|WHAT IS HUMIDITY? -TYPES OF HUMIDITY|
It is a term that everyone uses, but technically speaking, not always accurately. We sometimes assume air is at high humidity when we are uncomfortably warm. Sometimes we are not aware of high humidity when the air is cool around 70°F.
Personal comfort varies depending on one’s health, clothing, activity level as well as the air conditions and velocity around a person.Humidity refers to the content of water vapour present in the gaseous form at a particular time and place.It is measured by Hygrometer.
It refers to the capacity of an air of certain volume at certain temperature to retain maximum amount of moisture content.It is directly related with temperature i.e., higher the temperature, higher the humidity capacity and lower the temperature lower the humidity capacity.
TYPES OF HUMIDITY
The total weight of moisture content (water vapour ) per volume of air at definite temperature is called absolute humidity.It change with the change in temperature. So it decreases from equator towards poles and from oceans to the continents.
It is defined as the mass of water vapour in grams contained in a kg of air and it represents the actual quantity of moisture present in definite air.
It is expressed as a measure of the amount of water vapor the air contains as a percentage of the total amount it could contain at a specific temperature. If you think of air as a paper towel for a moment, it can only hold a specific amount of water at a specific temperature. However, unlike a paper towel, the total amount of moisture the air can hold changes as the temperature changes. As the air becomes warmer, it can hold a greater mass of moisture.
Consider this example of how the relative humidity changes as temperature changes with indoor air at 75°F and 60% RH. If this air cools down (not from an air conditioner) to 70°F, the air can no longer hold as much moisture, however the actual amount in the air has not changed, so it increases to about 70%.
SATURATED AIR The air having 100% relative humidity is called saturated air
DEW POINT The temperature at which an air becomes saturated is called dew point.