Air current passes through workers (4)
I believe the answer is:
mien
'air' is the definition.
(thesaurus)
'current passes through workers' is the wordplay.
'current passes' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'through' is an insertion indicator (I've seen this in other clues).
'workers' becomes 'men' (man is a kind of worker).
'i' placed into 'men' is 'MIEN'.
Can you help me to learn more?
(Other definitions for mien that I've seen before include "attitude" , "Facial expression sounds miserly" , "A countenance like mine" , "(One's) manner, bearing" , "The carriage" .)