It's the first study to trace the fluctuation of a natural (not human-caused) aerosol around the globe over the course of a century.

这是第一个试图勘测整个世纪地球表面自然(非人造)环境中悬浮颗粒的研究。

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An aerosol, natural or artificial is made to flow through a length of tubing, the aerosol particles diffuse to the walls.

让自然或人造气溶胶通过一段管道，气溶胶粒子就扩散到管臂上。

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