In addition to lost life, there is also a cost to quality of life. Air quality is one of the biggest contributors to the risk of senile dementia. But also the gas composition is known to affect cognition in the short run as well, with a measurable difference in cognitive tests when indoor CO2 is elevated.
> On average, cognitive scores were 61% higher on the Green building day and 101% higher on the two Green+ building days than on the Conventional building day (p < 0.0001). VOCs [volatile organic compounds] and CO2 were independently associated with cognitive scores.
> Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios, 0.06–0.56), but performance on the focused activity scale increased.
No need to bring in effects to cognition, even. It just sucks to live in a place where “(tonight’s run|tomorrow’s hike) is canceled because the air quality is shit” is a thing.
I think it’s highly likely that in 20 years we will view diesel cars like we do leaded fuel. An insanely bad idea that we knew was bad at the time but continued to use.
Man, that article is a bummer! I grew up in a house with an open fireplace and for long periods we literally used it to cook on (out of poverty, not choice). Those are some of my happiest memories. And now some crazy "rationalist" wants to take away my open fire? IT'S ALL LIES I SAY.
> I have discovered that when I make this case, even to highly intelligent and health-conscious men and women, a psychological truth quickly becomes as visible as a pair of clenched fists: They do not want to believe any of it.
LOL this happens whenever I talk about this issue with people here in Poland. Part of it is their family is here, it's hard to immigrate, deep down they know it is a problem. It was upsetting to tell my Polish wife that we need to move out of Poland and to scary USA but... she agreed with me and we're doing it. For us, the risk of death is far higher here with all the smoke. Even the California wildfires are relatively harmless in comparison, we get that every year in Poland and no one cares, at least in Calfornia everyone recognizes that it's a problem and people stay at home.
But here, wood burning(or even coal burning), is a part of the culture, giving warm fuzzy memories at granny's house burning horrid things in the furnace for others to enjoy.
I think some people are so afraid of dangers to their health that they are even afraid to acknowledge them. I think I've seen a lot of this during the pandemic. When you try make people acknowledge the dangers they are facing they are going to panick and defend their peace of mind furiously.
Anyways, good luck in the US. Avoid getting shot, having a pool, drinking sugared water instead of water, any medical issue and getting on the bad side of the law in any way. ;-)
You realize your risk of death of air pollution in polish cities is 160/10,000 people? In the US the risk is 5 in 100,000 people.
sugar water will be a problem, I did not like this about the USA.
medical issue - with FAANG you're fine
bad side of the law: in the communities we live in faang, again, not a problem, you're on the right side of the law. Unless you're black, then that is quite a problem unfortunately.
> Nothing else is so important while also being so easy to address.
It's actually not that easy to address if you don't have extra cash laying around. Most people in the world will not do the things on this list.
Other things it leaves out, like frying food (edit: I'm a moron, it does mention it down the line), or buying furniture or clothes that off-gas VOCs, or living or working in a place with fiberglass-lined air ducts, or using a gas range or oven.
HEPA filters cannot remove nanoparticles and ionizing filters ionize the air, and well, ozone is not good for us. So plants are far superior in this regard to air purifiers, which are useless
Wish I could remember where I read it but the conclusion was that having indoor plants solely to increase air quality isn't a good idea. Obviously it's somewhat better than nothing but so minor as to be largely insignificant given how much air exchange there is with the outside world when you aren't on a shuttle
The other issue with plants is that having them in any decent numbers means you’re likely to have at least some with a mold/fungus/pollen issue, so they actually reduce air quality. Outdoors that’s not so much of an issue because there’s airflow and the mold/fungus/pollen is dispersed, while inside your room it’s limited to a very small amount of still air.
and doesn't filter CO2 in any way measurable. You would need your entire place filled with the right plants to make a difference. I tried, and failed at this when I realized I'd have to get way more plants.
How is it possible to separate DALYs lost from high BMI from DALYs lost from low vegetables and/or low physical activity? The author never fully explains the methodology behind the graph.
I don't understand how the author arrives at the conclusion that "[air quality] is often the most effective health intervention, period".
How do you take that away from the plots? If you're in the US my prime take-away would be to keep your BMI in check.
The first graph shows ~2 deaths per 1000 people per year. Surely more than 2 persons/1000/year die in those countries. What are the causes for the other ~10-15 deaths/1000/year?
Given the information in the article, I don't see anything to support the central thesis about air quality. The reasoning for it is so thin that I have no idea whether it's true or not.
Most of the world lives outside the US, so "often" would seem to apply to the potential improvement in DALYs.
BMI reductions are also notoriously difficult, while many of the mitigations listed in the article are low effort and relatively low cost. You could plausibly include this in your comparison of effectiveness.
Thank you for this extensive resource on air quality. Yes, it needs to get more attention as it is one of the main drivers of mortality of environmental risks.
One thing one has to bear in mind is that often when you optmize your home for low PM (e.g. with air purifiers and fixing of air leackage) your CO2 will get very high causing headaches and reduce cognitive performance.
So it always makes sense for indoor air quality monitoring to measure PM and CO2 in parallel.
We have open source, open hardware build instructions for a very reliable Air quality sensor that can be used to measure PM2.5 and also CO2 [1]. It is very accurate for the fraction of the costs of commercial sensors. You can build it for less than USD 20 (or with CO2 for less than USD 50) and send the data to our cloud server or any other backend.
I am more than happy to send you some free PCBs (you just paypal me the cost of the postage) and you can build your own sensor and log the data. Contact me if you are interested.
I've seen a study or two that claim that the bulk of some PM, like brake dust for example, is much smaller than 2.5um. Having exposure to the industry, do you have hopes for sensors that can identify smaller particles than .3um (that's the smallest Purple Air goes).
How should someone contact you? I looked into setting up something on an Arduino last year, and the CO2 sensor I ended up purchasing was not very good, so it's cool to see someone thinking about this problem domain.
Yes the Senseair S8 is very good. Only problem is that the automatic baseline calibration sometimes needs 7-10 days to kick in. But you can also do a manual calibration.
We use the Senseair S8 CO2 sensor which is very accurate and of high quality.
Some of the TVOC sensors give an estimated CO2 level (eCO2) which is not recommended because these values are not very accurate.
In practice, how does one try to achieve a balance between CO2 and PM? Do you open the windows for a while when CO2 is up and PM is down, and then close them and run your purifiers when CO2 starts to go back down? Is it possible to keep both low with HEPA filters on the windows?
The best case solution would be a passive house with MVHR (Mechanical Ventilation with Heat Recovery) and incoming air filtration. This means your home has a steady flow of fresh, low-CO2 air that is filtered for pollen and other particles (depending on the air filter chosen).
Another solution is to install a positive pressure system with high performance HEPA filters. This is especially recommended if you live in areas with very high air pollution.
i put my air purifiers on low when the windows are open to deal with the particles i throw up by moving around and doing stuff indoors. with the windows closed (usually only at night), i put the air purifiers on medium/high.
i live in LA on a relatively busy neighborhood street and according to my air quality meter, it’s true. concentrations go down during the day (windows open) and up at night (windows closed).
edit: i mentioned the road to note that outdoor pollution is higher during the day, yet opening the windows despite that lowers overall particulate levels indoors. it may be different in indian cities or cities like beijing with much higher pollution levels.
The crazy thing is there are no nearby cars. There is a highway about 1.5km away which I assume it must all blow from. There is nothing else within 1.5km
> co2 and pm should both go down with windows open.
Very much depends on where you live. I have a few DIY air quality stations with data being piped to Grafana. I just looked at the latest data, the average outside PM level for the past 5 months has been around 100 µg/m³, while inside it's around 10 µg/m³.
This spring happens to be pretty windy and this skews the outside levels down, otherwise the ratio would be much worse.
I keep my HEPA filters on with the windows always open.
If the air quality is decent outside, it is easy to maintain a PM2.5 rating of near <10 like this.
In California fire season I have a box fan on high in the window pushing air in (and sealing the areas around the window) through an MPR 2800 furnace filter (which is better than the 99.97% rated hepa filters, would be marked as a ULPA filter I believe in different contexts) with this I can maintain the ~0 PM2.5 rating inside even when the AQI outside is >300 while keeping CO2 in check.
It's been quite surprising how easily the CO2 spikes with closed windows and doors in the bedroom with just one person... I essentially always have a window in each room open several inches, cracked isn't enough, usually with at least one fan pushing air through a window.
