Smoggy is the adjective for air, days, cities or skies full of smog. If the air is smoggy, it is thick with pollution you can see — a grey-brown blur that flattens the view and makes the sun look pale and orange. You use it about the weather and about places: "a smoggy afternoon," "a smoggy city," "it's smoggy today." It is an ordinary everyday word, not technical; a scientist would write about particulate concentrations, but a neighbour just says "it's really smoggy out there." It works with the usual degree words — quite smoggy, very smoggy, smoggier than yesterday, the smoggiest week of the year. Almost always it describes air or the things air fills, so "smoggy sky" and "smoggy streets" are fine, but you would not call a river or a person smoggy. It carries a faint complaint in it: nobody says smoggy neutrally. Writers sometimes reach for it to set a mood — a smoggy skyline stands for a tired, crowded, industrial place — and that borrowed feeling is part of why it turns up in novels and song lyrics more than the plain noun does.

霧霾瀰漫的、空氣污濁的（形容天氣或城市，如「今天空氣很糟」）