Keep it clean: Dirty humidifiers and health problems

Dirty water tanks and filters in humidifiers can grow bacteria and mold. This can be a concern for people with asthma and allergies. But dirty humidifiers also can be a concern for healthy people. By releasing bacteria or mold into the air, they may trigger flu-like symptoms or even lung illnesses. Evaporators and steam vaporizers may be less likely to release airborne allergens than cool-mist humidifiers.