A solution that one of our customers uses (Prem Tinsulanonda International School) is the installation of a positive pressure system. They are able to achieve near zero AQI in their classrooms when you have more than 300 US AQI outside.
I don't know the answer to that specific question, but I do know it's an NDIR sensor. The Wikipedia page on that sensor type likely answers your question—
Also in Canada and interested in getting some PCBs. Not sure if OP is selling if not i would be into splitting the cost of getting a batch made if its economical
That's a great resource, thank you. As a tinkerer who is already quite far down the ESP8266 rabbit hole, are you able to tell me if your software distribution has any particular "special sauce" around the interpretation of the data from these sensors? Or is it predominantly glue between the sensors and the OLED display / your cloud service?
I am interested in replicating your hardware stack but implementing the software stack using the esphome framework which supports all of the components used in your DIY solution.
There is no secret sauce needed. The Plantower sensors tell you the PM2.5 in micrograms directly and we just display it to the OLED display or send it to a server. It is all open source so you can check the code.
I'm definitely interested to build one of these. Located in Vancouver Canada. Maybe you can mention in a reply to your own post how people can contact you (if you can't still edit your post)?
I have an AirVisual Pro, which is quite expensive, but my half finished air quality monitor project had been on the bench for much too long.
I have windows open all the time, air conditioning on too often, and dehumidifiers and HEPA filters as well. It is not efficient or particularly environmentally friendly... but I want a CO2 level < 800 ppm and a PM2.5 level under 10... so here we are.
My next half baked idea is figuring out a way to have a sealed home and an appliance (or messy bench-top device) to remove CO2 from the room continuously and exhale outside -- current ideas revolve around using a carbonate (lithium? sodium?) in water in an electrolysis cell and an aquarium bubbler to collect CO2 and expel it outside. The best I've been able to accomplish so far is baking CO2 out of baking soda (sodium bicarbonate) and sealing it in about a cubic foot container and achieving ~300 ppm CO2 (lower than outside which is ~400-450).
Bubbling air through quicklime slush is an easy way of removing CO2. You can turn the calcium carbonate that forms back into quicklime by applying heat.
But it's probably better if you invested into a counterflow heat exchanger for ventilating your home. You can recover a large part of the heating/cooling energy.
The question is how much CO2 can I fix with a reasonably sized apparatus and really I would prefer a continuous system (which is why electrolysis) rather than a batch system.
Also I would prefer levels lower than outside, obviously air exchangers will necessarily be worse than just being outside.
I don't know for sure, but there are certain things I notice which I think may have been improved when I started keeping track of CO2 and keeping my windows open. (I don't spend most of my time outside and I certainly don't sleep outside; outside levels might be 450 but inside levels even with my mitigations are usually around 700)
Like so many things I think it is a small effect; it's not like I can go anywhere for a week to experience 300ppm air.
I haven't gone to the levels of designing experiments and data tracking on myself. The fact that I've lived with allergies and a broken nose most of my life probably hasn't helped my personal respiration characteristics.
I'd assume that some chemist or other has already published a paper about that. But you could probably figure it out yourself experimentally by weighing quicklime, letting it react and weighing it again. Start a youtube channel to finance the project :)
Well I've gotten as far as purchasing 20 pounds of baking soda... my experiments thus far haven't been able to remove a detectable amount of CO2 from a room.
My literature searches haven't had much success thus far, lacking a chemistry degree hasn't helped. I have found some things but not enough to come to any sort of engineering designs. I'm assuming it's one of those things that's almost too simple for anyone to have bothered writing a paper about unless they had the exact sort of ideas I did. (OR they're using terms that I haven't been able to come up with yet)
Try buying 20 lbs of calcium hydroxide, it is sometimes used for soap making iirc, so it should be available on amazon. Bubbling air through a concentrated solution should do something. At least at the CO2 concentrations of exhaled air you get visible amounts of insoluble carbonate: https://www.youtube.com/watch?v=Vl9A8Iyc_LY
You might try using oxygen conentrator with high throughput to concentrate oxygen from outside and pump it into your home.
With small device I could drop CO2 levels to zero in volume of a gargabe bag in few minutes.
But that would give you oxygen rich atmosphere. You'd probably want to add some inert gas to that. Nitrogen preferably. Are there nitrogen concentrators?
Also all of that is probably really dangerous because human body doesn't detect oxygen level, just CO2 level. So you might easily pass out and suffocate without any warning if your oxygen supply unit get damaged but your nitrogen supply unit doesn't.
Could you get a few more plants around the house? Plants can remove things like benzene, formaldehyde, xylene, and toluene. Maybe not the fastest but certainly don't cost much once you have them.
Unfortunately this myth, which I also once believed, has been debunked. You just need waaaay too many plants to actually have an effect. The tests the myth were based on all assumed a closed system, which just isn't realistic.
From one randomly googled article on the myth of house plants cleaning the air:
"To remove toxins, you would need at least 10 plants per square foot."
To remove how many "toxins" exactly? Like, let's say I actually have a shitload of plants, like my ceiling is just lined with peace lilies. Presumably there is some % of something being removed, I'd be curious to hear what that is.
But CO2... to simplify imagine being a vegetarian, how much plant matter would you eat in a day? How much plant matter grew in one day in your houseplants? The only way plants are going to fix carbon is by adding it to their own mass. Just think about a conservation of carbon atoms. There's no way any plants in your apartment are going to make a dent in the carbon cycle of your personal environment.
There are arguments to be made for lots of things sticking to or getting sucked into the leaves of plants... maybe if there were a whole lot of plants a meaningful amount of VOCs or other pollutants could be removed... maybe.
If you think about it you have to grow an amount of plant matter comparable to the amount of food you eat in order to maintain levels (considerably less of course because a lot of carbon goes down the toilet, but still a fixed fraction, this would take full sun an a considerable area, like a fraction of an acre)
You are describing an anaesthesia circle breathing system, otherwise known as a rebreather scuba set. :-)
You would need to consider the occupant oxygen consumption. A typical human respiratory quotient is 0.8 (0.8 mole of CO2 produced for every 1 mole of O2 consumed). You’ll get a net inward movement of gas into house all things being considered.
Anyway, don’t do if. If you do it ‘right’ the argon will slowly build up and you’ll asphyxiate. Thankfully achieving that level of seal is very difficult.
If you are really worried about PM2.5, just wear a PAPR.
Oh I'm not interested in hermetically sealing my apartment, there are no worries of normally constructed buildings being able to withstand a meaningful difference in oxygen pressure between inside and outside. CO2 pressure though can easily be increased by a large factor (5x is easy) and maintained with humans inside and closed doors and windows.
PM2.5 is easy to maintain with HEPA filters.
CO2 is not easy to maintain without forced ventilation, and really I would like to try inside levels lower than outside levels. (say 300 ppm)
I’m intrigued by the idea of chemically scrubbing co2 at home as well. Hepa filters are easier to use than I’d expected. The next big step is co2 reduction.
Don’t those requirements conflict? Maintaining a partial pressure difference between inside and out for CO2 but simultaneously preventing a partial pressure difference in O2? I guess with a large enough scrubber running constantly it might work but it will be highly inefficient - a bit like running AC at full blast with open windows.
They do to a degree but overall composition of the atmosphere has so much oxygen and so little co2 that the dynamics are quite different.
There’s something like 50x as much oxygen in the atmosphere as co2 so a relative change of 1% nominal value will correct itself fifty times faster for oxygen than for co2 between outside and inside (ok a wild simplification, but still)
The result is that without really intense sealing it’s basically impossible to make a difference in indoor oxygen levels whereas with even a cracked window i can maintain co2 levels two to three times outdoor concentrations in my apartment.
Running a co2 fixer with the place shut up would be more like... running the air conditioner full blast with the place shut up. Yes there would be losses but they would be relatively contained.
note that the effects of periodically higher co2 concentrations on overall health is inconclusive at best (life evolved with significant co2 around). particulate matter and atmospheric pollutants (like voc’s), however, are most assuredly detrimental to our health, so it makes sense to act mainly on the latter (with air filters/purifiers) over the former.
the point is that humans (and life in general) have entirely evolved with varying levels of co2, so the excess levels found in a fairly closed room is unlikely to be a really serious risk (vs. a sealed room with much higher concentrations, where it's obviously a serious asphyxiation risk). this risk, according to research, is currently inconclusive at best.
the concentrations and types of particulate matter, however, is unprecedented, and as such, presents a higher inate risk, something that scientific research is really only starting to grapple with but so far is showing to be likely a serious risk to many (most?) species on earth.
with that said, i'm not trying to discourage your project in any way, just saying that for most people, addressing particulate (plus voc) risk is likely going to be the overwhelming majority of the benefits to be found in relation to indoor air quality. reducing co2 could be worthwhile if you have an especially airtight room/house, but nearly no houses are that airtight (passiv houses are meant to be so, however).
