Meng Fan1,2, Liangfu Chen1,2, Shenshen Li1,2, Mingmin Zou 1,2, Lin Su1,2, Jinhua Tao1,2

  • 1 State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China
  • 2 Joint Center for Global Change Studies, Beijing 100875, China

Received: April 22, 2015
Revised: August 10, 2015
Accepted: October 13, 2015
Download Citation: ||  

  • Download: PDF

Cite this article:
Fan, M., Chen, L., Li, S., Zou, M., Su, L. and Tao, J. (2016). The Effects of Morphology and Water Coating on the Optical Properties of Soot Aggregates. Aerosol Air Qual. Res. 16: 1315-1326.


  • Optical properties calculated for two mixtures between soot aggregates and water.
  • A relationship among Df, RH and N modeled to simulate the soot aggregates shrinkage.
  • The impact of shrinking and monomer is larger for smaller particles.
  • For soot aggregate in water droplet, core shape is important when the shell is thin.



Soot particles positively influence radiative forcing due to their strong absorption. Because of their chain-like structure, aggregated soot particles become more compact with the aging process, and the monomers or particles are always covered by water coatings. The optical parameters of two typical soot-water mixtures (i.e., an aggregate with core-shell monomers and a soot aggregate inside a water droplet) at 550 nm were investigated using the superposition T-matrix method, with a focus on the impact of the morphology and water coating of soot aggregates. For the soot aggregate with core-shell monomers, a relationship among the fractal dimension, relative humidity (RH) and monomer number was established and used to calculate optical parameters. The intensity of forward scattering declined with the increasing RH. The Cext, Csca, Cabs and SSA are much more insensitive to RH under higher RH conditions (RH > 90%) than at a lower RH level. In addition, hygroscopic shrinkage and the thickness of water coating have stronger effects on the optical properties of larger aggregated soot at higher RH than lower RH. For another mixing state, the soot aggregate inside a water droplet, the morphology of the soot core plays an important role in the optical properties when the thickness of the water shell is small. When the diameter ratio of the water droplet to the aggregated soot (D_ratio) changes from 1.2 to 2.8, Cext difference increases from 0.23 µm2 to 2.36 µm2 for particles with N = 100 and 500, whereas the SSA difference decreases from 0.12 to 0.01. If the agglomerated structure of the soot core is not considered, the Cext, Csca and SSA will be underestimated for a relatively small D_ratio of 1.2. Ignoring the soot core in the water droplet could introduce large errors into the calculation of the optical parameters, and ignoring the structure of the aggregated soot core could enlarge the errors.

Keywords: Soot particle; Water coating; Optical property; The superposition T-matrix

Share this article with your colleagues 


Subscribe to our Newsletter 

Aerosol and Air Quality Research has published over 2,000 peer-reviewed articles. Enter your email address to receive latest updates and research articles to your inbox every second week.

77st percentile
Powered by
   SCImago Journal & Country Rank

2022 Impact Factor: 4.0
5-Year Impact Factor: 3.4

Call for Papers for the special issue on: "Carbonaceous Aerosols in the Atmosphere"

Aerosol and Air Quality Research partners with Publons

CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit
CLOCKSS system has permission to ingest, preserve, and serve this Archival Unit

Aerosol and Air Quality Research (AAQR) is an independently-run non-profit journal that promotes submissions of high-quality research and strives to be one of the leading aerosol and air quality open-access journals in the world. We use cookies on this website to personalize content to improve your user experience and analyze our traffic. By using this site you agree to its use of cookies.