Refers to gas, steam, or fumes emitted from volcanoes, hot springs, or industrial sources. Often used in geological or environmental contexts.
Volcanic gas sometimes contains toxic fumes.
White steam was rising from the fumarole.
fumarole · blowhole (of a whale, etc.)
Compound of 噴 (ふん, 'spout, emit') and 気 (き, 'gas, air, spirit'). The term is transparently derived from its kanji components.