Since the beginning of winter, indoor air has become dry, and many people have started using humidifiers to regulate air humidity. However, regarding the use of household humidifiers, many people may use them improperly, and some operations may even cause serious health problems. Below, let us learn some scientific facts about the use of household humidifiers;

Does using a humidifier cause PM2.5 levels to rise?

When using a humidifier, some people notice that the air quality sensors in certain air purifiers or PM2.5 testing instruments show an increase in PM2.5 concentration. Why is this happening?

This is likely because most PM2.5 testing instruments or air purifiers use infrared or laser sensors. These sensors detect particles primarily through the principle of light scattering. Both water droplets and dust particles cause scattering, and PM2.5 testing instruments cannot accurately distinguish between them. Therefore, these water mist particles are misidentified as PM2.5. When using a household atomizer for humidification, the concentration of water particles in the air rises significantly, and when detected by the PM2.5 instrument, the PM2.5 reading naturally increases.

Is atomizing tap water equivalent to inhaling haze?

Many online sources claim that when using household humidifiers, pure water should be used for humidification and atomization instead of tap water, because chlorine atoms and microorganisms in tap water might be blown into the air with the mist, causing pollution. If the tap water has high hardness, the mist sprayed by the humidifier may contain calcium and magnesium ions, which can produce white powder and pollute indoor air. Is this true?

This is certainly not true. The tap water we use daily has undergone multiple layers of filtration. Although some trace factors may exist, their content is extremely small. The main component of tap water is water, and inhaling water mist particles into the respiratory tract causes almost no harm (excessive inhalation or flooding definitely causes harm, so let us not split hairs).

The so-called "haze" (Smog) actually refers to fog plus haze, with dust particles as the main component. Inhaling dust into the respiratory tract is extremely harmful.

Of course, if you ask if pure water can be added? The answer is definitely yes. If conditions (finances) permit, pure water can be used; otherwise, cooled boiled water is also fine. Most bottled water on the market is actually pure water (A small tip: you might think bottled water is mineral water, but most of it is actually pure water. Have you ever looked at the ingredients of bottled water when buying it? You can check next time, and you will find that most common bottled “mineral waters” are actually pure water).

Can adding disinfectants to a humidifier purify water and air?

Some people add various disinfectants to their humidifier because they are too lazy to clean it but afraid of bacteria growing inside. They believe this can effectively sterilize the water and, as the mist enters the air, kill airborne bacteria as well. Little do they know that adding these disinfectants can cause great harm to the human body.

When a humidifier atomizes the disinfectant, it is inhaled into the body, which can cause serious damage to the respiratory tract, leading to chronic respiratory diseases or even pulmonary fibrosis.

Can adding essential oils, vinegar, or Banlangen to a humidifier promote health and soothe the mind?

To balance moisturization for beauty and disease prevention, many people like to add “ingredients” such as aromatherapy essential oils, vinegar, or Banlangen to their humidifier.

This practice is actually unscientific and more likely to trigger respiratory diseases.

During winter and spring, under the double impact of dry climate and indoor heating, humidifiers have become a “lifesaver” for many. Some young people like to add essential oils to humidifiers. This way, the air is not only moist but also carries a faint fragrance, providing effects like soothing the nerves and aiding sleep.

Some elderly people even add Banlangen and vinegar to their humidifiers. They believe that through the atomization of the humidifier, the active ingredients can be released into the air to prevent colds and disinfect the environment.

In reality, substances that are truly used for treatment and can act on the lungs must have certain water solubility, lipid solubility, a specific particle count, and the ability to bind with alveolar epithelial cells to be absorbed by capillaries. If any substances from essential oils, Banlangen, or vinegar are released into the air via a humidifier, they are foreign bodies to the lungs, which can aggravate symptoms of diseases like asthma and emphysema, and may even lead to hypersensitivity pneumonitis.

Winter air is too dry, which can easily lead to symptoms such as dry nasal mucosa and bleeding. A humidifier can increase air humidity and help protect the human airway. However, a humidifier is merely a device for increasing humidity; do not treat it as a physical therapy or medical device. Such practices are not recommended and, if handled improperly, can affect health. (If it truly had such miraculous effects, don’t you think businesses would promote them vigorously?)

My humidifier has a sterilization function and I use pure water, so I don’t need to clean it?

Whether it is a household ultrasonic atomizing humidifier or a cold evaporative humidifier, if you do not pay attention to cleaning it during daily use, you may contract “humidifier pneumonia.” Symptoms may include fever, coughing, and even chest tightness or shortness of breath. If you find yourself with “humidifier pneumonia,” you should seek treatment at a nearby hospital promptly.

Generally, household humidifiers should ideally have their water changed daily and be cleaned at least once a week. This is because although water evaporates into the air, impurities stay behind in the humidifier and accumulate over time to form scale. In such cases, it doesn’t matter if you use pure water, cooled boiled water, or if the device has UV or silver ion sterilization; unclean mist particles can cause fungal respiratory infections. Long-term inhalation of pollutants may lead to acute lung infections.

In winter, when using a humidifier, it is best to place it near a heater. This way, the atomized mist can be carried by the rising heat, allowing it to dry quickly into water vapor and distribute more evenly throughout the room.

Furthermore, humidifiers should not be used for extended periods; an air humidity level of 40-50% is sufficient. You should also ensure the room is ventilated for 30 minutes to 1 hour every morning. Adjust the mist volume based on the dryness of the indoor air, as excessive humidity can also trigger respiratory diseases.