kPa. Otherwise it'd be Kelvinpascals. And while pressure is often said to be x atmospheres, they usually use bar, which is an SI-derived unit (equal to 10⁵ Pa), which is close enough to the old usage of atmospheres.
There seem to have been two different atmospheres that were pretty close anyway. One being defined as air pressure at sea level, the other being defined as the pressure of 10 meters of water.
There seem to have been two different atmospheres that were pretty close anyway. One being defined as air pressure at sea level, the other being defined as the pressure of 10 meters of water.