Indoor Humidity: How It Affects Health, What It Should Be, and How to Improve It

Contents:

• What is air humidity?
• What determines air humidity?
• Where does moisture come from in the home?
• What is the optimal air humidity?
• How to measure air humidity?
• Why is low air humidity dangerous?
• What problems does high humidity cause?
• What conclusions can be drawn?

What is air humidity

Humidity is defined as the content of water vapor in the air. In physics terms, humid air is a mixture of dry air and water vapor. Combined with temperature, air purity, and air movement, humidity plays a key role in shaping the microclimate. Maintaining optimal humidity levels is important for human health, comfort, and the preservation of various materials in rooms. The correct humidity balance helps prevent disease and improves overall well-being.

Meteorologists measure air humidity using two main methods: psychrometric and hygrometric. The psychrometric method is based on the use of two thermometers, one of which is humidified. The difference in temperature readings allows us to calculate the relative humidity. The hygrometric method involves the use of instruments that directly measure the water vapor content of the air. Both methods play a key role in meteorology, as accurate humidity data is necessary for weather forecasting and understanding climate conditions. Correctly determining humidity helps in a variety of fields, including agriculture, construction, and healthcare.

• Absolute humidity is literally grams of water vapor per cubic meter of air. The more water vapor, the higher the absolute humidity, and vice versa.
• Relative humidity is the degree to which the air is saturated with moisture. It is calculated as a percentage, taking into account how much water vapor is currently in the air and how much it can still hold.

If the relative humidity is 40%, this means that the air still has the potential to hold 60% of its moisture.

We perceive only relative humidity, which can vary significantly. Outdoors, humidity levels can be both higher and lower than indoors, such as apartments. This is important to consider, as differences in humidity can affect human comfort and health. The correct level of humidity in an apartment contributes to a favorable microclimate, which is especially important in changeable weather conditions.

What does air humidity depend on?

Relative humidity is directly related to the ambient temperature. High temperatures usually increase the air's ability to retain moisture, which leads to an increase in relative humidity. It is important to consider that temperature changes affect human comfort and health. Understanding this relationship is necessary for optimizing the indoor microclimate and improving quality of life. Proper regulation of temperature and humidity helps create a healthy atmosphere in both living and working spaces.

In winter, when the outside temperature is +5°C and the relative humidity reaches 100%, the air contains the maximum amount of moisture. However, when this cold air enters the apartment, the situation changes. Cold air has a lower ability to retain moisture compared to warm air. When indoor air is heated to 22°C, its ability to hold water vapor increases significantly. Although the total amount of water vapor in the air remains unchanged, its relative humidity decreases to 33%. This occurs due to the increased volume of air capable of holding moisture, which leads to more comfortable indoor conditions.

In hot summers, at +30°C, air humidity can reach 80%, even on a clear day. When the air conditioner is turned on, hot air from outside is converted into cold air. It is important to remember that cold air holds less moisture than warm air. If the indoor temperature drops from +30°C to +26°C or below, the humidity level increases. In some cases, it can reach 100%, leading to condensation—droplets of water on windows and walls. This phenomenon not only affects comfort but can also cause damage to building materials and the appearance of mold. Therefore, it is important to control indoor humidity levels, especially when using air conditioning.

Where does moisture come from in the home?External sources of moisture, such as rain, dew, sprinklers, and plants, are well known. However, where does indoor water vapor come from? The main sources of moisture inside buildings are ourselves. Human activity, including breathing and sweating, significantly increases humidity levels. In addition, household appliances such as washing machines, dishwashers, and showers also contribute by adding or removing moisture from the air. Understanding these factors will help you better control indoor humidity levels and prevent problems associated with excess moisture, such as mold and mildew.

What is the optimal humidity level?

The Environmental Protection Agency (EPA) recommends maintaining indoor humidity levels, such as those in a home or office, between 30% and 50%. However, some experts believe these standards should be revised. The correct humidity level promotes comfort and health, reduces the risk of allergies and colds, and prevents damage to furniture and building materials. It is important to consider that different climates may require individual humidity settings to achieve the optimal microclimate.

