samyoung DSM501A dust sensor

Hi,

I have a samyoung DSM501A dust sensor, I have an espruino code wich measures trough 30sec and calculates the low ratio about the documentation, what is:

PM1: 1.00459433333%
PM2.5: 0.61127766666%

How can I calculate the ug/m3 from the low ratio?

thanks
HyGy

I found this on some sites:

var concentration = 1.1*Math.pow(pm10lowratio,3)-3.8*Math.po­w(pm10lowratio,2)+520*pm10lowratio+0.62;­ // using spec sheet curve

but this calculates pcs/0.01cf how can I calculate it to ug/m3?

...does it not matter what matter the dust particles are of?

Specific weight, size, and count would go into that formula. I'm not aware of an average value for the specific weight. It does not look like that there is a simple formula to convert from count per volume to weight per volume. All references I found use a very complex and highly sophisticated anlysis of test/calibration samples taken in a very defined context to determine the weight(s). Count profiles of samples taken in comparable context are then mapped against the count profiles and related weight(s) of the test/calibration samples to 'estimate' the weight per volume concentration.

Hmm. Then how can I measure the pm10 and/or pm2.5? Need other device measuring device?

In hungary the national measuring network is measuring in ug/m3. So I want to compare my measurements with thays.