That's why fresh air is key. Crack a window or two open. Buy an air monitor that monitors CO2 (good proxy for overall freshness), VOCs (sometimes these build up much faster than CO2), and PM2.5.
If CO2 or VOCs are high, open windows more. If PM2.5 is high and coming from outdoors, turn on an air filter.
Yes, this means your heating and cooling bill will be a bit higher. But for your health and concentration, it's worth it.
I mostly solve any issues with VOC by "Stosslueften", but if that's not enough because the air quality outside is too bad, a CR box is an effective, easy to build and almost perfectly silent design, especially if you do it with decent quality pc fans.
Hackers may prefer other options.
The cheapest real ones I've found are on the order of ~$150
They all assume that they will be exposed to atmospheric concentrations of CO2 at least once a week.
I like to familiarize myself with any appliance I buy, so I tend to read the manual at least once. And yes, it's usually a waste of time. :)
If you have a meter that shows you a graph on your phone, you can watch it reach equilibrium. It's very obvious.
So many seem to rely on automatic ‘calibration’ - which just seems to consist of “let’s assume the lowest sensor readings of the last while correlate to baseline atmospheric CO2”.
For a meter that’s never taken outside, this is obviously going to mean it’s reading too low all the time after a few ‘calibration’ cycles. And, worse, it's likely to be more wrong in less well ventilated spaces.
You calibrate it by setting it outside for a bit to establish the baseline and then bring it inside. The detected CO2 level noticeably tracks with the number of people in the living room in which it is located and whether outside air is being pulled in, either due to the furnace or having multiple windows open.
We do not use the app, so I can't comment on that. And my only complaint is that it has to be plugged in otherwise it runs out of power in an hour or two.
My problem with this advice is not that it's difficult to measure pollution levels (it really isn't), but that there's no "fresh air" outside for many of us. In many parts of the world, the air is significantly worse outside than inside even without running an air purifier (and with a purifier the difference in particulate levels can run into 100× or more during winter).
Some years ago I looked at the few papers that measured the difference in gaseous pollutants (like NO2 and SO2) inside and outside with windows open and windows closed, and for some reason closed windows do provide limited protection against them. Nobody really understands why AFAIK, it shouldn't work that way since they're mixed with air in a gaseous mixture from which they can't be filtered out without a specialized chemical filter, but it does help.
No surprise. A lot of homes are still being heated by combustion. Gas heating is relatively clean if the burners are properly maintained, oil burners are a hit and miss, but everything else... wood pellets are often declared as the "green" alternative, but that's only valid for CO2 (and even there, the actual benefit for the climate is massively debated) - these things spew an awful lot of particulate emissions, brick-wood ovens are even worse, especially when people illegally throw in too humid firewood or, worse, garbage that has no business being incinerated outside of an industrial high temperature facility with proper exhaust stack treatments.
Unfortunately, as you say, in many parts of the world people are too poor to afford proper heating fuel sources, and it's costing them and their countries so much productivity and money in the long run... and in developed countries, there still are a sizable amount of people who have no idea how to properly heat their ovens, how to prepare their firewood or that just outright skirt garbage disposal fees. Jörg Kachelmann, founder of the weather service Meteomedia, has extensively written about that topic in the past [1] and keeps ranting on social media about it under #holzofengate.
[1] https://www.t-online.de/nachrichten/panorama/id_84671908/kac...
Maybe my numbers should be 100 and 10,000, but it doesn't matter, I know when I need to turn the air exchanger on turbo and when we are back to "normal".
The bigger challenge is with my windows open, my heating just can't even keep up! It'll be maxed out and only 18c.
I do the German-style luften twice a day, but if our interiors are just absorbing the compounds and releasing it when the windows are shut, then that's not even going to help much.
https://natural-resources.canada.ca/stories/spotlight-energy...
I have been investigating easier to retrofit decentralised MVHR systems such as the Prana Recuperator, Ventaxia Tempra and the Blauberg Vento. They can be noisy (not a problem for me, I don't mind noise) and quite expensive as you have to fit a number of units in different rooms, but still easier than retrofitting ducting.
Das ist nicht genug und klingt ehrlich gesagt grauslich.
Not German approved.
They're trying to heat it.
That article and the supposed experts are idiotic. Condensation is a function of relative temperatures and humidities. If your house is warmer than outdoors, then you're not going to get condensation from outdoor air.
At 70% RH and 15C air temperatures, the dew point is 10C - which could easily be achieved along the exterior walls of an older more poorly insulated house.
My house is bone dry in winter with the windows regularly open. The humidity concern is idiotic.
https://ambientweather.com/indoor-wireless-air-quality-monit...
We have low-voc foam in the attic, which outgasses voc’s slowly and constantly. (They measure voc release at application time, not over the product lifetime).
I started actively venting the attic a two months ago. The whole house reeked of foam for a week or so whenever the windows were closed.
It’s fallen off a lot, even though the attic foam is 5 years old.
I think the sponge analogy is correct. If the house is sealed, the VOCs accumulate in the atmosphere, and are reabsorbed into the foam at the rate they are released into the air.
