Single-particle Investigation of Antarctic Sea Spray Aerosols Using Low-Z particle EPMA, Raman Microspectrometry, and ATR-FTIR Imaging Techniques

초록

The Antarctic region, which is isolated from anthropogenic sources, is one of the few pristine places to study natural sea spray aerosols (SSAs) with minimum anthropogenic influence [1]. There are conflicting opinions on correlations between levels of chlorophyll-a as an indicator of biological activity in seawater and organic species in SSAs [2-5]. A recent our study [1] showed differences of chemical compositional characteristics between typical summertime and wintertime An-tarctic aerosol samples. However, it is not clear whether the different compositional features between two samples are due to their different sampling seasons or biological activities. To better understand about the Antarctic SSAs, additional Antarctic aerosol samples collected during Dec. 2011 and Sep. 2012 when the oceanic chlorophyll-a levels were in the range of 0.07-13.38 ?g /L were chosen. Antarctic aerosol samples which are representative for each season with having different chlorophyll-a levels are investigated on a single particle basis using quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), called low-Z particle EPMA, Raman microspectrometry (RMS), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) imaging techniques. Low-Z particle EPMA is applied to get information on morphology and size from SEM images and chemical compositions from X-ray spectra. The two vibrational spectroscopic techniques are used to identify organic and inorganic molecular species through Raman and ATR-FTIR spectra. Detailed characteristics of Antarctic aerosol samples are under examination and will be presented.