1, the actual water vapor density per unit volume of air d 1 and the percentage of saturated water vapor density d2 at the same temperature, that is, RH = d1/d2x100%;
2. The actual air vapor pressure p 1 is the percentage of the saturated vapor pressure p2 at the same temperature, that is, RH= p 1/ p2 x 100%.
Extended data:
Application of relative humidity:
1, to prevent colds:
(1) Low relative humidity accelerates the reproduction of influenza virus and pathogenic Gram-positive bacteria, and spreads with dust, resulting in disease epidemic;
(2) Low relative humidity can reduce the resistance of human respiratory system and induce and aggravate respiratory diseases.
2. Protect the collection of paintings and calligraphy:
(1) When the relative humidity is lower than 65%, mold cannot develop normally.
(2) If the relative humidity drops below 45% for a long time, the paper will become brittle due to drying, resulting in physical decay. Therefore, maintaining the lower limit of relative humidity of 50% is a strict requirement for the preservation of calligraphy and painting.
Baidu encyclopedia-relative humidity