If you leave the house completely open, the outgassing will not be offset by reabsorption.
I think the CO2 in our place accumulates faster than the VOCs I can smell, so opening the windows when the meter tells us to keeps the net rate of outgassing high, and the indoor pollution low. It seems like the outgassing is slowing down now.
I really should get some VOC meters.
Much better than cracking a window is the use of ERVs (energy recovery ventilators) and air filters on the incoming air.
An ERV is a fairly simple device that exchanges air with the outside while mitigating the loss of energy and humidity.
Any modern home build likely has an ERV as part of the design, but it’s not like they can’t be retrofitted, and I’ve even seen some DIY-friendly window unit ERVs (but I’ve never heard if those are any good).
Cracking a window is also costly, since it directly raises your heating and cooling bills. It's just an "invisible" cost that's easy for some people to ignore since it's hard to directly measure. An ERV pays for itself over time, so it's more a question of whether you can afford to just crack a window?
Living in an apartment makes this difficult because your landlord may not let you improve this situation, but just ignoring the cost of opening a window doesn't make the cost go away.
If you live somewhere uninhabitable like Texas, change heating for cooling.
Is the air cheap to heat? Even if it were, that still wouldn't solve the other issues that were mentioned.
The reason that I consider that explanation somewhat incomplete is the behavior of the air and the embodied energy. Imagine it’s winter, the exterior air is quite dry, and you open a window. You will easily lose a large amount of moisture, making the air uncomfortably dry. So you turn on a humidifier, but that will cool the room further with the evaporation of water. You also have to consider convective heat transfer. The fast-moving air is quite good at transferring heat to the outdoors. So, even if you don’t care about humidity, you will lose a lot of heat through convection.
But yes, strictly speaking, the thermal mass of the air is very low in most structures and situations.
You can also take the domestic calculations further.
If you have 50 kilos of dead weight for instance, whether it's a set of workout weights or a piece of furniture, and it's all a stable 10 degrees C through and through, it's going to take 50 kilos of 30 C warm air constantly coming into intimate contact with the dead weight however long it takes before your dead weight gets to 20 C and the air does too.
That can be a whole lot longer without forced air. But it still takes 50 kilos of air no matter what.
>the thermal mass of the air is very low
This is exactly it, along with heat exchange capacity.
If you pull out the water hose you could spray it down with 50 kilos of water in no time, but not everybody's living room can withstand that :)
Now if you had 500 kilos of 20 C furniture along with everything else, and you opened your windows and let out the full 50 kilos of air which was fully replaced by 0 C air, then shut the window to achieve a closed system once again, you'd still be sitting on 20C furniture for some time and only breathing 0C air for a short period before the overwhelming mass of the furniture itself warmed the much lesser mass of air right back up a few degrees, and to about 18 C eventually. Which none of the other heated mass will drop below.
With no additional heat added, assuming insulation was perfect, but that's the number of degrees lost from one single full air exchange alone under those conditions.
While the windows are open is the time to vacuum the carpets, drapes and furniture so you can get some forced air through them and let absorbed irritants out instead of just stir it up and move it around. The high-surface-area porous materials can soak up more than you think.
Air exchange matters again because some of the irritants are not the kind that evaporate or "dissolve in air" very fast, and they might have had all kinds of continuous time to accumulate.
You've got to figure that curtains can hold grams of unwanted stuff in their pores from previous bad air days, furniture ounces & carpets pounds plus a lot of the latter is solids which may give off odors or stir up allergens for quite some time once it has gotten into the pores and other tortuous passages. That's a lot of air exchange when you do the math.
Change your air filter after stirring things up and breathe easier after that :)
I feel you about the pollen. I use a Blueair filter, and that keeps PM 2.5 and PM 10 in check.
Sounds very country dependent. I really doubt it's true here in the UK. But then, UK housing is just garbage all around unless you build something custom and put a lot of money and attention into it.
Yes, I meant in the US. Apologies for not making that clearer. I don't think ERVs are uncommon in new construction outside the US, but I don't know as much about that.
A couple examples I see on Google. I'm not advocating for any of these, because I have no idea if they are any good, but I see no technical reason an ERV couldn't work as a window unit. Maybe it's an underserved market and someone should make a business out of that.
A much more DIY example that's probably closer to what you were talking about with "hacking together" a solution: https://www.mychemicalfreehouse.net/2023/10/window-mounted-p...
It's easily the favourite thing in my home. It filters the outdoor air, reducing pollen and mosquitoes. It keeps out excess moisture in summer. I don't have to open a window when it's cold. It automatically goes into overdrive after a particularly steamy shower. It's great.
Yes you have to take into account running an air filter for PM2.5, closing the window while a truck is idling outside, running your humidifier or dehumidifier if you want.
But you need fresh air coming in somehow, at a certain rate. There's no way around it. Pollution in terms of VOC's, and CO2, is always higher indoors than outdoors, because things indoor generate it and don't remove it.
It's not usually the only option. Installing an ERV is an option for the more than half of the population that owns their own property in the US, and an ERV will save money and pay for itself compared to opening your windows, in addition to the other benefits.
