Định Nghĩa và Ý Nghĩa của "[be] in the air"

What is the origin of the idiom "be in the air" and when to use it?

The phrase "be in the air" is an idiom used to convey that a particular feeling, atmosphere, or sense of anticipation is present or noticeable. The origin of this phrase is not precisely documented, but it likely draws from the idea that changes in the air, such as shifts in weather, can be sensed.