smog

Fog that has become mixed and polluted with smoke.

A form of air pollution produced by the photochemical reaction of sunlight with hydrocarbons and nitrogen oxides that have been released into the atmosphere, especially by automotive emissions.

A noxious mixture of particulates and gases that is the result of urban air pollution

To get a smog check; to check a vehicle or have it checked for emissions.

air pollution by a mixture of smoke and fog