting substantial contributions from tire and brake wear in the nano-fraction stage. The results indicated that levels of MNP were elevated during daytime hours in urban areas and during winter months in rural regions. A subsequent statistical analysis revealed moderate correlation (R2=0.64) between PM (<0.49 μm) and MNPs abundance in backup stage. An exposure assessment was conducted according to particle-based and mass-based data, indicating that smaller MNPs, particularly during urban nights and rural winter days, pose a heightened risk to pulmonary health. The findings underscore the importance of implementing standard procedures and specific strategies to address the pervasive presence and health effects of airborne MNPs for better air quality management and policy development.