The apparatus 1 further comprising {HEAD ~ an outlet filter} immediately before the outlet for purified air to remove a majority of particles in {TAIL ~ the air stream} of the apparatus 
The apparatus 1 further comprising { HEAD ~ an outlet filter } immediately before the outlet for purified air to remove a majority of particles in { TAIL ~ the air stream } of the apparatus
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH