Since Federation starships were kept at 1 atm, the atmosphere of a Borg cube was therefore kept at just over 103 kilopascals, or approximately 1.02 atm.
Warp core pressure aboard Starfleet ships was measured in kilopascals. Upon being pulled into the Delta Quadrant, the USS Voyager's warp core pressure was down to 21 kilopascals. Upon unlocking the magnetic interlocks, they were able to increase it to a stable rate of 25 kilopascals. (VOY: "Caretaker")
The pressure encountered from the leading edge of shock waves encountered by the USS Voyager following the explosion of a supernova was over 90 kilopascals – over 30% higher than predicted. (VOY: "The Q and the Grey")