Atmospheric microplastics over ocean: abundance, distribution and transport

Atmospheric transport was considered as an important pathway through which MPs (microplastics) enter the ocean since the early 2019s, but the source, transport, and fate of atmospheric MP have not well known. Besides, the connection between terrigenous atmospheric MP emissions and impacts over the ocean is not well known. In this conference, we will present our research about the variations of atmospheric MP over the ocean based on the three transoceanic survey, include the west Pacific Ocean, south china sea and east Indian ocean. Results suggest that synthetic MP comprised 25.89 % of total atmospheric particles over the west Pacific Ocean, with most being cotton and cellulose (51.68%). We found that the atmospheric MP was sparsely distributed over ocean, with different characteristics. The mean abundance of atmospheric MP over the western Pacific Ocean during the sampling period were 0.841 ± 0.698 items/100 m³. The abundance of atmospheric MP over the Pearl River Estuary (4.2 ± 2.5 items/100 m³) was significantly higher than that over the East Indian Ocean (0.4 ± 0.6 items/100 m³). However, the abundance of atmospheric MP in the SCS (0.8 ± 1.3 items/100 m³) was not significantly different from the East Indian Ocean and Pearl River Estuary. Results indicated that the size of airborne MP fiber over ocean is probably not the limiting factor during the long-range transport. Research reveal that MP undergoes long-range transport, more than 1000 km away. Furthermore, backward trajectory model analysis preliminary showed the potential sources of atmospheric MP over ocean. Our study provides the better understanding on the impact of atmospheric transport on global plastic cycle.