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The cognitive costs of air pollution (patrickcollison.com)
1020 points by jseliger 17 days ago | hide | past | web | favorite | 285 comments

I think this is an important question to answer, but the shehab paper (the first link) provides vertically no useful information. They didn't blind the assessors carrying out the cognitive studies, which on its own invalidates their conclusion. They also didn't randomize the ordering, but appear to have "investigated for order effects", found "no statistically robust difference", then proceeded to have every participant do the "post exposure" test second, making it highly likely that fatigue alone could explain their effects. With only 30 subjects, their tests for ordering effects are likely underpowered.

Also note that they did 11 different tests, but didn't appear to correct for multiple comparisons [1]

This would be a really interesting problem to study, but you'd probably want to look at academic performance in college students before and after transfer between universities e.g urban vs rural (presuming you can measure differences in pollution) between the two, you'd expect to see a relative drop in academic performance going from rural to urban, now that would worry me. But this study is unhelpful.

[1] https://en.m.wikipedia.org/wiki/Multiple_comparisons_problem

Just want to say it's impossible to tell which paper you're referring to.

The first link on the page isn't a paper. The word shehab doesn't appear anywhere on the page. The word shehab doesn't appear anywhere in the first paper linked. The three quoted sentences / fragments you provide don't appear anywhere in the first paper linked. I opened some of the papers and didn't see any with n=30.

Patrick quietly dropped the entire first paragraph in the examples list a few hours ago: https://web.archive.org/web/diff/20191118190006/201911190530...

Oh wow. I think that is a bad style. Once your article gets that discuss you should not simply delete an entire paragraph but rather comment on it...

Thank you.

If the effects are permanent then your results would be inconclusive if studying the same people transferring between polluted and non polluted universities.

> "Exposure to CO2 and VOCs at levels found in conventional office buildings was associated with lower cognitive scores than those associated with levels of these compounds found in a Green building." – Allen et al 2016. The effect seems to kick in at around 1,000 ppm of CO2.

The last time this came up I bought a CO2 meter for my office. I was quite surprised how often it went over 1,000. Outside air runs around 450.

I increased the duty cycle of the house fan, and open a window when it reaches 800. Right now I'm at 505.

Buying the meter was a really good investment.

In the comments on that lesswrong post from a few years back, you raised a good question that is perhaps easily answered:

    it has the same issue as Kurzban's blood-glucose/willpower
    criticism: if the brain needs more oxygen than it's getting
    why doesn't one simply breath a little more? While sedentary
    during these sorts of tasks, you have far more breathing
    capacity than you should need
Seems quite likely (or at least very possible) that we've outpaced evolution here, right?

Prior to the industrial revolution, seems our bodies would never have needed to adapt to a rapid spike in environmental CO2 levels. Our brains are necessarily good at signaling the body when they need more oxygen; they're not necessarily good at realizing when they're dealing with other issues they're not adapted to react to.

I believe there may be a common misunderstanding the relationship between CO2 levels and oxygen in one's body, at least as it was explained to me by doctors during my mom's struggles with COPD.

Blood oxygen saturation levels and CO2 levels are not inversely correlated. One of the problems with late-stage COPD and reduced lung function is that while it's relatively easy to get a person's oxygen levels up (just administer oxygen!) they still suffer the effects of excess CO2 in the blood. A late stage COPD sufferer can have > 95% O2 saturation in their bloodstream and still suffer the other effects (including cognitive issues) that result from the excess CO2.

(Apologies for responding you wrote four years ago)

Thanks for these links Gwern, down the rabbit hole I go. But how would you summarize the situation? Is it that there's not a definite study that proves the whole thing?

One of the big trends in green/sustainable building is creating relatively air tight buildings in order to cut down on heating and cooling costs (see: Passiv Haus, Passive House, Pretty Good House). In order to do that, though, mechanical ventilation is needed. As a result, Heat-Recovery Ventilation & Enthalpy-Recovery Ventilation residential units can be installed for only $2k-$4K. Seems like a worthwhile investment (for when it’s not convenient or possible to open a window).

I live in a relatively new apartment building that has heat recovery system installed in all apartments by default. My apartment is 73sqm, the ventilation unit is rated at 300m3/h. The building is located in a busy part of town with lots of traffic around. The city has a humid continental climate (Dfb) so it does get pretty cold during winter.

It does help a lot and I couldn't imagine living without it.

- Filters out particle pollution - https://twitter.com/eugenijusr/status/1105740301493260289

- Removes CO2 - averages ~650ppm in all rooms, almost never goes higher than 1000ppm (3 person household).

- Retains up to 85% of heat (based on the specs) using the exchanger, but also has an active electric heater inside that can be turned on in winter for ultimate comfort.

- Removes moisture from the bathroom and kitchen and dumps it into the drain via a separate drain pipe.

- Isolates from the outside noise as you can keep your windows closed shut all the time.

It does have some drawbacks however:

- Up to +6dB noise in rooms when running at full power (I run it at 20% at night which only adds ~+1dB).

- F7 class filters need to be changed every 3-6 months (~50€).

- Air intake grill with a pre-filter mesh needs thorough cleaning every 6-12 months as it usually gets clogged with debris in spring and autumn.

Not sure if it's due to these drawbacks or lack of knowledge lots of residents don't actually use their unit. You can tell by the open windows all year round. Most say it's too noisy for them - most probably due to lack of maintenance. Others are just plain ignorant saying opening windows is the only way to get "fresh air".

The other upside to sealing plus mechanical ventilation (instead of leaky-building ventilation) is that your building is always fresh. Leak-driven ventilation leads to a building that is drafty on windy days and stuffy on calm days.

Plus if the leaks involve air circulating though insulation in the cavity or attic, whatever is in there will end up in your house air. That could be dust from construction, parts of the insulation material, or decomposing rodents.

Unless the system is of exceptionally poor design, air is never moved at enough speed to pick up dust.

If it is, the whatever dust that gets picked up ends up in filters in the first week of operation.

Except these heat exchangers have two filters that need cleaning very 3 months and most people never do it, so they don't really function properly.

Is the 3 months interval a regional thing, or based on the heat exchanger? Mine have 1 year intervals, and with a subscription for filters it is easy to remember to change the filters

>Is the 3 months interval a regional thing, or based on the heat exchanger?

both. That is it varies between different units but also varies with local conditions, if your local conditions are "heavy-duty" (very high humidity, smog, area with lots of dust or lots of pollens etc.) you should consider replacing more frequently than rated intervals.

Trouble with passive houses is a) people open windows. b) hate fan noise. c) the designs are brittle and prone to catastrophic failure. d) energy consumption isn't going to an issue over the life of the building. e) In Europe and North America the replacement rate for housing is in the low single digits.

And f) most passive house designs have humidity/mold issues down the road, unless proper and frequent maintenance is done. (I've read about passiv haus and similar a while back).

