Use of electrically enhanced aerosol plasma spectroscopy for real-time characterization of beryllium particles

The best warning of human exposure to elevated toxic aerosol particles is a monitor that can provide a near-real-time alarm function. Use of surrogate indices such as particle-number concentration, mass concentration, and/or other flow-diagnostics variables is ineffective and could be costly when false positives do arise. We have developed a field-portable system specifically for monitoring beryllium particles in the air in near real-time. The prototype monitor is installed on a two-shelf handcart that can be used in workplaces involving beryllium extraction, machining, and parts fabrication. The measurement involves no sample preparation and generates no analytical waste. The operating principle of the monitor is electrically enhanced laser-induced electrical-plasma spectrometry assisted with aerosol-focusing technology. Performance data of the monitor indicate a dynamic range spanning over four orders of magnitude, and the monitor is capable of detecting an airborne beryllium concentration of 0.05 μg m^-3. In reference, the Department of Energy (DOE) standard for beryllium is 0.2 μg m^-3 within an 8-h average, while the Occupational Safety and Health Administration standard for beryllium is 2 μg m^-3. In addition, the monitor is capable of simultaneous detection of multiple elements using an Echellette spectrometer if needed. The capability of simultaneous detection provides a convenient means for positive identification and possible quantification of multiple elements in near real time. We present the instrument development and calibration data and results from field demonstration conducted at a DOE facility in Oak Ridge, Tennessee.