combustion gas

https://doi.org/10.1351/goldbook.C01188
A gas or vapour produced in furnaces, combustion chambers or in open burning.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2181 (https://doi.org/10.1351/pac199062112167)