There is a slow moving disaster in the Midwest where houses constructed in the last 25 years are rotting from the inside due to leaks and internal condensation. Problems are. Sealed construction means moisture can't escape. Think insulation hides problems until major damage occurs.

I'm also skeptical because houses we build today should be in use a 100 years from now. And it's really obvious that renewables aren't supply limited like oil and gas. But in the passive house world it's always 1980.

We built a ton of them here in Sweden, but the name escapes me. They were marketed with being able to last for 'at least 20 years' when being built, which should have been a warning sign not to spend $1m on for it on a <$100k family income.

Mold is only an issue in hot climate. When it's never above 25C / 75F _and_ humidity is controlled, there is never any mold.

Never above 25C... so Iceland, Greenland and Svalbard? Actually not even those, they are pretty humid above 0 celzius

If we relax "never" to "not more than 60 days a year", that would be most of Canada, northern US, most of Europe and Russia. No idea what's going on in southern hemisphere, but I guess Argentina/Chile and southern Australia are the same.

This obsession with mold looks to me as an exclusively US thing. I have no first-hand data but I guess it's due to insufficient air flow combined with air conditioners pushing humidity all the way up.

Mold is an issue in Finland, mostly for insulated houses with poor ventilation. Many schools and public buildings have mold and other air issues due to saving on heating.

It's pretty rare for it to get above 25C where we live in Scotland - pretty sure it didn't get that warm at all this year.

Cold climate, surely? Mold as a result of internal condensation?

I was talking about internal temperature.

Cold climate results in low humidity. If you're mostly heating your home (as opposed to running aircon 24/7), air inside tends to be of lower humidity than outside. So low that it becomes uncomfortable and one has to use humidifiers.

The only place mold has any chance in those conditions are the leak spots on the fridge door seal.

I think the Passiv Haus standard of 0.6 air changes per hour at 50 pascals is kinda nuts, and likely not worth it. The more relaxed "Pretty Good House" goal of 2 ACH is still pretty tight and requires ventilation, but is a bit more forgiving and acknowledges that a moderate amount of electricity for HVAC isn't so hard to come by. The catastrophe with older houses in the Midwest (where I'm from) is that they'll each put out a dozen or more tons of CO2 each winter due to fossil fuel heating.

Regardless, the point is that even if you don't have one of these super-airtight houses, you can still install an HRV/ERV for not a ton of money. I'm considering one for my vacation cabin where the primary heat is a wood stove.

I did the same thing at my office and brought it into a conference room with 7 other people. We watched the CO2 climb to about 900 and then it started going down. Seems the climate control system is also tracking CO2 and it started pushing fresh air in when the level got too high. A nice surprise that we have systems managing this - I don't know how common that is in offices though.

Could be a correlation with heat: seven people in a tiny room can generate enough heat so that the thermostat kicks in.

Anecdotal, but I used to work in an IT department where some areas had good, or at least tolerable, ventilation and some very clearly did not. The difference in moods and productivity between teams in each was distinct enough to notice, but, at the time, I don't think anyone would have thought of CO2 levels as a confounding issue.

I think this is a common (maybe required?) thing in HVAC systems where they detect CO2 and turn on when it climbs too high.

Perhaps when we commit code, we should have a script that adds "this code was written at x ppm CO2" to the commit message :)

I learned long ago to not even try to write code when I'm above a certain threshold of tiredness. I just have to tear it all out again after a night's sleep.

"Written at BAC .04 / couple of pints, no smokes"

I see low CO2 spaces becoming the next big thing for the privileged classes as CO2 levels rise. Weworks of the future will be advertising this as a definite selling point. Mansions with scrubbers getting it down to 200ppm

Opening a window works fine.

I recall reading once that the health of poorer people was better one or two hundred years ago because poorer people ate cheap food - i.e. vegetables - rather than a meat-heavy diet.

Opening a window only works up until ambient CO2, which will continue to rise. A scrubbed interior atmosphere is already a selling point during fire season in the Bay Area.

Seriously, I’ve always thought people in Sydney compared to France were taller and healthier because they have more oxygen... Not only they are outdoors often, but they also have less stuffy buildings. Classrooms in France are the epitome of “stuffy”, and it’s frequent for me to leave a theater because there is 400 people and the vents are off. The usual reaction is to imply I’m sensitive ;)

After watching this Tom Scott video https://www.youtube.com/watch?v=1Nh_vxpycEA I bought this CO2 monitor: https://amazon.com/gp/product/B00MB93CK8 It worked quite well and showed that I don't have anything to worry about. Now I'm trying to pass it on to someone else. I'll be willing to sell it for half price if anyone is interested.

If anyone is interested it seems you can find (more or less reliable) sensor modules for about $20, such as the MH-Z19, and read it from to an arduino or esp.

sent you an email!

I put one in my son's bedroom and was blown away. He's 3, and calls me in to sleep with him sometimes. It's a small room, and we keep the doors closed so his sister doesn't wake him up and I was blown away by how high the CO2 got with both of us in there: https://www.reddit.com/r/dataisbeautiful/comments/cek4dm/co%...

What did you use to measure? Unfortunately all the ones I've seen linked here are too expensive for someone like me who doesn't live in America. I wonder if there are cheap ones out there that maybe not so precise but at least measure something.

Does anyone know of a cheap IoT type sensor for CO2? It can be any type, even RasberryPi or Arduino based. I'm not interested in sensors without connectivity options.

About the levels, I'm working on an IoT project and I've seen data from a public school that has heating with radiators (so no real ventilation). One classroom with the sensor would routinely rise above 1000 ppm, with peaks over 3000ppm. Then you'd observe a sudden drop in CO2 level and temperature as they would open up a window. It's insane how high it can get especially if the building lacks proper ventilation.

There are a bunch of raw sensor components that you can connect to an Arduino or Pi. I ended up going with the Sensirion SCD30 but also tested options from Amphenol's Telaire line. Both are pretty easy to communicate with using an Arduino.

I haven't tested an MH-Z19 but that's a popular cheap option.

I bought this guy for the office - works well https://www.amazon.de/gp/product/B00TH3OW4Q

I have a slightly more capable one but the results are similarly motivating. Right now I'm more concerned with the particulate counts... if 27 is bad, does 120 worse and going outside into 700+ me dumberer?

inside: https://www.uradmonitor.com/tools/dashboard-04/?open=8200009...

outside: https://www.uradmonitor.com/tools/dashboard-04/?open=8200011...

In the office at work is better: https://www.uradmonitor.com/tools/dashboard-04/?open=8200011...

When I was living in Lakemba this prompted me to rig a HEPA filter outside and run my bedroom at positive pressure. That helped a lot. But I've had to move for work so now I'm renting a cardboard box (ok, technically it's "fibro" on piles with a leaky wooden floor. Outside ~= inside)

What device did you use to capture all the data including radiation?

