Danger Dust

This study highlights the promising potential of green roofs in mitigating microplastic pollution in coastal urban areas. Green roofs demonstrated an impressive average interception efficiency of more than 97.5% for trapping microplastics from atmospheric deposition.

The estimated annual interception flux of atmospheric microplastics in Shanghai is 1.70 × 1012 n L−1 (56.2 t yr−1).

The research found that higher rainfall intensities slightly increased interception efficiency due to enhanced moisture content and reduced hydraulic gradient, decreasing the driving force for stormwater and microplastic infiltration. Fibers were more challengeable to be captured than fragments. Most microplastics were retained in the planting soil layer (66–92%), with the overground part of vegetation contributing modestly.

However, the long-term operation of green roofs may lead to aging and degradation of plastic components, potentially generating new microplastics. These findings offer valuable insights and data for developing future microplastic pollution management strategies.