Fresh air - and that's essential for a man (6)
I believe the answer is:
adrian
'for a man' is the definition.
(I've seen this before)
'fresh air and' is the wordplay.
'fresh' indicates anagramming the letters.
'air'+'and'='airand'
'airand' with letters rearranged gives 'ADRIAN'.
'that's essential' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for adrian that I've seen before include "The Secret Diary of ... Mole, Aged 13? (Sue Townsend)" , "Name of Roman emperor and only English pope" , "Sir -- Boult, conductor" , "Man" , "-- Mole, Sue Townsend's creation" .)