Click the "home" link on those pages to go to the uradmonitor home page.

From your indoor page, CO2 min is 375 ppm. How did you get that below the atmospheric value of ~410 ppm?

I have no real idea, especially because the outside unit is about 10m away and shows ~700ppm. I will try swapping them to see whether it's a calibration issue, but right now the outside unit is at work with me so I can open it up and take photos.,

On the other hand, a paper on 'Effects of Exposure to Carbon Dioxide and Human Bioeffluents on Cognitive Performance' (2015) concludes that 'only exposures to bioeffluents when CO2 reached 3,000 ppm significantly affected performance of some cognitive tasks. Increased arousal level at this exposure can be used to explain the observed results.'.


Reminded me of the videos by Kurtis Baute: "I sealed myself in a Jar".


Been meaning to do this; do you have a link or recommended model?[EDIT: I see you already responded with the model below - https://www.amazon.com/gp/product/B001PDGFR8/ ]

I'm very sensitive to lack of oxygen in a room. Our office is old and some days they don't run the A/C if it's not hot enough outside, and I feel like I'm suffocating and my productivity suffers.

Where please? What model.

I own this one as well, it's supposed to be one of the more accurate models available for the price

Where did you get the information about this model being more accurate than other models in the same price range?

This was the article that gave me that impression iirc - https://medium.com/@dhh/air-quality-matters-but-dont-trust-f...

I'm not the OP, but I use this one with similar results: https://www.amazon.com/gp/aw/d/B01FYWU2IS

One of these days I'm going to have to rig up something to start the house fan when the CO2 goes above 800 ppm and I think you'd need a different sensor with a realtime output port for something like that.

Direct feedback is cool, but a simple schedule is really easy & reliable. Even occupancy detection isn't all that critical- nobody wants to come home to a stuffy house, and most people's schedules are very predictable.

These days IoT is so widespread that something like a $25 WeMo smart outlet is hard to beat. Hard wired is "best" but a million times more hassle and more expensive.

If you want a reference on setting this up to meet industry standards on demand controlled ventilation practices see ASHRAE 62.1 and 62.2 standards

Curious, did you notice the cognitive effect yourself?

No. But I do notice I think better when jogging - whether that is due to fresh air outside or increased blood flow, who knows. Probably both.

Perhaps you could use one of those blood oxygen saturation meters to find out what is going on.

Which meter did you buy?

Anyone interested should also check out the open source citizen science project https://luftdaten.info/en/

Build your own inexpensive sensor, contribute to the global network. See also https://github.com/opendata-stuttgart

It frustrates me that there are so many of these networks and they don't talk to each other. I deliberately went with a system that measures multiple values, but then I see other people going "we only measure one thing instead of nine so our units cost half as much".

I should try to script at least my systems so they write into as many of the open networks as I can manage.


Unfortunately, yes, the space is fragmented. A long while ago I chose https://luftdaten.info/en/ because sensor firmware, DB, and tools are truly open source (GPL, ODbL, MIT). Next to supporting many sensors, it also allows for your own back-ends (API, InfluxDB). The community is awesome and has hacker values.

The inexpensive part makes citizen science viable in sub-economic and hobbyist settings.

https://openaq.org/ is trying to consolidate air quality data, but I'm uncertain of their licensing and goals.

For people living in the US like me, this is where you find US pollution maps: https://usa.maps.luftdaten.info/

Holy cow, that must be a German project; Germany has nearly 100% coverage, the USA has almost none.

I was expecting China and India to be dark purple

If you want a more international / american version, check out purple air: https://www2.purpleair.com/

Is purple air the proprietary version?

No it's another independent community effort, go read it's about page.

Sorry for a pointless post, but this project gives me the CCC vibes. Y'all should attend one day, it's brilliant! In fact it's so rich in things and hacker exhibitions that you don't even have to go to the talks!

What is CCC? Searching brings up many things.

The 36th Chaos Communication Congress organized by the Chaos Computer Club, a traditional event run by the community for the community. Takes place from Dec 26 to Dec 30 in Leipzig (Germany). Tickets are available on this Thursday (November 21th) from 21:00:00 CET till, judging from past experience, 21:00:01 CET.

Given this is HN and OP mentions attending, they are likely referring to the Chaos Computer Congress, a German tech/hacker conference.

For clarification: CCC is used for Chaos Computer Club, who organizes the C3, the Chaos Communication Congress. Confusion guaranteed ;) for more info visit https://events.ccc.de/

I'd love to set up something like this in my garden. Could I figure this out without speaking German?

Certainly. When using the flashing tool referenced here: https://luftdaten.info/en/construction-manual/

...you simply select the English firmware `latest_en.bin`. Or one of the languages you prefer.


I don't know you, but in every lecture in college that was done in a room with no air flow, I got distracted every five minutes or so. If the proportion of C02 had a cognitive effect that I could feel, then I wouldn't be surprised if other kinds of contaminants do the same.

Can’t find a source, but there’s a similar thing with long meetings — after two hours in a conference room, you’ve added enough CO2 to affect cognitive function.

I think you may be referring to this publication: https://energyanalysis.lbl.gov/publications/co2-indoor-pollu...

From Western Europe I moved to Mexico City. I work and live here now, and this city suffers intense amounts of pollution almost every day. When you take an Uber somewhere they all drive with their windows open (airco's are expensive to run) and you get the full blast of diesel trucks and older cars' fumes.

I came here for a girl. I'm leaving because of pollution. The city is amazing in its own right, but I feel like I'm breathing lung cancer.

Damn, I’m about to go to Mexico City—was planning to stay for a few months, but I hate dirty air. Is it like that all over the city, or just certain parts?

Mexico City sits in a former volcano, so the air pollution of one of the world's largest metropolitan areas is trapped in there.

It's a valley, not a volcano.

I stayed for a week for work ( lot of traffic that seemed typical after walking around, San Miguel Chapultepec, Mexico City, Federal District) in mornings when I awoke and blew my nose into paper tissue it was dark with the dirt? filtered by I guess my nose/respiratory system. This has never happened to me in Northern California or living near downtown Houston/Austin, Texas.

That happens to me when I was living in London too.

It's definitely better/worse in some areas. Condesa is probably your best option.

Cool, that’s where I’ll be staying. That’s reassuring.

This is fantastic stuff. Some personal anecdotes, moving from Ireland to a heavily industrialized city in Northern China definitely felt like a kick to the head to my output.

I've felt similar effects since moving from Sydney to Kathmandu. Looking forward to my eventual move back to Ireland in the coming years not only for my own health but for that of my children. Unfortunately Kathmandu is going down the path of major Indian cities; there are improvements but the lack of oversight on construction / dust as well as older vehicles with poor fuel makes for a lethal combination causing a dust bowl effect.

