How long would the air on a dead world stay breathable?

[Agemegos]

Originally Posted by ericthered

How long does that take though?

Millennia, but not many. I once saw an estimate that the recovery time from the anthropogenic greenhouse effect was expected to be two thousand years. To get toxic effects from CO₂ you'd need a higher concentration than we expect from anthropogenic CO₂ releases, so it would take longer, but equilibration is presumably exponential, so not all that much longer.

And won't other processes be drawing the oxygen out of the air as well?

Presumably. I'm just saying that accumulation of CO₂ wouldn't be a persistent problem.

[DeadParrot]

Might matter if you are talking a "Age of Dinosaurs" or "Current Times" loss of life. Age of Dinosaurs only has to deal with biomass degenerating without the aid of any critters. Current times has the same problem plus all of the millions of gallons of chemicals and oil products normally kept in storage. Add in all of the nuclear power plants that might react poorly to loss of human supervision. By the time your space explorers arrive, possible there could be plenty of O2 but with deadly levels of radiation and toxic chemicals.