Realistic values for PM 2.5?

[starbuck93]

Hey guys. I booted up my AirGradient DIY yesterday and the PM values were all at 0 for a long time. They did eventually pop up when we cooked dinner. So I’m wondering if this looks about right? I expected to see slightly higher than 0 but I have no frame of reference.

I flashed ESPHome on the board and this is the Home Assistant history graph from the past 24h. The numbers pop up to 1 every once in a while, too, with a max of 52. I had also installed the official AirGradient version via Arduino but that also reported 0.

Thanks!

Edit: whoops, just read Question about overall calibration and why my numbers are all over the map? and looks like that answers my question.

[MallocArray]

I’ve had the same thing, where mine was showing 0 and wasn’t sure if that was correct. I went to accuweather.com for my zip code and click on More Details under Air Quality to get an estimated PM2.5 for your area. Mine was really low for my area, 7-10, and inside should be lower than outside, so I think it is reasonable for it to be 0.

You could try taking it outside for 10 min and see if it shows non-zero numbers.

[Achim_AirGradient]

Easiest is just to create some smoke, e.g. with a candle. The sensor should pick this up quickly.

Also, keep in mind that we display PM2.5 in µg/m3 and not US AQI. In low concentrations, US AQI is roughly 3 times µg/m3.

So the unit might give the impression that the sensor shows too low, if people are used to the US AQI index.

You can calculate the values with this calculator: AQI Calculator - US EPA Scale convertor