For renters, that's where the window units I mentioned come in, but there aren't as many options there as I would hope yet. If people don't ask for ERVs en masse, then apartments won't offer ERVs as a benefit to attract tenants unless they are legally required. Helping people understand that options exist seems like the first step to changing things. Ideally, even window-unit ERVs wouldn't be the only option for renters. Nearly 90% of households in the US have air conditioning now (which I believe includes rentals), because people asked for air conditioning and were willing to pay for it. ERVs have the added benefit that they don't just make things better, but they should pay for themselves in energy savings too. Maybe I'm too optimistic. I believe the 2024 IECC building codes make ERVs mandatory in new construction in climate zones 6 through 8, as one example of a change that is coming.
I’d like to do a custom build like you so the fan speeds are variable.
As an aside, I open up my window, but sometimes smokers decide to take a break outside and...well. Other times, I have neighbors barbecuing.
If I don't shut the windows quickly I've just replaced stale and somewhat harmful air with oxygenated and definitely harmful air.
I have a purple air sensor outside. One day I'll get around to making the air exchanger smart enough to turn off when the smoke from fires makes the air outside worse than inside, it turn off the air exchanger when inside air is good enough, etc.
Not even necessarily. People these days are accustomed to keeping their homes at comfortable T-shirt temps even in the dead of winter, but if you dress appropriately for the season you can drop your indoor temperatures 20F or more from what people normally set the thermostat to while still maintaining a safe margin to keep your pipes from freezing.
Additionally why this is not good news, these materials were not supposed to be sponges to begin with. So, it's like discovering a bad side effect. Again, better to know than to not know, but it's not what one would call good news.
The long-term health outcomes are probably significantly worse for people that served in diesel subs than nuclear because of the constant exposure to fossil fuel volatiles. Just being in there for a 20 minute tour made me feel like I just smoked 20 cigarettes.
Sometimes old heads...
Yup. Indoor smoker homes are the worst because cleaning alone is often not enough. Cheap landlords just slap a coat of paint on to hide the visible stain, better landlords use nicotine blocker paint that's pretty expensive... but that's only good for moderate smoke. Decent ones run a few ozone generators for a few weeks while no one and no thing is inside, with the added danger that the decomposition products are toxic on their own and the ozone might damage the electrical wiring.
The only actually reasonably safe way to deal with a heavily smoke laden home is to rip out everything where the smoke has seeped into. For the Americans here, that may mean a complete teardown as the cardboard, insulation and even framing wood will be soaked in smoke residue; Europeans have it a bit better because for us, it's usually enough to remove the plaster but leave the brick/concrete walls alone.
Homes that have been affected by fire are often written off for the same reason, even if the fire itself didn't blaze in the home (say, a lower apartment burned off). The smoke seeps everywhere, especially in older buildings where doors aren't airtight or you got bathroom/kitchen exhaust vents without backflow prevention, and fire smoke is orders of magnitude worse in its effect than cigarette smoke - cigarettes are at least plant based materials, household fire smoke is riddled with stuff like dioxine (from plastics) and other highly toxic combustion products.
Most listings fail to mention whether previous owners were smokers, and most sellers either aren't sensitive to and/or haven't experienced the off-gassing that occurs once devices warm up through actual use.
So this is actually the main reason I'm thrilled about the MiSTer project and the growing number and variety of FPGA-based clones being released today.
Smaller space, but easier to get fresh air into.
From what I've gathered, consumer devices hit acceptable accuracy for CO2/temp/humidity but PM2.5 is hit-or-miss, and VOC readings are more "relative change indicators" than absolute values..
DIY with Home Assistant is more work/fun yes but again only gets similar accuracy AFAIK (with potentially better automation)..
Yeah, make sure to get a lot of ventilation, but that doesn't require any study. Even without any any pollutants, indoor air will have a bad quality. And your body deals with minor amount of bad stuff just fine.
Now, consider what happens when you wash that plastic with a cocktail of chemicals in your dishwasher...
Obviously very hard/dense plastics (melamine comes to mind) are less prone to this
2rsf•4mo ago
One unclear point for example is what happens with the deposited toxins, how hard is it to clean them? are they transferred by touch?
hylaride•4mo ago
If you live in a house with central HVAC, a decent, regularly replaced filter will help a lot (make sure to only use full blown HEPPA filters if your furnace supports it otherwise you'll have all sorts of airflow issues). Otherwise you can buy air purifiers. The study measured smoke (cigarette and wildfire) as well as insecticides, so minimizing exposure to both is probably the easiest first step (not smoking inside is easy, but wildfire depends on how porous your house is).
amluto•4mo ago
Also, don’t put a HEPA filler in your HVAC return — not only is it unhelpful overkill, it will have excessive static pressure drop, thus wasting power, increasing noise, reducing airflow, and potentially damaging the blower. Use an appropriate filter in the MERV 13-16 range.
imp0cat•4mo ago
If you're considering one, make sure to get an air purifies where the carbon filter can be changed independently from the main filter.