Relative humidity is the ratio of the actual amount of water vapour in the air to the maximum amount of water vapour the air can hold;
Relative humidity(%)= Actual Amount of water vapour in the air(g/m³)/Maximum amount of water vapour the air can hold(g/m³) × 100
Relative humidity is measured using a sling psychrometer
When the air holds the maximum amount of water vapour the air can hold, the relative humidity is 100% and the air becomes saturated. The temperature at which saturation occurs is known as the dew point temperature. Condensation will occur at the dew point temperature.
Factors Affecting Relative Humidity
Amount of Water Vapour in the air
The more the amount of water vapour in the air, the higher the relative humidity
Since relative humidity is the amount of water vapour in the air divided by the maximum amount of water the air can hold, then it would be more humid if the amount of water vapour in the air increases.
Example, if the air can hold a maximum of 10g/m³ of water vapour, and that the air has 5g/m³ of water, the relative humidity would be 50%. If there is more water vapour in the air, example, the amount of water vapour in the air becomes 7.5g/m³, and that the maximum amount of water vapour the air can hold remains the same, then the relative humidity becomes 75%.
Temperature
The lower the temperature, the higher the relative humidity
Example, the amount of water vapour in the air is 15g/m³ and at a temperature of 35°C, the maximum amount of water vapour the air can hold is 30g/m³. Therefore, the relative humidity would be 50%. If the temperature drops to 15°C, and that the maximum amount of water vapour the air can hold drops to 20g/m³, then the relative humidity would increase to 75%
No comments:
Post a Comment