Long Live! the Doomsday Poison Is Oxygen?

In 3038, a meteorite fell, radiation filled the air, and the entire world became a wasteland. Human beings have mutated, the surface is full of poisonous gas, and they are lingering in underground cities. They can only fish in a limited area of activity and consume limited resources. Dou Che, who traveled to the shelter, joined the surface exploration team for the sake of his missing relatives. "Remember! The surface of the earth is full of highly toxic oxygen. Even with the latest filter, you can only be exposed to it for three hours!" Oxygen? You should have told me earlier! As a result, Dou Che became the only person in the vast wasteland who could walk freely on the surface. A supermarket twenty kilometers away? Okay, ten electromagnetic rifles for one pound of rice is not too much, right? A gas station a hundred kilometers away? Just exchange a ton of fusion fuel rods for a liter of gasoline. Beauty, this is the legendary chocolate, and these few gold coins... It's useless for you to thicken it, I'm a serious businessman! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.