The local measuring stations with professional sensors give a value of 5-15. The purple air sensor give a value 40-70. I have thought of two possible problems:
There is no unit given for the measured values. Normally in my region it is µg/m³. Is this also true for these sensors?
Or maybe it’s because they are a bit too old and therefore a bit dirty inside.
Thank you for the hint. Do you mean this option?:“Tasmanian PM2.5 scale (ug/m^3)”
When I apply this the values are still a bit to high but now much lower.
Who is your local air quality authority? And you have PA-II Classic sensors, not Flex
You might try setting the map as follows, if you are looking for PM2.5 in μg/m³ to compare with locally calibrated equipment:
Data layer: Raw PM2.5
Apply conversion: US EPA
It may be difficult to get close agreement if your air pollutants require specialized correction factors. US EPA’s adjustment was developed with wood smoke as a primary pollutant.
You might also try performing the sensor maintenance described here, especially if the A and B sensors are wildly different:
