It's so hot! Just looking at the temperature is not enough!

Heat is the deepest impression of summer for you and me in Taiwan, especially in modern times when the greenhouse effect has intensified. The temperature has risen year by year, but is it too hot? Is it enough to just look at the temperature? In fact, it is not. In developed countries, there are various evaluation methods for "hot". Here is the introduction:

As can be seen from the above table,Comprehensive temperature thermal index (WBGT)andHeat index (Heat index, HI), Seems to be more commonly used (in fact, there are other thermal assessment methods). Then why not just use the temperature directly for the assessment? Because

Physiological heat perception is affected by many environmental conditions such as temperature, wind speed, solar radiation, and relative humidity.

The difference in thermal perception will be reflected in the physiological performance of the human body, such as: perspiration, heart rate, etc., under extreme thermal environments, it may cause health hazards to personnel, but limited by the limitations of actual conditions, it is impossible Data monitoring for all relevant environmental conditions anytime and anywhere, so scholars have modeled for several conditions that have a greater impact on thermal perception (common environments often usetemperatureandhumidityThe greatest impact), and finally progressed into various thermal indicators. The following introductionComprehensive temperature thermal index (WBGT)andHeat index (Heat index, HI)Two commonly used indicators:

◆ Comprehensive temperature thermal index (WBGT)

Comprehensive temperature thermal index, The English is:Wet-Bulb Globe Temperature, abbreviated as:WBGT.The higher the index, the higher the risk of heat hazard. The calculation method is as follows:

People exposed to sunlight outdoors

Comprehensive temperature thermal index = 0.7 × (natural wet bulb temperature) + 0.2 × (black bulb temperature) + 0.1 × (dry bulb temperature)

Those who are not exposed to sunlight indoors or outdoors

Comprehensive temperature thermal index = 0.7 × (natural wet bulb temperature) + 0.3 × (black bulb temperature)

The above measurement of WBGT uses three indicators:Natural wet bulb temperature, black bulb temperature, dry bulb temperature, But onlyThe dry bulb temperature is the value measured by the thermometer we generally use, The other two temperatures require more special instruments to measure, or use more complicated data conversion. Therefore, WBGT will have greater difficulty in real-time monitoring.

◆ Heat index (Heat index, HI)

Heat index, The English is:Heat Index, abbreviated as:HI.The higher the index, the higher the risk of heat hazard. The main reference for this indicatorAir temperaturewithRelative humidityTwo factors, because the human body can take away heat by perspiration, but when the humidity is higher, the evaporation rate of water will decrease, thus affecting the body's heat dissipation. The calculation formula of this indicator is more complicated, so I won't introduce it here.

The following lists the heat index comparison table at different temperatures and humidity,As the air temperature or relative humidity rises, the heat index will increase, and the risk of thermal hazards will also increase.:

From the previous introduction, we can find that the WBGT and HI two thermal indicators have at leasttemperatureandhumidityFactors such as temperature and humidity are indeed two important factors that affect the human body’s heat dissipation. Therefore, if you feel very hot in the future, it is recommended not only to reduce the temperature (such as turning on the air conditioner), but also to consider reducing the humidity. (Such as: Turn on the dehumidifier) Miles!

【MyDocSay tips】
existOutdoor activityIf there is a possibility that the risk of heat hazard may increase, it is impossible to have an air conditioner or dehumidifier at this time.Replenish cold water (to cool down), spray cold water on the body surface (to cool down), move to a cool place (to cool down), wipe off body surface sweat with a towel (reduce body surface humidity), fan (increase moisture evaporation rate)And so on as an alternative.