WordNet sense 1 (a particular environment or surrounding influence):

ambiance, ambience

WordNet sense 2 (the weather or climate at some place):

atmospheric state

WordNet sense 3 (a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade):

ATM, standard atmosphere, standard pressure

WordNet sense 4 (the mass of air surrounding the Earth):

air

WordNet sense 5 (a distinctive but intangible quality surrounding a person or thing):

aura