Investigation of refractory black carbon-containing particle morphologies using the single-particle soot photometer (SP2)

Journal Article · Fri Jul 24 00:00:00 EDT 2015 · Aerosol Science and Technology

DOI:https://doi.org/10.1080/02786826.2015.1074978· OSTI ID:1213369

Sedlacek, III, Arthur J. ^[1]; Lewis, Ernie R. ^[1]; Onasch, Timothy B. ^[2]; Lambe, Andrew T. ^[2]; Davidovits, Paul ^[3]

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1. Brookhaven National Lab. (BNL), Upton, NY (United States)
2. Aerodyne Research, Inc., Billerica, MA (United States); Boston College, Chestnut Hill, MA (United States)
3. Boston College, Chestnut Hill, MA (United States)

An important source of uncertainty in radiative forcing by absorbing aerosol particles is the uncertainty in their morphologies (i.e., the location of the absorbing substance on/in the particles). To examine the effects of particle morphology on the response of an individual black carbon-containing particle in a Single-Particle Soot Photometer (SP2), a series of experiments was conducted to investigate black carbon-containing particles of known morphology using Regal black (RB), a proxy for collapsed soot, as the light-absorbing substance. Particles were formed by coagulation of RB with either a solid substance (sodium chloride or ammonium sulfate) or a liquid substance (dioctyl sebacate), and by condensation with dioctyl sebacate, the latter experiment forming particles in a core-shell configuration. Each particle type experienced fragmentation (observed as negative lagtimes), and each yielded similar lagtime responses in some instances, confounding attempts to differentiate particle morphology using current SP2 lagtime analysis. SP2 operating conditions, specifically laser power and sample flow rate, which in turn affect the particle heating and dissipation rates, play an important role in the behavior of particles in the SP2, including probability of fragmentation. This behavior also depended on the morphology of the particles and on the thermo-chemical properties of the non-RB substance. Although these influences cannot currently be unambiguously separated, the SP2 analysis may still provide useful information on particle mixing states and black carbon particle sources.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC00112704
• OSTI ID: 1213369
• Report Number(s): BNL-108214-2015-JA; R&D Project: 2016-BNL-EE630EECA-Budg; KP1701000
• Journal Information: Aerosol Science and Technology, Vol. 49, Issue 10; ISSN 0278-6826
• Publisher: American Association for Aerosol Research
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES