Seasonal light absorption properties of water-soluble brown carbon in atmospheric fine particles in Nanjing, China

Atmospheric Environment, Год журнала: 2018, Номер 187, С. 230 - 240

Опубликована: Июнь 2, 2018

Язык: Английский

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Light-absorbing organic carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions

Scientific Reports, Год журнала: 2017, Номер 7(1)

Опубликована: Июль 31, 2017

Light-absorbing organic carbon (OC), also termed brown (BrC), from laboratory-based biomass burning (BB) has been studied intensively to understand the contribution of BB radiative forcing. However, relatively few measurements have conducted on field-based and even fewer examined BrC anthropogenic combustion sources like motor vehicle emissions. In this work, light absorption methanol-extractable OC prescribed laboratory gasoline emissions was using spectrophotometry. The methanol extracts showed a strong wavelength dependence for both mass coefficients at 365 nm (MAC365, m2 g-1C) - used as measurement proxy were significantly correlated (p < 0.05) elemental (EC)/OC ratios when by each fuel type. No significant correlation observed pooling fuels, indicating that burn conditions types may impact characteristics. average MAC365 emission samples is 0.62 ± 0.76 g-1C, which similar in magnitude (1.27 g-1C). These results suggest addition BB, be an important source urban areas.

Язык: Английский

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Broadband optical properties of biomass‐burning aerosol and identification of brown carbon chromophores

Journal of Geophysical Research Atmospheres, Год журнала: 2017, Номер 122(10), С. 5441 - 5456

Опубликована: Апрель 25, 2017

Abstract The radiative effects of biomass‐burning aerosols on regional and global scales can be substantial. Accurate modeling the smoke requires wavelength‐dependent measurements parameterizations their optical properties in UV visible spectral ranges along with improved description chemical composition. To address this issue, we used a recently developed approach to retrieve time‐ spectral‐dependent ambient from 300 650 nm wavelengths during nighttime bonfire festival Israel. During biomass burning event, overall absorption at 400 increased by about 2 orders magnitude, changing single scattering albedo background level 0.95 0.7. Based new retrieval method, provide effective complex refractive index 350 for freshly emitted slightly aged aerosols. In addition, PM 2.5 filter samples were collected detailed offline analysis water‐soluble organics that contribute light absorption. Nitroaromatics identified as major organic species responsible 500 nm. Typical chromophores include 4‐nitrocatechol, 4‐nitrophenol, nitrosyringol, nitroguaiacol; oxidation‐nitration products methoxyphenols; known lignin pyrolysis. Our findings emphasize importance both primary secondary solar radiation forcing.

Язык: Английский

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Chemical characteristics of brown carbon in atmospheric particles at a suburban site near Guangzhou, China

Atmospheric chemistry and physics, Год журнала: 2018, Номер 18(22), С. 16409 - 16418

Опубликована: Ноя. 19, 2018

Abstract. Light-absorbing organic carbon (or brown carbon, BrC) in atmospheric particles has received much attention for its potential role global radiative forcing. While a number of field measurement campaigns have differentiated light absorption by black (BC) and BrC, the chemical characteristics BrC are not well understood. In this study, we present co-located real-time composition measurements to explore relationship between optical at suburban site downwind Guangzhou, China, from November December 2014. BC contributions were estimated using seven-wavelength aethalometer, while non-refractory PM1 was measured with high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Using Ångström exponent (AAE) method, that contributed 23.6 % total 370 nm, 18.1 470 10.7 520 590 10.5 660 nm. Biomass burning (BBOA) highest coefficient among sources aerosols. Its contribution decreased but low-volatility oxygenated (LVOOA) increased increasing wavelength, suggesting need wavelength-dependent analysis association makeup. Clear correlations N-containing ion fragments observed. These also depended on their degrees unsaturation/cyclization oxygenation. current study relates fragments, more detailed characterization is warranted constrain relationship.

Язык: Английский

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Identification of species and sources of atmospheric chromophores by fluorescence excitation-emission matrix with parallel factor analysis

The Science of The Total Environment, Год журнала: 2020, Номер 718, С. 137322 - 137322

Опубликована: Фев. 14, 2020

Язык: Английский

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