This really bothers me. I live in a VERY polluted place, and unfortunately moving away won't be an option for me for at least half a decade. What can I do to minimise the health effects of such an atmosphere? I'm planning on getting an indoor air filter for my home.

Buy a cheap PM detector (There are a few on Amazon using the Plantower sensor that are ~$50.) Buy any HEPA air filter for your home. Buy the best cabin air filter you can for your car (Bosch makes HEPA filters for some cars), and try to get your office to install something, or just buy one for your desk.

The hard math of it is that no matter what you do, you aren't going to be able to reduce your exposure by more than 75% or so, because you have to go outside sometimes, so going super high end on filtration makes essentially no difference in terms of total exposure.

As an aside, I recently bought a car that has a cabin air filter, a first for me. I am genuinely surprised at how much of a difference it makes, especially on air quality alert days. (I live in the Bay Area, which isn't too bad, but we've had plenty of Spare the Air alerts this year.)

> The hard math of it is that no matter what you do, you aren't going to be able to reduce your exposure by more than 75% or so, because you have to go outside sometimes, so going super high end on filtration makes essentially no difference in terms of total exposure.

Couldn't you get a mask for outdoor use?


Sure, but what about when you eat? What about when you're exercising? My point is that caring much about filtration efficiency quickly stops mattering after you've done the obvious things, because there are simply going to be times where you're not breathing filtered air, and those will very quickly become your main source of exposure.

This also means that if you feel like you need to get a mask, you should probably get the most comfortable, least restrictive one, even with a worse rating because (say) 90% filtration all the time is better than 99% filtration 80% of the time (if the discomfort causes you to take it off 20% of the time)

You can. However a mask on your face is not comfortable and so in practice I doubt you would wear it unless there was great need.

I wore a mask all day Saturday while working on the insulation in my attic. I can report it was easier to breathe at the end of the day than times I've been in there without a mask. (fiber glass is not easy on the lungs - though there may be some other factor not related to the mask involved). However I also had red marks across the back of my head where the bands were digging in. It was also more tiring to breathe wearing the mask all day.

I think it's more like 99% on particularly bad days, because where I live over 100 ug/m3 is common during the fire season (which is apparently now November to April)

But if you live in places where the particulates are normally low then yeah, cutting from 50 to 5 is hard.

Is the Plantower sensor a very precise one? I'd like to buy an air monitor, but of course there's no way (at least for me) to know which ones are precise and which aren't.

If you care about accuracy, my understanding is that the Purpleair is your best choice. I don't care about absolute accuracy, although it seems to agree within 10% or so with nearby putpleairs.

The main reason for a monitor is just to make sure your filtration is working and sized appropriately. Take it outside, take a reading, take it inside, see if it's a lot lower. I don't see a need to spend a lot for this or install something that connects to my wifi and needs to be updated etc.

Starts with monitoring. Awair or laseregg are good quality monitors. Then you can assess how well filters work.

I think there are masks you can use outside too. You can also check which times of day/days are worst. And which streets. You can carry the laseregg around for local measures.

Just google brands and find that they may be not so accurate or may be calibrated for some specific region of China


So may be better solution are local laboratories with calibrated equipment

Masks are tricky.

Most "light" masks are for huge particles and can't defend against most of dangerous chemicals

Military and science masks are working good against some chemicals and do not protect from another. Except solutions with O2 tanks on your back

PurpleAir also makes an indoor air quality sensor that measures particulate matter: https://www2.purpleair.com/products/purpleair-pa-i-indoor

Not sure how it compares with Awair or laseregg.

I have no affiliation with PurpleAir, but they are pretty popular in Utah.

I'm not sure what _VERY_ polluted means, but you might consider taking up more physical activity. On GCN youtube cycling channel they argued (including interviews with some health professionals) that even if you live in a city with considerable pollution, the positive effects of commuting on a bicycle outweigh the negative effects of air pollution. They were primarily talking about Britain-scale pollution of course. The principle might change if transfered to a more extreme environment. Something to look into.

My hunch is OP lives in an Indian metro. I absolutely do not recommend commuting on a bike or exposing self to outdoor air in any way during a commute in an Indian metro.

Any physical exertion that makes you breathe harder will cause you to take in more pollution, worsening the effects. Even if exercise helps to offset the damage, your best bet in a polluted place would be to do it inside.

There's been studies done specifically on people cycling to work, and IIRC the conclusion was that the overall QALY result was significantly positive. But that does depend on your baseline - for someone who is fit and active anyway the marginal gain might be small, but for the average person the 10+ QALYS you get from being active vastly outweigh the combined (run over + pollution + injury) cost.

https://eos.org/articles/novel-air-pollution-study-gauges-in... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2920084/

It's about the balance of positive and negative effects. There's always some kind of pollution and there's always some kind of benefit from exercise. The benefit from commuting on a bicycle is considerable. Question is how does the effect of pollution compare. If air quality is better indoors and you can do it indoors, great, but for many people commuting is one of the few opportunities to be physically active.

I'm assuming Delhi?

Not much you can do except get out. I've already started moving out for the first 2-3 weeks of November and working from a city like Panjim

Its not difficult, firstly buy a monitor which tracks CO2, PM2.5, VOC:


Tracking CO2 is very useful for internal spaces.

And an Air purifier: https://www.amazon.com/Purifier-Display-Formaldehyde-Sterili...

Why is the first step to monitor it, not 'get a HEPA filter & fan / purifier'?

Monitoring seems like it's interesting to do if you want to, but if you already know it's an issue, just start addressing it?

Yeah, I'm confused by all the comments saying this too, especially since those detectors are yet another nontrivial expense.

If you know you're in a polluted environment, why would you need instrumentation before taking action? To me it's like getting blood work done before you err on the side of exercising.

If you're closing up your house to avoid outside air pollution, you will spike your CO2 levels.

You need to keep enough ventilation going to ensure you don't exceed 800ppm CO2.

You also need to monitor the PM2.5 levels to ensure your air purifier is working.

An air quality monitoring device is an essential piece of equipment for anyone.

> You also need to monitor the PM2.5 levels to ensure your air purifier is working.

But if you don't have an air purifier, and you're concerned about air quality, surely you want to get one before you start worrying about whether or not it's working?

Or both at the same time, sure, my only point is that if there's already concern I don't see the point in monitoring before or without mitigating.

Do you live in Beijing?

We got an expensive swedish air purifier but it still sucked hard (noisy, made the air smell very stale). You might be able to mitigate some of the effects, but not all of them. And if young kids are involved (or you are expecting), screw the career, move.

Did you get an IQAir? I bought the GCmultiGas and I get the kind of stale air, I think it is just hyper sanitized or something. That filter cleared up my sinus issues in like two days.

It’s called BlueAir I think? That life is behind me now. I love living in china, but the air pollution is a deal breaker.

Find one that can filter nano particles.


