[Alpha Kodiak]

It seems to me that on a methane or hydrogen atmosphere world, an oxygen source would essentially be the "fuel" for the fire, so your cigarette lighter would contain some sort of oxygen producer to allow a flame. As to percentages of gasses in the atmosphere, remember that the largest component of our atmosphere is actually nitrogen, which is inert. On a methane world, chances are that any quantity of oxygen, or any other reactive gas would already have been "burned" into a non-reactive compound. I realize that I am using terms loosely from a pure chemistry standpoint, but you get the idea.