title: Radiative absorption enhancement from coatings on black carbon aerosols.
abstract: The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4±0.8m(2)g(-1) was enhanced to 9.6±1.8m(2)g(-1) at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (EMAC) rises from 1.4±0.3 in fresh combustion emissions to ~3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average EMAC of 2.25±0.55, and sulfates were primary drivers of the enhanced BC absorption.
authors.affiliation: Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Xinjuan
authors.initials: X
authors.lastname: Cui
authors.affiliation: Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Lingxiao
authors.initials: L
authors.lastname: Yang
authors.affiliation: Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China. Electronic address: bingchen@sdu.edu.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.affiliation: Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China. Electronic address: jmchen@sdu.edu.cn.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate Research, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: August
authors.initials: A
authors.lastname: Andersson
authors.affiliation: Department of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate Research, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Örjan
authors.initials: Ö
authors.lastname: Gustafsson
keywords: Aerosol mixing states; Black carbon; China; Lensing effect; Radiative absorption