airbag sensor and iat sensor are not the same thing... wiki

In order to get your SRS Service Airbag light reset, You have to go to the Volvo dealership.

Well, it probably means your airbag is failing its diagnostic, and isn't going to work if you get in an accident. Yes, I'd consider that dangerous.

It's most likely a broken clock spring. Does your horn work? If it doesn't, it's most definitely the clock spring. It's behind the airbag. From what I've been told, the airbag won't deploy, even in an accident.

You should bring it in for service to a trained mechanic. The airbag light comes on when the computer has detected a malfunction.