Senserion SPS30 measurements and AQI

Other Hardware Sensors
1

Hi, I have a general question on the measurements that the Senserion SPS30 reports. Basically I'm trying to get to an Air Quality Index (AQI) reading from the measurements that the SPS30 provides

The PMx measurements are put into 4 'bins' depending on particle size, this is from the datasheet.

Mass concentration size range
PM1.0 0.3 to 1.0μm
PM2.5 0.3 to 2.5μm
PM4 0.3 to 4.0μm
PM10 0.3 to 10.0μm

As you can see each level up is a cumulative figure including the bin below. However, when I see published AQI readings on websites they do not look like cumulative readings and the calculation is seeming on a number which is unique to that particle size.

Here is the link to the AQI calculation:

https://forum.airnowtech.org/t/aqi-calculations-overview-ozone-pm2-5-and-pm10/168

I've searched around the web and looked at wikipedia etc but can't seem to find a source which describes the binning of particle sizes and their relationship to the AQI readings that are published on various pollution information websites

2

ok - I think I'm going to answer my own question here (Having done more research). It does seem that the PM10 figure is ALL particles 10micron and below (as pm2.5 is ALL particles 2.5micron and below). It's just a bit counter intuitive that the PM10 figure includes all other (smaller) particle sizes.

It just goes to show that you need at least the 2 common particles sizes reported (Pm2.5 & PM10) to get any appreciation of the distribution of particles in any given volume of air.

I guess you could easily do calculations to subtract one bin number from another. This would give you a specific range IE

PM10-PM4 would give you the result for particles >4 but <10 microns. However this would be a figure which is 'non standard' so not possible to compare with other published figures.