Humidity and Relative
Humidity
Meaning
of humidity and difference between humidity and relative humidity, relative
humidity measurement methods and the units.
It
has been a topic of confusion to differentiate between humidity and relative
humidity. Relative humidity is an important factor that affects the quality of
pharmaceutical products. It is important to control the humidity in the areas
like granulation and compression.
Humidity
and relative humidity both measures the amount of water present in the air but
both of these have difference in the method of measurement.
Humidity
in air depends upon the atmosphere of the area and the season of the year. In
the dry areas as desert, humidity remains very low while in area near ocean and
rainforests it remains very high. It also remains higher in rainy season than
the summer. Air can hold a limited amount of moisture or water vapour. When
moisture increases above its limit, it turns into the droplets those are known
as fog.
Humidity is the
amount of moisture or water present in the air in the form of water vapours.
It is measured in grams of water in letter of air (mass/volume). It is
also known as absolute humidity.
Relative humidity is
the percentage of the moisture against the highest possible level of moisture
in the air at specific temperature. Relative humidity is measured higher on
lower temperature because cold air holds more water vapours than the warm air.
Relative humidity is measured by the hygrometer and also known as %RH.
Example:
If air of any area has half of the water vapours that it can carry then its
relative humidity would be 50%. 100% is the highest and 0% is the lowest value
of relative humidity that can be found in any area.