Essentially all air filters filter nano particles.


That's specific to HEPA filters. Most air filters are not as capable as HEPA filters.

Read the rest of the article. The cheap furnace filter filters nanoparticles too, just not as well. Both larger and smaller particles are pretty easy to filter. It's the ones around 0.3um that are the toughest to filter.

That's brutal! We're poisoning ourselves.

I don’t believe the nature study results presented there. The MMSE is such a basic test that it is almost impossible to score less than full marks unless you are cognitively impaired. I’ve run through it hundreds of times with patients. The other tests are more cognitively demanding. Looking at the Table 1 of that nature study, there appears as if there would be a significant difference in the distribution of ages - couple extra older people in one of the study groups. I think this is a false positive result

Reading his bullet points, I am not sure why the correlation between daily stock market returns and air quality supports the argument that air pollution reduces IQ.

One hypothesis is that part of the short-term stock movements is causing about publicly visible stupid acts, causing either physical or PR disasters of various sizes. That would imply some correlation, but a relatively small one.

Many if not most trading decisions are not executed from a NYC office. The exchange servers aren’t in NYC either, but like that matters.

How do you all monitor air quality?

I personally have a couple of devices (an Awair and a Flow). They seem to under-report PM2.5 compared to purpleair, airnow, and waqi.

The South Coast (California) Air Quality Management District does some really thorough tests on the quality of the various low-cost sensors: https://www.aqmd.gov/aq-spec/evaluations/summary-pm

Anyone want to review this table and suggest a currently commercially available option in the $300 and lower price range? I may have time this afternoon but if anyone does go thorough it I'm interested to know.

Based on my reading of the table, the PurpleAir II sensors seemed to be the best of the sub $300 for PM1.0 (field R^2 of 0.96 to 0.98) and PM2.5 (field R^2 of 0.93 to 0.97). The PM10 readings were not as good (field R^2 of 0.66 to 0.70).

After skimming the rest of the table, it looks like the PurpleAir II sensors might have some of the best field R^2 for PM 2.5 and PM 1.0

That sensor is also available from Adafruit: https://www.adafruit.com/product/3686 I got it hooked up to a RaspberryPi that exposes sensor readings in Prometheus format.

Do you have a PurpleAir II to compare against? I suspect that there will be some extra calibration or signal processing some to make it more accurate that will be missing in the raw sensor.

EDIT: The link we're discussing says this explicitly: "[...] These particle counts are processed by the sensor using a complex algorithm to calculate the PM1.0, PM2.5 & PM10 mass in ug/m3. [...] PurpleAir PA-II uses two identical PMS5003 sensor units attached to each other and placed in the same shelter. [...]"

I don't think you can recommend the PMS5003 as a substitute for the PurpleAir II.

That sensor available at Adafruit uses the same algorithm for calculating PM levels, it's literally the same chip. Maybe using 2 of them yields more accurate results though.

The specs for particulate matter are identical:



The Adafruit sensor is just the sensor, the PurpleAir II is two sensors plus extra logic that processes the readings to give extra accuracy.

You can't expect one sensor to give the same performance as two sensors plus correction logic. If it was that easy, PurpleAir could just put a case on a PMS sensor and be done with it.

If that was true, then why are the specs for the PurpleAir II identical with the Adafruit sensor ?

You provide absolutely no data to back up your claims that there is extra logic on the PAII or that 2 sensors are better than one.

I agree, looking at devices around the sub-$300 price point that were lab tested, PA-II has good performance and seems to be readily available.

If you just want a sensor rather than a full retail device I'd recommend the SPS30. I have one and it's very easy to work with and per that table, is very accurate, while not needing any extra software correction. It's also cheaper than that table suggests: you can buy it for ~$50USD from Mouser.

I have one of these and it's easy to hook it into your home automation stuff as it presents a CIFS share and it's simply a matter of attaching and reading a text file.

However, the damn thing turns on it's front display and backlight randomly at all hours of the day and night. If you are a sensitive sleeper this thing definitely can't be on your list of items. I contacted their support and was ignored. Generally wouldn't recommend.

you can try changing the power saving mode (under 'performance'). it lets you adjust when the screen auto turns off/on

>*Field R2

Under the table is definition of R^2

>The coefficient of determination (R2) is a statistical parameter measuring the degree of relation between two variables. ....

The more - the better. Range [0; 1)

More device in your area === better quality of measurement

Isn't the table sorted alphabetically?


My bad

Measurements from PurpleAir's network of public sensors are available for free.

It's a useful tool if the locals in the area that you're interested in are using PurpleAir's sensors.


The inexpensive SDS011 holds up very well and works for this global citizen science project very well: https://luftdaten.info/evaluation/

I have a uHoo monitor (yes, it is a dumb name).


It logs temperature, relative humidity, air pressure, CO2, CO, TVOC, PM2.5, NO2, and ozone. They are about $300. The device itself doesn't have any UI; you need to connect to it via a phone app.

Do you act on this information? Is there really much you can do to mitigate the effects?

> Do you act on this information? Is there really much you can do to mitigate the effects?

Couldn't you run a HEPA filter to reduce the particulates?


For me just running an evaporative cooler roughly halves the counts, but that's from over 100 to about 50 so it's a kinda of a mixed blessing. But since my rented house isn't airtight or even close to it, there's not a lot I can do other than move.

Personally I have a PurpleAir II filter (as mentioned in a different part of this thread.) I also turn wood in an indoor environment, and run a HEPA filter which reduces the PM2.5 in the air drastically, and quickly.

If you have central air, you can put a good filter in your air return. If you don’t, you can buy a standalone air purifier.

Any idea how good the Awair monitors are? I recall a report saying they were just so-so but Awair recently updated them to be more accurate.

I personally use an IQAir Air Visual which is highly rated and meant to be very accurate as far as consumer grade stuff goes. It's solid, reliable and the iOS app has been great.

That said after installing piHole I noticed it making 17000 DNS requests a day to a non-existent host: https://imgur.com/tPgwGoK

Explains why the DNS Resolver on my router (pfSense) kept crashing at least.

I have pms3003 you can get for about 12 USD on AliExpress.

I bought a small usb-to-serial adapter connected to Raspberry Pi Zero W.

Here's a combo with a similar device here:


There are plenty of comparisons available online, but there's a good overview site here: https://aqicn.org/sensor/

I've built my own "IoT" Sensors by hooking up a bunch of components to an ESP32 on a breadboard. I ended up going with:

- CO2: Sensirion SCD30

- Particulates: Amphenol SM-UART-04L

- VOC: Sensirion SGP30

- Temperature/humidity/pressure: Bosch BME680

After hooking everything up I just wrote some code to pipe sensor readings to InfluxDB, which is connected to Grafana.

In the end I have no way of properly testing accuracy but the sensors are consistent between units and behave as expected when exposed to fresh air, which is the most I can look at right now.

