Airborne particles have significant impacts on health, visibility, and climate. Here, an overview of what is known about particle chemical composition is presented, along with open questions and challenges that are central to relating composition to life cycles and impacts.

中文翻译：

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关于空气中颗粒物化学成分的开放性问题

空气中的颗粒物对健康、能见度和气候有重大影响。在这里，概述了有关颗粒化学成分的已知信息，以及对于将成分与生命周期和影响相关联的核心问题和挑战。