The objective of this program was the development, design, and fabrication of six personal-sized, completely self-contained dust monitors capable of real time as well as time-averaged monitoring of the concentration of respirable particles in coal mines in the range of 0.1 to 100 mg/m3. The operation of these monitors is based on light scattering and passive air sampling. The design stressed overall miniaturization, ruggedness, simplicity, and versatility. These instruments incorporate a single-chip cmos microprocessor to perform all signal processing, data display and storage, and timing functions. The overall dimensions of these devices are approximately 10 by 10 by 5 cm.