Mihye Lee

Hydrogen peroxide, organic hydroperoxide species, and formaldehyde were found to be enhanced within biomass burning plumes during the Transport and Atmospheric Chemistry near the Equator ‐ Atlantic (TRACE A) experiment. This enhancement could have resulted from direct emission by the fires or by secondary photochemical production. In this study, direct production of hydroperoxide and formaldehyde from biomass burning is proposed and examined through comparisons of hydroperoxide and formaldehyde

Abstract Stable carbon isotopic compositions (δ 13 C) were measured for 23 individual organic species including 9 dicarboxylic acids, 7 oxocarboxylic acids, 1 tricarboxylic acid, 2 α ‐dicarbonyls, and 4 fatty acids in the aerosols from Gosan background site in East Asia. δ 13 C values of particle phase glyoxal and methylglyoxal are significantly larger than those previously reported for isoprene and other precursors. The values are consistently less negative in oxalic acid (C 2 , average −14.1‰)

Hydrogen peroxide, organic hydroperoxide species, and formaldehyde were measured in the troposphere over the South Atlantic, Brazil, and southern Africa during the NASA Global Tropospheric Experiment (GTE) Transport and Atmospheric Chemistry Near the Equator‐Atlantic (TRACE‐A) experiment, an investigation into the cause of an observed seasonal ozone maximum in this region. H 2 O 2 and CH 2 O concentrations were extremely high, up to 14 and 5 ppbv, respectively, and are the result of direct produ

An HPLC (high-performance liquid chromatography) method was developed to quantify hydrogen peroxide, methyl hydroperoxide. Hydroxymethyl hydroperoxide, ethyl hydroperoxide, and peroxyaectic acid in the atmosphere. Gas-phase hydroperoxides are collected in aqueous solution using a continuous-flow glass scrubbing coil and then analyzed by an HPLC postcolumn derivatization system. The detection system is based on fluorescence, produced by the product of the reaction of hydroperoxides with peroxidas

Abstract. For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM2.5 concentration was 89 µg m−3, exceeding the Chinese national standard of 75 µg m−3 in 24 h. The maximum PM2.5 concentration was 307 µg m−3, which characterizes

Abstract Black carbon (BC) and brown carbon (BrC) aerosols that are released from the combustion of fossil fuels and biomass are of great concern because of their light-absorbing ability and great abundance associated with various anthropogenic sources, particularly in East Asia. However, the optical properties of ambient aerosols are dependent on the mixing state and the chemical composition of absorbing and non-absorbing aerosols. Here we examined how, in East Asian outflows, the parameters of

In this study, the volume mixing ratio of 55 volatile organic compound (VOC) species was measured every hour using the online TD-GC-FID system during the period from January 2018 to December 2019 in Seoul. The most abundant species were ethane (10.0 ppbv) and toluene (4.1 ppbv), with alkanes and aromatics accounting for 57.5% and 31.5% of the total VOCs (TVOC), respectively. The mixing ratios of the TVOC were markedly higher in July and November, mainly owing to the presence of aromatics and alk

As a part of ABC‐EAREX 2005 (Atmospheric Brown Cloud–East Asia Regional Experiment 2005), trace gases and compositions of PM 2.5 were measured at Gosan supersite in Jeju Island during 13–30 March 2005. Aerosol constituents were determined continuously on site at 1‐a intervals. The mean concentrations of gases were 56 ppbv for O 3 , 297 ppbv for CO, 3.2 ppbv for SO 2 , and 2.2 ppbv for NO x . For PM 2.5 , the average mass concentration was 27.3 μ g/m 3 , and mean concentrations of nss‐SO 4 2− , o

Abstract. The black carbon (BC) and carbon monoxide (CO) emission ratios were estimated and compiled from long-term, harmonized observations of the ΔBC∕ΔCO ratios under conditions unaffected by wet deposition at four sites in East Asia, including two sites in South Korea (Baengnyeong and Gosan) and two sites in Japan (Noto and Fukuoka). Extended spatio-temporal coverage enabled estimation of the full seasonality and elucidation of the emission ratio in North Korea for the first time. The estimat