Absolute Humidity Calculator

Absolute Humidity Calculator:

Enter the values of partial pressure of water vapour, P_w(Pa),  universal gas constant, R_(J/mol.K) and temperature, T_(K) to determine the value of Absolute Humidity, AH_(g/m3).

Enter Partial Pressure of Water Vapour :		Pa
Enter Universal Gas Constant :		J/mol.K
Enter Temperature :		K
Result – Absolute Humidity :		g/m3

Absolute Humidity:

Absolute humidity (AH) is the measure of the amount of water vapour present in a given volume of air. It is typically expressed in grams of water vapour per cubic meter of air (g/m³) and represents the mass of water vapour in a specific volume of air. Absolute humidity is important in meteorology and various fields, including HVAC (heating, ventilation, and air conditioning), where controlling humidity levels is crucial for comfort and preventing damage to materials.

The formula for absolute humidity is based on the density of water vapour in the air. It depends on the temperature and the partial pressure of water vapour. As the temperature increases, the air’s capacity to hold moisture increases, leading to a higher absolute humidity. Absolute humidity can be measured using instruments like hygrometers or by calculating it from other related factors such as temperature and relative humidity.

The relationship between absolute humidity (AH) and temperature (T) is crucial in understanding the physical properties of air. For instance, higher temperatures allow air to hold more moisture, whereas cooler air leads to condensation as the moisture-holding capacity decreases.

Absolute Humidity, AH_(g/m3) in grams per cubic metres is calculated as the ratio of the partial pressure of water vapour, P_w(Pa) in Pascals to the product of the universal gas constant, R_(J/mol.K) in Joules per mole Kelvin and temperature, T_(K) in Kelvin.

Absolute Humidity, AH_(g/m3) = P_w(Pa) / R_(J/mol.K) * T_(K)

AH_(g/m3) = absolute humidity in grams per cubic metres , g/m³.

P_w(Pa) = partial pressure of water vapour in Pascals, Pa.

R_(J/mol.K) = universal gas constant in Joules per mole Kelvin,J/mol.K.

T_(K) = temperature in Kelvin, K.

Absolute Humidity Calculation:

1. Given: P_w(Pa) = 2.5Pa, R_(J/mol.K) = 8.314J/mol.K, T_(K) = 298K.

Absolute Humidity, AH_(g/m3) = P_w(Pa) / R_(J/mol.K) * T_(K)

AH_(g/m3) = 2.5 / 8.314 * 298

AH_(g/m3) = 1.008g/m³.

2. Given: AH_(g/m3) = 12.5g/m³, R_(J/mol.K) = 8.314J/mol.K, T_(K) = 298K.

Absolute Humidity, AH_(g/m3) = P_w(Pa) / R_(J/mol.K) * T_(K)

P_w(Pa) = AH_(g/m3) * R_(J/mol.K) * T_(K)

P_w(Pa) = 12.5 * 8.314 * 298

P_w(Pa) = 31066.7Pa.