Block of flats. Apartment is fairly well sealed. If I seal the windows I can drive up CO2 levels to 1500. I have plastic windows with seals that have "unsealed" mode. In this mode window is just barely opened. Like 1mm gap between a window and a frame.
And one window cracked like that is enough to drop CO2 levels below 800 while there's one person in the apartment.
From my armchair-research, there are scale challenges with plants.
Algae is commonly the go-to for CO2 scrubbing for it's relative efficiencies. Algae might scrub 1-3 grams of CO2 per liter per day (https://www.osti.gov/servlets/purl/1485133).
Humans exhale approximately 1kg CO2 per day.
I consider 300-1000 L of algae scrubber tanks per person a lot of volume.
Thank you for all of you interested in getting the PCBs. To send me a message please go to https://www.airgradient.com/diy/ and send me a message with the orange chat button. Thanks!
There was a bit of interest last time I remember you posting on here as well - have you thought about putting up a batch on something like crowd supply? I think it would sell well enough to make it worth your time, and fire season is coming up again soon.
Yes that might be a good idea but I am very happy that so many people are interested in building one and that we can increase the awareness on air quality so I am happy to do the work ;)
Yeah, this is an interesting enough problem to me that I recently started researching how to build an arduino version of what this person is offering - in my head, I basically reinvented the product they're offering, without all of the nasty bits of actually having any idea how it works. I would definitely pay a reasonable amount of money for a set of sensors that Just Worked that would collect data in my house.
Yes, sometimes some components are not available for all countries. Just search for the same sensor on aliexpress. There are many vendors for the same sensor. Some will ship to the US.
I understand how fixing leakages, or more generally, not properly ventilating your place, would increase CO₂ levels, but where do air purifiers come into the picture? Is it just because someone who has an air purifier is also more likely to not ventilate (to keep PM2.5 down?), or are air purifiers themselves somehow bad for CO₂ levels?
I can't guess why they would be, and searching around a bit doesn't seem to suggest that's the case either.
I'm curious whether the issue the author identifies (real or not) with ultrasonic humidifiers applies also to humidifiers that simply blow air through a wet membrane..
I have both a humidifier and purifier working 24/7, several meters apart and I've noticed that tap water in any form does make the purifier work harder, but demineralized doesn't.
I've got an ultrasonic humidifier. I found that running it for a few hours with Brita filtered water made my whole room full of white dust. So I started using only distilled water. Since getting distilled water means I have to walk a few blocks and refill a 10 liter container every two days, I'll probably not buy an ultrasonic humidifier in the future.
This seems pretty poorly researched, or at least poorly presented.
The numbers the author uses to quantify "life cost", as far as I can tell, come entirely from one graph in the section "A heuristic to quantify harms". The author examined the life-years lost from exposure to ambient particles in multiple countries around the world, concluding that
>being exposed to 2500 PM2.5 for one year costs 1 DALY
But that line comes from a chart with a range of about 10-100 describing constant exposure to ambient particles. Even if we assume the author's line is correct, identifies a real effect, and correctly ascribes causality, it is not reasonable to draw the conclusions they do.
The author speculates burning a cone of incense, which will produce a concentration of about 4000 for a few hours. This is forty times the largest value on the graph and is some 100,000 times shorter in duration. It is ludicrous to try to extrapolate without a great deal more evidence.
And, obviously, the types of particles found in the air outside are not the same as the ones found inside.
It's a shame that there is some good information on this page ruined by this one bit of shoddy statistics.
This is a good list. One other important thing to do if you can help it is to never live near a road. Any road, even infrequently driven on ones. If there's only one car per day on a road, but you live ten feet from it, and occasionally the wind blows the exhaust in your direction, you're breathing that in. Walls don't help. Live at least one mile in a straight line from highways.
That's a more ideal solution, but it's probably faster to move than for a city to make changes like that. You can try to stock up on food and grow crops to minimize driving.
put urban roads (and parking) underground, and use industrial scrubbers at air exchange. expensive but worth it. tax fossil fuels/carbon to subsidize this and internalize the environmental costs.
yes, but this way, we could have our (expensive) cake and eat it too. we could free up the above ground streets for electric buses, pedestrians, bikes, malls/parks, and the like, make cities denser/more walkable, remove asphalt/concrete to lower the heat island effect, add trees/plants everywhere, and all sorts of human centered stuff. it’s not so realistic (though the boring company may help with that), but what a vision it is!
To some extent yes. I remember one of my first experiences in Chicago taking the Metra Electric from Hyde Park to downtown and getting out at the north entrance which dumps you out at Lower Water Street, which is very disorienting if you are not familiar with the area.
Where I live it takes several years to paint a pedestrian crossing. Even if we decided to put all traffic underground, nobody alive today would see that project finished.
Often things are said to the effect of it being weird that we're capable of spaceflight, but infrastructure is too hard and expensive. The lack of fluidity in the labor market, i.e. pinning people to a field or worse, a company, for a lifetime creates a lot of that inefficiency, I think.
I know the idea is that specialization is good for everyone, and people doing certain kinds of work should be good at it, but I think allowing more diversity in the types of work people do, more intermingling, and more fluidity are realistic goals with a lot of advantages. We already have a big problem in matching qualified people with jobs efficiently. If we get substantially better at that, we can do it more rapidly, and allocate resources much more intelligently, since demands change in every profession as things develop. I would actively welcome breaks in my knowledge work to do the many types of "dumb labor" I can do when it's useful. It's something to ponder.
i’ve had streets near me repaved twice, many repainted more than twice, and a water main under a street replaced/repaired twice, in the past 10 years, while other pothole-riddled streets nearby are still waiting their turn. it’s inscrutable why that is.
I mean, the article only provides individual tips to fight the global problem of air solution. Extinguishing candles with a lid and avoiding incense won't do shit in the grand scheme of things. It's like putting a bandaid on an open leg fracture.
> IMO, cities should just ban almost all car traffic from the centres so people can live car free without being poisoned.
This would have a much greater impact on the problem for sure, but sadly nobody likes that, some people think owning a car is freedom while it's slavery.
It will take time for exhaust particles to be significantly reduced as a result of EVs, plus, the increased weight of EVs will create more tire and asphalt wear, which is also quite bad (possibly worse).
Regenerative braking largely solves the brake pad issue. Some EVs are efficient enough that brake rotors rusting over from not being used is a concern.
I was thinking the same thing. All this time I had been living near a busy thoroughfare because I assumed it was good for me. I'll have my realtor on the phone this afternoon. How bad could the Texas market be?
I'm surprised "having a bonfire" isn't on this list, but I'm afraid to see how detrimental it might be.
The nostalgia factor is sort of wearing off now that I'm 40 and don't want my clothes to smell bad or have a low-key asthma attack. The last time I went camping in a campground and everyone had a fire going, the whole park was completely choked with smoke that it made going for a walk really crappy. It's such a weird activity, driving cars out to the woods to pay to burn dead trees.
Pretty close to being on the list. "Have a really smoky fire at home. Life cost: 1 day"
Considering the close association of food, warmth, security and socialization with the habitual use of fire for at the very least several hundred thousand years of human history, is it really any surprise that some people still enjoy the practice?
I'm surprised this doesn't mention gas stoves and ovens. Gas is the "high end" option, yet creates totally unnecessary PM2.5 pollution in your home. Children growing up with gas stoves have higher rates of asthma.
Few years ago I moved from a little apartment with an electric range to an SFH with gas everything.
"Good for you," my gas-enthusiast family said, "now you have a REAL stove"
It still takes forever to boil water in a pot. The food tastes the same. I wonder why furnaces have these fancy high-efficiency heat exchangers and stoves don't? Cost?
I wouldn't mind going back to electric. I just assumed it cost more, but maybe cooking isn't significant compared to running a furnace.
