**6. Conclusions**

MPs have been well studied in marine and freshwater environments, but MPs in the atmosphere have received little attention from researchers and society. Microplastics in the atmosphere enter the body mainly through inhalation and further systemic exposure, causing toxic reactions and disorders in various organs and systems and even posing a potential risk of cancer to animals and humans.

Due to the lack of practical methods for detection and analysis, we are still unable to gain a more detailed understanding of the global distribution, sources, and fate of atmospheric MPs, let alone further elucidate the mechanisms of toxic action of atmospheric MPs on animals and humans. We sugges<sup>t</sup> that the scientific community conduct in-depth research on atmospheric MPs in the future, especially to explore relevant sampling and detection methods and establish a common industry standard. Further quantitative analysis of atmospheric MPs of different types and properties will be conducted to explore the toxicity mechanism and additive effect of their combination with other pollutants through in vivo experiments.

**Author Contributions:** Conceptualization, H.Y. and J.W.; methodology, Y.Y.; software, Y.H.; validation, H.Y. and J.W.; formal analysis, Y.H. and Y.Y.; investigation, M.J.; resources, H.Y. and Y.H.; writing—original draft preparation, H.Y. and Y.H.; writing—review and editing, H.Y. and Y.H.; visualization, Y.H.; supervision, H.Y. and J.W.; project administration, H.Y. and J.W.; funding acquisition, H.Y. and J.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was funded by the National Key Research and Development Program of China (2018YFD0900604), the Guangdong Forestry Science and Technology Innovation Project (2021KJCX012), Provincial Science and Technology Special Fund Project for Zhongshan City (major special project + Task list managemen<sup>t</sup> mode) (2021), Rural Science and Technology Commissioner Service Team project of New Rural Development Institute, South China Agricultural University (2021XNYNYKJHZGJ022), Provincial Projects with Special Funds for Promoting Economic Development of Marine and Fisheries Department of Guangdong (SDYY-2018-05), the Project of Guangzhou Association for Science & Technology (K20200102008), the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2018), the National Natural Science Foundation of China (42077364), the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (311021006), and Key Research Projects of Universities in Guangdong Province (2019KZDXM003 and 2020KZDZX1040). We appreciate the provision of SCAU Wushan Campus Teaching & Research Base.

**Data Availability Statement:** Not Applicable.

**Conflicts of Interest:** The authors declare no competing financial interests.
