
Installing air filters in classrooms has large educational benefits? - rafaelc
https://www.vox.com/2020/1/8/21051869/indoor-air-pollution-student-achievement
======
bobcostas55
Andrew Gelman: "No, I don’t think that this study offers good evidence that
installing air filters in classrooms has surprisingly large educational
benefits."

[https://statmodeling.stat.columbia.edu/2020/01/09/no-i-
dont-...](https://statmodeling.stat.columbia.edu/2020/01/09/no-i-dont-think-
that-this-study-offers-good-evidence-that-installing-air-filters-in-
classrooms-has-surprisingly-large-educational-benefits/)

~~~
Luc
This is so good! Gelman's comments on the study are a better HN post than this
article.

This is important stuff - you can already see people researching air filters
in other comments, taking the supposed results of this study as settled truth.

~~~
Someone1234
I'd just like to say, before the mods change the thread link, that the
original article is important to understand the context of why air filters
were installed.

Even if the Vox article is potentially flawed you need to read both to grasp
the full picture.

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sundvor
Great article.

It would be interesting if we could monitor productivity in the major
Australian CBDs these days. A lot of the big office buildings don't have the
capability to filter the unhealthy / toxic bushfire smoke, and the workers get
to suffer.

And on that, good luck trying to find any purifiers, anywhere in Australian
stores.

~~~
blaser-waffle
For the yankees, that's Central Business District (CBD), not something
marijuana related.

I'm in Canada and have had days of smoke from the Fort Mac fires roll through
-- it's rough.

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burfog
At home it matters too. I recover faster from chest colds when I remember to
keep the HEPA filter running. (instead of a simple speed knob, it boots up to
a multilingual color display that I can't even dim, and of course the filter
defaults to "off")

Here is a common air quality problem. Anybody have ideas?

My house is in a hot and humid area, so I run the air conditioning most of the
year. The duct work appears to be made of bare fiberglass pressed into sheets,
with foil on the outside. This is cheap, quiet, and thermally insulating. It
does however have a soft highly porous surface that collects black mold.

It doesn't appear possible to do anything about the mold. Thanks to the soft
porous surface, scrubbing would tear up the ducts and be ineffective.

Ideally the ducts would have a polished bare silver surface, sturdy enough to
scrub. Well, nobody has that, it would be expensive, and I'd have to rip out
the drywall of nearly every room in order to install something like that.

What do I do?

~~~
proee
Remove the material with mold from the space. Duct work is a terrible idea in
humid climates. It's better to get those individual wall AC units per room.
Mold is nasty stuff that will cause long term health problems.

~~~
t34543
Mini splits still need to be cleaned and evaporator coils collect
mold/mildew/contaminates just the same.

Regardless of what you have periodic maintenance is what makes a difference.

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derefr
Half of the reason I enjoy working from home, is that my office has horrible
stagnant air. I think _far_ better anywhere (home, coffee shops, the park)
that _isn 't_ my office.

~~~
jschwartzi
I've actually purchased a couple of indoor plants, a snake plant and a peace
lily, to help generate oxygen indoors. I noticed the air "tasted" better about
a week after I put them in the room. And I also noticed the air in my office
feels better than the air in my apartment which has no plants. Whether that's
something measurable I don't know, but while having these plants here I feel
like I perform better.

~~~
lkbm
[https://www.gardenmyths.com/houseplants-increase-oxygen-
leve...](https://www.gardenmyths.com/houseplants-increase-oxygen-levels/) did
some looking into this possibility.

The TL;DR is that you're not likely to have enough plants to make a
significant difference in terms of CO2/oxygen.

Doesn't mean there's no positive effect, but it's probably not due to oxygen
levels.

~~~
hanniabu
> Photosynthesis converts CO2 to O2, but plants also respire. During
> respiration they convert sugar and oxygen into CO2 and water. This is the
> reverse of photosynthesis, and it happens in all cells, all of the time, day
> and night.

Interesting, I wonder how that'll contribute to the snowball effect of global
warming since as it gets hotter I'm sure they'll perspire more.

~~~
im3w1l
Plants work on a similar principle as human nutrition. CO2 in - CO2 out =
weight gain. A growing plant is on average* a net absorber of carbon dioxide.

* On average, not constantly. Since they can't do photosynthesis in the dark, they release CO2 at night.

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montecarl
Is there any known mechanism through which air quality affects cognitive
performance? The article does not suggest or refer to any research on the
subject.

~~~
MS90
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6138768/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6138768/)

[https://www.pnas.org/content/115/37/9193](https://www.pnas.org/content/115/37/9193)

[https://www.apa.org/monitor/2012/07-08/smog](https://www.apa.org/monitor/2012/07-08/smog)

~~~
voxic11
Your first link says the mechanism is unknown right in the beginning. Third
link doesn't mention mechanisms at all. Only the second link attempts some
guesses. But it still concludes that "It is beyond the scope of this paper to
test the exact mechanism, so we leave it as agenda for future research."

~~~
tlb
Typically, knowing the mechanism comes long after solid evidence of the
effect.

The mechanisms by which cigarettes cause lung cancer are surprisingly complex
and weren't fully understood for a long time, but it's obvious that some kind
of mechanism is plausible.

So usually the bar for taking something seriously is: statistical evidence of
a significant harmful effect, and at least one plausible hypothesis for a
mechanism. But you don't have to be sure of the mechanism.

------
protomyth
When we ran a daycare we were specifically told NOT to install air filters
because there was research that suggested it would cause the children to
develop problems and have a reduced resistance. I would guess for older kids
it's fine, but you might want to consider that if you have or will have kids
when talking about the home, or come up with some mitigation strategies.

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tibbydudeza
I would install air conditioners in our district schools rather ... dunno how
kids can concentrate or function during those balmy summer days.

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ajra
Assuming the filters do what the article supposes they do, what would be the
cheapest and easiest way to test the air quality in my home and workplace?

~~~
sundvor
You could build your own with a Raspberry Pie and an sds011 sensor.

Edit: Example @
[https://aqicn.org/sensor/sds011/](https://aqicn.org/sensor/sds011/)

~~~
ajra
Thanks! I have an unused Pi lying around so it's a great suggestion for me.

~~~
sundvor
Nice! Cheers, I've ordered my own sensor and will be buying my own Pie as
well. Will be a fun learning experience for me.

I realised I pasted the wrong link above, although still of interest. Anyway,
here's a Pie specific article: [https://www.raspberrypi.org/blog/monitor-air-
quality-with-a-...](https://www.raspberrypi.org/blog/monitor-air-quality-with-
a-raspberry-pi/)

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BurningFrog
A reminder that while most studies are decent, the ones that go viral with
surprising and important results are almost always wrong!

