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The more we study it, the more we learn how harmful the air inside our homes is.

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.

This is advice that gets thrown around a lot, but it's missing the important bit of how to buy a meter that's both reasonably accurate and affordable. There are countless articles online showing how widely commonly sold meters vary in their readings. What's more, paying more often does not mean you'll get a more accurate reading. Sure, there's diminish returns and past a certain point it doesn't matter, but many meters are completely unreliable.
The problem is there are a lot of effectively 'fake' CO2 monitors. They can't monitor CO2, they only monitor something else and work backwards to estimate CO2 levels.

The cheapest real ones I've found are on the order of ~$150

I tried to do this (buy an affordable priced, reasonably accurate meter) and, after probably after reading the same articles as you, reached the conclusion that there are no meters that are accurate and affordable.

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.

I have an "INKBIRD WiFi Indoor Air Quality Monitor" (INK-CO2W) and consider it useful and reliable for my purposes.

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.

The Awair Element is the best option for consumers who want something easy and relatively inexpensive.

Hackers may prefer other options.

The challenge with opening the window isn't even the cost - which is substantial - from about £250/month to £400/month if I have my windows open even a little bit.

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.

Get a heat recovery exchanger.

https://natural-resources.canada.ca/stories/spotlight-energy...

For those prices, buy an Ambient Weather base station along with this CO2 sensor:

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.

> German-style luften twice a day

Das ist nicht genug und klingt ehrlich gesagt grauslich.

Not German approved.

Why do you need it to be cooler than 18c?
Every home should have a heat recovery ventilation system. It gives you fresh outside air in the whole home, but filtered to remove PM2.5 and without the inefficiency.
Many new builds will, especially in places with required efficiency standards, but the average house in the US is 40 years old. And leaky as hell.
Can you say more? Maybe link to a useful page or product(s)?
I built a window vent with a variable-speed computer fan and an esp8266 that communicates with a CO2 monitor and raises the speed when the CO2 gets too high. I have a very fine mesh on the window screen that's designed to filter out pollen and dust. It works really well. I usually only turn it on at night, because that's when my wife and I are both in the room and the CO2 can really build up.
I use an ikea air filter that just so happens to fit perfectly in the window + a smart outlet and co2 sensors.

I’d like to do a custom build like you so the fan speeds are variable.

Good advice on the CO2 monitor. Cheap and surprisingly effective. I haven't considered the VOC--any recommendations?

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.

> Yes, this means your heating and cooling bill will be a bit higher.

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.

I bought an aranet 4, it's quite eye opening how you sometimes get a lot of CO2 buildup without even noticing.

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.

Outside air isn’t a panacea. There is often plenty of pollution right outside your window unless you live on an idyllic beachfront property. The humidity level outside is also rarely what you want in your home, whether it is too high or too low.

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).

Crack a window open (Except if you live in a city)
Those monitors are useless. Unless they're VERY expensive they only show a change over a short period of time
Yeah thermodynamics though; generation of electricity for that extra heat or cold waste heats up planet.
> The findings suggest that regular ventilation alone may be insufficient to remove many indoor contaminants. Physical cleaning activities such as vacuuming, mopping and dusting are necessary to effectively remove compounds with high partition coefficients from surface reservoirs.

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.

This is also one of the saddest aspects of retro computing.

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.

This sounds similar to what happens in cars that have been smoked in, but there are even more soft surfaces, nooks and crannies in a car.

Smaller space, but easier to get fresh air into.

We have a basement garage in our house which has probably not seen a car since the 80s. It still smells of gasoline.
Concrete absorbs petroleum spills. You may need to identify areas that are stained and do a thorough cleaning to try to extract as much as possible.
How do you have a basement garage? I've seen some weird arrangements, but did the driveway have some massive slope or something?
I'm asking myself if building a DIY setup or buying something like Airthings Wave Plus will actually track these compounds at decent accuracy - and if anyone here has gone down this rabbit hole for family health?

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)..

You can (within reason) calibrate these cheap CO2 easily with esphome and an outdoor air reference point overtime. I’ve had to do it for thermometers as well.
This is why your plastic ketchup bottle still smells like ketchup after washing it multiple times - at a microscopic level, plastics essentially look like uncooked ramen/instant noodles, basically a big tangle of polymer chains which act like a sponge.

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

The article doesn't seem to have immediate actionable recommendation, and is mainly a brick in a wall that can lead (or not) to better design decisions.

One unclear point for example is what happens with the deposited toxins, how hard is it to clean them? are they transferred by touch?

Well, it's a classic research paper. They're essentially only supposed to report findings.

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).

Having moved into a home previously owned by a chain smoker ten years prior, I have no problem believing this. We've had to run ozonators in rooms repeatedly to finally get the smell out.
I wonder what the air quality inside a submarine is like, after spending 60 days submerged. How does it smell?
I've toured a '60s era Cold War diesel-electric sub that's been a museum for ~20 years, and it still absolutely reeked of diesel. Combine that with the smell of a couple dozen dudes that haven't showered properly in weeks, and your answer would be not good.

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.

Isn't this obvious? I don't know, maybe there are some details of this study that are are scientifically useful, but as a news it's pointless?

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.

I think that the crowd on HN tend to enjoy learning, and thus wouldn’t find it pointless to read.
Brings back memories of how much the old people I know would open every door and window to let in "fresh air".

Sometimes old heads...

newsflash: permeable materials are permeable
Not really good news for my OCD.
Sounds like good news. The sponges take harmful chemicals out of our environment.
Not good news, it's just better to know, than to not know. These sponges don't take chemicals out of our environment, they trap it and slowly release it where we would need cleanness. These chemicals would have gone away a long time ago, but the sponges kept them there.

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.

...to then re-release them gradually over the next days and months. So, no.