SEM-EDX Analysis of Aerosol Samples

One of the important environmental issues in upstate New York is the acid rain problem in the Adirondack Mountains, which is associated with atmospheric aerosols. As a part of a systematic study to understand the transport, transformation, and effects of airborne pollutants in the Adirondack Mountains, we are performing an analysis of atmospheric aerosols collected at Piseco Lake. In previous work, we used proton induced X-ray emission (PIXE) [1] spectrometry to measure the concentrations of elements in aerosol samples as a function of the size of the particulate matter. The results of the PIXE analysis indicate significant concentrations of sulfur in small particles that can travel great distances and may contribute to acid rain. Here we report on the investigation of the small-particle aerosol samples using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) to obtain elemental information on individual particles. Many of the particles contain large concentrations of sulfur and oxygen that may indicate the presence of sulfur oxides from industry and coal combustion that are known contributors to acid rain, but they are not always in the same ratio. There are also many particles that contain significant concentrations of elements commonly found in soil (Al, Si, K, and Ca)