Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Light absorption enhancement of black carbon in urban Beijing in summer
https://orcid.org/0000-0003-3768-1770
https://orcid.org/0000-0002-5203-8778
https://orcid.org/0000-0001-6249-2280
https://orcid.org/0000-0003-2354-0221
Abstract The light absorption enhancement (E abs) of black carbon (BC) caused by non-BC materials is an important source of uncertainty in radiative forcing estimate, yet remains poorly understood in relatively polluted environment such as the megacity Beijing. Here BC absorption enhancement at 630 nm was in-situ measured using a thermodenuder coupled with a soot particle aerosol mass spectrometer and a single scattering albedo monitor in Beijing in summer. The project average (±1σ) E abs was 1.59 (±0.26), suggesting a significant amplification of BC absorption due to coating materials. E abs presented a clear daytime increase due to enhanced photochemical processing, and a strong dependence on the mass ratios of non-BC coatings to BC (RBC). Our results showed that the increase in E abs as a function of RBC was mainly caused by the increased contributions of secondary aerosol. Further analysis showed that the BC absorption enhancement in summer in Beijing was mainly associated with secondary formation of nitrate, sulfate and highly oxidized secondary organic aerosol (SOA), while the formation of freshly and less oxidized SOA appeared not to play an important role.
Graphical abstract Display Omitted
Highlights A significant BC absorption enhancement (∼1.6) in summer in Beijing. Light absorption enhancement depends strongly on the amount of BC coatings. SIA and highly oxidized SOA play the most impacts on absorption enhancement.
Light absorption enhancement of black carbon in urban Beijing in summer
https://orcid.org/0000-0003-3768-1770
https://orcid.org/0000-0002-5203-8778
https://orcid.org/0000-0001-6249-2280
https://orcid.org/0000-0003-2354-0221
Abstract The light absorption enhancement (E abs) of black carbon (BC) caused by non-BC materials is an important source of uncertainty in radiative forcing estimate, yet remains poorly understood in relatively polluted environment such as the megacity Beijing. Here BC absorption enhancement at 630 nm was in-situ measured using a thermodenuder coupled with a soot particle aerosol mass spectrometer and a single scattering albedo monitor in Beijing in summer. The project average (±1σ) E abs was 1.59 (±0.26), suggesting a significant amplification of BC absorption due to coating materials. E abs presented a clear daytime increase due to enhanced photochemical processing, and a strong dependence on the mass ratios of non-BC coatings to BC (RBC). Our results showed that the increase in E abs as a function of RBC was mainly caused by the increased contributions of secondary aerosol. Further analysis showed that the BC absorption enhancement in summer in Beijing was mainly associated with secondary formation of nitrate, sulfate and highly oxidized secondary organic aerosol (SOA), while the formation of freshly and less oxidized SOA appeared not to play an important role.
Graphical abstract Display Omitted
Highlights A significant BC absorption enhancement (∼1.6) in summer in Beijing. Light absorption enhancement depends strongly on the amount of BC coatings. SIA and highly oxidized SOA play the most impacts on absorption enhancement.
Light absorption enhancement of black carbon in urban Beijing in summer
https://orcid.org/0000-0003-3768-1770
https://orcid.org/0000-0002-5203-8778
https://orcid.org/0000-0001-6249-2280
https://orcid.org/0000-0003-2354-0221
Abstract The light absorption enhancement (E abs) of black carbon (BC) caused by non-BC materials is an important source of uncertainty in radiative forcing estimate, yet remains poorly understood in relatively polluted environment such as the megacity Beijing. Here BC absorption enhancement at 630 nm was in-situ measured using a thermodenuder coupled with a soot particle aerosol mass spectrometer and a single scattering albedo monitor in Beijing in summer. The project average (±1σ) E abs was 1.59 (±0.26), suggesting a significant amplification of BC absorption due to coating materials. E abs presented a clear daytime increase due to enhanced photochemical processing, and a strong dependence on the mass ratios of non-BC coatings to BC (RBC). Our results showed that the increase in E abs as a function of RBC was mainly caused by the increased contributions of secondary aerosol. Further analysis showed that the BC absorption enhancement in summer in Beijing was mainly associated with secondary formation of nitrate, sulfate and highly oxidized secondary organic aerosol (SOA), while the formation of freshly and less oxidized SOA appeared not to play an important role.
Graphical abstract Display Omitted
Highlights A significant BC absorption enhancement (∼1.6) in summer in Beijing. Light absorption enhancement depends strongly on the amount of BC coatings. SIA and highly oxidized SOA play the most impacts on absorption enhancement.
Light absorption enhancement of black carbon in urban Beijing in summer
Xie, Conghui (Autor:in) / Xu, Weiqi (Autor:in) / Wang, Junfeng (Autor:in) / Liu, Dantong (Autor:in) / Ge, Xinlei (Autor:in) / Zhang, Qi (Autor:in) / Wang, Qingqing (Autor:in) / Du, Wei (Autor:in) / Zhao, Jian (Autor:in) / Zhou, Wei (Autor:in)
Atmospheric Environment ; 213 ; 499-504
21.06.2019
6 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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