The air in your may be contaminated with various nasty elements including viruses, bacteria, carcinogens and chemicals. These may arise from high-energy devices being used on skin or hair, or, may simply be breathed into the air by patients/clients.
In particular, during the current Covid-19 pandemic, we must be aware of the potential hazard with that virus in the air. It can sit on aerosolised saliva droplets in the air for hours after being exhaled by an infected person.
Mike wrote an article on this topic (click here) for the Aesthetic journal (February 2021). In it he discusses the various ways we can tackle such a problem using filtration and ultra-violet light devices.