@epierre I obtained the following equation by polynomial fit the low ratio vs particle (pcs/283ml) graph in the DSM501 datasheet.

concentration = (0.1 * pow(ratio, 2)) + (619 * ratio) + 50;

Please help to check whether the equation is correct.

@epierre I am working on a dust sensor project using Samyoung DSM501A. I am confused with the identical calculation formula used in the Samyoung DSM501A and Shinyei PPD42NS dust sketch.

concentration = 1.1pow(ratio,3)-3.8pow(ratio,2)+520*ratio+0.62;

My understanding is that the formula is based on the specific product's data sheet curve. Is the formula for DSM501A, PPD42NS, or both?