Spray creates a moister distribution (8)
I believe the answer is:
atomiser
'spray' is the definition.
(I know that spray can be written as atomiser)
'a moister distribution' is the wordplay.
'distribution' is an anagram indicator.
'moister' is an anagram of 'tomiser'.
'a'+'tomiser'='ATOMISER'
'creates' is the link.
(Other definitions for atomiser that I've seen before include "Device for making liquid into a fine spray" , "Spraying device - same riot (anag)" , "Dispenser for turning liquid into a fine spray" , "Perfume spray" , "Mister" .)