Megan M McRee, Vaios Moschos, Marc N Fiddler, Dario Massabò, Jason D Surratt, Solomon Bililign
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引用次数: 0
Abstract
Biomass burning (BB) is a major source of atmospheric fine carbonaceous aerosols, which play a significant, yet uncertain, role in modulating the Earth's radiation balance. However, accurately representing their optical properties in climate models remains challenging due to factors such as particle size, mixing state, combustion type, chemical composition, aging processes, and relative humidity (RH). In our study, we investigated BB organic-rich aerosols generated from smoldering sub-Saharan African biomass fuels. Fuel samples were collected in Africa and aerosols generated in the laboratory. We quantified key optical parameters, including mass cross-sections for extinction (2.04 ± 0.32 - 15.5 ± 2.48 m2/g), absorption (0.04 ± 0.01-0.3 ± 0.1 m2/g), and scattering (1.9 ± 0.68-15.3 ± 5.5 m2/g). Wavelength-dependent properties were used to determine absorption and scattering Ångström exponents. The single scattering albedo of these aerosols ranged from 0.8 ± 0.03 to 1.0 ± 0.04 and we observed a wavelength-dependent behavior. Extinction emission factors were determined at a wavelength of 550 nm, with values ranging from 42 ± 5 to 293 ± 32 m2/kg. Notably, optical properties exhibited fuel-type dependence, with differences observed between hardwood samples and other fuels, such as grass and animal dung. Aging increased mass extinction and scattering cross-sections at 550 nm, while humidity had the opposite effect across all fuels. Nitrate radical oxidation, both in photo and dark aging conditions, also influenced these properties. The findings are expected to close the gap in our understanding of optical properties of BB aerosol emissions in one of the least studied regions of the world - Africa - providing information to climate and air quality models for the region.
期刊介绍:
Aerosol Science and Technology publishes theoretical, numerical and experimental investigations papers that advance knowledge of aerosols and facilitate its application. Articles on either basic or applied work are suitable. Examples of topics include instrumentation for the measurement of aerosol physical, optical, chemical and biological properties; aerosol dynamics and transport phenomena; numerical modeling; charging; nucleation; nanoparticles and nanotechnology; lung deposition and health effects; filtration; and aerosol generation.
Consistent with the criteria given above, papers that deal with the atmosphere, climate change, indoor and workplace environments, homeland security, pharmaceutical aerosols, combustion sources, aerosol synthesis reactors, and contamination control in semiconductor manufacturing will be considered. AST normally does not consider papers that describe routine measurements or models for aerosol air quality assessment.