Why is PM10 obsolete?

Real-Time Map Data Layers
1

Why is the value for PM10 marked as obsolete in the map? In the European Union, air quality monitoring is based on this value, among others.
Kind regards

2

Hi @jheiler

PurpleAir sensors still produce PM10 values, but the decision to mark them as obsolete was based on the SQAMD evaluations that have shown that PurpleAir sensors are poor at measuring PM10.

3

A more technical answer is that PM10 is actually 2 different “modes” of particles: fine (0-2.5 um) and coarse (2.5 to 10 um). PM10 = PM2.5 plus PM-coarse. They have different physical and chemical properties, and different health effects, and are usually not well correlated. PM2.5 is part of PM10. If all the PM10 (0 to 10 um) is PM2.5, then the PA will measure it ok. If it is all PM-coarse, it will not measure it in a useful manner. From a health perspective, PM2.5 is the one of most concern most of the time in most places.