The last few months air quality here has been pretty sh.. smokey. There have been various fires and preventative measures occurring, so completely understandable. I am curious how others detect / handle similar poor air quality conditions...
Some people cheap out and rig up a simple box fan with HVAC filters:
How to make a box fan air purifier: 3 different methods - Digital Trends
I believe this method gained popularity in the US during the covid pandemic, although I question its effectiveness at removing viral particles from the indoor air. Smoke/odor removal seems less controversial though, as those particles are larger than viruses or the respiratory droplets they hitch a ride on.
I like having an air purifier that I can control remotely/automate so that it'll kick up the fan speed in response to indoor air conditions (although many air purifiers have an auto mode to do this on their own).
I'm currently using a few air purifiers branded as Levoit, which I get from Amazon. Their mobile app is called Vesync. They can be integrated with Hubitat or Home Assistant, though it's unfortunately cloud-only. I don't consider this "essential" though so I can accept that the integration's not local.
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I'd question the air quality Dyson fans detect compared to EcoWitt or even Philips....
The Ecowitt air sensor detects particulate matter over a certain level and turns off the Lunos HRV system. There's an air filter in the house that automatically cranks up when it detects pollutants but it's not tied to the automation system. Then we basically suffer through higher levels of CO2 until the winds shift and the smoke clears (usually only a day or two and thankfully has happened only a couple of times in past two years). Ecowitt sensor turns it all back on when particulate matter drops.
Ecowitt also informs adjustment of the Lunos fan speeds based on CO2 levels, which happens more often than smoke but usually only because we have guests over. They all seem to insist on breathing during their visit.
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Perhaps this topic will turn (devolve?) to a discussion of the seemingly unending Canadian forest fires. Or, California. Or, Maui.
Maybe.... Hopefully it will be a little more subdued, like the outcome of the local fires round here. I was not looking to perpetuate any more general discussions, just see how people (or their home) responded to poor air quality when fires or other environmental events occurred nearby.
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4 posts were split to a new topic: Offshoot of air quality discussion
I use a combo of Apple weather to push outdoor AQI (not released) and Purple Air for indoor AQI. I have a "Nicer outdoors" automation that opens/closes windows based off indoor/outdoor temp, humidity, rain and AQI. If any of the sensors says the outside sucks, my windows stay closed.
I don't have an automation for outdoor air sucks and indoor air sucks... yet. In theory though you could turn on your HVAC fan, ceiling fans and any air purifiers... assuming your smoke alarm is not going off and maybe there is no motion in the kitchen too.
Unfortunately, if you do have a fire, circulating air will make that situation MUCH worse.
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I’m in the same boat… it is definitely something I should look into though! My air exchanger does have a hepa filter, so maybe it doesn’t really matter…?
This might belong in it's own topic, but what air quality sensors do people use?
I have the EcoWitt CO2/2.5/10 sensor in the main living area which I am very happy with, but as I start to look at adding sensors to the study, bedroom and potentially outside, the price of the EcoWitt sensor is a little bit of a turn-off, Purple Air even more 
.
There’s ample scientific evidence supporting their use for both smoke and viral particle removal. Search for "Corsi-Rosenthal Box".
The biggest issue with the classic "box fan" design is noise. People since have created designs based on PC fans that are very quiet and are hardly noticeable running full-time at maximum speed (there are no downsides as long as the output air flow is directed to not be inconvenient to occupants).
Personally I'm not in the news-worthy category of air quality, just a "this could be worthy of a HE post"
I use the AirThings Vue. Works quite well, but is cloud based, not local.
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A PM 2.5 sensor would tell you.
I own Airthings units as well - a Wave Plus and a View Plus. With the C8 Pro now supporting Bluetooth maybe there will be a way to integrate locally at some point?
The Awair Element is nice (but expensive) and has a local HTTP interface.
I'm currently trying out the Ikea Alpstuga (Matter over Thread) which is cheap and has a PM 2.5 sensor.
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Thanks I’m familiar with the term and some of the scientific literature published about them.
I remain skeptical that in real-world conditions (not controlled experiments) they can meaningfully reduce the risk of one person transmitting an airborne virus to another person (which is much more challenging to evaluate experimentally).
If you’ve seen articles that were designed to evaluate that kind of question, please share. I certainly haven’t spent a huge amount of time looking.
As you say that would be a challenging experiment to design - a room filter is obviously not equivalent individual protection to a fitted N95 mask. The literature I have seen concerned reduction of risk in the aggregate, and the results were pretty compelling - I'll see if I can find some links to share.
Think of it this way: a 4-filter CR box running at full speed "inhales" air at something like 2000x the rate of one person's lungs, so filtering efficacy doesn't have to be 100% for the filter to catch much more particulate matter than any person in the room. I'll take those odds 
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ECOWITT WH46D, which amazon says is currently unavailable. Very happy with it.
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I wish Google would provide the link that is what I asked for... and what they displayed... 
But yes.... I expect that is likely what I have also setup in my Living Area, providing CO2 and PM 2.5 and 10 readings. I'd be happy to have one in each room, but it is a little expensive for that. My thinking is to get some less expensive options for the areas I want to monitor less frequently.
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Agree - Too expensive for multiple rooms. We built this property as multiple buildings, so expensive for that as well. But each building is primarily a large single space (two floors in one building) with few closed doors so that helps. I run one of these in our main living space (in the "living" / TV space) and another over in my wife's studio, which doubles as our guest house.
I don't have one in my office (separate building) but perhaps I should. I find myself sleepier there than anywhere else, but I fear that may be due to a diminished interest in making Powerpoints for children (20-somethings) to take into meetings with slightly older children (30-somethings) to discuss things neither of them are taking the time to actually understand. But that's a different topic, I suspect.
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Yes, CO2 deprivation vs motivation deprivation can be hard to distinguish without data.... 
Sometimes both can be present...
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