The University of Tokyo did a recent study to measure the effectiveness of face masks that prevent the spread of the coronavirus. For this, the researchers created an infection simulator in an air chamber, where they put two mannequin heads facing each other. The first one never wears a face mask and has a nebulizer that continuously discharges virus particles against the other person. The manikin that receives the particles, which operates with a ventilator that mimics human respiration, was given three different tests: 1) with a cloth mask, 2) with a surgical mask, 3) with an N95 respirator. The result was that with cloth masks the absorption of the virus was reduced by 40 percent. With the surgery mask, that figure reached 50 percent. But with the N95 Respirator, the reduction reached 90 percent.