It does take a while to boil water (although not nearly as long in my experience), and food tastes the same, but there's essentially zero time waiting for the heating element to heat up. For me that's the big difference -- near-instant control over the amount of heat being applied.
Why would someone downvote that? Pretty lame. I'm sharing my personal, relevant experience. Make a comment if you somehow disagree or thing I missed the mark... Like.. what?
> I wonder why furnaces have these fancy high-efficiency heat exchangers and stoves don't? Cost?
I don't see how a design like that would work for a range. The purpose of a range is to heat small, movable objects (pots) to high temperatures (~500°F) with good responsiveness (= short time constants). The purpose of a furnace or water heater is to heat fluids contained in large spaces or tanks to modest temperatures (~100°F) with very limited responsiveness (= long time constants).
The heat exchanger really helps the case of heating a stream of fluid, as that's where the exchange is most useful. The physical and thermal mass of the heat exchanger and flue condenser are both considerable.
I'm not seeing how to make a gas rangetop significantly more thermally responsive without making it no longer practical. For people who can't abide gas for whatever reason, induction units are supposedly excellent these days. (I've never tried one. They can't possibly be worse than an electric smoothtop range, though!)
Induction stoves are pretty good for dumping watts into water. However, it's very hard to get a good mid-range temperature. Gas makes it really straightforward to get something cooking at exactly the heat you want.
I imagine this will change, though. I would have thought induction hobs are cheaper to produce, since it's just a copper coil and a bunch of power mosfets.
I think I have tried 5 different models in the last few years, from the very cheap, to the relatively pricey, and all were relatively lacking when it came to fine control.
I don't think there's any real reason why they shouldn't have fine temperature control - presumably the temperature is controlled by the switching speed of the mosfets in the coils?
I think it used to boil faster? My grandma replaced her stove and noticed it took forever to boil. The service guy said regulations around the volume of gas have increased the time it takes to boil water.
No idea if that's true or not, but I'd believe it.
I don't think we should do domestic cooking with gas for reasons that include respiratory health, but it's worth noting that the link between modern domestic gas ovens and childhood asthma is very weak relative to other risk factors, which might be why it's not mentioned in the article.
"When the meta-analysis puts everything together, they come to the conclusion that gas cooking produces a small increase in asthma risk for children, perhaps a 1.5 percentage point increase in risk." (https://emilyoster.substack.com/p/gas-stoves-finally)
The study in question: "Our meta-analyses suggest that children living in a home with gas cooking have a 42% increased risk of having current asthma, a 24% increased risk of lifetime asthma and an overall 32% increased risk of having current and lifetime asthma."
To me, a 24% increase in risk of lifetime asthma is significant and well worth avoiding both at an individual level and a societal level, given that good alternatives are readily available.
Given this 24% number, I guess the "1.5 percentage points" you quoted must be the absolute increase in asthma prevalence across the population, i.e. gas stoves in every home would cause 1.5% of people to develop asthma (when they otherwise wouldn't have it). That seems quite bad actually. If true, not using gas stoves (currently in 35% of households) could have prevented over a million cases of asthma in the US alone.
Very interesting to me that gas is considered the 'high end'-option, I presume in the U.S?
Where I live, the high end-option is to get an induction stove. I have one, and it's extremely pleasant to cook on. Granted, I've never cooked on gas because that alternative is mostly not used, in my experience.
Heat is not equally intense or similarly distributed between different stove types. Gas cooking delivers intense heat along a trajectory that follows the curve of the pan, and allows for thin pan materials with low heat capacity. The natural result of this is the wok, which cooks the best over a gas flame on high settings.
Want a restaurant-quality stir-fry? Your only choice is a wok on an intense gas plume. The thin material of the wok gives it low heat capacity, meaning that when you turn on the heat it rises in temperature very fast, and cools relatively fast when you turn it off. This allows very precise control necessary to get the best flavor. The wok is curved, which is critical to mixing ingredients correctly while cooking, but the gas flame does a fine job of following the form of the pan to give adequate heating throughout. Electric or induction stoves come short on both aspects: you need thicker pans (higher heat capacity) with flatter resistive elements built-in. You simply can't get the same flavor with those setups.
So no, it's not so simple as "heat is heat."
Pay attention to the kitchen next time you're in a Chinese or Thai restaurant. They really make use of the industrial gas-powered ranges that are universally equipped in their kitchens.
Gas is popular for the instant and fine grained control over temperature. You get much of the same advantages by using induction. I've had a cheap electrical furnace for ages and it is a bit limiting but you get used to it. Asian wok cooking uses gas burners to get the wok up to high temperature. High temperatures are important for that type of cooking. Another trick they use is to use thin metal for the wok so it conducts heat quickly. That's much harder to do with an electrical furnace but not impossible. If you use cast iron pans, they hold the heat much better and longer. It takes ages for them to heat up though. For flavor, cook over wood or charcoal. That's why outdoor grills are popular and why the gas variety of that is a bit frowned upon by grilling enthusiasts. Cooking on an open fire also is quite nice. But of course living next to a place where that is done is not great for your lungs.
I believe part of the perception of gas as 'high end' is the observation that many restaurants use gas. However, from what I understand, many restaurants use gas because it is the cheapest way to get BTUs into pans - gas is CHEAP, and restaurants use a lot of it.
That said, certain types of high temp cooking like wok cooking require jet-burner gas stoves to get the right sort of flavor, but I think induction is superior in most cases.
Also, high-heat wok cooking, while delicious, is terrible for air quality.
It really depends where you live, where I live in Asia electric (induction) is the high end option and gas is the standard. Electric also doesn't work great with a wok.
Having lived in Central America, I can tell you that almost none of the recommendations[1] here are relevant, at least in relation to the kind of air pollution that kills the numbers of people shown in those graphs. Smoky fires (mostly for cooking) inside small huts are everywhere in much of the world, and very few of the affected people understand the risks. Even if they did, they rarely have any viable alternatives.
If you tried to tell those people about particle counters or HEPA filters, you might as well tell them about cold fusion while you're at it. Sure, all the things mentioned might help, but for anyone with the means to follow the recommendations in this article (and with the ability to read an article), I can almost guarantee that air quality is not going to be a major factor in your life expectancy.
[1] With the exception of "Be careful about smoke when cooking."
It's not just about life expectancy, but life quality. I think we'll one day be surprised just how many mental health and chronic illnesses are significantly attributable to air pollution, in all its forms.
That's a fair point, though I'd still wager that for those of us not cooking over open fires, those effects are likely very minimal - at least in contrast to the people mentioned earlier.
Everything's relative, sure, but pay close attention to your sense of well being the next time you're in a car with an air freshener, or someone sprays febreeze in a room. You'll probably start to feel uneasy and/or have dulled senses very quickly. Do that often enough, and the abuse adds up.
Even here in Poland. People burn anything to stay warm, oil even. The unhealthy pollution starts in November then ends in March. The entire time everyone, including children, are outside, pretending like it's not a problem. People running in the streets. And when you bring it up to people they get angry. Schools don't close, everyone continues like it's normal.
I'm moving back to the west coast USA soon. I could live in a shack and my family would be better off. People complain about the wildfires, but in Poland they get it every year, and for longer. Try forbidding your kids to go out(too young to wear a mask) the entire winter... Even if you somehow make the perfect environment at home, those kids will eventually have to physically go to school and brave pollution. Before the pandemic I was the only crazy one with a mask during high pollution days. If kids wore a mask because of pollution then I was told they would be ostracized.
So, other than that elephant in the room, it's a perfect country.
Thank you. I thought I was the only one in Poland with this view! My Polish wife gets angry when I mention it. I'm trying to rescue us (we have a young child) but she is resistant. Well done for escaping.
Thank you. As a native Polish dweller I'm fully with you on this one. Fortunalelly I have no kids so I just spend winters at home with my air purifier and laugh brutally at anyone concerned if their kale is exactly organic.
Pandemic, making wearing mask socially acceptable really did me a solid.
A simple 20 x 20 Box fan with a furnace HEPA filter placed against it (just turn on fan and place filter behind it) will do wonders for your indoor air quality. The 3M 2200 Series Filtrete Filters are amazing. You also always want to cook with the Hood Fan going. The particulate that is created during cooking is so small it can pass through the lungs into your blood stream causing havoc.
