btw if you install the Plume labs Air Quality App(beta) you can select the USA aqi in the settings. but that doesn’t show your own device
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Isn’t PM2.5 equal to PM2.5?
Right now the Purple Air devices near me read 93, 92, 99 for PM2.5. The devices are all about 2 miles away.
But my Plume Labs Flow 2 reads 4 for PM2.5. Flow 2 is outside in the backyard.
And the Flow 2 AIR app say it’s 45 for PM 2.5. for my street. (The AIR app is different from my Flow 2 device app, anyone can use the Plume Labs AIR app. )
Crazyland between SeaTac airport and Tacoma - wind blew in a wall of smoke, humidity at 15%, and check out this AQI graph from the last 2 hours.
Now winds 30+ ‘of course’ on the day guys are supposed to work on the roof, but at least it’s not trash day which is when we normally get the winds 
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Here is a link the the whole white paper that Sunny referenced. https://plumelabs.zendesk.com/hc/en-us/article_attachments/360039609054/Article_Plume_Index_.pdf
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that can’t be right. A value of 4 for pm2.5 in flow 2 is about 2 ug/m3.
The value of 90 you see in pleasanton is the usa AQI. You have to go to ug/m3 to compare. 90 boils down to about 30 ug/m3, but that is still way off. Contact support I would say. Or give it a few more days to settle in.
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Well, it just jumped a LOT, from PM 2.5 of 4, to values much higher for all the PMs.
Before I could write them down, all the PMs are back down low.
Give it a week to calibrate itself. (If I remember correctly it mentions that in the manual)
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(if you click on the values in the flow app, you get a graph and you can see the values by scrolling the cursor along the time axis)
You might have figured that out by now but the way AQI works is that any raw data like PM2.5 or VOC or NO2 value is non-uniformly scaled (that’s what is in the graph above). but something like NO2 has different health impacts then PM2.5, that’s why it uses a different scale. So each parameter is converted to some AQI value on its own. The general AQI is just the maximum of those converted values. For example, a NO2 aqi of 20, a pm2.5 aqi of 40 and an VOC aqi of 35 would result in a general AQI of 40 (the max of 40 and 35 and 20).
Many authorities have their own idea of how unhealthy NO2 or PM2.5 is, that’s why there are so many different AQIs.
I read that about letting NO2 settle down, but no sure it applies to PM values and Flow 2. I almost got ahold of Plume Labs live today, but it’s challenging, as they are on Paris time.
And OMG, this AQ stuff is a bit hard to compare, with so many different interpretations of AQ.
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I just found this website where you can convert USA AQI values to concentrations https://www.airnow.gov/aqi/aqi-calculator/
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Sunny, I think you previously pointed out that Purple Air shows both USA values and the concentrations above. Right?
yes it can (at least on the map)
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I’ve about had it with my Flow 2 and the lack of support.
It may go back to Amazon soon.
Wildfires and smoke all over California. Purple Air has a bunch of sensors near me.
They are all pretty consistent numbers.
Flow 2 says the Air Quality is good, and reads way lower than all the Purple Air numbers. Crazy jumping around too. Flow 2 support is on Paris time, nine hours away. Got up early enough today, but chat was getting error messages. Emails are not answered.
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well yeah, that’s what I would do in such a case… send it back.
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I really wanted Flow 2 to work. I wanted something I could use inside, and perhaps use some outside.
But I can’t use it if I have to trust that it’s even reasonably accurate.
mine does work just fine. You could ask amazon for a replacement.
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You probably want to turn off the indoor sensors (2nd checkbox on the bottom of the legend box) and change to LRAPA in the top right drop-down (that currently says None). The LRAPA algorithm is meant to correct for the difference between wood smoke and other particles. I think wood smoke is lighter so it registers higher, but I don’t remember for sure.
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great find. that brings down the current value of pm2.5 to 14 ug/m3. What is the current outdoor reading of the flow2 @ride525?
Thanks dxlka,
The indoor sensors have a bold circle around them, so I tend to ignore those. But it’s interesting to see inside numbers are lower.