how to calculate ppm from partial pressure

Use Equation 2 or 3 below (or Equation 4 or 5) to calculate dew or frost point temperature from vapour pressure (requires iteration if using Equations 4 or 5).

Use Equation 1 to calculate water vapour pressure from saturation vapour pressure and known relative humidity.

Use Equation 2 or 3 below (or Equation 4 or 5 for greater accuracy) to find the saturation vapour pressure from ambient temperature.To convert from relative humidity and ambient temperature to dew point Use these values of vapour pressure in Equation 1 to find relative humidity.

Convert dew-point temperature and ambient temperature into water vapour pressures using Equation 2 or 3 below (or Equation 4 or 5 for greater accuracy).To convert from dew point or frost point to relative humidity Conversions between these two parameters must be carried out via the intermediate step of evaluating both the actual vapour pressure of water and the saturation vapour pressure at the prevailing temperature. Unfortunately, there is no simple, direct formula for converting between dew point and relative humidity. Relative humidity (in %) = e/ e s × 100 (Equation 1) The relative humidity is the ratio of the amount of water vapour, e, in the air to the amount of water vapour, e s, that would be in the air if saturated at the same temperature and pressure. Where the condensate is ice, this is known as the frost point. The dew point, or dew-point temperature, is the temperature at which dew, or condensation, forms as you cool a gas.

How to calculate ppm from partial pressure