Imagine you heard from someone that you were surrounded by millions of microorganisms. At home, at work, in the gym, even in nature: Every day they are there. Sounds scary doesn’t it? These microorganisms that surround us are called airborne biological particles or just bioaerosols for short and are categorized under the general term aerosols. You’ve heard that word before, right? Just as a refresher, aerosols are generally defined as “colloidal systems of (liquid or solid) particles suspended in a gas (usually air).”