Shapes of soot aerosol particles and implications for their effects on climate

Kouji Adachi, Serena H. Chung, P R Buseck

Research output: Contribution to journalArticle

215 Citations (Scopus)

Abstract

Soot aerosol particles (also called light-absorbing, black, or elemental carbon) are major contributors to global warming through their absorption of solar radiation. When embedded in organic matter or sulfate, as is common in polluted areas such as over Mexico City (MC) and other megacities, their optical properties are affected by their shapes and positions within their host particles. However, large uncertainties remain regarding those variables and how they affect warming by soot. Using electron tomography with a transmission electron microscope, three-dimensional (3-D) images of individual soot particles embedded within host particles collected from MC and its surroundings were obtained. From those 3-D images, we calculated the optical properties using a discrete dipole approximation. Many soot particles have open, chainlike shapes even after being surrounded by organic matter and are located in off-center positions within their host materials. Such embedded soot absorbs sunlight less efficiently than if compact and located near the center of its host particle. In the case of our MC samples, their contribution to direct radiative forcing is ∼20% less than if they had a simple core-shell shape, which is the shape assumed in many climate models. This study shows that the shapes and positions of soot within its host particles have an important effect on particle optical properties and should be recognized as potentially important variables when evaluating global climate change.

Original languageEnglish (US)
Article numberD15206
JournalJournal of Geophysical Research: Atmospheres
Volume115
Issue number15
DOIs
StatePublished - 2010

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Soot
soot
Aerosols
climate
aerosols
aerosol
Mexico
optical property
Optical properties
Biological materials
optical properties
Climate models
organic matter
electron
Global warming
megacity
Solar radiation
Climate change
radiative forcing
Sulfates

ASJC Scopus subject areas

  • Atmospheric Science
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Shapes of soot aerosol particles and implications for their effects on climate. / Adachi, Kouji; Chung, Serena H.; Buseck, P R.

In: Journal of Geophysical Research: Atmospheres, Vol. 115, No. 15, D15206, 2010.

Research output: Contribution to journalArticle

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