Question

How would I convert relative humidity to specific humidity? The variables I have are vapor pressure, air temperature, and relative humidity.

Answer #1

We know that

Relative humidity can be defined as the ratio of vapour pressure
of water (at a temperature and pressure) to the vapour pressure of
gas over water φ = p_{w} / p_{ws} 100%

specific humidity can be defined as the ratio of the mass of
water vapor in air to the total mass of the air ans water vapour
x_{s} = 0.622 p_{ws} / (p_{a} -
p_{ws})

Where

φ = relative humidity

x_{s} = specific humidity of air vapor mixture
(kg/kg)

ρ_{ws} = density of water vapor

ρ = density of the moist or humid air

we have air temperature , vapour pressure and relative humidity

φ = p_{w} / p_{ws}

x_{s} = 0.62 p_{ws} / (p_{a} -
p_{ws})

so on rearranging we may say that

x_{s} = 0.62 φ ρ_{ws} / (ρ - ρ_{ws})

The relative humidity of air equals the ratio of the partial
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vapor pressure of water at 68 oF is 17.54 torr. The answer is 20,...

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On a hot summer day in Washington, D.C., the temperature is
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______kg

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Imagine a 2000 ft^(3) of an air-water vapor mixture at 14.7 psi,
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B. Dew Point in Fahrenheit
C.Mass of Air
D. Mass of Vapor
E. Saturated Pressure for the water vapor in the mixture.
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G. Partial Pressure for Dry Air
H. Mass of dry air
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J. Entalphy of saturated Vapor in BTU/lbm

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