Please understand I do not want to come across as uncaring about your hearing, but you might be the one and only person to complain about lack of road/air noise.
I personally do not see this as an issue at all, because people always move out of the way of emergency vehicles and they have flashing lights. By observing your mirrors and surrounding, you will be able to see it coming
Our driver training here informs us to check our mirrors every 10 seconds. This way you always know what is going on around you.
As an after thought, your profile picture is of a motorcycle, I imagine you ride? Those are stupid loud, how do you deal with not hearing fire engines while riding that?