Active Sampling Particulate Monitor/Data Logger.

The personal/DataRAM (pDR), the world's smallest most versatile aerosol monitor/data logger, provides real-time measurement and direct readout of concentrations of airborne dust, smoke, mists, and fumes. A new model, the pDR-1200, uses an attachable pump module or a separate sampling pump according to particle size. Compact, lightweight, and easy to use, this model is ideal for respirable, thoracic, and [PM.sub.2.5] monitoring, as well as continuous-emissions and test-chamber monitoring. With optional inlet accessories, the pDR-1200 provides ambient-air measurements under variable-wind or high-humidity conditions.

When the pump is operated at specific sampling-flow rates, an optimally designed metal cyclone provides precisely defined particle size cuts. At 4 liters per minute, the cut point of the standard cyclone is 2.5 microns ([micro]m), as required for [PM.sub.2.5], monitoring. The attachable pump module allows for cut points between 2.0 and 10.0 [micro]m. With a larger, separate pump, this range can be extended down to 1.0 [micro]m. Aerodynamic particle size distributions can be computed with instrument readings and an algorithm provided.

In addition to providing real-time particulate concentration readings, the pDR-1200 has an integral filter holder (for 37-millimeter filters) located directly downstream of the photometric sensing stage. This feature allows concurrent gravimetric measurements or subsequent chemical analysis of collected samples. Primary gravimetric calibration of the instrument is easily accomplished under field conditions: The user simply adjusts the calibration constant to coincide with the filter-determined concentration.

The unit has a large-capacity data-logging capability and interfaces with a personal computer via included software for data tabulation, graphing, and so forth. Other features include an auto-ranging digital output signal as well as two analog outputs (voltage and current), which can be fed to a process controller for ventilation control or to a remote data processor or display. The concentration range for the analog signal can be selected with a personal computer. The pDR-1200 also has an on-board programmable audible alarm with switched control output.

The pDR-1200 is powered by an internal 9-volt battery (with 24-hour duration), or it can run continuously and unattended from AC line current through the power supply/charger provided with the unit. The pump module operates from either an optional rechargeable battery pack or from AC line current.