Answer:
Smog
Explanation:
Smoke plus fog becomes smog
which is fog or haze intensified by smoke or other atmospheric pollutants.
"exhaust emissions are mainly responsible for the smog"
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a contraction (portmanteau) of the words smoke and fog to refer to smoky fog due to its opacity, and odor.
