The Droplet Measurement Technologies AG-100 aerosol generator is designed to provide flow of polystyrene latex (PSL) microspheres for calibration of optical particle counters. The AG-100 is self-contained and needs no external air supply. An internal pump provides filtered air for the nebulizer air and the dilution air flow. A suspension of PSL microspheres is nebulized and mixed with dilution air before being delivered to the instrument being calibrated.