A group of researchers from Duke University experimentally determined which protective masks are the most reliable. According to experts, the greatest effectiveness was shown by N95 standard respirators, usually used by medical professionals. Three-layer surgical masks and cotton masks, which are easy to make at home, protect you from viruses almost as well. The results are published in the journal Science Advances.
Tightened control over the wearing of personal protective equipment and a shortage of materials for their production have led to the widespread use of alternative masks, in particular homemade ones. Scientists tested 14 of the most popular types of protective accessories. To do this, they sprayed aerosols through the fabric, and then using a laser and a mobile camera recorded the amount of emissions entering the environment during the conversation. For the accuracy of each model was tested for ten times.
The best result was shown by tightly fitting face masks of the N95 type – not all models, but only those that do not have a built-in valve. It turned out that in the presence of the latter, others are more at risk. Also high protection is provided by surgical respirators and masks made of combined materials that provide additional filtration.
The most useless were cloth bandages and bandanas. Moreover, the fleece gaiter masks used by runners are considered dangerous. These protective accessories not only do not block saliva drops, but also contribute to their fragmentation. In other words, passing through the mask, the saliva breaks down into smaller particles that are easier to transport through the air. Researchers note that such masks are only effective against dust and exhaust gases.