The ideal range of relative humidity in indoor spaces is 40-60%, according to Dr. Stephanie Taylor, an infection control consultant at Harvard Medical School. Together with colleagues, Dr. Taylor initiated a petition to experts at the World Health Organization (WHO) asking them to establish this range as a recommendation. Currently, the WHO focuses on indoor air quality but does not provide specific recommendations for minimum humidity levels in homes. Maintaining optimal indoor humidity is important for health, as it can reduce the risk of infection and improve overall well-being.

Taylor cites a number of studies confirming that humidity in the range of 40–60% provides maximum protection against airborne viral infections. This transmission route involves the movement of airborne droplets containing viral particles that are produced when an infected person coughs, sneezes, or breathes. Maintaining optimal humidity makes droplets heavier and more quickly settle on the floor or other surfaces, making them easier to remove during wet cleaning. Thus, maintaining the correct indoor humidity level is an important factor in the prevention of viral diseases.

According to Rospotrebnadzor standards, the optimal air humidity in residential premises should be between 35% and 45%. Maintaining this level of humidity helps create a comfortable atmosphere and prevents the development of harmful microorganisms. To maintain optimal humidity, it is recommended to use humidifiers and regularly ventilate the premises. The correct level of humidity also helps maintain a healthy respiratory system and improve the overall well-being of residents.

Rospotrebnadzor has established maximum permissible levels of relative humidity for temperatures above +25°C. These standards are important for maintaining a comfortable and healthy indoor microclimate. Compliance with the established humidity values ​​helps prevent the development of diseases and negative impacts on human health. The correct level of humidity contributes to improved well-being and a reduced risk of allergies and respiratory diseases.

How to measure air humidity

A hygrometer is a device for measuring air humidity that displays the level of relative humidity. These devices are widely available in hardware stores and are available in two main types: analog and digital. Modern hygrometers can also measure temperature and additional air parameters, making them a versatile tool for monitoring indoor microclimate. Choosing the right hygrometer will help ensure optimal conditions for health and comfortable living.

Reading is an important part of our lives, providing an opportunity to broaden our horizons and deepen our knowledge. It helps develop thinking, improve communication skills, and enrich our vocabulary. It's important not only to read books but also to stay up-to-date with current news and articles online. This helps you stay informed about current events and topics. Read regularly, choosing a variety of genres and formats to get the most out of it. Reading not only entertains but also inspires, opening the door to new ideas and perspectives. Moisturizing your facial skin is a key step in maintaining its health and youthfulness. Proper hydration helps prevent dryness, flaking, and premature aging. To achieve the best results, it's important to consider your skin type and climate. The first step to moisturizing is cleansing. Use gentle cleansers that respect the skin's natural balance. After cleansing, it is recommended to use a toner, which will help restore moisture levels and prepare the skin for further care. The next step is to use a moisturizer or serum. Light gels are suitable for oily skin, while richer textures are suitable for dry skin. Pay attention to the ingredients: look for ingredients such as hyaluronic acid, glycerin, and oils that effectively retain moisture.

Don't forget the importance of regular moisturizing. Apply products twice a day: morning and evening. Also, take into account seasonal changes: during the cold season, more intensive care may be required, while in the summer, it is better to choose light formulas.

Additionally, be sure to drink enough water, as the internal hydration of the skin also plays a role. Protecting your skin from the sun with creams with SPF will help prevent moisture loss and premature aging.

By paying attention to facial hydration, you can achieve a healthy and radiant appearance.

The dangers of low air humidity

During the heating season, indoor humidity levels may drop below optimal values. This leads to faster evaporation of moisture from the skin and mucous membranes, increasing the risk of dehydration. Proper humidity levels are important for maintaining health and comfort, especially during the colder months when heating is used heavily. To avoid problems associated with low humidity, it is recommended to use humidifiers and regularly ventilate rooms.

