https://cs2.paradoxwikis.com/Pollution#Air_pollution
Air pollution lowers the citizens' health if near residential zones. Air pollution travels with wind direction and expands and dilutes as it mixed with unpolluted air. Rain will reduce air pollution.
Air pollution it is caused mainly by traffic and industry, with the exception of farming and forestry specialized industry. It is also caused by other polluting buildings, such as fossil-fuel power plants and garbage management buildings, which have an area around them they will pollute. Even if the source of the pollution is removed, it will take some time for the air pollution to disappear. If non-polluting buildings have uncollected garbage for a long time, they will also pollute the ground. Sewage water can also cause air pollution, especially near the outlet or treatment plant.
留意有臭味,都當空氣污染...