Nateman’s Ark? Now there’s a blast from the past.
More like a cave supplied with a nuclear power plant for power and lights. You would have allot of noxious nitrogen oxide (smog) blotting out the sun. You have to have a means for spitting that air up again to make it breathable. (A cave is a nice place to stay warm. It's would get cold outside because not much light is hitting the ground anymore!)