Microplastics have been recognized as a global marine environmental issue, but their sources, particularly the contribution of atmospheric transport, remain obscure. Here, we determine the transport efficiency of atmospheric microplastics (AMPs) from land to sea using multimedia observations from both sea and land in the South China Sea in conjunction with atmospheric trajectory modelling. Furthermore, we extrapolate AMP inputs to the ocean at a global scale. The results show that only 1.8% of AMPs are transported and deposited into the sea, with most remaining on land. The global mass of AMPs entering the sea is 233.14 t, which is much less than the river exports. Therefore, we conclude that the atmospheric transport is not the main pathway for land-sourced microplastics to enter the sea, and suggest that more attention should be given to riverine MPs in future efforts to control marine MP pollution.

Microplastics, Atmosphere, Transportation