I have 3 running in my home and they haven't been turned off for over 1.5 years, still going strong. The filters I buy at Costco when on sale (3 for $29).
This one has been on the fan 24x7 for the last 2 months and is still good for a couple of more.
As another commenter noted, it depends on your air, but a decent HEPA filter (H13/H14 etc.) will last a very long time if you remove the coarse dust first with a prefilter.
The prefilter is typically a lot cheaper and is replaced more often. Even some non-woven filter fabric (like that used in vacuum cleaner filters) will dramatically increase the HEPA filter life, is super cheap, and can be washed for reuse.
My purifiers use an F8 prefilter and H13 HEPA filter, and the HEPA filter will last about 2 years.
We run box-fan filters during wildfire season here in the PNW and change them out after the season ends. Last year they were quite gray after all of the fires. We run Honeywell HEPA cleaners year round and bring the box fans out to supplement as needed.
> It's not just about life expectancy, but life quality. I think we'll one day be surprised just how many mental health and chronic illnesses are significantly attributable to air pollution, in all its forms.
In the USA yes, especially the west coast. In Poland I was about to get a condo constructed but not doing that anymore, but the process was quite interesting. The insulation blew most everything in the USA out of the water. Mostly because they have no choice given the really cold winters. During the winter pollution gets really bad and if you shut the windows, pollution goes down indoors, but so does CO2. Ideally you have a hepa filter + outdoor A/C that brings in warm filtered air during the winter.
Noise dampening is still an issue. Where I'm living, the whole flat is subject to resonance, when old buses drive by. It's like living inside the throat of a bass vocalist. That, and I hear every laugh a child has outside, even though I'm on 7th floor (8th, if you count like USA-ians do). It's terrible.
We are at that point from a technology perspective - look up passive houses - but it's still far too niche an area. For new construction, it's actually not that much more expensive, and is also far more comfortable and energy efficient also.
EVs reduce tailpipe exhaust near roads but it's worth noting that brake abrasion dust isn't going away anytime soon and it's considered very bad to breathe, possibly in the same league as diesel emission particles.[1] I guess regenerative braking on an EV reduces this somewhat.
Depends on how much your drive. Drive only now and then and brake only the bare minimum, you can get really rusty brakes. I ended up having to get towed with brakes being seized due to rust and lack of use.
Well yes, weather will cause rust. Good use of brakes can clean it up and keep the mechanism from seizing. Lack of braking = lack of use as far as the brakes are concerned.
I could run my errands without braking at all (except when stopping at a parking lot). Anticipate lights and traffic flow, downshift to slow down.. that's how I used to drive. At home I could even park without braking to slow down, thanks to a small incline at my parking spot.
My previous car, which had automatic transmission, didn't have really show any issues with rust because I actually had to brake when driving around town. Same weather, same locale.
Anecdotal, but since recently getting a plug-in hybrid I've only been using regenerative braking except for the most abrupt stops. Whenever you approach a red light or junction it's not hard to stay within the regen braking zone.
I’ve always made it a game to see how little I can use my brakes, whether in bumper-to-bumper traffic or more wide open suburban roads. I never understand why people need to race up to red lights just to do a hard brake. I take solace thinking they probably replace their brakes 20% more frequently.
Yes, I have owned a Prius and Corolla Hybrid and on both vehicles the front rotors always go very rusty because I only ever press the brake down enough to activate the regenerative braking (for better fuel economy). The regenerative braking power of these vehicles is about 20-30kW.
And as a side effect, I haven't needed to replace the brake pads for about 150,000 kms on the Prius. Actually the mechanic told me that they look brand new. I haven't experienced any problems from the rust yet. The front rotor on the Corolla (2020) seems to be a much better, newer design, and doesn't rust nearly as much as the Prius (2014).
endnote. For anyone considering the new Corolla Hybrid ... I rate it very highly as perhaps the best car ever designed.
That’s a bummer to hear, and I saw other folks mentioning that on this thread too. Could you describe the climate in which you’re located? Maybe a humid, salty coastal climate will affect that differently than a dry, dusty climate.
Most definitely in the city. Regen handles the vast majority of braking for me. Depends on how strong the regen is in your vehicle I guess, but it's definitely possible to make it strong enough.
What? I am driving EVs multiple times a week in a European city and regenerative breaking is always happening at every brake action until mechanical brakes kick in.
That must reduce appliance of mechanical brakes at least by half.
You can turn regen braking off, but why would you unless maybe the EV model feels like shit when switching between regenerative and mechanical brakes.
I drive a 12yo hybrid and my annecdotal experience suggests that isn't correct.
I drive mainly around the city and had to replace brake pads recently as they became rusty (salt during winter). The pads had been on for 80,000km and were less than half worn. On regular ICE cars (which have bigger brake pads) you'd usually have to replace them well before that point as they'd be worn down. I'd imagine they last even longer on newer hybrid and EVs.
Most EVs indeed use regenerative braking. Which means your brake pads last a lot longer as you barely use them. Tire particles are a bigger problem. Just think of the mass of tires that you erode away before you replace them (routinely) and compare that to the brake pads you replace much less often. And it's not just the tires that erode but also the road. Asphalt particles are nasty as well. Though most of that dust is quite coarse and doesn't stay in the air as long. But then, tire and road dust is apparently the biggest source of microplastics in our oceans. It washes away, enters our sewers, rivers, and eventually the oceans. It's bad for different reasons as well.
Actually EVs are much worse than ICEs for tire dust and road abrasion, as they tend to be much heavier than an equivalent ICE car, with much more torque.
A lot of people don't know how to use engine braking, I guess teaching them that is going to significantly increased your brake pad life on existing vehicles in circulation.
Remember there are 3 brakes in your car, handbrake, foot brake and engine braking.
Foot brake and handbrake are effectively the same thing because they operate on shared friction components using mechanical wires instead of hydraulic lines. There maybe a different mechanism but it ultimately uses the same drum or disc.
Engine braking (jake braking) by trucks is illegal by statue in many cities and towns because it's very loud. Also, engine braking is riskier in terms of costs (stresses to drivetrain, torque converter, transmission, engine) than brake pads, so people aren't going to do it. Furthermore, they rarely have the skills or transmission to be able to do it conveniently. In addition, if it were more efficient or safer, it would likely be a feature, but I've never seen it in a standard transmission passenger vehicle.
I'm completely not a car mechanic, so the following is essentially a question phrased as a statement. But I'm a bit skeptical about this idea.
I assume you mean the engine break in a manual tranmission car (AKA stick shift in the US). But that relies on your clutch, which is still a friction based mechanism. Admittedly if you're breaking you're probably going to change gear either way, but the amount of friction depends on the difference in revs between the two parts coming into contact, which is presumably going to be larger if you're using it to engine break. So it seems to me that you're reducing wear on your brake pad but just switching that to increase wear on your clutch - with similar effects on air quality.
The clutch is only actuated when changing between gears. Engine braking happens when in gear, and at that point the clutch plates are compressed together and spin as one unit - no dust being generated. Any significant slipping of the clutch would make it burn up very quickly, since cars use dry clutches which cool down by radiating heat into the air.
Engine braking happens because engines have very high internal resistance - with motorcycles for example, there's no parking brake, you just leave it in 1st gear and it will not roll. So when you're not on the throttle, the inertia of the wheels/drivetrain will keep the car moving and the engine RPMs from dropping to idle instantly, but over time the engine will drain that inertial energy and slow down the car.
Also, engine braking is pretty weak on modern manual cars AFAIK. At least in my Honda Civic it basically doesn't engine brake, compared to my motorcycle. The effect is there but very minor.
Another reason why we should not be making this big push for EVs but instead try to shift our infrastructure away from personal vehicles and towards mass transit and micromobility.
EVs will still make this picture look the same and are thus inherently an inefficient form of transport:
The biggest pitfall I see with this is we’re extrapolating from large doses of air pollution to very tiny ones.
Clearly we have enough evidence to say that smoking a pack a day or living in a smog-filled city will cut years off your life. But we would need truly gigantic samples to show that blowing birthday candles or broiling fish once a week will cut weeks off your life.
Instead these conclusions are being derived on linear extrapolations from large air particulate doses. Yet many things in biology follow the principal of hormesis, where a small dose or a toxin may be harmless or even helpful.