I have an Awair and two Foobots, they're basically completely unreliable and the software for them is pretty bad.

I've been tempted to get the purple sensors because at least the purple map seems reliable (so maybe their stuff is better?).

I have an arduino uno hooked up to CCS811 (a tiny air sensor chip). We're floating around 550ppm C02 right now, but earlier I was terrified as I watched the levels spike to 4500.

I have an Awair. I don't really trust the baseline values but I do trust the deltas. I mostly use it to inform me when I should open a window or turn the air purifier or humidifier on.

I have Xiaomi Mijia Air Detector and Xiaomi Mi Purifier 2S. The air detector reports CO2, PM2.5 and TVOC, Purifier reports only PM2.5.

Dylos AQM is the gold standard. It's pricey though and has an old school interface (no fancy UI, IoT or "AI").

I have a uHoo and it’s been great. The readings are inline with some control sensors I got to test the readings.

Most small particles are bad for health.

Small particle emissions can be anything, diesel cars emissions, stone dust and flour from bakeries. All small particles are bad for the lungs. Long term exposure of air pollution will lead to health problems.

Although all small particles are bad for the lungs, there must be a difference in their effects on brain and organs, depending on what those small particles are made of since PM 2.5 particles pass through lung lining and into the blood to be distributed around the body.

From the original source:

> Stock market returns are lower on polluted days.

I don't want to dismiss the entire article, but I think this points to possibility that there is some bad statistics going on here. I don't see how daily stock returns are proof of, or even related to, cognitive ability on a daily basis.

This is exactly the type of finding you'd expect with p-hacking.

Maybe people are more negative because of traffic, noise and frustrated about getting to work later. I find it hard to imagine a way to control for this short of making people breathe these substances separately and seeing if they actually do have lower IQs. You can then control for the other factors. These all seem to be epidemiological studies that we can't show the pollution is for sure the root cause. It could, for example, be that pollution is 25% of the result for example with more noise, traffic, irritation etc. being the other 75%.

This is probably just a coincidence. Stock markets perform lower on Mondays: https://www.macroption.com/stock-market-performance-volatili...

Traffic is probably generally higher on Mondays, though I have only anecdotal evidence.

The journal article explicitly calls out day of week and controls for it...

Heh, a rare example of the "proof of correlation isn't proof of the absence of causation" fallacy. No reason that stock markets couldn't perform worse on Mondays because of the extra traffic pollution.

But it's not like companies provide daily sales performance data to trade on. Markets move on speculation. They aren't actually pegged to company performance.

How would lower cognitive ability make markets move lower on a daily basis? All I can think is higher pollution creating greater pessimism among traders.

Markets aren't perfectly efficient. Some trades are dumb. People with lower cognitive ability are more likely to place an order and forget to check fundamentals first, forget to check competitor data, or quiet frankly make whopper mistakes like confusing a ticker symbol. Think of the loons you see on /r/wallstreetbets and other spots. They live on a spectrum, and all of us have bad days.

People with impaired cognitive ability are more likely to make dumb mistakes. That seems pretty obvious to me. The only question is whether or not the effect is large enough to measure using a coarse statistic like this, but that's a quantitative argument.

Yes, but for most dumb trades, there is someone on the other end making a deal. So the 'dumb' trades would have to lean more towards selling rather than buying.

Perhaps pollution just makes one more pessimistic and therefore bearish.

??? Who ever said correlation => not causation.

Pretty much every internet comment section for the last 2 decades.

I don't think so. `Correlation => Causation` is used all the time - this is the bread and butter of clickbait headlines and articles "new study shows that...", but `Correlation => ^Causation` requires some sophistication to state ... while being wrong at the same time. Maybe a tactic used to mislead? I haven't seen it ever used.

To be clear `Correlation => ^Causation` is different to `Correlation => TRUE`. (In other words, there is nothing you can deduce from correlation alone).

Read the linked journal article; the authors don’t actually claim it is about cognitive ability, they attribute it to lower risk taking on those days.

As someone who works for a quantitative hedge fund, you wouldn't believe how many similar results I see of researchers showing a statistically significant predictor of stock market returns. Almost every single one of them is garbage.

But your point stands. The paper has nothing to do with cognitive ability. So why is it being used as evidence?

Is it even possible for a statistically significant predictor of stock market to be both known to the public and not garbage?

> As someone who works for a quantitative hedge fund, you wouldn't believe how many similar results I see of researchers showing a statistically significant predictor of stock market returns. Almost every single one of them is garbage.

Are you able to share any that aren't (or weren't) garbage?

Here's a disappointingly simple and well known one: Momentum. It produces real, statistically significantly, excess risk-adjusted returns over an index.

The remarkable thing is that it has been well known for decades, and continues to work. Many fortunes have been made by systematically exploiting it.

Ones that aren't garbage are valuable! Until the rest of the market adjusts, and then they're garbage.

Exactly, there is no actionable publicly known indicator. Because the moment it becomes known by a large enough group of traders, it becomes useless.

He could share past insights that are no longer relevant. I obviously don't expect him to give away a stock tip worth millions of dollars.

It's a review article. The paper you mention was just one of many cited. And sure, those are all different papers written by different authors and it's surely not unlikely that there are errors in there. But the reason for reviews like this one is to point out that all these different results support the same basic hypothesis.

As far as stocks, specificaly: really? People with cognitive trouble make bad stock picks all the time. Most of us have grandparents who have exhibited exactly this kind of mistake. While it's surely true that the bulk of analyst-driven trades are checked by methods that aren't sensitive to pollution (or just by analysts in different climates), there are certainly enough single-decider trades going on to show a small effect like this if it exists.

I mean, no, one oddball stock market paper doesn't prove much of anything. But in combination with a bunch of other research like this, it's worth taking seriously.

To clarify, the paper studied "air quality in the vicinity of Wall Street".

"I don't want to dismiss the entire article"

Good. Because you can't cherry-pick one dubious-seeming journal article and use it as a justification to ignore several completely unaffiliated articles.

I wish the argument against pollution would be the simplest one.

Go to a massively unpopulated area and just breath. Feel the difference? Isn't it intoxicating?

Who gives a crap if umpires make worse calls? Just fight pollution because it's obvious pollution is bad for humans and the planet.

Normally I'm all for extra evidence, but in a situation like this come on. It's basically like immaterial evidence against genocide by saying, I don't know, saying the increased production of bullets to commit genocide reduces national science and health budgets by 12% (fake stat just for context). Who cares! It's just plain bad.


(ps - rant isn't against the article, but a broader frustration about the topic)

I like thinking of it as waste, as opposed to bad. Good-bad is the moral realm. Waste is the realm of practicality. The danger is in causing defensiveness, due to judgment, in people whose open-mindedness would be beneficial. I'm not being apologetic of anyone. It's just that this doesn't have to happen through a dramatic conflict of good v. evil (which probably wouldn't work anyway); there are much better alternatives.

