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arjie | on: Air Purifiers as White Noise Machines
What are people's target AQIs? I have indoor monitors in our high-rise building in SF and live 100 m from the freeway and we have:

    PM2.5: 2.6 µg/m³
    PM10: 0.5 µg/m³
    VOC index: ~97
    CO₂: ~505 ppm
That's the baseline. When we're cooking, like now, it's:

    PM2.5: 10.8 µg/m³ (AQI ~46)
    PM10: 17.5 µg/m³
    VOC index: 122
    CO₂: 572 ppm
None of those seem particularly concerning. We have a gas range, and 15 min past the end of cooking everything is fine. I must imagine that most people don't live right next to the freeway so they probably have even better air quality except during wildfire season.
gpm | parent | next
CO2 - I'm thrilled with anything less than 800 ppm (half justified by being the lowest number I've ever seen a study suggest might have health effects, half justified by being at a point where I personally don't notice that I'm more drowsy).

PM2.5 - My impression is the health risks here are more cumulative exposure (and include things I'd like to go without in my life, like alzheimers) and a pretty straight line of "lower is better all the way to zero". The WHO's guideline is mean exposure of 5 µg/m³ so I guess I'd adopt that if I had to put a number on it. (But it's a mean, I wouldn't worry about briefly exceeding it)

PM10 - No real opinion (I'd rather worry about PM2.5)

VOC index - I'm not sure this is a standardized thing, but the version I've come across is an index relative to the average that particular sensor has seen in the last 24 hours. So there's no standard possible here.

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As for a gas range I would worry about NOX considering the studies with them causing and aggravating asthma. That said your CO2 levels are low so I suspect you might have sufficient ventilation that this isn't a huge issue for you (especially if that ventilation is in the form of a fume hood over your stove that you actually use).

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amluto | parent | next
VOC index means literally nothing. (I've read the datasheet, implemented some kludges to log raw data, and contemplated the formulas. The data is high-pass filtered. You literally cannot conclude anything about a single measurement if you assume the sensor is somehow magically perfect. You might conclude that there is more VOC (or less -- not all VOCs have the same sign in their effect) when cooking than when not cooking.)

I target 0 PM2.5, but this only necessarily makes sense as a target if you have the ability to filter your home's supply air. And a good vent hood should be able to avoid any detectable bump while cooking (although a vent hood without filtered makeup air may cause a bump due to increased infiltration of exterior air).

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jefftk | parent | next
There's either a typo or something wrong with your sensor: you can't have pm10 < pm2.5.

(Equivalent to saying you have more people under 2.5 years old than under 10 years old.)

kj4211cash | parent | next
We have higher numbers than those and live fairly far from any freeway. Maybe your high-rise is doing better than you think.
dgacmu | parent
Depending on the month, my kitchen AQI averages between 1-4, representing PM2.5 values of 0.1 - 0.8 ug/m^3. Bedrooms are likely better as they don't have the gas stove.

CO2 while occupied is generally under 750; I'd prefer to keep it under 700 but we also balance that with energy efficiency for that make-up air; I don't have an ERV, so we suffer a little there.

(We don't live by a freeway but - (a) Pittsburgh's air isn't great; and (b) the canadian wildfires were pretty bad here at times this summer, and that was what caused that 0.8 ug/m^3 pm2.5 spike).

We have, um, a lot of air filters left over from covid, though, so we're a little spoiled in terms of being able to manage AQI easily.