- #1
- 23,523
- 10,869
- TL;DR Summary
- What is the white powder a humidifier emits and is it harmful to breathe?
Ultrasonic humidifiers atomize water and inject it into the air, where it evaporates. Anything dissolved in the water precipitates out as a white powder, which is noticeable as dust on surfaces throughout the room, especially near the humidifier. If the output is high enough, it can even form a visible white cloud throughout the room. Obviously that means we breathe it. So the question is, what is it and is it harmful?
For additional context, I bought a PM2.5 detector (2.5 μm and larger particles) after the wildfires last summer. The results are interesting. (Maybe later we can discuss the hazards of gas cooking and microwave popcorn...). Among the results are poor air quality readings in my bedroom with my combination ultrasonic/evaporative humidifier on. This morning in a test it read 160 μg/m3, which is "unhealthy" According to the WHO. It reads in single digit precision and can read as low as 0-1 if the HVAC has been running a while or I'm using my air purifier. Now, of course not all particles are created equal, and this scale was invented to measure particulate air pollution, which is mainly a nasty carbon soot cocktail. But what about what this humidifier is putting out?
I've done some "research" and the results are thin. Sources mainly just say it's the same stuff as in drinking water, so that means it's fine. Be we all know that drinking and breathing it aren't the same. And it may not even be the same chemical in each case. Note, the EPA says research has not found a risk, but a medical case report claims injury to an infant due to sustained exposure.
My tap-water source is very hard (primarily calcium and magnesium), but I use a softener. I don't have any bags of the salt it uses, but google tells me it's sodium chloride - table salt. The softener uses an ion exchange process that removes calcium and magnesium and leaves the sodium. Does the sodium stay dissolved? Pure sodium metal explosively reacts with water to form sodium hydroxide (NaOH). Does this happen just after the ion exchange? These questions are why I put this in the chemistry forum.
An SDS I found for sodium hydroxide lists an inhalation hazard level of 1 mg/m3. An SDS for sodium metal mentions "metal fume fever" as an inhalation hazard, which doesn't sound good, but they don't list concentration guidelines.
Thoughts?
For now I'm running my hated air purifier when the humidifier is on.
For additional context, I bought a PM2.5 detector (2.5 μm and larger particles) after the wildfires last summer. The results are interesting. (Maybe later we can discuss the hazards of gas cooking and microwave popcorn...). Among the results are poor air quality readings in my bedroom with my combination ultrasonic/evaporative humidifier on. This morning in a test it read 160 μg/m3, which is "unhealthy" According to the WHO. It reads in single digit precision and can read as low as 0-1 if the HVAC has been running a while or I'm using my air purifier. Now, of course not all particles are created equal, and this scale was invented to measure particulate air pollution, which is mainly a nasty carbon soot cocktail. But what about what this humidifier is putting out?
I've done some "research" and the results are thin. Sources mainly just say it's the same stuff as in drinking water, so that means it's fine. Be we all know that drinking and breathing it aren't the same. And it may not even be the same chemical in each case. Note, the EPA says research has not found a risk, but a medical case report claims injury to an infant due to sustained exposure.
My tap-water source is very hard (primarily calcium and magnesium), but I use a softener. I don't have any bags of the salt it uses, but google tells me it's sodium chloride - table salt. The softener uses an ion exchange process that removes calcium and magnesium and leaves the sodium. Does the sodium stay dissolved? Pure sodium metal explosively reacts with water to form sodium hydroxide (NaOH). Does this happen just after the ion exchange? These questions are why I put this in the chemistry forum.
An SDS I found for sodium hydroxide lists an inhalation hazard level of 1 mg/m3. An SDS for sodium metal mentions "metal fume fever" as an inhalation hazard, which doesn't sound good, but they don't list concentration guidelines.
Thoughts?
For now I'm running my hated air purifier when the humidifier is on.
Last edited: