A concentration of 0.01 % co is lethal. how is it possible to smoke a cigarette and not die immediately?

Apples to oranges: Your concentration is looking at the measurement in the air that is being breathed. And it makes a great difference the concentration as it exists in the body. Obviously the amount delivered in cigarettes is less than immediately lethal. It does however attach to red blood cells and stays till they die reducing oxygen deliver to the tissues of the body.

Apples and oranges: A concentration of 100 parts per million (which is 0.01%) can be lethal, but smoking a pack of cigarettes gives us a concentration of 5-10 ppm, which is enough to harm our health but not enough to kill us. A single cigarette will produce a concentration of 0.05- 0.1 ppm, depending on how people inhale, hold it in, and the kind of tobacco.