Abstract
Physical and chemical characterization of airborne particles on-line and in real time can provide direct measurement regarding the dynamics, phase partition, and the transformation of aerosols and chemical species associated with the aerosol particles. This information is extremely useful for a wide range of applications such as emission control and process optimization. A compact laser-based instrument has been developed at the Oak Ridge National Laboratory for measurement of elemental composition on aerosol particles. Laser-induced plasma spectroscopy (LIPS) was employed as the principle in the design of the field-portable instrument. It was found that the LIPS technique itself was insufficient to detect trace metals (i.e., mercury and chromium) in aerosols at a level commonly found in source emissions. The LIPS technique could achieve a detection of aerosol mercury at 9.8 ng m-3, and chromium at 98 ng m-3 with a precision of ± 1%. We have enhanced the detection sensitivity for the LIPS measurement of these two species by coupling the spectroscopic technique with an aerosol beam-focusing device. The signal enhancement was about two orders of magnitude over traditional nonfocusing approach. The reported elemental detection level of our instrument was for aerosols of a number median diameter of 300 nm and the geometric standard deviation of 1200 nm. Each measurement was accomplished in an interval approximately 1-2 min.
| Original language | English |
|---|---|
| Pages (from-to) | 219-229 |
| Number of pages | 11 |
| Journal | Fuel Processing Technology |
| Volume | 65 |
| DOIs | |
| State | Published - Jun 2000 |
| Event | The 1998 Conference on Air Quality: Mercury, Trace Elements, and Particulate Matter - McLean, VA, USA Duration: Dec 1 1998 → Dec 4 1998 |
Funding
The research was funded by the Strategic Environmental Research and Development Program administrated by the US Department of Defense, Department of Energy, and the Environmental Protection Agency under the contract number CP1060-97. The author acknowledges Madhavi Martin for performing the experiments and William Linak of US Environmental Protection Agency for review and helpful suggestions. Dr. Martin was supported in part by an appointment to the Oak Ridge National Laboratory Postdoctoral Research Associates Program administered jointly by the Oak Ridge National Laboratory and the Oak Ridge Institute for Science and Education. The author also acknowledges the two anonymous journal reviewers for their insightful comments leading to this final manuscript. Oak Ridge National Laboratory was managed by Lockheed Martin Energy Research for the US Department of Energy under contract number DE-AC05-96OR22464. This document is the publication number 4898 of the Environmental Sciences Division at the Oak Ridge National Laboratory. The submitted manuscript has been authorized by a contractor of the US Government under Contract no. DE-AC05-95OR22464. Accordingly, the US Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or all others to do so, for US Government purposes.