Re: I smell like a urine...

It might be that the smell is there all the time, but you only notice it during a change of temperature or air quality. I have BB, and the smell is coming from back of tongue, sinuses etc. I also notice funny smells when going from indoors to outdoors, or when entering an elevator etc, so you could have the same problem. It's like you get used to the smell, but then alerted to it when changing environment...
You can find out everything about BB at this forum:

http://health.groups.yahoo.com/group/BreathHelp4U/

Or it might have other causes. Anyway, I notice the same thing, so if you find something out, let me know :->

/Karl Tweet