Similar models have been used for years and are still the gold standard when predicting the health effects of radiation exposure. Yet mountains of evidence show that radiation workers, who are regularly exposed to small dosages of otherwise harmful regulation do not have anywhere near the cancer rates we’d expect from the linear extrapolation models.
Could you give some citations for studies on radiation workers? The permissible doses in most countries are extremely low and there are not that many people working in the industry. This makes me wonder they manage to achieve statistically significant results.
Sorry for the pendantry: it sounds like you mean linear interpolation, rather than extrapolation. Extrapolation is where you project outside the range of previously collected data, and is particularly likely to result in false conclusions. Interpolation is where you estimate a value inside the range of collected data from points around it, and is usually a lot less dangerous. But I agree with your point that, in this case, it does seem pretty baseless.
But the article is extrapolating, not interpolating.
Extrapolation is when you're extending to outside of the measured data range. In this case, the measurements were all of large values, and it's extrapolating (linearly) to small values. Just because the values being extrapolated to are smaller, rather than larger, doesn't make it interpolation.
Which is precisely why this has the risk of false conclusions, like you say.
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This study made quite a few ripples when it came out: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037
> On average, cognitive scores were 61% higher on the Green building day and 101% higher on the two Green+ building days than on the Conventional building day (p < 0.0001). VOCs [volatile organic compounds] and CO2 were independently associated with cognitive scores.
There was also this one, about decision making: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1104789
> Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios, 0.06–0.56), but performance on the focused activity scale increased.
This one is a high-level overview of the literature on air pollution and health: https://ehp.niehs.nih.gov/doi/10.1289/EHP4869
LOL this happens whenever I talk about this issue with people here in Poland. Part of it is their family is here, it's hard to immigrate, deep down they know it is a problem. It was upsetting to tell my Polish wife that we need to move out of Poland and to scary USA but... she agreed with me and we're doing it. For us, the risk of death is far higher here with all the smoke. Even the California wildfires are relatively harmless in comparison, we get that every year in Poland and no one cares, at least in Calfornia everyone recognizes that it's a problem and people stay at home.
But here, wood burning(or even coal burning), is a part of the culture, giving warm fuzzy memories at granny's house burning horrid things in the furnace for others to enjoy.
Anyways, good luck in the US. Avoid getting shot, having a pool, drinking sugared water instead of water, any medical issue and getting on the bad side of the law in any way. ;-)
sugar water will be a problem, I did not like this about the USA.
medical issue - with FAANG you're fine
bad side of the law: in the communities we live in faang, again, not a problem, you're on the right side of the law. Unless you're black, then that is quite a problem unfortunately.
It's actually not that easy to address if you don't have extra cash laying around. Most people in the world will not do the things on this list.
Other things it leaves out, like frying food (edit: I'm a moron, it does mention it down the line), or buying furniture or clothes that off-gas VOCs, or living or working in a place with fiberglass-lined air ducts, or using a gas range or oven.
In anything but that air exchange will happen much faster than a houseplant can grow.
I love plants but I can’t imagine they do much unless you have an absolutely massive quantity.
Plants still look nice though.
> The science is clear: Indoor vegetation doesn’t significantly remove pollutants from the air
How do you take that away from the plots? If you're in the US my prime take-away would be to keep your BMI in check.
The first graph shows ~2 deaths per 1000 people per year. Surely more than 2 persons/1000/year die in those countries. What are the causes for the other ~10-15 deaths/1000/year?
Given the information in the article, I don't see anything to support the central thesis about air quality. The reasoning for it is so thin that I have no idea whether it's true or not.
BMI reductions are also notoriously difficult, while many of the mitigations listed in the article are low effort and relatively low cost. You could plausibly include this in your comparison of effectiveness.
> How do you take that away from the plots? If you're in the US my prime take-away would be to keep your BMI in check.
They mean in terms of cost/benefit. Reducing BMI is notoriously difficult.
One thing one has to bear in mind is that often when you optmize your home for low PM (e.g. with air purifiers and fixing of air leackage) your CO2 will get very high causing headaches and reduce cognitive performance.
So it always makes sense for indoor air quality monitoring to measure PM and CO2 in parallel.
We have open source, open hardware build instructions for a very reliable Air quality sensor that can be used to measure PM2.5 and also CO2 [1]. It is very accurate for the fraction of the costs of commercial sensors. You can build it for less than USD 20 (or with CO2 for less than USD 50) and send the data to our cloud server or any other backend.
I am more than happy to send you some free PCBs (you just paypal me the cost of the postage) and you can build your own sensor and log the data. Contact me if you are interested.
[1] https://www.airgradient.com/diy/
Not affiliated in any way.
To send me a message please go to https://www.airgradient.com/diy/ and send me a message with the orange chat button. Thanks!
Positive pressure systems can virtually achieve zero AQI inside even on the worst polluted days. You can read more here: [1] https://www.airgradient.com/blog/2020/01/08/positive-pressur... [2] https://seetheair.wordpress.com/2021/04/26/thailand-school-s...
i put my air purifiers on low when the windows are open to deal with the particles i throw up by moving around and doing stuff indoors. with the windows closed (usually only at night), i put the air purifiers on medium/high.
edit: i mentioned the road to note that outdoor pollution is higher during the day, yet opening the windows despite that lowers overall particulate levels indoors. it may be different in indian cities or cities like beijing with much higher pollution levels.
Very much depends on where you live. I have a few DIY air quality stations with data being piped to Grafana. I just looked at the latest data, the average outside PM level for the past 5 months has been around 100 µg/m³, while inside it's around 10 µg/m³.
This spring happens to be pretty windy and this skews the outside levels down, otherwise the ratio would be much worse.
If the air quality is decent outside, it is easy to maintain a PM2.5 rating of near <10 like this.
In California fire season I have a box fan on high in the window pushing air in (and sealing the areas around the window) through an MPR 2800 furnace filter (which is better than the 99.97% rated hepa filters, would be marked as a ULPA filter I believe in different contexts) with this I can maintain the ~0 PM2.5 rating inside even when the AQI outside is >300 while keeping CO2 in check.
It's been quite surprising how easily the CO2 spikes with closed windows and doors in the bedroom with just one person... I essentially always have a window in each room open several inches, cracked isn't enough, usually with at least one fan pushing air through a window.
You can read more on it on the See the Air Blog: https://seetheair.wordpress.com/2021/04/26/thailand-school-s...
https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor
(replying to you to not pollute parent level replies)
I am interested in replicating your hardware stack but implementing the software stack using the esphome framework which supports all of the components used in your DIY solution.
https://esphome.io/components/sensor/senseair.html
https://esphome.io/components/sensor/pmsx003.html
https://esphome.io/components/sensor/sht3xd.html
https://esphome.io/components/display/ssd1306.html
I have windows open all the time, air conditioning on too often, and dehumidifiers and HEPA filters as well. It is not efficient or particularly environmentally friendly... but I want a CO2 level < 800 ppm and a PM2.5 level under 10... so here we are.
My next half baked idea is figuring out a way to have a sealed home and an appliance (or messy bench-top device) to remove CO2 from the room continuously and exhale outside -- current ideas revolve around using a carbonate (lithium? sodium?) in water in an electrolysis cell and an aquarium bubbler to collect CO2 and expel it outside. The best I've been able to accomplish so far is baking CO2 out of baking soda (sodium bicarbonate) and sealing it in about a cubic foot container and achieving ~300 ppm CO2 (lower than outside which is ~400-450).
But it's probably better if you invested into a counterflow heat exchanger for ventilating your home. You can recover a large part of the heating/cooling energy.
Also I would prefer levels lower than outside, obviously air exchangers will necessarily be worse than just being outside.
Current levels outside as measured by my device just now are about 450ppm.
Like so many things I think it is a small effect; it's not like I can go anywhere for a week to experience 300ppm air.
I haven't gone to the levels of designing experiments and data tracking on myself. The fact that I've lived with allergies and a broken nose most of my life probably hasn't helped my personal respiration characteristics.
My literature searches haven't had much success thus far, lacking a chemistry degree hasn't helped. I have found some things but not enough to come to any sort of engineering designs. I'm assuming it's one of those things that's almost too simple for anyone to have bothered writing a paper about unless they had the exact sort of ideas I did. (OR they're using terms that I haven't been able to come up with yet)
With small device I could drop CO2 levels to zero in volume of a gargabe bag in few minutes.
But that would give you oxygen rich atmosphere. You'd probably want to add some inert gas to that. Nitrogen preferably. Are there nitrogen concentrators?
