> And it is not a placebo effect.

How do you know?

You do not deserve the downvotes. Just because the purifier takes particulates out of the air doesn’t mean the effects on humans isn’t placebo

Sure, but this is misplaced skepticism. There have been many studies attesting to the harms of PM 2.5 and the benefits of intervention. The onus isn't on a single consumer to set up a double blind, randomized test for himself, the onus is on you to simply google for the many that have been already done.

https://www.sciencedaily.com/releases/2018/08/180822112406.h... https://www.ncbi.nlm.nih.gov/m/pubmed/26022815/ https://www.atsjournals.org/doi/full/10.1164/rccm.201010-157... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165134/ https://www.atsjournals.org/doi/full/10.1164/rccm.200704-632... https://ehjournal.biomedcentral.com/articles/10.1186/1476-06...

Just because it has an effect on the average person doesn't mean it must have an effect on every person. It can still be a placebo for any one individual, and I don't see the harm of asking how does one double-check if the effect is real or not.

There isn't much harm, there just isn't much point either. We don't usually interrogate people's assumptions down to axioms and provable claims, because it's impossible to live that way. Do you have personal experimental data to prove that eating handfuls of mud is likely to hurt your stomach?

>Do you have personal experimental data to prove that eating handfuls of mud is likely to hurt your stomach?

I do have evidence that eating mud is likely to hurt my stomach: the relevant body of literature showing that this is a likely event for the population I'm part of.

In OP's case, however, considering that the relevant body of litetuare shows that placebos are very effective for improving sleep quality, I would say it's very reasonable to ask someone to elaborate on why they are so convinced that their method of treatment is not a placebo for sleep quality.

No one is saying they have to "prove" it--they can just elaborate on their conviction: perhaps OP had many insomnnia treatments before and this was the only one that showed efficiency. Not a proof, but it is some circumstatial evidence. On the other hand, maybe OP is not aware how effective placebos are, in which case his statement may be too strong to straight-out declare that "it's not a placebo effect."

> the relevant body of literature showing that this is a likely event for the population I'm part of

Please link some examples, because I somehow doubt that you referenced them before forming an opinion. I think we all know eating lots of mud is a bad idea without referencing literature, let alone qualifiers about population groups.

I'm curious if you've lived in any of these hyper-polluted cities. The health effects of breathing such smog is absolutely palpable.

Here's a couple of studies on how PM2.5 affects your arteries, blood pressure, stress hormones, etc. I don't doubt all of these effects can add up to a better or worse night's sleep.

- "clear cardiopulmonary benefits of indoor air purification among young, healthy adults", after only 48 hrs of intervention: https://www.ncbi.nlm.nih.gov/m/pubmed/26022815/

- "significantly higher blood pressure, hormones, insulin resistance, and biomarkers of oxidative stress and inflammation among individuals exposed to higher PMs": https://www.ncbi.nlm.nih.gov/m/pubmed/28808144/

>Please link some examples, because I somehow doubt that you referenced them before forming an opinion.

That's because I assumed it was meant to be a hypothetical example--I don't actually have an opinion on the health effects of eating mud.

The point is that one claim is regarding the likelihood of X happening due to Y (in general), and the other claim is about the affirmation that X happened because of Y (in a specific case.) Likelihood is confirmed by scientific articles that employ statistical inference methods such as the ones you have been posting, while the other claim is undemonstrable by the scientific method, so it is commonly supported through further circumstantial/anecdotal evidence, which is what I assumed the other poster asked for.

Anyway, given that most of your comment is posting more scientific articles, we're probably arguing about different things.

This seems ripe for placebo. Installing purifier and indeed measuring lower PM, means naturally you feel less worried and more relaxed!

It's time to hire someone to maybe break the filter somewhen for a duration. And hack the meter to report invalid data.

I've always thought it would be an interesting service where someone did this with medication/supplements. They sent you supplies of both the real and sugar pill meds for a certain duration and you recorded how you felt.

