Ya sorry, that was my doing on the other forum about the atomic breath. I'll go into more detail...
If I were charged of making Godzilla as realistic as possible and then had to tackle the fact that this 300+ Foot animal had to breath some sort of fire I would do this...
I would make his Atomic Breath literally just that, a really intense wave of heat that comes out of his mouth like a nuclear vent. It would transparent but anything behind it would be distorted. (Like jet exhaust or heat waves off in the distance on a highway) Then I would give it the blue/orange tint. Anything that his breath would touch would instantly be immolated where there is NO chance of survival if you are caught in it. This way he still has the trait and it isn't him just shooting out fire like some cliche fantasy dragon.
Of course the easy thing to do is to use what has always been used. However you can argue in the first two movies, it has misty/breath quality to it. Then it has evolved from a blue blow torch to death star beams in later movies. It was just a guess at how it might be presented in the movie. I can't imagine it won't be in the movie since it is such a staple of Godzilla and it would be an asterisk on the movie if they don't put it in.
(I tried to Photoshop what I was talking about to the best of my ability aka 5 minutes of work)
http://i.imgur.com/rvSal80.jpg?1http://i.imgur.com/DOG3LNf.jpg?1Not exactly what I had in mind but you get the idea. I would want it to pop a little more or a little bit more glowing and maybe emphasis the heat wave more.