Also all of that is probably really dangerous because human body doesn't detect oxygen level, just CO2 level. So you might easily pass out and suffocate without any warning if your oxygen supply unit get damaged but your nitrogen supply unit doesn't.
More heat than is common for home appliances I know! A commonly referenced stat is 825 C. There's really a gradient: https://en.m.wikipedia.org/wiki/Calcium_carbonate#Calcinatio...
From one randomly googled article on the myth of house plants cleaning the air:
"To remove toxins, you would need at least 10 plants per square foot."
But CO2... to simplify imagine being a vegetarian, how much plant matter would you eat in a day? How much plant matter grew in one day in your houseplants? The only way plants are going to fix carbon is by adding it to their own mass. Just think about a conservation of carbon atoms. There's no way any plants in your apartment are going to make a dent in the carbon cycle of your personal environment.
There are arguments to be made for lots of things sticking to or getting sucked into the leaves of plants... maybe if there were a whole lot of plants a meaningful amount of VOCs or other pollutants could be removed... maybe.
You would need to consider the occupant oxygen consumption. A typical human respiratory quotient is 0.8 (0.8 mole of CO2 produced for every 1 mole of O2 consumed). You’ll get a net inward movement of gas into house all things being considered.
Anyway, don’t do if. If you do it ‘right’ the argon will slowly build up and you’ll asphyxiate. Thankfully achieving that level of seal is very difficult.
If you are really worried about PM2.5, just wear a PAPR.
PM2.5 is easy to maintain with HEPA filters.
CO2 is not easy to maintain without forced ventilation, and really I would like to try inside levels lower than outside levels. (say 300 ppm)
There’s something like 50x as much oxygen in the atmosphere as co2 so a relative change of 1% nominal value will correct itself fifty times faster for oxygen than for co2 between outside and inside (ok a wild simplification, but still)
The result is that without really intense sealing it’s basically impossible to make a difference in indoor oxygen levels whereas with even a cracked window i can maintain co2 levels two to three times outdoor concentrations in my apartment.
Running a co2 fixer with the place shut up would be more like... running the air conditioner full blast with the place shut up. Yes there would be losses but they would be relatively contained.
It's been, what, 30? 50? million years since atmospheric CO2 levels matched current outdoor levels, much less what happens inside.
the concentrations and types of particulate matter, however, is unprecedented, and as such, presents a higher inate risk, something that scientific research is really only starting to grapple with but so far is showing to be likely a serious risk to many (most?) species on earth.
with that said, i'm not trying to discourage your project in any way, just saying that for most people, addressing particulate (plus voc) risk is likely going to be the overwhelming majority of the benefits to be found in relation to indoor air quality. reducing co2 could be worthwhile if you have an especially airtight room/house, but nearly no houses are that airtight (passiv houses are meant to be so, however).
And then air purifier can keep PM2.5 levels below 10 on the lowest setting while outside is above 30
And one window cracked like that is enough to drop CO2 levels below 800 while there's one person in the apartment.
There are these things called "plants"...
https://en.wikipedia.org/wiki/NASA_Clean_Air_Study
Algae is commonly the go-to for CO2 scrubbing for it's relative efficiencies. Algae might scrub 1-3 grams of CO2 per liter per day (https://www.osti.gov/servlets/purl/1485133).
Humans exhale approximately 1kg CO2 per day.
I consider 300-1000 L of algae scrubber tanks per person a lot of volume.
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I can't guess why they would be, and searching around a bit doesn't seem to suggest that's the case either.
>Just use an evaporative or steam humidifier, which seem to create almost no particles.
https://molekule.science/should-you-choose-an-ultrasonic-hum...
quite interesting
The numbers the author uses to quantify "life cost", as far as I can tell, come entirely from one graph in the section "A heuristic to quantify harms". The author examined the life-years lost from exposure to ambient particles in multiple countries around the world, concluding that
>being exposed to 2500 PM2.5 for one year costs 1 DALY
But that line comes from a chart with a range of about 10-100 describing constant exposure to ambient particles. Even if we assume the author's line is correct, identifies a real effect, and correctly ascribes causality, it is not reasonable to draw the conclusions they do.
The author speculates burning a cone of incense, which will produce a concentration of about 4000 for a few hours. This is forty times the largest value on the graph and is some 100,000 times shorter in duration. It is ludicrous to try to extrapolate without a great deal more evidence.
And, obviously, the types of particles found in the air outside are not the same as the ones found inside.
It's a shame that there is some good information on this page ruined by this one bit of shoddy statistics.
IMO, cities should just ban almost all car traffic from the centres so people can live car free without being poisoned.
To some extent yes. I remember one of my first experiences in Chicago taking the Metra Electric from Hyde Park to downtown and getting out at the north entrance which dumps you out at Lower Water Street, which is very disorienting if you are not familiar with the area.
I know the idea is that specialization is good for everyone, and people doing certain kinds of work should be good at it, but I think allowing more diversity in the types of work people do, more intermingling, and more fluidity are realistic goals with a lot of advantages. We already have a big problem in matching qualified people with jobs efficiently. If we get substantially better at that, we can do it more rapidly, and allocate resources much more intelligently, since demands change in every profession as things develop. I would actively welcome breaks in my knowledge work to do the many types of "dumb labor" I can do when it's useful. It's something to ponder.
> IMO, cities should just ban almost all car traffic from the centres so people can live car free without being poisoned.
This would have a much greater impact on the problem for sure, but sadly nobody likes that, some people think owning a car is freedom while it's slavery.
Dust and particulates that settle on asphalt will still be a problem though.
The nostalgia factor is sort of wearing off now that I'm 40 and don't want my clothes to smell bad or have a low-key asthma attack. The last time I went camping in a campground and everyone had a fire going, the whole park was completely choked with smoke that it made going for a walk really crappy. It's such a weird activity, driving cars out to the woods to pay to burn dead trees.
Considering the close association of food, warmth, security and socialization with the habitual use of fire for at the very least several hundred thousand years of human history, is it really any surprise that some people still enjoy the practice?
https://dynomight.net/air/#:~:text=Have%20a%20really,1%20day
Few years ago I moved from a little apartment with an electric range to an SFH with gas everything.
"Good for you," my gas-enthusiast family said, "now you have a REAL stove"
It still takes forever to boil water in a pot. The food tastes the same. I wonder why furnaces have these fancy high-efficiency heat exchangers and stoves don't? Cost?
I wouldn't mind going back to electric. I just assumed it cost more, but maybe cooking isn't significant compared to running a furnace.
I don't see how a design like that would work for a range. The purpose of a range is to heat small, movable objects (pots) to high temperatures (~500°F) with good responsiveness (= short time constants). The purpose of a furnace or water heater is to heat fluids contained in large spaces or tanks to modest temperatures (~100°F) with very limited responsiveness (= long time constants).
The heat exchanger really helps the case of heating a stream of fluid, as that's where the exchange is most useful. The physical and thermal mass of the heat exchanger and flue condenser are both considerable.
I'm not seeing how to make a gas rangetop significantly more thermally responsive without making it no longer practical. For people who can't abide gas for whatever reason, induction units are supposedly excellent these days. (I've never tried one. They can't possibly be worse than an electric smoothtop range, though!)
Induction stoves are pretty good for dumping watts into water. However, it's very hard to get a good mid-range temperature. Gas makes it really straightforward to get something cooking at exactly the heat you want.
Are you sure you’ve used an induction stove and not just a regular electric stove?
Glass flat top electric stoves are not usually not induction stoves though they look the same.
I think I have tried 5 different models in the last few years, from the very cheap, to the relatively pricey, and all were relatively lacking when it came to fine control.
I don't think there's any real reason why they shouldn't have fine temperature control - presumably the temperature is controlled by the switching speed of the mosfets in the coils?
No idea if that's true or not, but I'd believe it.
"When the meta-analysis puts everything together, they come to the conclusion that gas cooking produces a small increase in asthma risk for children, perhaps a 1.5 percentage point increase in risk." (https://emilyoster.substack.com/p/gas-stoves-finally)
https://academic.oup.com/ije/article/42/6/1724/737113
To me, a 24% increase in risk of lifetime asthma is significant and well worth avoiding both at an individual level and a societal level, given that good alternatives are readily available.
