Micro/nanoplastics in the Shenyang city atmosphere: Distribution and sources

The contamination of atmospheric particulate matter with diameters ≤2.5 μm (PM2.5) by micro/nanoplastics has increasingly attracted scholarly interest. These micro/nanoplastics can be inhaled into the human respiratory system, potentially leading to respiratory and circulatory diseases. However, current methodologies for quantifying small-sized micro/nanoplastics are inadequate, leading to a limited understanding of their determination and sources. This study aims to conduct both qualitative and quantitative analyses of micro/nanoplastics in PM2.5 in Shenyang City utilizing pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), while also investigating their pollution characteristics and sources. Micro/nanoplastics were detected in all atmospheric PM2.5 samples, with polyethylene (PE) and polyvinyl chloride (PVC) identified as the predominant components. The highest recorded mass concentration of micro/nanoplastics was 28.92 μg/m³, with an average concentration of 7.62 μg/m³, accounting for 12.33% of the total PM2.5 mass. The findings indicate a positive correlation between the concentrations of PM2.5 and micro/nanoplastics, suggesting that PM2.5 may serve as a significant transmission medium. The primary sources of micro/nanoplastics have been identified as domestic, industrial, and agricultural activities. This study represents the first assessment of micro/nanoplastics in Shenyang, highlighting the importance of understanding their characteristics and sources. It provides compelling evidence regarding airborne pathways and the potential health impacts of atmospheric microplastics on human health.