Humidifiers and Lung Health: Benefits, Risks, and Safer Options

While humidifiers can be helpful for dry air, inadequate cleaning and sterilizing may allow bacteria and other microorganisms in the water to become airborne.

In some cases, these particles can be inhaled into the lungs, posing a risk to individuals with vulnerable airways.

Joseph Falkinham, a leading microbiologist who studies lung pathogens, has explained that humidifiers can disperse organisms such as nontuberculous mycobacteria (NTM) into indoor air. These bacteria are known for forming persistent biofilms in the lungs and can pose particular risks for individuals with bronchiectasis or other conditions that increase airway susceptibility to infection.

Why ultrasonic humidifiers raise concern

Dr. Falkinham is especially concerned about ultrasonic humidifiers, and the reason comes down to how they work. Ultrasonic humidifiers use high-frequency vibrations to break water into a very fine mist. Everything in the water gets aerosolized, including minerals, bacteria, and fragments of biofilm that may be growing inside the device.
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Because the particles created are extremely small, they can remain suspended in the air longer and be inhaled deep into the lungs. This increases the potential for waterborne organisms, such as NTM and Pseudomonas, to reach the inflamed airways.

Why evaporative humidifiers are considered safer

Evaporative humidifiers work differently. They use a wick or filter and a fan, allowing only water molecules to evaporate into the air. Most bacteria, minerals, and heavier particles are left behind in the reservoir or trapped in the filter rather than becoming airborne.
For this reason, if a humidifier must be used, evaporative models are generally considered safer than ultrasonic models.

Lower-risk ways to add moisture to the air

Lower-tech approaches reduce risk by relying on evaporation rather than aerosolization. Examples include boiling water on the stove or using ceramic containers on radiators. When possible, using sterile or well-filtered water can further minimize exposure.

What works for me

What works for me may not be right for everyone, but adding moisture to the air without a traditional humidifier works well in my home. On occasion, I use an electric teapot filled with sterile water and leave the lid open as it boils to add moisture to the air. The kettle turns off automatically, and I unplug it when it is finished.

For those interested in learning more, the Bronchiectasis and NTM Info & Research Connect Forum offers thoughtful discussions about environmental precautions. This patient-only forum frequently includes input from Dr. Falkinham, including conversations about humidifiers and why evaporative approaches may be safer than ultrasonic devices.

Medical disclaimer

This content is for educational purposes only and reflects personal experience and general information. Always consult your physician or care team before making changes to your health or home care practices.