GRIMM EDM 365 Transportable Outdoor Environmental Dust Monitor simultaneously measures the PM10, PM2.5, PM1 values every sixty seconds and displays them as number concentration (number of particles/m³).  The aerosol spectrometer works at a flow rate of 72 liters/minute. The constant flow rate is maintained by a large external flow controlled pump. Sheath air assures cleaning of the optic which means extended periods of remote operation are assured.