Can a waterproof mask stop the spray?

There is a method on the Internet to distinguish whether a mask can stop the spray: "Use a mask to catch the water. If it does not leak, it means that it can be waterproof. Only such a mask can stop the spray" In fact, this statement is incorrect.

Masks that are waterproof may not be able to block the droplets, and masks that can block the droplets are not necessarily waterproof.

No water leakage can only indicate that the mask has a hydrophobic layer, which plays a role in preventing liquid splashing. The droplets and droplet cores are essentially particulate matter , mainly relying on electrostatic adsorption filter layer .

● respirator and medical surgical masks have liquid barrier requirement, so there will be a hydrophobic layer functions as a barrier blood, body fluids, spatter.

●  Normal N95 / KN95 has no liquid barrier requirements, but it can also effectively block droplets, and the effect is better than medical surgical masks .

●  A mask with only a hydrophobic layer but no particle filtration efficiency requirements can be waterproof, but the barrier effect of droplets cannot be determined .