*Review* **Characteristics, Toxic Effects, and Analytical Methods of Microplastics in the Atmosphere**

**Huirong Yang 1,2,3,†, Yinglin He 1,2,†, Yumeng Yan 1,2, Muhammad Junaid 1 and Jun Wang 1,2,4,\***


**Abstract:** Microplastics (MPs) (including nanoplastics (NPs)) are pieces of plastic smaller than 5 mm in size. They are produced by the crushing and decomposition of large waste plastics and widely distributed in all kinds of ecological environments and even in organisms, so they have been paid much attention by the public and scientific community. Previously, several studies have reviewed the sources, occurrence, distribution, and toxicity of MPs in water and soil. By comparison, the review of atmospheric MPs is inadequate. In particular, there are still significant gaps in the quantitative analysis of MPs and the mechanisms associated with the toxic effects of inhaled MPs. Thus, this review summarizes and analyzes the distribution, source, and fate of atmospheric MPs and related influencing factors. The potential toxic effects of atmospheric MPs on animals and humans are also reviewed in depth. In addition, the common sampling and analysis methods used in existing studies are introduced. The aim of this paper is to put forward some feasible suggestions on the research direction of atmospheric MPs in the future.

**Keywords:** microplastics; atmosphere; distribution; characteristics; toxicity; quantitative analysis
