The common respiratory symptoms associated with COVID-19, such as a dry cough, nasal congestion, and a sore throat, cause discomfort. A humidifier is a non-medical supportive therapy used to manage these irritations. By releasing moisture into the air, these devices ease the feeling of dryness in the upper airways. While a humidifier is not a treatment for the viral infection itself, it is a helpful tool for symptom management and improving comfort during recovery.
How Humidity Relieves COVID Symptoms
Adding moisture to the air provides direct physiological relief to the respiratory system. Dry air irritates the sensitive tissues lining the nasal passages and throat, which are already inflamed by the viral infection. Humidified air soothes this irritation, making it easier to breathe.
Increased moisture helps thin the mucus secretions within the respiratory tract. When mucus is thick, it is difficult to expel, leading to congestion and a persistent cough. By thinning the mucus, humidified air allows for easier clearance.
The natural defense mechanism of the airways, known as mucociliary clearance, relies on sufficient moisture to function effectively. Tiny, hair-like structures called cilia move a layer of mucus to trap foreign particles and pathogens. In dry conditions, the movement of the cilia becomes compromised, but humidified air helps maintain this protective function.
Limiting Viral Spread Through Air Moisture
Beyond personal comfort, maintaining a specific range of indoor air moisture can affect the environment and the transmission of respiratory viruses like SARS-CoV-2. Scientific evidence suggests that relative humidity levels between 40% and 60% are optimal for reducing the viability and spread of these airborne pathogens.
In very dry air, aerosolized respiratory droplets released through breathing, speaking, or coughing evaporate quickly. This process makes the remaining viral particles smaller and lighter, allowing them to stay suspended in the air for extended periods and increasing the risk of transmission.
When the air has higher humidity, moisture causes the respiratory droplets to absorb water. These droplets become heavier and fall out of the air onto surfaces, which reduces the amount of time the virus remains airborne. Furthermore, higher humidity can accelerate the inactivation of the virus, reducing its overall stability.
Safe Operation and Cleaning of Humidifiers
The benefits of a humidifier are directly tied to its safe operation, as a poorly maintained unit can create health risks. It is recommended to use a cool-mist humidifier, especially in homes with children, as they pose no burn risk. Warm-mist vaporizers are effective at adding moisture but carry a scald risk if tipped over.
Daily use of distilled or demineralized water instead of tap water is necessary. Tap water contains minerals that are dispersed into the air as a fine “white dust,” which can be irritating to the lungs. These minerals also promote the growth of mold and bacteria within the water tank.
The water tank should be emptied, rinsed, and dried daily to prevent the formation of a biofilm. A deep cleaning using a vinegar or hydrogen peroxide solution should be performed every few days, followed by a thorough rinse to remove any chemical residue.
A hygrometer should be used to monitor the relative humidity level in the room. Humidity levels must be kept below 60% to prevent over-humidification, which can promote the growth of mold and dust mites. Proper placement is also important; the unit should be placed on a flat, water-resistant surface and kept away from walls, furniture, and electronics to prevent moisture damage.