Smoke and marine pollution here skinned smooth urbanite (4,7)
I believe the answer is:
city slicker
'smooth urbanite' is the definition.
(sophisticated or smooth city dweller)
'smoke and marine pollution here skinned' is the wordplay.
'smoke' becomes 'city' (smoke can informally mean a city).
'and' is a charade indicator (letters next to each other).
'marine pollution' becomes 'slick' (as in an oil slick).
'skinned' indicates the central letters.
The middle of 'here' is 'er'.
'city'+'slick'+'er'='CITY SLICKER'
(Another definition for city slicker that I've seen is " sophisticate".)