Jonathon's comment re: Air Quality Inside

During the latest podcast episode, Jonathon made a comment about his inside, also, having bad air quality. How does Jonathon or anyone else measure inside AQI? More pointedly, do inside monitors give you feedback on such things as smoke from wildfired?

I am asking because here in San Jose California, we have had made AQI lately. Thus, I went out and bought a Wave Plus (Airthings) smart indoor monitor. However, while it measures Co2, their support told me at does not measure the “same particles” that AQI measures. This made me very confused. I just want to make sure the smoke outside isn’t comimg inside. (Note: I have 4 air purifiers running 24/7)

You need a device that measures PM-2.5 indoors. There are dozens on Amazon - with varying reviews. You have to have a pretty drafty house/apartment to have it be as bad inside as out - but if it is in the “toxic” range outdoors and you aren’t doing any filtering indoors, you can bet you’ll at least be in the unhealthy range inside… Hope that helps.

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The air quality index uses ozone, PM10 and PM2.5. PM2.5 can make it deep into your lungs and to you blood stream IIRC.
You’ll want something that measures PM2.5.


The PurpleAir monitors received good ratings from a site I mention in this post:

Wildfire smoke generates a lot of PM2.5.

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Just got my purple air outdoor monitor today :slight_smile: Set up and reporting to the web in about 5-10 minutes. From looking around this monitor seems to have good correlation with the standard AQI PM2.5 numbers, at least for smoke. Purple air has some links to air quality districts that have done some quite thorough tests, and they have performed well. I’d love to have one in the garage too, as my guess is that they air quality there is only slightly better than the outside when the outside is bad.

As I understand it, the EPA AQI numbers are based on the weight of certain sized particles per cubic meter of air, and this is measured using special filters, as they actually need to capture the particles and weigh them. The way the simpler ones work is some kind of laser or optical measurement, which counts particles, but doesn’t weigh them. As a result, they are not measuring exactly the same thing. I have no idea if particle count or weight of particles is a better metric, but with consumer devices you may get a ‘valid’ measurement that is different from official AQI numbers.

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There’s multiple sites that discuss personal air sensors vs the AirNow monitors but here’s the first one that popped up for me:

I just don’t have an indoors, problems solved!