N95 mask with exhalation valve

N95 masks are the best of the available personal coronavirus protection products. Some of them have exhalation valves for easier exhaled air outlet. Those exhalation valves make it easier to breathe and accumulate less moisture. If the manufacturers of those masks are not up to the task, then those exhalation valves may not work, be open all the time. In practice, this means that your mask has a hole that allows unfiltered air to pass through. How to check? If you inhale and the mask filters the air properly, then that mask presses against your face during inhalation. If the mask presses against your face - that means that the hole does not exist, you can safely wear your mask.

The N95 mask with exhalation valve can be covered with a simple medical mask if there is a risk that you may infect other people who do not wear any masks at all with your exhaled virus.