Long-distance atmospheric transport of microplastic fibres influenced by their shapes
Long-distance atmospheric transport of microplastic fibres influenced by their shapes
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DOI：
10.1038/s41561-023-01264-6
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发表时间：
2023-09
影响因子：
18.3
通讯作者：
Shuolin Xiao;Yuanfeng Cui;J. Brahney;Natalie M. Mahowald;Qi Li
中科院分区：
文献类型：
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作者：
Shuolin Xiao;Yuanfeng Cui;J. Brahney;Natalie M. Mahowald;Qi Li
最近的研究强调了大气在微塑料纤维远距离迁移中的重要性。然而，它们在大气中的干沉积尚未完全了解，常见的球形假设导致在预测其传播距离和大气停留时间方面存在很大的不确定性。微塑性纤维的直径变化很大，可以长达100 μm，也可以细至2 μm。微塑料纤维的沉积可能极大地影响其在大气中的干沉积。在这里，我们开发了一个基于理论的沉降速度模型，用于模拟不同尺寸和形状的微塑料纤维的大气传输。该模型预测了一个较小的空气动力学尺寸的微塑料纤维比估计使用体积等效的球形同行。我们发现，作为圆柱形的扁平纤维的治疗，由于采样微塑料纤维的尺寸的不确定性，会导致高估其干沉积速率。占纤维厚度在采样微塑料纤维导致平均增强的停留时间超过450%相比，圆柱形的。结果表明，扁平纤维的长距离运输比以前认为的要有效得多。
Recent studies have highlighted the importance of the atmosphere in the long-range transport of microplastic fibres. However, their dry deposition in the atmosphere is not fully understood, with the common spherical-shape assumption leading to significant uncertainties in predicting their travel distance and atmospheric residence time. Shapes of microplastic fibres vary greatly, which can be as long as 100 μm and as thin as 2 μm. Shapes of microplastic fibres may greatly affect their dry deposition in the atmosphere. Here we develop a theory-based settling velocity model for simulating atmospheric transport of microplastic fibres in different sizes and shapes. The model predicts a smaller aerodynamic size of microplastic fibres than that estimated by using volumetrically equivalent spherical counterparts. We find that the treatment of flat fibres as cylindrical ones, due to uncertainty in dimensions of sampled microplastic fibres, would cause overestimation of their dry deposition rate. Accounting for fibre thickness in sampled microplastic fibres leads to a mean enhancement of residence time by more than 450% compared to cylindrical ones. The results suggest a much more efficient long-range transport of flat fibres than previously thought.