Spread out to clear the air broadcasting on top of Derryclare (8)
I believe the answer is:
diffused
'clear the air broadcasting on top of derryclare' is the definition.
I can't tell whether this definition defines the answer.
'spread out to' is the wordplay.
'spread out' becomes 'diffuse' ('diffuse' can be a synonym of 'spread out').
'to' becomes 'd' (I can't justify this - if you can you should believe this answer much more).
'diffuse'+'d'='DIFFUSED'
Can you help me to learn more?
(Other definitions for diffused that I've seen before include "Scattered; spread" , "Spread or sent out in all directions" , "Widely spread" , "Spread over a wide area" .)