Calculate absolute humidity

Calculate absolute humidity \(\rho_v\) (kg/m³) from vapor pressure \(e\) (Pa) and temperature \(t\) (K).

Usage

cal_absolute_humidity(e, t, t_unit)

Arguments

e

Numeric. Vapor pressure in Pascal (Pa).

t

Numeric. Air temperature in Kelvin (K), degree Celsius (°C), or degree Fahrenheit (°K).

t_unit

Character string. Unit of the temperature value. Must be one of "celsius", "fahrenheit", or "kelvin".

Value

Numeric value of absolute humidity in kg/m³.

Details

Absolute humidity \(\rho_v\) (kg/m³), or density of water vapor, is the mass of moisture per total volume of air. It is calculated using the formula:

$$\rho_v = \frac{e}{R_v \cdot T}$$

where \(e\) is vapor pressure (Pa), \(T\) is air temperature (Kelvin), and \(R_v\) is the specific gas constant for moist air (487 J·kg⁻¹·K⁻¹).

The temperature input is converted to Kelvin based on the provided t_unit before calculation.

References

Davis, Robert E., Glenn R. McGregor, and Kyle B. Enfield. “Humidity: A Review and Primer on Atmospheric Moisture and Human Health.” Environmental Research 144 (January 2016): 106–16. https://doi.org/10.1016/j.envres.2015.10.014.

Examples

cal_absolute_humidity(e = 1200, t = 25, t_unit = "celsius")
#> [1] 0.008264517
cal_absolute_humidity(e = 1200, t = 298.15, t_unit = "kelvin")
#> [1] 0.008264517