Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Effect of ambient humidity on the light absorption amplification of black carbon in Beijing during January 2013
Abstract Black carbon (BC) and its mixing state were measured with a ground-based single particle soot photometer in urban Beijing during the extremely polluted winter of 2013. Up to 70 ± 14% of the BC-containing particles were thickly-coated during periods of haze, compared to 37 ± 9% on non-hazy days. The thickly-coated number fraction (NFBC-thick) increased with increasing BC, reaching a plateau at ∼80–90% when BC concentrations were ≥15 μg m−3 and visibility was ≤2 km. Regional inflows brought more aged, highly thickly-coated BC to Beijing during haze. The absorption coefficient showed a distinct linear correlation with BC concentration; the mass absorption efficiency (MAE) of BC was acquired, with an overall mean of 4.2 ± 0.01 m2 g−1 at 870 nm. The MAE of BC amplified with increasing ambient relative humidity. This was largely explained by the increase in NFBC-thick, which was likely due to the enhanced production of secondary aerosol under humid conditions.
Highlights BC concentrations and mixing states were investigated using an SP2 in urban Beijing. BC fraction in PM2.5 decreased during haze though its concentrations increased. The number fraction of thickly-coated BC increased significantly during haze periods. The light absorption of BC was amplified in response to the increasing ambient RH.
Effect of ambient humidity on the light absorption amplification of black carbon in Beijing during January 2013
Abstract Black carbon (BC) and its mixing state were measured with a ground-based single particle soot photometer in urban Beijing during the extremely polluted winter of 2013. Up to 70 ± 14% of the BC-containing particles were thickly-coated during periods of haze, compared to 37 ± 9% on non-hazy days. The thickly-coated number fraction (NFBC-thick) increased with increasing BC, reaching a plateau at ∼80–90% when BC concentrations were ≥15 μg m−3 and visibility was ≤2 km. Regional inflows brought more aged, highly thickly-coated BC to Beijing during haze. The absorption coefficient showed a distinct linear correlation with BC concentration; the mass absorption efficiency (MAE) of BC was acquired, with an overall mean of 4.2 ± 0.01 m2 g−1 at 870 nm. The MAE of BC amplified with increasing ambient relative humidity. This was largely explained by the increase in NFBC-thick, which was likely due to the enhanced production of secondary aerosol under humid conditions.
Highlights BC concentrations and mixing states were investigated using an SP2 in urban Beijing. BC fraction in PM2.5 decreased during haze though its concentrations increased. The number fraction of thickly-coated BC increased significantly during haze periods. The light absorption of BC was amplified in response to the increasing ambient RH.
Effect of ambient humidity on the light absorption amplification of black carbon in Beijing during January 2013
Wu, Yunfei (Autor:in) / Zhang, Renjian (Autor:in) / Tian, Ping (Autor:in) / Tao, Jun (Autor:in) / Hsu, S.-C. (Autor:in) / Yan, Peng (Autor:in) / Wang, Qiyuan (Autor:in) / Cao, Junji (Autor:in) / Zhang, Xiaoling (Autor:in) / Xia, Xiangao (Autor:in)
Atmospheric Environment ; 124 ; 217-223
16.04.2015
7 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Light absorption enhancement of black carbon in urban Beijing in summer
| Elsevier | 2019