mephitic
Foul-smelling or noxious, particularly of a gas or atmosphere.
"I could have borne the sight of his crutch," said she, "but the crutch and the nephew together really oppress me like a mephitic vapour."
Where it comes from
From Latin mephīticus, from mephītis; compare French méphitique.
Adapted from the Wiktionary entry mephitic (CC BY-SA 4.0).