The Casella Microdust Pro is an ideal instrument for hand held or area monitoring of dust and particulate concentrations in the workplace. It provides a real time indication of the airborne dust in terms of the concentration in milligrams per cubic meter (mg/m3). A scrolling time history chart display as well as the normal digital display shows the current, highest and average concentration levels in a clear and concise manner. Dust concentration levels can be logged into the memory of the meter that will hold over 15,000 samples for later download to the Windows program that is provided with the standard Microdust Pro kit. An individual optical calibration filter is provided with every unit to allow the user to setup the instrument and return it to its factory calibration while in the field. The unit will store the calibration correction factors for up to 4 different dust types to allow comparative results to samples taken with traditional air sampling pumps and gravimetric filters.