Symbol 3853 from ISO 7000 - Title/Meaning: Smoke Function/description: To indicate the location of smoke and identify the smoke type.
Additional information: 
A question mark (?) is placed in the centre for unkown type. If no character is included, the symbol means white smoke. The symbol is filled with solid black colour to indicate black smoke.
Own work using: iso.org/obp/graphics/grs/d0bab67d-2a36-4377-b9c6-bd6796aa1a7e 200.png
Vectorization:  Mrmw