The paper style dust masks are garbage so don't use them unless they have a vent on the front and have a metal band where the nose fits so you can mould it to fit snug across bridge of the nose and will eliminate glasses fogging but I personally never use that style. If they cause your glasses to fog it also means you are breathing in the stuff you really shouldn't be breathing in. I use the silicon rubber style with the replaceable cartridge and depending on what I am doing depends on what cartridge I use and what pre filter is placed on the end. Silicosis is when you inhale silica and is the reason we had to change most of our grinding wheels at work due to their silica content. You should also always use a dust mask when using angle grinders, especially when using a cut off wheel as they are held together with fibre glass which is just as bad as asbestos when inhaled.