Adafruit PM2.5 Air Quality Sensor Units

Hello all!

I was wondering if anyone had a deeper idea about what units the PM2.5 Air Quality Sensor outputs in. I can see in the documentation I have the choice between “Standard”, “environmental” and particles per decillitre.

While the last one is quite obvious, I am trying to figure out what on earth the other two units are actually measuring in, unfortunately neither the datasheet nor google have been much help here, does anyone have an idea? I am hoping to compare to known measurements reported in micrograms per L.


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Hi Cameron,

Glad to see someone getting into particle sensing! I’ve been looking for a PM0.1 sensor for UFPs that come off printers for a while now, but can’t find one.

As for the specs, what sensor were you using? A link or SKU would be super helpful!


Ah silly me. The unit was

PM2.5 Air Quality Sensor and Breadboard Adapter Kit - PMS5003

and I’m using the Adafruit_PM25AQI.h library.


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When I used one of these Plantower devices in a project I used the particles per 0.1L as it made more sense to me.
The Standard values I think, refer to a factory calibration or known environment.
The Environment ones refer to where the device currently is located.

The data sheet uses micrograms per cubic metre.
I think it is trying to give an indication of the weight of particles.

Link is to Environmental Science and Technology Briefs for Citizens,
Understanding Units of Measurement published be Center for Hazardous Substance Research
Kansas State University.

May be of use to you, don’t really understand it too much myself.

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Thanks Jim.

I guess I’ll have to compare it to my known measurements myself.


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