In map settings when choosing what size pm in raw measurements, the signs are “greater than” ie particles >2.5 but I am used to pm2.5 referring to all the particles 2.5u and smaller. As you go down in size, the particle concentration increases substantially which would go along with it actually being cumulative and >0.5 including all particles larger, but that would be a big departure from convention. Is the sign wrong or are you doing something different here? Thanks.
Greater-than is correct. The sensor can’t discriminate particle size below around 0.3μm, and the outputs from the sensor are already summed. In this way, it reports data similar to a microscale. If you need specific bands then subtract the values.
Beware, the sensors have some unexpected behavior in the raw particle size measurements. Read the datasheet and relevant research papers before making too many assumptions.