Low indoor humidity, ranging from 20-30%, can lead to various problems. It contributes to dry skin and mucous membranes, which can cause discomfort and increase the risk of colds. Low humidity can also negatively impact respiratory health, leading to a dry cough and throat irritation. In addition, insufficient humidity increases the risk of static electricity and damage to wooden furniture. To avoid these negative consequences, it is recommended to use humidifiers and control the humidity level in the room, maintaining it within the optimal range.

• Dry skin. Have you noticed that in winter you need more face cream to avoid feeling tightness? Also, sensitive skin, deprived of moisture, is less able to resist bacteria, resulting in rashes [10].
• Cough. Dry air itself does not cause illness, but if the humidity in the room drops, bronchial asthma and chronic bronchitis can worsen. With these diseases, the mucous membrane of the respiratory tract has difficulty protecting itself from dust particles, allergens and bacteria, so coughing is activated to quickly remove excess from the bronchi [11].
• Eye irritation. Fluctuations in air humidity in the room are more noticeable to people with dry eye syndrome. It occurs when there is little tear fluid or a lack of other components to retain moisture on the surface of the eye. When working at a computer, moisture evaporation is already accelerated, and if the air in the room is dry, unpleasant symptoms are added - burning, itching, the need to blink frequently [11].
• Nosebleeds. People prone to nosebleeds are bothered by this problem more often in the winter months [12].
• Rapid pulse. In a room with humidity less than 45%, the body overreacts to stress. This is the conclusion reached by American experts. They observed how the pulse changes in people who live or work in a "dry" room. The lower the humidity in the room, the higher the heart rate. Researchers believe that dehydration is the cause. The body reacts to dehydration with stress, and a rapid pulse is one of its main signs [11].
• Risk of contracting influenza. With the onset of cold weather, flu season begins. This is due not only to the fact that we spend a lot of time indoors or catch a cold more easily. Influenza A viruses survive more easily in low humidity indoors - be it an office, apartment, or cafe [6].

Viruses remain active much longer in dry air, since droplets with viral particles quickly dry out and do not lose their viability. At low humidity, the mucous membranes of the nose and respiratory tract dry out, which makes it easier for viruses to penetrate the body's cells. This increases the risk of infection and the spread of infections. Maintaining optimal indoor humidity levels can help reduce the likelihood of infectious diseases, as damp conditions create a less favorable environment for viruses.

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Indoor temperature, humidity, and lighting play a key role in creating a comfortable and healthy atmosphere. The optimal room temperature should be between 20 and 22 degrees Celsius. This ensures comfort for most people and minimizes the risk of colds. Air humidity is also important: the ideal level is 40-60%. This helps prevent mold growth and maintains respiratory health.

As for lighting, natural light is of great importance. Ideally, the room should receive sufficient sunlight throughout the day. If natural light is insufficient, you should consider installing high-quality artificial lighting. Using a variety of light sources, such as ceiling lamps, wall sconces, and floor lamps, will help create a pleasant atmosphere and improve visibility.

Maintaining these parameters not only contributes to a comfortable stay indoors but also has a positive effect on overall well-being and productivity.

Humidifiers are an important element in maintaining a comfortable indoor climate in winter. As Akiko Iwasaki, professor of immunobiology and cell biology, notes, the use of humidifiers helps prevent dry air, which, in turn, contributes to better health. Dry air can negatively impact your respiratory tract, skin, and overall well-being. Humidifying the air helps reduce the risk of colds and allergies, creating a more comfortable living and working environment. Therefore, especially during the winter, it's worth paying attention to the humidity levels in your home and considering using humidifiers to maintain an optimal microclimate.

If you don't have the necessary resources, there are several alternative solutions you can consider. It's important to analyze the situation and determine what options are available. This may include finding temporary substitutes, using available tools, or seeking professional help. Streamlining processes and wisely allocating resources will help minimize the impact of a missing element. Also, don't forget about using online resources and communities for support and ideas.

