[[Humidity unit conversions]], [[Humidity, wet bulb, and dry bulb temperatures]] Reference - [engineering toolbox](https://www.engineeringtoolbox.com/relative-humidity-air-d_687.html) [[relative_humidity_wet_dry_bulb_temperature.pdf|Chart - Relative humidity from wet and dry bulb temperatures]] ## Relative humidity >[!Definition] > Quantity of water in air relative to the capacity of air to hold water ### Relative humidity by pressure Relative humidity = $\frac{p_w}{p_{ws}}*{100\%}$ where $p_w$ = water vapor partial pressure (mbar, psi, atm) and $p_{ws}$ = water vapor saturation pressure (mbar, psi, atm) ==at a specific dry bulb temperature== ### Relative humidity by mass Relative humidity = $\frac{m_w}{m_{ws}}*{100\%}$ where $m_w$ = mass of water in the given volume of air (kg, lb) and $m_{ws}$ = mass of water required to saturate the given volume of air