Single-Particle Characterization of Atmospheric Aerosols Collected at Gosan, Korea, during the Asian Pacific Regional Aerosol Characterization Experiment Field Campaign Using Low-Z (Atomic Number) Particle Electron Probe X-ray Microanalysis

Abstract

A quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), namely low-Z (atomic number) particle EPMA, was used to characterize the chemical compositions of the individual aerosol particles collected at the Gosan supersite, Jeju Island, Korea, as a part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). On 4-10 April 2001 just before a severe dust storm arrived, seven sets of aerosol samples were obtained by a seven-stage May cascade impactor with a flow rate of 20 L/min. Overall 11,200 particles on stages 1-6 with cutoff diameters of 16, 8, 4, 2, 1, and 0.5 microm, respectively, were examined and classified based on their secondary electron images and X-ray spectra. In general, sea salt particles were the most frequently encountered, followed by mineral dust, organic carbon (OC)-like, (NH4)2SO4/NH4HSO4-containing, elemental carbon (EC)-like, Fe-rich, and K-rich particles. Sea salt and mineral dust particles had a higher relative abundance on stages 1-5, whereas OC-like, (NH4)2SO4/NH4HSO4-containing, Fe-rich, and K-rich particles were relatively abundant on stage 6. The analysis on relative number abundances of various particle types combined with 72-hr backward air mass trajectories indicated that a lot of reacted sea salt and reacted mineral dust (with airborne NOx and SO2 or their acidic products) and OC-like particles were carried by the air masses passing over the Yellow Sea (for sample "10 April") and many NH4HSO4/ (NH4)2SO4-containing particles were carried by the air masses passing over the Sea of Japan and Korea Strait (for samples "4-9 April"). It was concluded that the atmosphere over Jeju Island was influenced by anthropogenic SO2 and NOx, organic compounds, and secondary aerosols when Asian dust was absent.

Raman microspectroscopy and vibrational sum frequency generation spectroscopy as probes of the bulk and surface compositions of size-resolved sea spray aerosol particles

“…19,20 The analysis of single particles can reveal not only their chemical constituents, but also their phase and mixing state (how species are mixed in different populations of particles). 5,[21][22][23] Experimental probes of single aerosol particles include scanning electron microscopy (SEM) or transmission electron microscopy (TEM) 21,22 coupled to energy-dispersive X-ray analysis (EDX), [24][25][26] scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure microspectroscopy (STXM-NEXAFS), 27 attenuated total reflection Fourier transform infrared imaging (ATR-FTIR), 28 particle analysis by laser mass spectrometry (PALMS), 5 and aerosol time of flight mass spectrometry (ATOFMS). 23,29 Raman microspectroscopy provides a great deal of information regarding the chemical composition and speciation of individual SSA particles.…”

Investigation of aged aerosols in size-resolved Asian dust storm particles transported from Beijing, China, to Incheon, Korea, using low-<i>Z</i> particle EPMA

“…For the detailed characterization of the complex mixtures of atmospherically-processed Asian dust aerosols, many analytical techniques have been utilized, in which the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA, also called low-Z particle EPMA) has proven to be a powerful and useful tool with a relatively short sampling time and without a complicated sample pretreatment process Ro, 2005, 2006;Geng et al, 2009aGeng et al, , 2011a. This single-particle analytical technique, which is based on scanning electron microscopy (SEM) coupled with an ultra-thin window energy-dispersive X-ray spectrometry (EDX), can simultaneously detect the morphology and constituent elements of an individual particle and provide information on the aging process and transformation of many environmentally-important particles, such as nitrates, sulfates, and carbonaceous species (Maskey et al, 2010;Choël et al, 2005Choël et al, , 2007.…”

Investigation of aged aerosols in size-resolved Asian dust storm particles transported from Beijing, China to Incheon, Korea using low-<i>Z</i> particle EPMA

“…For the detailed characterization of the complex mixtures of atmospherically-processed Asian dust aerosols, many analytical techniques have been utilized, in which the quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA, also called low-Z particle EPMA) has proven to be a powerful and useful tool with a relatively short sampling time and without a complicated sample pretreatment process Ro, 2005, 2006;Geng et al, 2009aGeng et al, , 2011a. This single-particle analytical technique, which is based on scanning electron microscopy (SEM) coupled with an ultra-thin window energy-dispersive X-ray spectrom-etry (EDX), can simultaneously detect the morphology and constituent elements of an individual particle and provide information on the aging process and transformation of many environmentally-important particles, such as nitrates, sulfates, and carbonaceous species (Maskey et al, 2010;Choël et al, 2005Choël et al, , 2007.…”