I’m sure you know this already, but just in case, air particles come out of your mouth when you talk, cough, etc. The Washington Post used an infrared camera to demonstrate:
To visually illustrate the risk of airborne transmission in real time, The Washington Post used an infrared camera made by the company FLIR Systems that is capable of detecting exhaled breath. Numerous experts — epidemiologists, virologists and engineers — supported the notion of using exhalation as a conservative proxy to show potential transmission risk in various settings.
