atmosphere · noun /ˈæt.mə.sfɪər/
atmosphere (FEELING)
B1 no plural the feeling which exists in a place or situation
Dictionary examples:
There's a very relaxed atmosphere in our office.
There has been an atmosphere of gloom in the factory since it was announced that it would be closing.
Learner example:
You'll also love the friendly atmosphere here. (Preliminary English Test; B1; Swiss German)
the atmosphere
B2 the mixture of gases around the Earth
Dictionary example:
These factories are releasing toxic gases into the atmosphere.
Learner example:
I'm against cars because their CO2 emissions destroy the atmosphere. (First Certificate in English; B2; Spanish)
atmosphere (AIR INSIDE)
B2 no plural the air inside a room or other place
Dictionary example:
The atmosphere in the room was so stuffy I could hardly breathe.
Learner example:
The atmosphere in the halls also became hot and humid, thus making the whole experience rather unpleasant. (First Certificate in English; B2; Chinese)