Generally, denying people access to healthcare in for the sake of experimentation is unethical.

On the other hand, measuring lower PM is indeed a quantifiable metric.

Yeah it depends what question you are trying to answer:

1. Does my air purifier filter out PM2.5?

or

2. Dos lower PM2.5 make me sleep better?

For #1 there is no placebo effect (there is no human element!)

Try this: Start smoking a pack of cigs every day (evenly spaced out throughout the day, from dawn to dusk) for 3 months.

Then, stop. Observe your lung function and comfort levels throughout the next 3 months.

I am rather certain that you will feel a difference. :)

Yes. Recently moved to a high PM 2.5 area, running ionizers in the bedroom and the rest of the house improves things immensely. This is exactly how it feels.

I think he means based on the size of the effect it's unlikely to be a placebo.

right, but 50% of the effect of opiates is placebo, so we shouldn't be too surprised. https://www.ncbi.nlm.nih.gov/pubmed/11207392

Placebo's effect on pain is one of if not the largest placebo effect, but the effect size on sleep is much smaller.

Well the reasoning was pointing towards high chance of placebo though. He said there was lots of grime and also something he could measure was different, which means psychologically a lot greater chance and effect for placebo.

I don't think that's how it works. In the hypothetical world where he reports no grime on filters and no difference in readings yet his sleep is better, would you predict lower chance of placebo?

That is actually a great thought experiment.

A treatment being a placebo implies nothing about the effect size!

Most placebo effects are modest and the ones that aren't are usually mixed in with regression to the mean effects(which are usually pretty modest). So OP is implying that if an effect is especially large it's less likely to be placebo.

Placebo effects on depression are enormous.

please read the very next sentence. peace.

We've proven that the air filter can remove particulates from the air. We haven't proven that it's improvement on your sleep is any more than a placebo.

That doesn't answer my question, unfortunately.

You do have a point.

Right right, but if you look at https://melmagazine.com/en-us/story/i-had-toxins-sucked-out-... you can see that things do change in colour sometimes and it may have nothing to do with the outcome.

Are you sure? We had one of the bigger Blue Airs (605) in Beijing and I didn’t like using it at all. When it was a 150-200 day, I would just run it before sleep with the windows closed. On worse days, we ran it all night, but it was loud and made the air smell like ozone, giving me a headache. I’m so glad I live in the Seattle area now and can open the window at night.

Making the air smell like ozone means it’s probably doing something unhelpful/actively harmful in addition to filtering. Did it have an ionizer or similar?

No, it’s a Blue Air so doesn’t include an ionizer, it just when HEPA filter.

Huh weird, seems highly rated, too. If it was loud in addition to the ozone smell and there was definitely no ionizer, I wonder if the motor was faulty.

It could have been fake. I bought it in a Chinese mall after all. 6000 kuai also. But I doubt it, I think it could have just been the stale air in the apartment getting to me, you can’t open the windows when you are using it of course.

A real HVAC with air filtering will circulate air from the outside, so is quite different.

Where is the ozone coming from then? Something doesn't seem right.

It was just a smell to me. I don’t think there was any ozone in there.

Arcing from poor quality brushes in a DC motor.

A filter alone doesn't ionize the air though...

You'll be getting a headache from the excess CO2 buildup with the windows closed. If you want to effectively control and monitor indoor pollutants, you also need to buy a CO2+PM2.5 portable monitor. They cost about $80 on Aliexpress.

I'd bet than investing in cleaner vehicles (ICE > EV) and energy source (call > renewable/nuclear) would have much greater health and climate benefits and for much higher ROI.

Why not both? I’m temporarily in an area That regularly sustains pm2.5 levels the WHO considers dangerous at 24 hour exposure. I’d rather buy a cheap and effective air purifier and mask than change the entire population over to renewables and electronics.

It’s like refusing to wear a mask next to the california wildfires saying it’d be a cleaner solution to just put out the flames.