• Adjust the room temperature. Open windows to slightly lower the room temperature—this will help retain moisture. If you can regulate the temperature yourself, set it to around 22°C.
• Add steam. Turn off the bathroom exhaust fan and leave the door slightly open after taking a shower or bath. Boil some water in the kitchen and let the steam fill the space with moisture.
• Make sure you moisturize your body. Moisturizing creams, eye drops, lip balm, and nasal sprays with sea salt will help.
• Dry linens in the room. Hang still damp clothes and textiles in the room.
• Place plants. When you water the plant, the moisture remains in the soil and evaporates from the surface of the plant. Ficus, ferns, and ivy are suitable.
• Remember to drink plenty of fluids. There is a simple way to understand that the body needs more water: when dehydration begins, the body conserves water, urine becomes less, and its color becomes more saturated [15].

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Water Balance: Concept and How to Maintain It

Water balance is the relationship between water intake and loss in the body. Maintaining optimal water balance is key to human health. Too little or too much fluid can lead to various problems, including dehydration or edema.

To maintain water balance, it is necessary to monitor the amount of fluid consumed. It is recommended to drink enough water throughout the day, especially in hot weather or during physical activity. It is important to keep in mind that not only water but also moisture-rich foods, such as fruits and vegetables, also help hydrate the body.

In addition, you should pay attention to your body's signals. Thirst is the first sign that the body is lacking fluid. Regularly drinking water, especially before and after physical activity, will help avoid negative consequences.

Maintaining water balance also depends on individual characteristics of the body, such as age, level of physical activity, and climatic conditions. A healthy water balance is the key to good health and the efficient functioning of all body systems.

What problems does high humidity cause?

When the air humidity level exceeds 60%, dampness occurs in the room. The air becomes "heavy", a musty odor appears, and breathing becomes difficult. However, the problem of high humidity is not limited to unpleasant sensations. Medical experts warn of serious risks associated with high humidity. Here are two main dangers to consider.

• Allergies. High humidity in a room can lead to mold and dust mites, which provoke allergies in people with bronchial asthma. These microorganisms are present in any room, but they are small in number and therefore do not cause much harm. But high humidity creates ideal conditions for their growth and reproduction [3].
• Poor sleep. Sleep Foundation experts note that high humidity can shorten the duration of the slow-wave and rapid eye movement (REM) sleep phases. Thus, very humid air in the bedroom can cause problems with sleep and restoring energy [16].

To maintain optimal humidity levels in the room, use a kitchen hood and an exhaust fan in the bathroom. In most cases, this is sufficient. If the humidity level continues to exceed 60%, it is recommended to consider additional measures.

• Dehumidifiers. They absorb moist air, remove moisture from it, and return a dry stream to the room.
• Handy adsorbents. Excess moisture can be absorbed by baking soda, salt, coffee, cereals, and even activated carbon. Try placing dishes with such contents around the room, changing them periodically.
• Slow air conditioner mode. Do not turn it on at full power to prevent the humidity from rising too quickly.

What conclusions can be drawn?

Since the early 1990s, the concept of "sick building syndrome" has entered scientific circulation. This term describes a range of unpleasant symptoms experienced by people during prolonged stays in closed spaces. Usually, health improves after going outside. The severity of this syndrome directly depends on the number of workstations, the office equipment used, the air conditioning system, lighting, as well as the quality of ventilation, temperature, and humidity. These factors play a key role in creating a comfortable and safe environment for employees.

To prevent "sick building syndrome," it is necessary to maintain an optimal microclimate in it. This includes ensuring high-quality ventilation, maintaining a comfortable temperature, and controlling humidity levels. A healthy indoor climate improves air quality and creates favorable conditions for human health. Optimal indoor humidity should be between 40 and 60%. Within this range, choose the level that is most comfortable for you. These conditions create the most favorable atmosphere for humans and also minimize the risk of bacterial, viral, and mite growth. Maintaining the correct indoor humidity promotes improved well-being and health, and also prevents the development of allergies and colds. Arundel A, Sterling E, Biggin J, and others examined the indirect effects of relative humidity on health indoors in an article published in the journal Environmental Health Perspectives. This study, published in 1986 in volume 65 on pages 351-361, examines various aspects of the influence of humidity on human health. The study highlights the importance of maintaining optimal indoor humidity levels to improve overall health and prevent illnesses related to low or high humidity.