An atmosphere (atm) was a unit of measurement that describes the force exerted by the weight of air molecules in an atmosphere and is measured on Earth in pascals. One atm (standard atmosphere) was defined as 101,325 Pa. The Federation typically measured the atmospheric pressure of planets they encountered by relating to "Earth-normal." The atmospheric pressure of the habitats aboard the Nyrian biosphere vessel, encountered by USS Voyager in 2373, were kept at an Earth-normal atmosphere or one atm. (VOY: "Displaced")