 Bio aerosols are particles composed of biological materials such as bacteria, viruses, fungi, and other organisms that can be found in the atmosphere. These particles have both physical and biological properties, making them unique from other types of atmospheric particles. During the COVID-19 pandemic, there was significant progress made in understanding the role of bio aerosols in air quality, climate change, and human health. Bio aerosols were found to play a key role in haze air pollution, allergies, and infectious and inflammatory diseases. Interdisciplinary research is necessary to further understand how these particles interact with the earth system, as well as their potential impacts on public health. This article was authored by Shenfongxia and Yao Maoxing.