I agree with everything you said. Just wanted to stack my rant on yours there.

I would like to agree with you as I also think trying to find a pragmatic solution is easier than thinking in abstract terms like good/bad, but ultimately waste just takes us to questions about what is being wasted, and wasteful to who. It's a no brainer than relocating to somewhere to avoid emissions can be seen as wasteful for some industries. Besides, framing waste in purely monetary terms, just means that we need to balance the equation for profit, not to what is best for people. The question of alignment between profit and human welfare is still am ethical one.

You haven't reduced the complexity, just hidden it behind the facade of taking "pragmatic economic decisions".

I'd argue that talking about waste exposes the complexity (reality in simpler terms), while ethics or morals obscure it.

When I say waste, I mean the waste in the widest sense: potential, future, life, etc.

For what it's worth, since you mention it, I don't think that capitalism isn't compatible with an ecological society. It's just that if you're gonna replace all values with a price tag, you have to be accurate with your pricing. For example, the price of diesel has to reflect, among other things, the full effect on the environment.

it's just that the amount of waste is way too large for the environment to digest

Solution: everyone must consume less, cut unnecessary things, and there are many in most people lifestyles

We need to quantify how bad pollution is exactly. How many people should be allowed to die because the ICE ambulance can’t reach them or the doctor isn’t able to travel to the hospital or food isn’t able to be delivered for a reasonable price etc.

Want some numbers from our government about pollution?

New coal legislation was pushed through with an intensive study by the EPA....

They said it would kill up to 14,000 people.

1) https://www.epa.gov/sites/production/files/2018-08/documents...

2) https://www.nytimes.com/2018/08/21/climate/epa-coal-pollutio...

You are right that there's a massive difference between populated and unpopulated areas. One is better because it doesn't have as many people. Just by breathing people create Co2. Just by existing people create waste. Not sure how that could be fixed.

Agreed. In a data-driven world, any claim not backed by data will be quickly dismissed :)

George Carlin - "The Planet is fine, the people are fucked ..."

> I wish the argument against pollution would be the simplest one

Arguments against pollution would be valuable if someone were actually arguing in favour of pollution.

If the effect were present, and as large as implied, you’d expect low IQ test results in ultra-polluted Chinese cities such as Shanghai and Beijing. And yet... http://www.city-data.com/forum/world/2348902-china-iq-map-pr...

No that is not what it is claimed. Pollution reduces your IQ, not that it makes your IQ lower than someone else's.

The people living in those cities form a so-called "self-selecting" sample. They are probably, on average better educated, and they recognize the value of education much better. They already would score higher than the others, that's why they moved to the city.

It might just as well be that the same people would score far higher in a non-polluted city.

The original post doesn't mention IQ. IQ is a terrible metric for studying short-term cognitive effects.

IQ has a bad rap (rightfully so, thus no disagreement there). In the cited works they use tests that in the past were called IQ tests - though here all are called cognitive-scores.

Why wouldn't IQ tests be great for studying short term cognitive effects? I would trust their values for these type of studies the most: how does lack of sleep, being drunk, after exercise, etc affect your ability to solve abstract problems.

It has far fewer variables to account for than predicting someone's long term success.

> Why wouldn't IQ tests be great for studying short term cognitive effects?

IQ testing is designed to test for intelligent behaviour, which is largely based on long-term neurological development. The connections in the brain, densities of neurons, and long-term potentiations don't change greatly on a short-term basis. Measures which fluctuate based on spot-performance factors are typically deemed unreliable for the purpose of IQ testing.

Cognitive deficits caused by exposure to drugs and other substances tend to impact functioning of the neurons, and are detrimental to measures of intelligence, but are more appropriately measured by more specific tests, which focus on factors such as reaction time, or motor accuracy. Consider the cognitive tests performed by police when driving under the influence of alcohol is expected, for instance. Such cognitive tests also help provide a clearer picture of how a substance affects the brain.

I believe that IQ tests (at least the majority of those that I took or seen) are mostly built as abstract problem-solving tasks, similar to those needed to be productive in modern society. Not sure how one would even measure the "intelligent behavior" that you mention.

In addition, to me, it sounds that you are arguing that a test on which you do worse when tired, sleepy, hungry etc. is not an appropriate test because it fluctuates depending on your state of mind. I don't get that.

> Not sure how one would even measure the "intelligent behavior" that you mention.

I meant behaviour in the general psychological / cognitive sense; how an actor responds to stimuli.

Current popular IQ tests are designed to test many facets of intelligent behaviour -- verbal comprehension, arithmetic, working memory, symbol searching, etc. Abstract problem solving is only one category of testing.

I'm arguing that to study short-term cognitive deficits, it makes more sense to use other measures of cognition. It appears this is actually what was done, but this was incorrectly re-reported as "IQ".

Large cities tend to concentrate IQ as smart young adults come to seek better fortune. Furthermore Chinese party selection system, which involves standardized tests and relocation of gifted children to better schools in big cities also contributes heavily.

Pardon my ignorance, but how is this IQ data obtained? It is reported by the government? Are IQ tests standardized?

>IQ tests standardized?

IQ tests can't be standardized across cultures. Even something like Raven's Progressive Matrices has a cultural component. https://www.apa.org/monitor/feb03/intelligence

Also China has some issues with the way they report scholastic achievement that make their results appear higher than they should. China is very selective about which students take standardized tests that are used for global comparisons--they aren't random samples.

Just because a test might have some component you can vaguely articulate as having some cultural influence does not make the test itself invalid for comparison across cultures. Claims that basic pattern recognition is somehow not a valid means of assessment across cultures are dubious at best.

>does not make the test itself invalid for comparison across cultures

If you can't accurately quantify the cultural component, then yes it does.

>Claims that basic pattern recognition is somehow not a valid means of assessment across cultures are dubious at best.

Basic pattern recognition isn't the only thing that's being measured--that's the problem. Even something as simple as how often a student has been exposed to a matrix of rows and columns has an impact on performance. Repeated exposure to similar tests also increases performance.

If it’s the best thing we have, then it’s worth using. You are proposing no alternative.

If you have only one poll with an unknown margin of error and it shows Candidate A at 51 and Candidate B at 49, then assuming Candidate A is winning just because it's the best thing we have is worse than just admitting we don't know.

Wrong information is often worse than no information.

That's one of the problems with PISA results. Policy makers look at other countries with higher scores and try to emulate them without understanding why their scores are higher. In that case it's just cargo culting education.

This doesn't mean that standardized testing is completely useless, but you have to know the limitations, and comparing results between cultures is one of the limitations.

All IQ tests are (ought to be) standardized for the target population.

The median IQ should be 100, with a standard deviation of 15.

If the median IQ is not 100 over the population, the test is flawed.

