Each sample result is logged as the number of particles counted in that single sample volume at each considered size for the class in question. Where a point was sampled two or more times, the mean number of particles at that point for each size is worked out from the individual samples (Formula A.3) and the concentration per cubic metre at that point follows from that mean and the sample volume (Formula A.4); a counter that calculates concentration itself may make the manual step unnecessary.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.