I lived on Russell Island for 6yrs and the sea air does have a impact on cars. Takes a while but all you have to do is hose it down every month or so to wash away the salt from the air that gets under and around the car because once they start to rust, it spreads quickly.
Mozzies and Midgees, aka sanflies. Theres plenty of them, thousands even. No avoiding them as Islands are small and close to waters all round so heaps of the little critters everywhere. I had to use coils or spray myself all the time while outside.