Investigations of SP-AMS Carbon Ion Distributions as a Function of Refractory Black Carbon Particle Type

Abstract

The soot particle aerosol mass spectrometer (SP-AMS) instrument combines continuous wave laser vaporization with electron ionization aerosol mass spectrometry to characterize airborne, refractory black carbon (rBC) particles. The laser selectively vaporizes absorbing rBC-containing particles, allowing the SP-AMS to provide direct chemical information on the refractory and non-refractory chemical components, providing the potential to fingerprint various rBC particle types. In this study, SP-AMS mass spectra were measured for 12 types of rBC particles produced by industrial and combustion processes to explore differences in the carbon cluster (C n C ) mass spectra. The C n C mass spectra were classified into three categories based on their ion distributions, which varied with rBC particle type. The carbon ion distributions were investigated as a function of laser power, electron ionization (on/off), and ion charge (positive or negative). Results indicate that the dominant positive ion-formation mechanism is likely the vaporization of small, neutral carbon clusters followed by electron ionization (C 1 C to C 5 C ). Significant ion signal from larger carbon cluster ions (and their fragment ions in the small carbon cluster range), including mid carbon (C 6 C to C 29 C ) and fullerene (greater than C 30 C ) ions, were observed in soot produced under incomplete combustion conditions, including biomass burning, as well as in fullerene-enriched materials. Fullerene ions were also observed at high laser power with electron ionization turned off, formed via an additional ionization mechanism. We expect this SP-AMS technique to find application in the identification of the source and atmospheric history of airborne ambient rBC particles.

Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

“…Positive matrix factorization (PMF) (Paatero and Tapper, 1994) was applied on the high-resolution mass spectra (HRMS) of organic aerosol (OA) obtained under laser off W-mode (M4 setting) to elucidate the OA sources/processes. We used the PMF evaluation tool version 2.08A (downloaded from: http://cires1.colorado.edu/jimenez-group/wiki/index.…”

Influence of Emissions and Aqueous Processing on Particles Containing Black Carbon in a Polluted Urban Environment: Insights From a Soot Particle‐Aerosol Mass Spectrometer

“…It has also been used in a variety of environments to measure specific rBC sources (e.g., Buffaloe et al, ; Corbin et al, ; Dallmann et al, ) as well as atmospheric rBC (e.g., Hayes et al, ; Lee et al, ; Wang, Ge, et al, ; Wang, Onasch, et al, ). Also, the SP‐AMS can be used to distinguish BC particle types in the lab (Corbin et al, ; Onasch et al, ) and in the field (Wang, Onasch, et al, ) by examining the distribution of C x + ( x ≥ 1) ions.…”

Characteristics of BrC and BC emissions from controlled diffusion flame and diesel engine combustion

“…Derived RIE BC were similar and ranged from 0.29-0.37 for all experiments with one exception; RIE BC was 0.58 for the diesel engine experiments conducted in 2016. In order to detect refractory large carbon clusters (Corbin et al 2014, Onasch et al 2015, the SP-AMS was tuned similarly as described in Malmborg et al (2019). Measurements on the miniCAST flame soot or aerosolized particles from fullerene soot standards can be used to evaluate the SP-AMS tuning between different experiments as demonstrated in chapter 3.2.1 of Malmborg (2020).…”