There are many particles in the air. You do not know which will affect you, which may lead you to the dead. There is this new virus, CORONA VIRUS, causing mass death in different countries starting china. So people need to care about themselves. They should use a disposable mask to defend the primary attachment of the virus. You can be safe a bit with it. You can many qualities of this mask. If you are working on the exposed site, you should use the several layer mask. There are many other personal protective you have to use.