PurpleAir PM2.5 ATM QAQC

Dear PurpleAir + Community,

I was doing QAQC of PurpleAir ¶ monitors (pm2.5_atm_*) over India and found lots of data as invalid. I would like your thoughts/opinion about it. Below is QAQC routine for PM2.5_ATM between channel A and B.

Attached is analysis of Sensor_Index=4105. QAQC was conducted using 10-,minutes data for entire period till 6/10/2022. Below criteria were used for QAQC of PurpleAir PM2.5:

10-minute PurpleAir PM2.5_ATM for all monitors

  • for PurpleAir ATM_A PM2.5 ≤ 0.3 µg/m3 and >=1000 µg/m3: Invalid
  • for PurpleAir ATM_A PM2.5 between > 0.3 and ≤ 100 µg/m3 : if difference between Channel A and B within ± 10 µg/m3 : Valid
  • for PurpleAir ATM_A PM2.5 > 100 µg/m3 and < 1000 µg/m3: if difference between Channel A and B within ± 10 % : Valid

Thank you!

1 Like

Over 1000 can happen as under 0.3 but they are rare and those conditions should appear in nearby units. An example of the high one was the large garbage dump fire.

I find that over 1000 tends involve small spiders. I had 6 plantower pms5003 sensors in the same and they would all trend the same ways but some do seem to be a fixed ratio off of others.