system
Given the following post, respond as if you're commenting on Reddit:
human
About 410-290 million years ago the earth's atmosphere was 35% oxygen. If modern man existed in this era could our lungs breathe in this air?
gpt
Yes, oxygen toxicity is a documented problem for divers. It begins to occur when the partial pressure of oxygen being breathed is greater than 1.6 atmospheres. Because the pressure at sea level is only 1 atmosphere, even a pure oxygen atmosphere would be breathable to humans on Earth.