1) air temperature: temperature is an indicator of the degree of air heat and cold, and commonly used are Celsius temperature and Kelvin temperature. The temperature of Celsius is expressed by the symbol T, and the unit is℃. Kelvin temperature is expressed by symbol T, and the unit is K. The relationship between them is: T=273. 15+t(K), and the temperature has great influence on people's comfort and health. Under normal circumstances, the human body temperature is maintained at 36.5-36.7℃. If the temperature is too high, the human body heat will not be released in time. If the temperature is too low, the human body will lose too much heat, and both cases will make people uncomfortable and even sick.
2) Humidity of air: The air in nature is a mixture of dry air and water vapor, which is called "wet air" or air for short. Air without water vapor is called "dry air". Wet air = dry air+water vapor Under a certain pressure, the higher the temperature of the air, the more water vapor it can hold; The lower the temperature, the less water vapor can be contained. The parameters reflecting air humidity are absolute humidity, relative humidity and moisture content.
① Absolute humidity: the mass of water vapor per lm "wet air (kg/ml).
② Relative humidity: the ratio of absolute humidity of wet air to saturated absolute humidity at the same temperature.
③ Water content: the mass of water vapor coexisting with 1kg dry air in wet air.
Air relative humidity is an important index to measure air humidity. When the relative humidity is too high in summer, the human body will feel sultry; When the relative humidity is too low in winter, you will feel thirsty.
3) Air cleanliness: Air cleanliness is an indicator of air freshness and cleanliness. Air freshness refers to whether the proportion of oxygen in the air is normal. Under normal circumstances, oxygen accounts for 23. 1% of air quality. Air cleanliness refers to the concentration of dust and harmful gases in the air.
4) Wind speed: Wind speed indicates the speed of indoor air flow. If the air velocity is too small, people will feel sultry at the same temperature and humidity; Moreover, the flow rate is too large, and the human body will feel a sense of blowing. Air temperature, humidity, cleanliness and flow rate are the four main factors that determine the air environment needed by people and production.