This O2 Filter (or called sometimes as Oxygen Filter) has the ability to lower the oxygen of the body it is on. While being quite slow, it has the advantage of not altering one of the other terraforming statistics. Levels beyond V are only reached through events.
"It's inelegant, but effective: a facility dedicated to simply filtering O2 out of the atmosphere and storing it in pressurized containers. From there, it can be shipped off-world, used for various industrial processes, or simply buried." - Ingame Description
Beginner Mode differs in time needed compared to Normal Mode. The Culture modifiers accounts to the total Biomass, Population, Credits, Research Time and/or Construction Time gained/lost for the buildings/research.
Normal & Expert Mode