Documentation on SD Card CSV data

Data
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Hi all,

I was lent a PurpleAir device to trail if it would be useful to the company I work for. I have not, and cannot register it, because I need to return it when I’m done.

I powered on my PurpleAir device and verified it was logging to an SD card, and left it alone for a week. Today I pulled the CSVs from the device, and it’s obvious it has been collecting air quality data, and that there is correlation to when there has been activity nearby. What isn’t obvious is what the various columns are. For example, if I were interested in PM10, I see the following columns:
-pm10_0_cf_1
-pm10_0_atm
-p_10_0_um
-pm10_0_cf_1_b
-pm10_0_atm_b
-p_10_0_um_b

By reading these forums I’ve been able to determine that “b” refers to the “b” sensor, and I can infer the columns without a “b” are the “a” sensor. I’ve also read that “atm” is an indoor calibration, and “cf_1” is an outdoor calibration, but I have not yet read what that means, specifically. By inference, “um” could be a raw column.

That said, where is this documented? I have been unable to find a page with explicit documentation on the data. In order for me to determine whether the sensor will be useful to our needs (we may order several hundred if so), I’m in need of some documentation explaining exactly what data it produces.

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Hi @AUPE, the documentation for SD data is found in our SD Card File Headers article.

ATM and CF1 are formulas used to generate a mass measurement (µg/m3) from particle counts. This is needed as particulate matter is generally measured in (µg/m3). Further information on this is found in our What is the Difference Between CF=1, ATM, and ALT? article.

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