I do a lot of remodeling, and I get into every kind of hazardous airborne particles you could imagine. There are times I have to use a respirator, but most of the time I just use a dust particle mask. I bought them by the cast and go through a half dozen or more a day. I thought they were the most feasible application, but over the years I noticed I had become a bit more sensitive to formaldehyde, fiberglass and the overall accumulation of unknown particles. I would put a foam strip on the nose piece to keep my breath from fogging up my goggles, and even an extra wrap to hold it on more snuggly. I have tried every type of mask on the market. They either just hung on my face like a cardboard box, clog up immediately or became saturated with moisture while breathing. Most were just way too expensive and over rated.