What are the experiments to prove that microorganisms are presented in air?

Experiments demonstrating the presence of microorganisms in the air include Louis Pasteur's swan-neck flask experiment, where he showed that sterilized broth remained free of microbial growth when air was allowed to enter but not dust particles. Another example is the use of Petri dishes exposed to the air, which later develop colonies, confirming that airborne microorganisms can settle and grow. Additionally, filtration of air through fine filters followed by incubation of collected particles can also reveal the presence of viable microorganisms. These experiments collectively establish that air contains a variety of microorganisms.