Dust can hang in the air for hours after the last cut and be stirred up off the floor simply by walking across it. So you need to wear that PPE (personal protective equipment) all the time you are in the shop. Only way to work without PPE is with a very powerful system exhausting outside or through very good filters. My opinion of air cleaners is that you are filtering the air with your lungs until the air cleaner has done its job. Entirely your choice as to what extent you take to handling the dust.