Dead rising 2 how to stop the green gas?

Ok i have just completed the game on the PS3 it was a good game and some good twists near the end :) but the really annoying thing is that the green gas that makes some of the zombies faster and stronger and spit blood at you is very annoying is there some way to get rid of the mutated zombies or turn of the gas so it dose not make any more of them. as i don't like the green haze it leaves over everything and the mutated zombies are ruining the fun of been able to kill and humiliate the normal zombies as im too buys trying to run away from the mutated ones as they can kill you quite fast. so please if you know how to stop the gas or how to get rid of the mutated ones please let me know thanks :)