EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mass-based mixing state of black carbon measured by a tandem CPMA-SP2 system in wintertime in the North China Plain

Shaowen Zhu1, Nan Ma1,2, Xihao Pan1, Wenlin Dong1, Jiangchuan Tao1, Juan Hong1, Yuxuan Zhang2, Guo Li2, Jeannine Ditas2, Hang Su2, and Yafang Cheng2
Shaowen Zhu et al.
  • 1Institute for Environmental and Climate Research, Jinan University, 510632 Guangzhou, China
  • 2Multiphase Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany

Black carbon (BC) is the most important light absorbing component in the atmosphere and has significant impacts on the climate, environment and public health. Its effects depend not only on its spatial-temporal distribution, but also on its physico-chemical characteristics. Mixing state is one of the most important properties of BC and strongly determines its hygroscopicity and radiative properties. During an intensive field campaign conducted in the North China Plain in winter 2018, mass-based mixing state of BC-containing particles were online measured with a Centrifugal Particle Mass Analyzer and Single Particle Soot Photometer (CPMA-SP2) tandem system. This technique directly provides the mass ratio of non-refractory coating matter to BC core (MR) in individual particles and does not require to assume the density, morphology and refractive index of BC core and coating in data retrieval, therefore has lower uncertainly compared with leading-edge fit technique. In our measurement, the mean number fraction of uncoated (MR=0), thin coated (0<MR<3) and thick coated (MR≥3) BC-containing particle during the campaign were respectively ~10%, ~35% and ~55%, indicating the strong aging process of BC-containing particle in the North China Plain. The median value of MR was much higher in polluted days than clean days, for example, the median value of MR with a particle mass of 8.56 fg (~220 nm in diameter) for polluted and clean days were ~3.2 and ~1.6, respectively. The mixing state of BC-containing particles obtained by different methods were also compared and evaluated.

How to cite: Zhu, S., Ma, N., Pan, X., Dong, W., Tao, J., Hong, J., Zhang, Y., Li, G., Ditas, J., Su, H., and Cheng, Y.: Mass-based mixing state of black carbon measured by a tandem CPMA-SP2 system in wintertime in the North China Plain, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18014,, 2020