Writing a sci-fi story, thinking of making the alien species ammonia-based. Obviously there are problems with that. On Earth, ammonia is a liquid under cryogenic temperatures. I think -28 degree Farenheit is its boiling point. Obviously, this is too cold for a human to survive for very long without some kind of really, really good thermal wear or some kind of environmental suit, both of which I was hoping to avoid. The other option I have, which would allow ammonia to be a liquid at more normal, room temperatures, is to simply increase the atmospheric pressure of the planet they're on. However, my research says that ammonia's boiling point is at 70 degrees under 128.8 psia. Normal Earth air pressure at sea level is 14.7 psia. So my two problems there is figuring out how many atmospheres a planet would need to have, to have a sea level pressure of 128.8 psia. I'm terrible at math, as you have probably figured out. THEN, what I need to figure out is if a human can even survive in 128.8 psia. It sounds a bit ... extreme. Then again, I do know deep sea divers acclimate to much higher pressures, but they can only breathe properly if they change their oxygen mixture. Requiring my human character to have a supplementary breathing apparatus in this story is a possibility, but I still don't know if any of this is possible. Can you guys help me out?