How do you calculate relative humidity from actual humidity?

Answer 1

Answer

actuall humidity is given as the amount of water. use a table stating how much water the air can hold at the given temp, this is your 100% humidity. now calculate howw much you got and that would be relative humidity

Answer:

To calculate relative humidity you need a wet bulb and a dry bulb thermometer and a psychrometric chart (a graph of the physical properties of moist air at a constant pressure). The chart graphically expresses how various properties relate to each other.

• Using an ordinary thermometer you read the dry bulb temperature(DBT). You will locate this temperature on the x-axis of the chart.
• Next you will determine the wet bulb temperature (WBT) from a thermometer who's bulb is covered with a wet wad of cotton and typically waved in the air until the temperature goes to its minimum. This works because dry air evaporates water and evaporation cools the wad. The temperature it reaches is related to the air's humidity. This value goes on the curved line at the top of the chart.
  
• The relative humidity (RH) is read off the chart from the intersection of the lines from these two points.

Answer 2

Relative humidity is calculated by taking the actual humidity (specific humidity or mixing ratio) and dividing it by the saturation humidity (maximum amount of water vapor the air can hold at a given temperature) then multiplying by 100 to get a percentage. The formula is: relative humidity = (actual humidity / saturation humidity) * 100.

Answer 3

You don't.

Humidity and temperature are not the same thing. Humidity will change with temperature however. The hotter the air is the more moisture it can hold, at 100% humidity the air can hold no more moisture. let's say it is 20C and 100% humidity. If the temperature then climbs to 30C the humidity will drop as the air's capacity to hold moisture has increased.

Answer 4

Relative humidity is the ratio of the actual humidity and the humidity when the air is saturated with water vapor. One way to measure relative humidity is with a psychrometer. A psychrometer is an instrument that uses the difference in readings between two thermometers, one having a wet bulb and the other having a dry bulb, to measure the moisture content or relative humidity of air. When air is saturated, the bulbs have the same temperature. When it is less than saturated, the moisture around the wet bulb evaporates, cooling the wet bulb until it is cooled to the temperature where the concentration of water vapor in the air would saturate air at that temperature.

Answer 5

You must have another piece of information (in addition to temperature), to compute relative humidity. The other piece of information can be dew point, specific humidity, vapor pressure, heat index, or wet bulb (vs dry bulb) temperature, or dry bulb (vs wet bulb) temperature. The formulas for computing these values are part of the field known as psychrometrics, and note the spelling-- psychro (with an "r"), not psycho

Answer 6

The heat index is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived temperature. The actual equation for the heat index is Heat Index = -42.379 + (2.04901523 x T) + (10.14333127 x R) - (0.22475541 x T x R) - (6.83783x10-3 x T2) - (5.481717x10-2 x R2) + (1.22874x10-3 x T2 x R) + (8.5282x10-4 x T x R2) - (1.99x10-6 x T2 x R2) In this equation T = Temperature in F and R = Relative Humidity in %.

Answer 7

Dew point is calculated by how much moisture and humidity is in the air. The dew point is calculated with a barometer.

Answer 8

If H = relative humidity,

T = air temperature in degrees C, and

D = dew point in degrees C,

H = e^(17.27 * (T * (237.7 + D) / (237.7 + T) - D) / (D - 237.7))

Answer 9

mass of vapour pressure(g)/mass of air(kg)