Characterization of Individual Atmospheric Aerosols Using Quantitative Energy Dispersive-Electron Probe X-ray Microanalysis: A Review

Abstract

Great concerns about atmospheric aerosols are attributed to their multiple roles to atmospheric processes. For example, atmospheric aerosols influence global climate, directly by scattering or absorbing solar radiations and indirectly by serving as cloud condensation nuclei. They also have a significant impact on human health and visibility. Many of these effects depend on the size and composition of atmospheric aerosols, and thus detailed information on the physicochemical properties and the distribution of airborne particles is critical to accurately predict their impact on the Earth's climate as well as human health. A single particle analysis technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA) that can determine the concentration of low-Z elements such as carbon, nitrogen and oxygen in a microscopic volume has been developed. The capability of quantitative analysis of low-Z elements in individual particle allows the characterization of especially important atmospheric particles such as sulfates, nitrates, ammonium, and carbonaceous particles. Furthermore, the diversity and the complicated heterogeneity of atmospheric particles in chemical compositions can be investigated in detail. In this review, the development and methodology of low-Z particle EPMA for the analysis of atmospheric aerosols are introduced. Also, its typical applications for the characterization of various atmospheric particles, i.e., on the chemical compositions, morphologies, the size segregated distributions, and the origins of Asian dust, urban aerosols, indoor aerosols in underground subway station, and Arctic aerosols, are illustrated.

Physicochemical Properties of Indoor Particulate Matter Collected on Subway Platforms in Japan

“…Fe might be origin from the steel dusts which were produced as numerous train wheels roll through the subway tunnels. Several earlier studies (Kim and Ro, 2010;Lorenzo et al, 2006;Okinaga et al, 2000) indicated that Fe was a major source of pollution in one of the world's most extensive commuter rail systems. And Mori et al (2007) reported that the thermal metamorphism of train wheels gene- CaO, FeO, etc.…”

Characterisation of individual aerosol particles collected during a haze episode in Incheon, Korea using the quantitative ED-EPMA technique

“…This single-particle analytical technique, which is based on scanning electron microscopy (SEM) coupled with an ultra-thin window energy-dispersive X-ray spectrometer (EDX), can not only simultaneously detect the morphology and constituent elements of a single particle, but also provide transformation information on many environmentallyimportant particles of micrometer size, such as nitrates, sulfates, oxides or mixtures, including carbon matrices (Kim and Ro, 2010;Choel et al, 2005;Geng et al, 2010).…”

Nondestructive Characterization of Municipal-Solid-Waste-Contaminated Surface Soil by Energy-Dispersive X-ray Fluorescence and Low-Z (Atomic Number) Particle Electron Probe X-ray Microanalysis

“…18,19 In general, natural soil particles result from weathering and eroding of crustal rocks, and the major constituents of soil are similar to those of rock-forming minerals. The most common minerals constituting earth's crust are silicates.…”

“…Because low-Z particle EPMA can clearly identify carbonate, sulfate, and nitrate particles, it has been proven to be useful for the characterization of diverse environmental aerosol samples. [18][19][20][21][22] The combined application of these two techniques for the characterization of river sediments polluted with heavy metals has been reported to be quite successful. [23][24][25] In this work, soils collected at MSW-contaminated and apparently noncontaminated countryside sites were investigated using these two nondestructive techniques for the detailed characterization of their inorganic chemical compositions.…”