Low-Z particle EPMA, micro-Raman, ATR-FTIR을 활용한 초미세 에어로졸의 특성분석

초록

The fine aerosol particles mainly consist of inorganic and organic species with various mixing ratios depending on atmospheric conditions. In this study, aerosol samples in the size range of PM1-2.5 and PM0.03-1 collected at the roof of Inha University, were comprehensively investigated using low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), Raman microspectrometry (RMS), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Most aerosol particles were identified as SOAs + (NH4)2SO4 based on their SEM images with significant CH2/CH3 and C=O peaks appearing in their ATR-FTIR spectra for PM0.03-1 samples collected on 15 July, 2020, indicating the major composition of organics. Several different types of D-G bands indicating carbonaceous species appeared based on RMS, which can be the clues to identify different combustion/emission sources of elemental carbon, i. e., diesel, coal combustion, and biomass burning. ZnCl-containing particles known to be emitted from vehicle or coal combustion were also observed, which should be released from local emission sources due to its rapid heterogeneous Cl substitution reaction. For the PM0.03-1 sample collected on 16 July, 2020, (NH4)2SO4 was dominant together with some organics, based on strong (NH4)2SO4 peaks in Raman and ATR-FTIR spectra. Nitrate was abundantly observed in the PM1-2.5 samples. By the application of the three analytical techniques more detailed compositional characteristics could be clearly elucidated.