How do temperature & humidity

affect the human body

Temperature and humidity gradients between the skin surface and boundary layer of air determine the rate of heat exchange

Every winter, it’s the same. Cold spells draw in, and just like magic, with the flick of a switch, it’s summer inside! Keeping warm is important, especially during the cold winter months. However, as soon as we shut the doors and close the windows, the environmental heat can play havoc with our skins.

So what can be done to ensure the environment is a little kinder to our health? A humidifier is a home appliance that can make a big difference to air quality. At home or in the office. No more sore throats or dry skin. Just some of the problems which can arise when the air is too dry.


Source: – High levels of humidity in a nature setting

What is Temperature and Humidity?

Temperature refers to the measurement of hotness or coldness of an entity or our environment while humidity refers to how much moisture is in the air. High temperature or low humidity can cause breathing problems and dry skin conditions. Too much humidity can also cause allergic reactions and lots of other problems in the home. If allowed to build up, over time, too much or too little moisture can cause serious damage to your house and it’s contents.

Humidity has a large role in climate and climate control, along with the temperature. Most people recognize humidity as moisture or dampness in the air. It is the amount of water vapour molecules in the air.

Humidity may also be measured in many different ways; Absolute humidity is the volume of water vapor. Specific humidity is the mass of water in the air. The relative humidity is the amount of vapor in the air to the amount it might hold when saturated, shown as a percentage. Relative humidity has the phenomenon of decreasing when temperature increases while the actual quantity of water vapor stays the same.

Temperature and humidity are the main environmental reasons that cause decay and deterioration; timbers rot, metals corrode, textiles fade, and deteriorate more quickly. Insects and molds generally like a warm damp environment. These effects given reason to the importance of climate control in buildings, structures, and our environment.


How changes in temperature and humidity affect our health

A largely invisible yet tangible phenomenon, humidity is one of those “necessary evils” that form our beautiful and balanced environment. In all outward appearances, the humidity seems to do nothing but bad – turns everything green, attracts critters, refuses to let your sweat evaporate, rots out wood and more. Let’s take a look into this sinister element of nature and see if we can understand it better.

Absolute humidity and specific humidity are quite similar in concept, with the former being a ratio of water weight per unit of volume – typically grams per cubic meter – and the latter being a ratio of water weight per unit of weight – typically kilogram per kilogram.

If you were to condense all the moisture in a given volume of air – say a cubic meter – the ratio of water per cubic meter is its absolute humidity. Because absolute humidity changes with temperature and pressure, it can confuse more complex fields such as chemical engineering and is therefore rarely used in these fields. For this reason – and to distinguish it from specific humidity – it is sometimes referred to as volumetric humidity.

The relative humidity is what most of us are more familiar with. It is the ratio – expressed as a percentage – of existing water vapor to the maximum water vapor the air can hold without condensing. The percentage indicates relative humidity, whereas other ratios such as those shown above are used for other humidity units.

So how does humidity affect us on a hot day? Humans are sensitive to humidity changes because our skin uses the air around us to get rid of moisture in the form of sweat. If the relative humidity is very high, the air is already saturated with water vapor, and our sweat won’t evaporate. When this happens, we feel hotter than the actual temperature.

Likewise, very low humidity can make us feel colder than the actual temperature. This happens because the dry air helps sweat evaporate more quickly than usual.

If the temperature outside is 23.8° C (75° F), humidity can make it feel warmer or cooler. Relative humidity of 0% would make it feel like it’s only 20.5° C (69° F). On the other hand, relative humidity of 100% would make it feel like it’s 26.6°C (80° F).


Health risks of high humidity

When the air has a high moisture content, as is the case in humid weather, this sweat cannot evaporate, leaving our bodies feeling hot and sticky. To cool off, our bodies must work even harder. This resulted in excessive sweating, increased rate and depth of blood circulation, and increased respiration. Excessive sweating can cause a loss of water and chemicals that the body needs to function properly, potentially putting our health in jeopardy.

High humidity can harm the human body. Because the air feels warmer than the officially recorded temperature, it can contribute to low energy and lethargy feelings. Also, hyperthermia, or overheating as a result of your body’s inability to let our heat effectively, can negatively impact your health in high humidity conditions. Some health risks which result from overexposure to humidity (hyperthermia) include:

  • Dehydration
  • Fatigue
  • Muscle cramps
  • Heat exhaustion
  • Fainting Heatstroke

Higher humidity also leads to increased bacteria in the air, making it hard for your employees to stay healthy. Mold can grow in the ducts, leading to allergic reactions and serious respiratory problems.


Source: – Hydrating well after exercise under the hot sun

 How it affects businesses

Temperature and humidity can impact energy usage at your commercial building since the system has to work harder to reduce moisture and keep the air at a comfortable temperature. An air conditioner is designed to remove moisture from the air and cool down the air, but when the levels are extremely high, it might not be able to keep up. One option is to reduce the pressure on your building’s A/C unit is to install a dehumidifier, but make sure to keep the level at about 30-45 percent humidity to avoid problems that come with dry air.

Too much moisture can also damage your company’s computers, equipment, devices, and other electronic. If you constantly have to replace these necessary items to get work done, you’ll spend a lot on your budget. Excessive moisture within a computer or mobile phone can also put the user at risk for electrical shocks.

When conditions are too humid, it may promote the growth of mold and bacteria that cause plants to die and crops to fail, as well as conditions like root or crown rot. Humid conditions also invite pests, such as fungus gnats, whose larva feed on plant roots and thrive in moist soil. The best way to monitor your environmental statistics is to get a reliable thermo-hygrometer. A good recommendation will be the ThermoPro TP55 LCD Digital Hygrometer Monitor that measures temperature & humidity and can be placed on a desk or wall mounted.

Source: ThermoPro TP55 LCD Digital Hygrometer Monitor by a coffee table

Dew point vs. relative humidity

There is yet another phenomenon that is related to humidity. Dew is basically condensation, and being that condensation is the saturation of air due to temperature-change, this temperature-change is also what causes dew to form. Condensation is essentially the bringing of water vapor to dew point via the lowering of temperature. The dew point is the temperature at which water vapor will begin condensing into water.

So how are dew point and relative humidity related? As the relative humidity gets higher (percentage), the closer the dew point gets to the current air temperature. In other words, maximum relative humidity – 100% – means that the current air temperature is at the dew point. The lower the relative humidity at a given temperature, the more the temperature needs to decrease to reach its dew point.



So now that we somewhat understand how humidity affects our health, we can take precautions to avoid suffering adversely at its hands. Why does a mattress get damp after sleeping on it directly on a cold floor? Why do closet walls (and everything between them) with no ventilation get moldy during the monsoon? Same reason!  – Relative humidity and dew point working together to slip you a fast one.

But look on the bright side. – It makes you appreciate the good in life. Plus, not enough humidity is a problem as well. In some countries, people sometimes have to use dehumidifiers. Still, in other drier regions and countries, people even have to use humidifiers to maintain a suitable environment for things such as musical instruments and certain precision products that would otherwise get damaged by the air’s lack of humidity.

Humidity can be controlled with a humidistat (humidity controller); this is used to regulate the humidity independent of temperature even though both affect each other.

If you are, on a personal basis, interested in taking a look at the RH inside your home, you can find all our thermo-hygrometers here. You can easily find meters which allow you to determine the dew point from your relative humidity and temperature readings.