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17 results on '"Heo, Gookyoung"'

4. Interpretation of the Effects of Anthropogenic Chlorine on Nitrate Formation in N2O5 Heterogeneous Chemistry Over Northeast Asia During KORUS-AQ 2016

Author

Jo, Hyun-Young, primary, Heo, Gookyoung, additional, Park, Jaehyeoung, additional, Lee, Hyo-Jung, additional, Jeon, Wonbae, additional, Kim, Jong-Min, additional, Kim, Saewung, additional, Kim, Jung-Kwon, additional, Liu, Yiming, additional, Liu, Pengfei, additional, Zhang, Bingquing, additional, and Kim, Cheol-Hee, additional

Published
2023
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5. Chemical characteristics and sources of PM2.5 in the urban environment of Seoul, Korea

Author

Kang, Seokwon, primary, Choi, Siyoung, additional, Ban, Jihee, additional, Kim, Kyunghoon, additional, Singh, Rahul, additional, Park, Gyutae, additional, Kim, Myeong-Bok, additional, Yu, Dong-Gil, additional, Kim, Joo-Ae, additional, Kim, Sang-Woo, additional, Park, Moon-Soo, additional, Kim, Cheol-Hee, additional, Lee, Meehye, additional, Heo, Gookyoung, additional, Jang, Yu-Woon, additional, Ha, Sang-Sub, additional, Park, Taehyun, additional, and Lee, Taehyoung, additional

Published
2022
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16. Crop Residue Burning in Northeast China and Its Impact on PM 2.5 Concentrations in South Korea.

Author

Lee, Jin-Ju, Lee, Jae-Bum, Kim, Okgil, Heo, Gookyoung, Lee, Hankyung, Lee, DaeGyun, Kim, Dai-gon, and Lee, Sang-Deok

Subjects
CROP residues, AIR quality, WEATHER
Abstract

The impact of crop residue burning in northeastern China on South Korean PM2.5 concentrations was assessed via weather conditions, air quality modeling (AQM), and PM2.5 composition data during two cases exceeding 35 µg·m−3 in November 2015. PM2.5 concentration simulations of Case 1 differed from observations by 3.7–17.6 µg·m−3, overestimating the levels by 6–36%; however, Case 2 varied by 20.0–59.8 µg·m−3 from observations, with a 53–91% underestimation. Case 1 was generally well simulated, whereas the Case 2 simulation failed because the emissions of crop residue burning in northeastern China, as confirmed through satellite analysis (MODIS fires and thermal anomalies) and previous research, were not considered. The portion of organic/elemental carbon ratio during Case 2 was 1.6–2.3 times higher than that of Case 1. These results suggest that it is necessary to consider the effects of crop residue burning in northeast China to establish countermeasures to improve air quality and air quality forecasting in South Korea. [ABSTRACT FROM AUTHOR]

Published
2021
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17. Condensed chemical mechanisms and their impact on radical sources and sinks in Houston

Author

Heo, Gookyoung

Subjects
Free radicals, Radical sources, Sinks, Aromatics chemistry, Alkene reactions, Condensed chemical mechanisms, Molecular chlorine emissions, Houston, Texas, Southeast Texas
Abstract

Free radicals play a critical role in the formation of tropospheric air pollution, but current condensed chemical mechanisms used in gridded photochemical models under-predict total radical concentrations. This dissertation evaluates three hypotheses regarding radical sources and sinks using environmental chamber data and ambient data from southeast Texas. The first hypothesis, that aromatics chemistry is under-represented as a radical source in condensed chemical mechanisms, was evaluated mainly by using environmental chamber simulations and in part by using ambient simulations. Results indicate that improved characterization of aromatics chemistry in condensed chemical mechanisms will lead to more rapid and extensive free radical formation. The second hypothesis, that alkene reactions are under-represented as a radical source in condensed chemical mechanisms, was also evaluated using chamber data and TexAQS-2000 data. Results indicate that the methods used in mechanism condensation lead to lower estimates of free radical production than detailed, compound specific models. The third hypothesis, chlorine emissions and chemistry as a radical source, was also evaluated in a series of sensitivity analyses with various levels of molecular chlorine emissions. Results imply that incorporating chlorine chemistry in condensed chemical mechanisms is expected to lead to more accurate modeling of OH, HO₂ and O₃, particularly for the southeast Texas region where relatively large chlorine emissions occur from various anthropogenic sources of molecular chlorine. The relative magnitudes of these radical sources (aromatics, alkenes, and molecular chlorine) in southeast Texas were also compared using box modeling with TexAQS-2000 data. Results indicate that the relative importance of these three types of radical sources depends on the strengths of their corresponding emissions.

Published
2009

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