Given this 24% number, I guess the "1.5 percentage points" you quoted must be the absolute increase in asthma prevalence across the population, i.e. gas stoves in every home would cause 1.5% of people to develop asthma (when they otherwise wouldn't have it). That seems quite bad actually. If true, not using gas stoves (currently in 35% of households) could have prevented over a million cases of asthma in the US alone.
Where I live, the high end-option is to get an induction stove. I have one, and it's extremely pleasant to cook on. Granted, I've never cooked on gas because that alternative is mostly not used, in my experience.
Want a restaurant-quality stir-fry? Your only choice is a wok on an intense gas plume. The thin material of the wok gives it low heat capacity, meaning that when you turn on the heat it rises in temperature very fast, and cools relatively fast when you turn it off. This allows very precise control necessary to get the best flavor. The wok is curved, which is critical to mixing ingredients correctly while cooking, but the gas flame does a fine job of following the form of the pan to give adequate heating throughout. Electric or induction stoves come short on both aspects: you need thicker pans (higher heat capacity) with flatter resistive elements built-in. You simply can't get the same flavor with those setups.
So no, it's not so simple as "heat is heat."
Pay attention to the kitchen next time you're in a Chinese or Thai restaurant. They really make use of the industrial gas-powered ranges that are universally equipped in their kitchens.
That said, certain types of high temp cooking like wok cooking require jet-burner gas stoves to get the right sort of flavor, but I think induction is superior in most cases.
Also, high-heat wok cooking, while delicious, is terrible for air quality.
>Smoke one cigarette 11 min
How is "boiling fish" 4x worse than smoking?
If you tried to tell those people about particle counters or HEPA filters, you might as well tell them about cold fusion while you're at it. Sure, all the things mentioned might help, but for anyone with the means to follow the recommendations in this article (and with the ability to read an article), I can almost guarantee that air quality is not going to be a major factor in your life expectancy.
[1] With the exception of "Be careful about smoke when cooking."
I'm moving back to the west coast USA soon. I could live in a shack and my family would be better off. People complain about the wildfires, but in Poland they get it every year, and for longer. Try forbidding your kids to go out(too young to wear a mask) the entire winter... Even if you somehow make the perfect environment at home, those kids will eventually have to physically go to school and brave pollution. Before the pandemic I was the only crazy one with a mask during high pollution days. If kids wore a mask because of pollution then I was told they would be ostracized.
So, other than that elephant in the room, it's a perfect country.
Pandemic, making wearing mask socially acceptable really did me a solid.
Air filters do reduce the amount of particles in the air if that's what you're asking.
https://www.homedepot.com/p/Lasko-20-in-Power-Plus-Box-Fan-B...
I have 3 running in my home and they haven't been turned off for over 1.5 years, still going strong. The filters I buy at Costco when on sale (3 for $29).
This one has been on the fan 24x7 for the last 2 months and is still good for a couple of more.
https://imgur.com/JfSjbbg
The prefilter is typically a lot cheaper and is replaced more often. Even some non-woven filter fabric (like that used in vacuum cleaner filters) will dramatically increase the HEPA filter life, is super cheap, and can be washed for reuse.
My purifiers use an F8 prefilter and H13 HEPA filter, and the HEPA filter will last about 2 years.
Filter class info here:
https://www.emw.de/en/filter-campus/filter-classes.html
If particles were as essential to health as claimed, smokers would have a much much shorter life expectancy.
Anyways, it's an interesting read but I'll take it with a grain of salt.
> It's not just about life expectancy, but life quality. I think we'll one day be surprised just how many mental health and chronic illnesses are significantly attributable to air pollution, in all its forms.
https://www.cdc.gov/tobacco/data_statistics/fact_sheets/heal....
Now I keep the window cracked, that keeps it down around 5-600. Outside is around 400.
Tire dust is also concerning.[2]
[1] https://academic.oup.com/metallomics/article/12/3/371/595624...
[2] https://pubmed.ncbi.nlm.nih.gov/22642836/
Rusting is for me more associated with the weather and lack of use of the whole car than with how much do you use breaks when you use the car.
I could run my errands without braking at all (except when stopping at a parking lot). Anticipate lights and traffic flow, downshift to slow down.. that's how I used to drive. At home I could even park without braking to slow down, thanks to a small incline at my parking spot.
My previous car, which had automatic transmission, didn't have really show any issues with rust because I actually had to brake when driving around town. Same weather, same locale.
And as a side effect, I haven't needed to replace the brake pads for about 150,000 kms on the Prius. Actually the mechanic told me that they look brand new. I haven't experienced any problems from the rust yet. The front rotor on the Corolla (2020) seems to be a much better, newer design, and doesn't rust nearly as much as the Prius (2014).
endnote. For anyone considering the new Corolla Hybrid ... I rate it very highly as perhaps the best car ever designed.
That must reduce appliance of mechanical brakes at least by half.
You can turn regen braking off, but why would you unless maybe the EV model feels like shit when switching between regenerative and mechanical brakes.
I drive mainly around the city and had to replace brake pads recently as they became rusty (salt during winter). The pads had been on for 80,000km and were less than half worn. On regular ICE cars (which have bigger brake pads) you'd usually have to replace them well before that point as they'd be worn down. I'd imagine they last even longer on newer hybrid and EVs.
But tire abrasion is arguably worse for EVs due to the higher initial torque. Does anybody know if there is any difference between EVs and ICEs?
It also would be cheaper to have carbon-captured concrete bicycle and walking paths rather than asphalt highways or roads.
Single-occupancy vehicles need to go away.
Remember there are 3 brakes in your car, handbrake, foot brake and engine braking.
Engine braking (jake braking) by trucks is illegal by statue in many cities and towns because it's very loud. Also, engine braking is riskier in terms of costs (stresses to drivetrain, torque converter, transmission, engine) than brake pads, so people aren't going to do it. Furthermore, they rarely have the skills or transmission to be able to do it conveniently. In addition, if it were more efficient or safer, it would likely be a feature, but I've never seen it in a standard transmission passenger vehicle.
I assume you mean the engine break in a manual tranmission car (AKA stick shift in the US). But that relies on your clutch, which is still a friction based mechanism. Admittedly if you're breaking you're probably going to change gear either way, but the amount of friction depends on the difference in revs between the two parts coming into contact, which is presumably going to be larger if you're using it to engine break. So it seems to me that you're reducing wear on your brake pad but just switching that to increase wear on your clutch - with similar effects on air quality.
Engine braking happens because engines have very high internal resistance - with motorcycles for example, there's no parking brake, you just leave it in 1st gear and it will not roll. So when you're not on the throttle, the inertia of the wheels/drivetrain will keep the car moving and the engine RPMs from dropping to idle instantly, but over time the engine will drain that inertial energy and slow down the car.
Also, engine braking is pretty weak on modern manual cars AFAIK. At least in my Honda Civic it basically doesn't engine brake, compared to my motorcycle. The effect is there but very minor.
EVs will still make this picture look the same and are thus inherently an inefficient form of transport:
https://urbanist.typepad.com/.a/6a00d83454714d69e2017d3c37d8...
Clearly we have enough evidence to say that smoking a pack a day or living in a smog-filled city will cut years off your life. But we would need truly gigantic samples to show that blowing birthday candles or broiling fish once a week will cut weeks off your life.
Instead these conclusions are being derived on linear extrapolations from large air particulate doses. Yet many things in biology follow the principal of hormesis, where a small dose or a toxin may be harmless or even helpful.
Similar models have been used for years and are still the gold standard when predicting the health effects of radiation exposure. Yet mountains of evidence show that radiation workers, who are regularly exposed to small dosages of otherwise harmful regulation do not have anywhere near the cancer rates we’d expect from the linear extrapolation models.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663584/
Extrapolation is when you're extending to outside of the measured data range. In this case, the measurements were all of large values, and it's extrapolating (linearly) to small values. Just because the values being extrapolated to are smaller, rather than larger, doesn't make it interpolation.
Which is precisely why this has the risk of false conclusions, like you say.
India is an example but in parts of the Netherlands where we have the worst air quality in Europe, we also see this.
It's hard to tell. But having a respiratory disease in an area of bad air quality won't help you.
At the same time early in the pandemic I remember reading that being a smoker had a moderate impact in reducing COVID symptoms severity.
[1] There is even a RCT on this, but no results yet https://clinicaltrials.gov/ct2/show/NCT04583410