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Comment by resoluteteeth | Hacker News Reader

> Better air quality is one of the best (and cheapest) ways to improve overall health.[1]

While I think that the things the person lists on that site are good precautions (although I think not using an ultrasonic humidifier would be better stated as only using distilled water with ultrasonic humidifiers), I think that saying that doing these things is "is one of the best (and cheapest) ways to improve overall health" is too strong, because while there are lots of studies showing population level correlations between pm2.5 particles and health problems, I don't think there is currently evidence specifically showing that things like using air purifiers actually improve health.

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  >I think not using an ultrasonic humidifier would be better stated as only using distilled water with ultrasonic humidifiers

That's a common misconception. They still atomize bacteria from the tank because nobody ever cleans & sterilizes their dehumidifier tank often enough. Distilled water users still report high indoor particle counts when it runs, which is how you know it's an ineffective prevention.

The cost of distilled water every year (even making it at home) means ultrasonic humidifiers are the most expensive option too.

Just use an evaporative pad humidifier.

https://www.youtube.com/watch?v=oHeehYYgl28

  >while there are lots of studies showing population level correlations between pm2.5 particles and health problems, I don't think there is currently evidence specifically showing that things like using air purifiers actually improve health.

Air purifiers reduce PM2.5 concentration, so if PM2.5 is bad for health then air purifiers are good for health.

This is like "there's no evidence parachutes improve survival after jumping from a plane."

> Air purifiers reduce PM2.5 concentration, so if PM2.5 is bad for health then air purifiers are good for health.

> This is like "there's no evidence parachutes improve survival after jumping from a plane."

A proposed intervention like air purifiers that have no direct evidence but are plausible because they reduce something that has been shown to be correlated with negative long term health outcomes is the opposite of something like parachutes that we directly know work.

This is a completely bizarre comparison and it's like saying that skepticism of an Alzheimer's drug targeting amyloid plaques is like doubting parachutes work because we know that amyloid plaques are correlated with Alzheimer's.

  > reduce something that has been shown to be correlated with negative long term health outcomes

Are you suggesting the link isn't causal? Because your argument only makes sense if you think air pollution particles aren't actually the cause of lung damage, which is the opposite of the scientific consensus.

The fact that you have to bring up amyloid plaques is especially a red flag, since this is famously a rare example of the failure of scientific consensus.

The point is that you can't know if an intervention works until you actually test it. There are tons of possibilities, including that some pm2.5 particles cause lung damage and some don't, in which case overall pm2.5 exposure would be correlated to negative health effects but using an air filter to reduce dust in your home might have little or no health benefit. We don't know yet.

Generally avoiding pm2.5 particles is a reasonable precaution but you can't say that things like air filters are actually the most effective health intervention someone can do until you test that experimentally. That's simply not how stuff like this works. There are virtually infinite health interventions that seem plausible but don't actually work when tested.

As with a treatment for alzheimer's disease, cancer, or heart disease, you can't simply say that X is correlated with disease, an intervention Y reduces X, so therefore Y must have positive health effects without actually testing Y.

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