The Oxford Thesaurus An A-Z Dictionary of Synonyms - exhalationn.

1) expiration, exhaling, breath, respiration, suspiration: The doctor could detect the wheezing only on exhalation. 2) vapour, breath, air, puff, whiff, exhaust, emission, steam, mist, gas, fog, fume, emanation, effluvium, evaporation: Poisonous exhalations from vents on the side of the volcano had destroyed all vegetation.