Suppose, In a room, Air is at 1 atm presssure. So should be the pressure of any water surface in the room. If the room temperature is cooled downed to dew point temperature, vapor (moisture) will start to condense at Tdp (dew point temp) and Pv (vapor pressure). In this phase changing process, the temperature and pressure of both saturated vapor and saturated liquid will be same and constant. (Tdp, Pv). So, the pressure of dew (saturated liquid) is Pv or 1 atm ? suddenly changes like jump discontinuity? what am I missing?