Subtask 2.12 - Air Quality Assessment and Control

Past particulate matter (PM) research projects conducted at the Energy & Environmental Research Center included data on PM size, morphology, and chemistry. The objective of this project was to improve automated analysis capabilities of the scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer. The SEM is now able to perform particle-by-particle analysis on the desired number of particles and provide size, morphology, and chemistry information for each particle. A new x-ray and image analysis system was purchased and implemented for improvements to data acquisition and analysis. This new analysis system is equipped with a digital-pulse processor, allowing for the determination of pixel-by-pixel chemistry, which significantly enhances our ability to characterize PM and other materials. In addition, this system is personal computer-based, which allows programming of the SEM to perform the automated image analysis along with detailed chemical information. This permits the incorporation of particle classification algorithms within the same computer system as the analysis is conducted. Additionally, the new Spirit software can now integrate full SEM control with imaging, elemental identification, and electron backscatter diffraction (EBSD) operation. The EBSD system has also allowed for phase identification within the SEM. Reexamination of previous samples collected on a polycarbonate filter for ambient-air PM2.5 analysis has shown that crystalline identification of individual particles can be done without further sample preparation or modification of the sample and/or sampling substrate