What is the concept of humidity? What is the normal humidity range

The less water vapor is contained in a certain volume of air at a certain temperature, the drier the air; The more moisture, the more humid the air. The degree of wetness and dryness of the air is called "humidity".

Normal humidity ranges between 40% and 60%. Air humidity indicates how dry the atmosphere is. If the humidity is too low, the person will feel dry; If the humidity is too high, the person will feel damp.

People will be more comfortable at 40% to 60% humidity. When the humidity is greater than 65%, the multiplication rate of microorganisms will be significantly accelerated, and the person will also feel sluggish and lack of energy. Maintaining the right air humidity is not only comfortable but also good for your health.

Variation of humidityThere are many factors that affect absolute humidity, mainly depending on the water vapor, the ability of the air to transport and retain water vapor, etc. Therefore, factors that affect water vapor such as precipitation, the presence of water bodies, soil moisture levels and evaporation conditions, conditions that affect water vapor transport such as wind, vertical airflow, etc., and conditions that affect the ability of air to retain water vapor such as air temperature, etc., may affect absolute humidity.

In general, the absolute humidity of tropical ocean air masses is higher than that of polar ocean air masses; At the same latitude, the areas affected by the oceanic air mass were more humid than the areas controlled by the continental air mass. The absolute humidity of the year is higher than the rainy season than the dry season. The variation of absolute humidity in a single day was the largest in the afternoon and the smallest in the early morning in the coastal areas and autumn and winter, showing a unimodal variation. For other areas, it is mostly bimodal, with two highs appearing at 9 10 o'clock and around sunset, and two lows appearing before sunrise and in the afternoon.

Generally speaking, a humidity between 40% and 60% is a good indication of how dry the atmosphere is.

In 2003, China announced the indoor air quality standard, and the air humidity should be 40%-80% when cooling in summer; In winter, heating should be controlled at 30%-60%. The suitable room temperature for the elderly and children is 45%-50%; For patients with respiratory diseases such as asthma, the most suitable room temperature is between 40% and 50%.

Factors influencing humidity

First, the amount of water vapor.

The water vapour in the air mainly comes from precipitation and evaporation from the underlying surface. Factors such as precipitation, water area, evaporation conditions, soil moisture content, vegetation coverage, and conditions affecting water vapor transport such as wind and vertical airflow will affect humidity.

2. Temperature - determines the maximum amount of water vapor that the air can hold.

The higher the temperature, the higher the amount of water vapor that the air can hold, so humidity must be related to temperature.

Absolute humidity is positively correlated with air temperature. Because under the same moisture conditions, when the temperature is high, the evaporation is fast, and the water vapor entering the atmosphere is more, and the absolute humidity is greater (the actual water vapor pressure is also large).

When the water vapor content is constant, the relative humidity is negatively correlated with the air temperature. Because the water vapor content does not change, the actual water vapor pressure does not change, and when the temperature is high, the saturated water vapor pressure is high, and the relative humidity is small.

Difference Between Absolute Humidity and Relative Humidity:

1. Absolute humidity refers to the amount of water vapor contained in a unit volume of air; In gram beams.

2. Relative humidity refers to the ratio of the actual water vapor content in the air to the saturation value water vapor content at a certain temperature, expressed in percentages.

3. Absolute humidity will not change with temperature and climate change, but relative humidity will change qualitatively with the increase of temperature and the decrease of temperature, usually the relative humidity will decrease with the increase of temperature.

4. The maximum amount of water vapor that can be absorbed by air with an absolute humidity of 1 cubic meter is called the maximum humidity or saturation point, and the maximum humidity depends largely on the temperature.

5. Absolute humidity refers to the density of water vapor in the air, and the weight (g) of water vapor in 1m air is expressed. The water vapor content is high, and the absolute humidity of the air is high. There is a limit to the amount of water in the air, and when it reaches its maximum capacity, it is called the saturated water vapor content.

Extended Material: Absolute Humidity].

It is the mass of water vapor contained in a unit of air, which is a physical expression of the degree of dryness and wetness of the atmosphere, usually expressed in grams of all water vapor in 1 cubic meter. Since the pressure of water vapor increases with increasing density, the absolute humidity segment of the air can usually be expressed as pressure.

Relative humidity is the percentage value of the actual water vapor density contained in the air and the saturated water vapor density at the same temperature. There is a relationship between the degree of dryness and wetness in the air and the amount of water vapor contained in the air that is close to saturation, while the absolute amount of water vapor in the air is not directly related to the amount of water vapor contained in the air.

Water vapor] Abbreviated as water vapor, it is a gaseous form of water (H2O), which turns into water vapor when it reaches its boiling point. At one standard atmosphere at sea level, the boiling point of water is or 212°F. Water can also slowly evaporate into water vapor when it is below the boiling point.

In a very low pressure environment (less than atmospheric pressure), ice will directly sublimate into water vapor. Water vapor may contribute to the greenhouse effect and is a type of greenhouse gas.