You should provide more context, but I'll take a guess. If you read (or sense something in the air, that means that you sense or are aware of some condition or something that is likely to happen. "She read a sense of panic in the air." = She sensed that those around her were in a panicked state. "He read a sense of urgency in the air from those at the meeting." = He sensed from those in the meeting thought that the matter (whatever it was) was urgent.

I think you are trying to say "read on air", which refers specifically to something read on either TV or radio, during a program on either device. Here is an example of how it is used: "Today, it was read on air that the death total for american soldiers in Iraq was over 10 thousand."

Yes Liutingting, I think fd maxey has a good address of this. It is like saying that someone is using a "sixth sense" or an intuition. They are reading some message, as though they could "smell" it it the air. --Warm Regards, Bruce