Intelligence researches don't use normalized IQ when they compare intelligence across target populations or across different times.

They use raw IQ score data.

Seems hilarious to assume they can be standardized within a culture too, whatever a culture may be.

but that's what IQ test are, standardized tests.

not sure where hilarity comes into play ... it has well defined statistical properties

perhaps you mean that the results of IQ tests can be, and often are grossly misinterpreted, that is not related to standardization

Yep. And that helps many IQ tests to be biased (consciously or not) in favor of the interests (and assumptions) that create the tests. EG a written test will inaccurately 'measure' the abilities of people who (for whatever reasons) can't read well. Those who are well-fed and -slept, secure, unfraid, healthy, and enjoy lots of educational opportunities will arrive for the test with an advantage.

Yeah, the reality is that you'll never be able to get reliable/unadulterated data on something that is both as personally impactful and as loosely defined as "intelligence". Everyone is going to bias toward interpreting the mode of thought that is most similar to their own as the definition of "intelligent".

Very few adults are comfortable with the idea that any substantial group of people are objectively more intelligent than themselves, because admitting that comes uncomfortably close to relinquishing autonomy, at least in contemporary Western understanding that says the more intelligent should rule.

European history throughout the 20th century shows the horrifying, depraved danger in capitulating to a ruling intelligentsia. We should earnestly hope that no group allows their self-interest, protected by native instinct, to be overridden by the despotic, unfeeling ideologies of "intelligent" rulership. That philosophy has shown itself over and over again to be a quick route to starvation, genocide, and widespread desolation.

Nevertheless, IQ is the most general/objective measurement we have, and it seems to be a reasonably good approximation on aggregate.

> European history throughout the 20th century shows the horrifying, depraved danger in capitulating to a ruling intelligentsia.

If you're referring to communism and national socialism here, those were rabidly anti-intellectual (the later particularly so).

The whole point of IQ is that it tests common factor (as in factor analysis) underlying different tests. There is known correlation between different testing methods.

It's official data released by Chinese. Which helps explain why Han Chinese are on top of the list.

I don’t think that explains it. Especially when you compare results with other countries with a large Chinese population like Singapore, Malaysia, and Indonesia.

How long have they been that polluted though?

Looks like that map is from 2005.

Recent Radiolab podcast talks about the one and maybe only benefit of IQ testing is geographic screening of toxins. For example, lead paints and lead as a fuel additive cause over a large sample a cumulative drop in IQ of 4 points. The statistics actually were the way this negative health effect was discovered in 1979. Testing for lead in the body that has replaced calcium isn't otherwise easy test (requires bone sample, or cleverly, kids' baby teeth).


I highly suspect toluene has something to do with it, seeing as how it's a potent neurotoxin and a byproduct of burning fossil fuels.

There's a study[1] by Richard Muller from Berkeley Earth that proposes an equivalence between air pollution and daily cigarettes smoked. He uses the number of deaths caused by these 2 factors as a common denominator to calculate the equivalence.

I believe cognitive cost would also be a good denominator. Something like "we find that an increase of 10 µg/m³ raises the probability of a chess player making an error by 1.5 percentage points. The same 1.5 percentage points would be caused by smoking 2 cigarettes per day."

Plug: I'm the author of an open-source mobile app[2] which does this pollution-cigarettes conversion. I think cigarettes gives a strong image of air quality for those who are unfamiliar with AQI.

[1]: http://berkeleyearth.org/air-pollution-and-cigarette-equival... [2]: https://shootismoke.github.io/

So logically living and working in the countryside is optimum for your IQ rather than polluted cities and areas?

The countryside can have some bad environmental problems too (expansion of fracking in the rural Midwest of America, etc).

Does fracking cause much air pollution of the type discussed in the article? I thought the main issue was groundwater and earth quakes , and methane gas release / flaring.

Plus there are many countryside areas with no oil.

Well to their point, there is more wood, brush or other similar types of burning in rural areas. Especially wood in the US as it is the source of heating homes in rural areas. Bonfires, etc are also more likely.

Whether or not that translates into more risk for your exposure to small particles is probably related to where you are (e.g. are you inside the house while the wood is burning, probably, so you are close to the source of it and probably have a lot of small particles around your house that get brought in every-time you open the door).

If its so rural that its just you for some distance then this might offset the fact that your wood burning stove is (probably) not providing any sort of filtering that a catalytic converter, control systems to more fully burn the fuel (so there aren't as many byproducts), or other devices normally used to remove byproducts of combustion. So it comes down to which of those byproducts are most toxic to you comparatively to other forms of pollution, the density of those particles and where you are in relation to them is going to determine your daily exposure in your environment.

Pretty sure there's more smoke from forest fires near California cities than smoke from brush fires in rural towns.

I don't know of anyone who uses a wood stove. Most would use natural gas, propane, or electric. Electric is common until you get too far North, then it's cheaper to get fuel.

It's very nice to live out here. You can see the stars and breathe fresh air.

Source: live in rural town.

Wondering where the optimum place for humans to live is, assuming around healthy agricultural practices (away from BigAg) without to much wood smoke pollution

The bushfires act as a counterbalance in Australia ...

Too true. I live near a significant recent bush fire & had my first run for a couple of weeks this morning - clear breathable air is a joy! These periods are pretty uncommon however - compared to the regular temp inversions & associated low air quality in Brisbane, for example.

Admittedly with the current climate collapse gaining pace at breakneck speed, it's possible that this may be the 'new normal' for the Australian bush very soon.

David Heinemeier Hansson (DHH of Rails fame) gave a great talk on this recently, though he focused more on indoor air quality and its cognitive impact:


My takeaway from this: If you live in new construction (owner, or renter), buy new furniture in the spring/fall when you can leave the windows open. Same for paint.

Anyone seen analysis or similar data for noise pollution?

This open source air quality citizen *science project now also has noise sensors going: https://luftdaten.info/laermsensor-bauen/

Plug: if you care about this topic and are interested in working on this problem, we're hiring at Aclima. We've got contracts with the major air quality regulators in California, and are looking to scale. Ping me at igor@aclima.io

Do you work with https://plumelabs.com ?

I live in Northern India. On occasions when I visit cleaner countries like NZ, Singapore etc. my productivity goes up. I thought this was because my colleagues were absent. Maybe PM 2.5 is also to blame!!

I have done some research into a budget home CO2/PM2.5/VOC sensor, and if you don't mind sending data to China, Cleargrass Air has awesome functionality in a nice design (plus mobile app) for about $130


Sydney is having a bad day :-( https://aqicn.org/city/sydney/

We would call 159 a clean air day in Beijing.

Forest and bush fires suck. Even Seattle air can smell bad when the wind blows in smoke from a big forest fire up in BC.

Sydney radio loves comparing it to Beijing. Then reminding us that we've just got that for a day.

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