Cleaner air can't be found here (6)
I believe the answer is:
vacuum
'cleaner' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for vacuum that I've seen before include "Emptiness" , "Area empty of matter" , "A region empty of matter" , "Space entirely devoid of matter" , "Space empty of matter" .)