Masks have played an important role in preventing the spread of covid-19. However, a recent study of DIY products does not provide adequate protection. With a surge of new coronavirus infections in nearly 12 states across the United States, this is a wake-up call for people who don’t pay attention to social distance and personal protective equipment. Robert Redfield, director of the U.S. Centers for Disease Control and prevention, said earlier: in terms of the prevention effect of the new coronavirus, wearing masks is more effective than vaccination, not to mention the efficiency of the first batch of vaccine products on the market may be less than 50%. During a recent Senate hearing, the director of CDC once again publicized the effectiveness of masks, saying that there was a clear scientific proof of the effectiveness of masks. Of course, the premise is that you wear a medical surgical mask that meets the standard, instead of using ordinary cloth to make your own. < p > < p > a study by the University of California found that the popular homemade cloth masks of the past few months have not been as effective as they should have been in reducing aerosol particles carried out between breathing and speaking. In all test scenarios, medical surgical masks and N95 masks were able to block up to 90% of particles and reduce the spread of airborne particles, compared with those without masks. < / P > < p > the embarrassment is that homemade masks can cause people to inhale more particulate matter than do not wear masks, because cotton masks themselves produce particles (tiny fabric fibers). Even if it can block some of the larger particles, it is difficult to judge whether it can block the exhaled particles. < / P > < p > to sum up, if you have already worn a mask without any trouble, please also make sure that the material is valid. Even if you can’t buy N95 specifications, you can at least buy a package of ordinary medical surgical masks in retail chains such as target. Global Tech