Characterization of atmospheric nitroaromatic compounds in Southwest China by direct injection liquid chromatography-tandem mass spectrometry analysis of aerosol extracts

Chemosphere, Год журнала: 2024, Номер 363, С. 142845 - 142845

Опубликована: Июль 14, 2024

Язык: Английский

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Measurement report: Formation of tropospheric brown carbon in a lifting air mass

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(16), С. 9263 - 9275

Опубликована: Авг. 26, 2024

Abstract. An enhanced formation of brown carbon (BrC) with a non-negligible warming effect at the tropopause has recently been found. However, its mechanism is unclear. Here, we report on BrC process that happens during air mass upward transport by conducting simultaneous measurements atmospheric 4 h time resolution mountain foot (MF, 400 m a.s.l.) and mountainside (MS, 1120 Mt. Hua, China, in 2016 summer. Our results showed daytime light absorption (abs365 nm) MS approximately 60 % lower than MF due to dilution caused planetary boundary layer expansion, but relative black about 30 higher MF, suggesting significant secondary lifting from MS. Such accounted for > 50 only 27 MF. Moreover, N:C elemental ratio was 15 mainly an aerosol aqueous-phase water-soluble organic nitrogen (WSON) compounds. Stable isotope composition further indicated such light-absorbing WSON compounds were produced reaction carbonyls NH4+. work revealed, first time, ammonia-induced aqueous reactions can significantly promote process, which probably responsible upper layer.

Язык: Английский

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Measurement Report: Optical and structural properties of atmospheric water-soluble organic carbon in China: Insights from multi-site spectroscopic measurements

Опубликована: Авг. 20, 2024

Abstract. To understand the spatial variation of optical and structural properties water-soluble brown carbon its influencing factors in China, light absorption, fluorescence, Fourier transform infrared (FTIR) spectrum organic (WSOC) different regions China are measured following same analytical methods. The average absorption coefficients mass efficiencies WSOC at 365 nm (Abs365 MAE365) rank from high to low as northwest > southwest north east regional site, with higher values Northern than Southern sites, inland areas coastal areas. resolved by positive matrix factorization model combined spectra abundant aromatic O-H C=C functional groups determined FTIR both indicate that compounds important light-absorbing substances WSOC, which also have a significant impact on fluorophores. Multiple linear regression analysis shows identified fluorophores fluorescence parallel factor contribute about 62–93 % all humic-like substance (HULIS) contributes most, especially highly‑oxygenated HULIS (29 %–50 %) long emission wavelengths. Combustion source emissions atmospheric chemical processes impacts some sites. Moreover, relative humidity (RH) can affect MAE365 decreasing increase RH when < 60 remaining relatively unchanged %. Taken together, this study promotes better understanding heterogeneity their China.

Язык: Английский

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Light Absorption Properties of Brown Carbon Aerosol During Winter at a Polluted Rural Site in the North China Plain

Atmosphere, Год журнала: 2024, Номер 15(11), С. 1294 - 1294

Опубликована: Окт. 28, 2024

Brown carbon aerosols (BrC), a subfraction of organic aerosols, significantly influence the atmospheric environment, climate and human health. The North China Plain (NCP) is hotspot for BrC research in China, yet our understanding optical properties rural regions still very limited. In this study, we characterize chemical components light absorption at site during winter NCP. average mass concentration PM1 135.1 ± 82.3 μg/m3; organics nitrate are main PM1. coefficient (babs,BrC) 53.6 45.7 Mm−1, accounting 39.5 10.2% total 370 nm. Diurnal variations reveal that babs,BrC lower afternoon, attributed to evolution planetary boundary layers. mainly emitted locally, both aqueous phase photooxidation reactions can increase babs,BrC. Notably, reduced when RH > 65%. During foggy conditions, facilitate formation secondary contribute bleaching BrC. This process ultimately causes decrease Ångström exponent (AAE) efficiency (MAE). contrast, babs,BrC, along with AAE MAE, rise due substantial primary emissions. study enhances polluted

Язык: Английский

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Heterogeneous formation and light absorption of secondary organic aerosols from acetone photochemical reactions: remarkably enhancing effects of seeds and ammonia

Atmospheric chemistry and physics, Год журнала: 2024, Номер 24(24), С. 14177 - 14190

Опубликована: Дек. 19, 2024

Abstract. Secondary organic aerosols (SOAs) from highly volatile compounds (VOCs) are currently not well represented in numerical models as their heterogeneous formation mechanisms the atmosphere remain unclear. Based on smog chamber experiments, here we investigated yield and pathway of SOA acetone photochemical reactions under low-NOx conditions presence preexisting haze particles ((NH4)2SO4 NH4HSO4) saline mineral (Na2SO4) ammonia-rich conditions. Our results showed that acetone-derived is remarkably enhanced via multiphase these seeds, especially for particles. We found aerosol acidity a key factor controlling pathways SOA, which acids, alcohol, carbonyls produced dissolve into aqueous phase seeds subsequently esterify and/or oligomerize SOAs consist larger molecules acidic but smaller neutral aerosols. Moreover, light absorption ability formed (NH4)2SO4 stronger than Na2SO4 particles, ammonia, due to N-containing organics. Through comparison with methylglyoxal (MGly), total 2.8–8.2 times irreversible uptake MGly, suggesting only considering MGly precursor will probably underestimate role global production since abundantly exists troposphere.

Язык: Английский

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