= GRIMM Sky OPC = The GRIMM Sky OPC is an optical particle counting instrument. It works by combining a laser, mirror and detector to measure the scattering off particles. The laser is focused at the centre of the measuring cell, which is the channel where the particles travel through. == Raw data format == The data format is a comma separated (csv) file which contains the particle counts at the resolution set during collection. It also contains GPS position and time stamps for each measurement epoch. == Specifications == The instrument has 32 channels or "bins" of particle sizes, ranging from 0.25um up to 32um, and is capable of measuring up to 2 million particles per cubic litre. The air is pumped into the instrument via an inlet nozzle. It can be operated at different time resolutions ranging from 1 second to 60 minutes.