Have you heard about disposable respirators? You should rest assured that these would be no different than N95 Mask Singapore. They would be able to filter and block the dirt, iron ore, coal, dust, and flour. You should rest assured that other materials of similar kind would also be able to block you out.
It would also be pertinent to mention here that sicknesses such as tuberculosis and flu could be avoided when you come across these disposable respirators in a proper manner. You would be given the additional benefits, disposal respirator, where you would have a built-in respirator that comes with it.