BFE and differences between type I and type IIR surgical masks

What is the bacterial filtration efficiency (BFE) of surgical masks?

The surgical masks are intended to avoid that the wearer contaminates the environment. They are made of a multilayer fabric: the first one, made of propylene, filters out the bigger particles; the second one, made of TNT, filters fine dust; the third layer, finally, is made of a high-coverage trilaminate propylene non-woven fabric.The bacterial filtration efficiency (BFE) of surgical masks is almost totally to protect the people around the wearer (it filters more than 95% of bacteria spreaded by the wearer), while is very scarce, about 20%, when talking about the protection of the wearer from the outside bacteria. The surgical masks are not in fact able to protect the user from very fine particles such as viruses.

What is the difference between type I and type IIR disposable surgical masks?

The type I disposable surgical masks must be worn by infected people, anyone who thinks was infected, or whoever is in contact with infected people. They act as a barrier against the liquid droplets (aerosol) contained in the exhaled air, limiting the spread of potentially infectious particles. The effectiveness of bacterial filtration of type I masks is 95% and that of type IIR is 98%. This is because the disposable surgical masks of type IIR are able to offer greater protection than type I. The type IIR masks protect, in fact, also from splashes of contaminated biological material, as well as from aerosols contained in exhaled air. They are generally used in health care by medical personnel to perform daily tasks.