• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.232-236
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• 2010

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.2
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• pp.131-157
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• 2016

A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.349-359
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• 2016

Researchers have traditionally assumed that aerosol particles containing secondary organic aerosols (SOAs) are to be in liquid state with low viscosity even at low relative humidity. However, recent measurements showed that SOAs can have high viscosity under certain conditions. Herein, new different techniques for measurements of viscosities of SOA particles are introduced. Moreover, laboratory studies for the viscosities and the phases of biogenic SOAs produced by ${\alpha}$-pinene, isoprene, limonene, and ${\beta}$-caryophyllene of atmospheric relevance are reviewed. Future studies for determination of the phases of atmospheric aerosol particles are also suggested.

• Particle and aerosol research
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• v.9 no.2
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• pp.89-102
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• 2013

24-hr $PM_{2.5}$ samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species($Na^+$, $NH^{4+}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of $PM_{2.5}$ and its chemical components. An Asian dust event was also observed, during which $PM_{2.5}$ concentration was 64.5 ${\mu}g/m^2$. Crustal materials during Asian dust event contributed 26.6% to the $PM_{2.5}$, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, ${NO_3}^-$, ${SO_4}^{2-}$, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, ${NO_3}^-$ and ${SO_4}^{2-}$. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.

• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.300-312
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• 2017

To improve the understanding of secondary organic aerosol (SOA) formation from the photo-oxidation of anthropogenic and biogenic precursors at the regional background station on Baengnyeong Island, Korea, gas phase and aerosol chemistries were investigated using the Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS) and the Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS), respectively. HR-ToF-AMS measured fine particles ($PM_1$; diameter of particle matter less than $1{\mu}m$) at a 6-minute time resolution from February to November 2012, while PTR-ToF-MS was deployed during an intensive period from September 21 to 29, 2012. The one-minute time-resolution and high mass resolution (up to $4000m{\Delta}m^{-1}$) data from the PTR-ToF-MS provided the basis for calculations of the concentrations of anthropogenic and biogenic volatile organic compounds (BVOCs) including oxygenated VOCs (OVOCs). The dominant BVOCs from the site are isoprene (0.23 ppb), dimethyl sulphide (DMS, 0.20 ppb), and monoterpenes (0.38 ppb). Toluene (0.45 ppb) and benzene (0.32 ppb) accounted for the majority of anthropogenic VOCs (AVOCs). OVOCs including acetone (3.98 ppb), acetaldehyde (2.67 ppb), acetic acid (1.68 ppb), and formic acid (2.24 ppb) were measured. The OVOCs comprise approximately 75% of total measured VOCs, suggesting the occurrence of strong oxidation processes and/or long-range transported at the site. A strong photochemical aging and oxidation of the atmospheric pollutants were also observed in aerosol measured by HR-ToF-AMS, whereby a high $f_{44}:f_{43}$ value is shown for organic aerosols (OAs); however, relatively low $f_{44}:f_{43}$ values were observed when high concentrations of BVOCs and AVOCs were available, providing evidence of the formation of SOA from VOC precursors at the site. Overall, the results of this study revealed several different SOA formation mechanisms, and new particle formation and particle growth events were identified using the powerful tools scanning mobility particle sizer (SMPS), PTR-ToF-MS, and HR-ToF-AMS.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.497-507
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• 2015

Real-time and quantitative measurement of the chemical composition in ambient aerosols represents one of the most challenging problems in the field of atmospheric chemistry. In the present study, time resolved application by Aerosol-into-Mist System (AIMS) following by total organic carbon analyzer (TOC) has been developed. The unique aspect of the combination of these two techniques is to provide quantifiable water soluble organic carbon (WSOC) information of particle-phase organic compounds on timescales of minutes. We also demonstrated that the application of the AIMS method is not limited to water-soluble organic carbon but inorganic ion compounds. By correlating the volume concentrations by optical particle sizer (OPS), water soluble organic carbon can be highly related to the secondary organic products. AIMS-TOC method can be potentially applied to probe the formation and evolution mechanism of a variety of SOA behaviors in ambient air.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.447-456
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• 2008

Limonene, pinene, and isoprene are abundant and ubiquitous volatile organic compounds (VOCs) which are found in various natural products and also produced from various manufacture processes. Limonene and pinene are major components of food additives and household products for enrichment of good flavors and elimination of malodors, and isoprene is a basal motif of monoterpenes such as limonene and pinene. They have shown many beneficial effects such as chemopreventive, chemotherapeutic, and antioxidant activities. Upon certain conditions, however, adverse effects of these compounds on human health have also been reported. Although they do not seem to have acute and severe toxicity to human, they can easily generate secondary organic aerosols (SOAs) when they react with oxygen and/or ozone, which have shown certain toxic effects on experimental animal models as well as on humans. Numerous household and scented products containing limonene, pinene, and isoprene are widely used in these days. However, biological consequences upon exposure to these products are largely unknown. The aim of this review is to summarize and analyze the current understanding on the biological effects of VOCs, in particular limonene, pinene, and isoprene, as well as their SOAs.

• Particle and aerosol research
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• v.14 no.4
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• pp.135-144
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• 2018

Based on a two-year measurement data, major sources for the ambient carbonaceous aerosols at the Anmyeon Global Atmosphere Watch (GAW) station were identified by using the Positive Matrix Factorization (PMF) model. The particulate matter less than or equal to $2.5{\mu}m$ in aerodynamic diameter (PM2.5) aerosols were sampled between June 2015 to May 2017 and carbonaceous species including ~80 organic compounds were analyzed. When the number of factors was 5 or 6, the performance evaluation parameters showed the best results, With 6 factor case, the characteristics of transported factors were clearer. The 6 factors were identified with various analyses including chemical characteristics and air parcel movement analysis. The 6 factors with their relative contributions were (1) anthropogenic Secondary Organic Aerosols (SOA) (10.3%), (2) biogenic sources (24.8%), (3) local biomass burning (26.4%), (4) transported biomass burning (7.3%), (5) combustion related sources (12.0%), and (6) transported sources (19.2%). The air parcel movement analysis result and seasonal variation of the contribution of these factors also supported the identification of these factors. Thus, the Anmyeon Island GAW station has been affected by both regional and local sources for the carbonaceous aerosols.