Chemical characteristics of PM2.5 during spring and fall at two sites in Chungcheongnam-do, South Korea; insight into Fe solubility and SO42− formation

Park, Seungshik; Son, Se-Chang; Lee, Kwang Yul

doi:10.1016/j.apr.2022.101350

Cited by 7 publications

(1 citation statement)

References 57 publications

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“…To determine the phase behavior of real aerosol particles, we collected seven different PM 2.5 samples during winter in a rural area, Seosan, in South Korea. It has been reported that severe PM 2.5 pollution occurs frequently in this area (Ju et al, 2020;Hwang et al, 2021;Park et al, 2022). During the sampling period, all seven samples indicated PM 2.5 pollution based on the guideline value of 15 μg/m 3 for 24-h mean PM 2.5 , according to the World Health Organization (2021).…”

Section: Resultsmentioning

confidence: 85%

Microscopic observation of a liquid-liquid-(semi)solid phase in polluted PM2.5

Gaikwad

Jeong²,

Kim³

et al. 2022

Front. Environ. Sci.

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Atmospheric aerosol particles are complex mixtures having various physicochemical properties. To predict the role and characteristics of such complex aerosol particles in air pollution and related atmospheric chemistry, our knowledge of the number and types of phases in complex aerosol particles should be improved. However, most studies on the phase behavior of aerosol particles have been conducted in the laboratory and have not used real-world aerosol particles. In this study, using a combination of optical microscopy and poke-and-flow technique, we investigated the number and types of phases of actual aerosol particles of particulate matter < 2.5 µm (PM2.5) collected on heavily polluted days in Seosan, South Korea in winter 2020–2021. From the microscopic observations at 293 K, it showed that the PM2.5 particles exist in a single liquid phase at relative humidity (RH) >∼85%, a liquid-liquid phase at ∼70% < RH <∼85%, a liquid-liquid-(semi)solid phase at ∼30% < RH <∼70%, and a (semi)solid phase at RH <∼30% upon dehydration. This reveals that three phases of atmospheric aerosol particles coexisting as liquid-liquid and liquid-liquid-(semi)solid would be the most common phases in the atmosphere considering ambient RH ranges. These observations provide fundamental properties necessary for improved predictions of air quality and aerosol chemistry such as reactive uptake of N2O5, size distributions, and mass concentrations of aerosol particles.

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Section: Resultsmentioning

confidence: 85%