What will help one see small particles on the air (5)
I believe the answer is:
specs
'what will help one see' is the definition.
'small particles on the air' is the wordplay.
'small particles' becomes 'specks'.
'on the air' shows a homophone (sound like).
'specks' is a homophone of 'SPECS'.
(Other definitions for specs that I've seen before include "Do they help one to see" , "what builders are doing?" , "you can see right through them" , "Glasses (sl.)" , "provider of focus" .)