effluvium

effluvium
    n 1: a foul-smelling outflow or vapor (especially a gaseous
         waste)
    

Effluvium \Ef*flu"vi*um\, n.; pl. {Effluvia}. [L., a flowing
   out, fr. effluere to flow out. See {Effluent}, a.]
   Subtile or invisible emanation; exhalation perceived by the
   sense of smell; especially, noisome or noxious exhalation;
   as, the effluvium from diseased or putrefying bodies, or from
   ill drainage.
   [1913 Webster]
    

48 Moby Thesaurus words for "effluvium":
      afterdamp, aroma, aura, blackdamp, breath, chokedamp, cloud,
      coal gas, damp, definite odor, detectable odor, ectoplasm,
      ectoplasy, emanation, essence, exhalation, exhaust, exhaust gas,
      exteriorized protoplasm, fetid air, firedamp, flatus, flavor,
      fluid, fragrance, fume, malaria, mephitis, miasma, odor,
      puff of smoke, redolence, reek, savor, scent, smell, smoke, smudge,
      spoor, steam, stench, subtle odor, trace, trail, vapor, volatile,
      water vapor, whiff