Lunar Settlement Artificial Atmosphere
The lunar colony will have a pressurized selection of acceptable gaseous environments. There are three main types of artificial atmospheres used in Space.
We have long exposure experimental knowledge with certain Artificial Atmospheres. On the Moon, the atmosphere will be made in accordance with the architecture followed.
Gas Combination Atmospheres
A combination of inert(s) gases with Oxygen would allow normal life and proper oxigenation. An example: air in normal conditions: a mix of 80% nitrogen and 20% oxygen. The Moon does not have any trace of Nitrogen; therefore, this gas would be imported from Earth representing an extended payload to be transported to the Moon. [1]
Lower Pressure Atmospheres
Plants [2] and Humans can live in lower pressure atmospheres. Extreme low atmospheres can cause the boiling of body fluids.