this is the real reason Tung Chung is so bad and why DB is usually alot better.
How does pollution circulate in the Pearl River Delta?
The pollution rises from everywhere, then it moves toward the cooler air over the Pearl River Estuary, then it falls and spreads out. This is why the Western New Territories and the Tung Chung area are especially polluted.
Pollution Circulation Pattern in the Pearl River Delta
Hong Kong University of Science and Technology