Using ATOFMS to Determine OC/EC Mass Fractions in Particles

Spencer, Matthew T.; Prather, Kimberly A.

doi:10.1080/02786820600729138

Cited by 93 publications

(91 citation statements)

References 62 publications

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“…The use of a single density, ρ p , for ATOFMS scaling has previously resulted in satisfactory PM mass reconstruction when compared to other quantitative measurements (Healy et al, 2012. However, a single density assumption is known to be incorrect due to differing particle compositions (Maricq and Xu, 2004;Spencer and Prather, 2006). Different particle classes will exhibit different particle densities.…”

Section: Atofms Data Analysismentioning

confidence: 99%

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Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

et al. 2017

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Abstract. An aerosol time-of-flight mass spectrometer (ATOFMS) was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica.Twenty-seven distinct ATOFMS particle classes were identified and subsequently grouped into eight general categories: EC-rich (elemental carbon), K-rich, Na-rich, amines, OC-rich (organic carbon), V-rich, Fe-rich and Carich particles. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM 1 , black carbon (BC), organic carbon, sulfate mass and ammonium mass). Total ATOFMS reconstructed mass (PM 2.5 ) accounted for 70-90 % of measured PM 10 mass and was comprised of regionally transported fossil fuel (EC-rich) and biomass burning (K-rich) particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and was therefore highly complementary to quantitative measurements made by Particle into Liquid Sampler ion chromatography (PILS-IC) and an aerosol chemical speciation monitor (ACSM), which have demonstrated that PM 1 and PM 10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA). This combined information suggests that combustion of fossil fuels and biomass produced primary EC-and OC-containing particles, which then accumulated ammonium, sulfate and alkylamines during regional transport.Three other sources were also identified: local biomass burning, marine and shipping. Local combustion particlesPublished by Copernicus Publications on behalf of the European Geosciences Union. (emitted in Corsica) contributed little to PM 2.5 particle number and mass concentrations but were easily distinguished from regional combustion particles. Marine emissions comprised fresh and aged sea salt: the former was detected mostly during a 5-day event during which it accounted for 50-80 % of sea salt aerosol mass, while the latter was detected throughout the sampling period. Dust was not efficiently detected by the ATOFMS, and support measurements showed that it was mainly in the PM 2.5-10 fraction. Shipping particles, identified using markers for heavy fuel oil combustion, were associated with regional emissions and represented only a small fraction of PM 2.5 particle number and mass concentration at the site.

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Section: Atofms Data Analysismentioning

confidence: 99%

“…The particle class labelling scheme used herein is regularly used in the literature (Dall'Osto and Harrison, 2006;Spencer and Prather, 2006;Ault et al, 2010;Pratt and Prather, 2012) and indicates either the probable source (e.g. sea salt) or the dominant species in the positive ion mass spectra (e.g.…”

Section: Atofms Data Analysismentioning

confidence: 99%

Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

et al. 2017

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“…Briefly, primary fossil fuel particles are characterized by the presence of carbon cluster ion peaks: C + n and C − n , representative of the elemental carbon (EC), and spectra that also contain weak m/z 27(C 2 H Spencer and Prather, 2006;Moffet and Prather, 2009). Biomass burning particles are characterized by an intense potassium peak m/z 39(K + ) with less intense carbonaceous markers (e.g.…”

Section: In-situ Aircraft Measurementsmentioning

confidence: 99%

Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements

et al. 2013

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Estimating the aerosol contribution to the global or regional radiative forcing can take advantage of the relationship between the spectral aerosol optical properties and the size and chemical composition of aerosol. Long term global optical measurements from observational networks or satellites can be used in such studies. Using in-situ chemical mixing state measurements can help us to constrain the limitations of such estimates.

In this study, the Absorption Ångström Exponent (AAE) and the Scattering Ångström Exponent (SAE) derived from 10 operational AERONET sites in California are combined for deducing chemical speciation based on wavelength dependence of the optical properties. In addition, in-situ optical properties and single particle chemical composition measured during three aircraft field campaigns in California between 2010 and 2011 are combined in order to validate the methodology used for the estimates of aerosol chemistry using spectral optical properties.

Results from this study indicate a dominance of mixed types in the classification leading to an underestimation of the primary sources, however secondary sources are better classified. The distinction between carbonaceous aerosols from fossil fuel and biomass burning origins is not clear, since their optical properties are similar. On the other hand, knowledge of the aerosol sources in California from chemical studies help to identify other misclassification such as the dust contribution

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“…5. Further, the C-ToF-AMS O/C ratio was correlated (R 2 = 0.5) with the A-ATOFMS oxidized organics/total organics ratio, calculated by dividing the relative peak area of m/z 43(CH 3 CO + ) by the sum of the relative peak areas of representative organic ions (m/z 27(C 2 H + 3 ), 29(C 2 H + 5 ), 37(C 3 H + ), 43(CH 3 CO + )), as defined by Spencer and Prather (2006). A-ATOFMS measurements show the accumulation of organic acids on biomass burning particles as the plumes aged (Fig.…”

Section: Organicsmentioning

confidence: 99%

Flight-based chemical characterization of biomass burning aerosols within two prescribed burn smoke plumes

et al. 2011

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Abstract. Biomass burning represents a major global source of aerosols impacting direct radiative forcing and cloud properties. Thus, the goal of a number of current studies involves developing a better understanding of how the chemical composition and mixing state of biomass burning aerosols evolve during atmospheric aging processes. During the Ice in Clouds Experiment-Layer Clouds (ICE-L) in the fall of 2007, smoke plumes from two small Wyoming Bureau of Land Management prescribed burns were measured by online aerosol instrumentation aboard a C-130 aircraft, providing a detailed chemical characterization of the particles. After ∼2-4 min of aging, submicron smoke particles, produced primarily from sagebrush combustion, consisted predominantly of organics by mass, but were comprised primarily of internal mixtures of organic carbon, elemental carbon, potassium chloride, and potassium sulfate. Significantly, the fresh biomass burning particles contained minor mass fractions of nitrate and sulfate, suggesting that hygroscopic material is incorporated very near or at the point of emission. The mass fractions of ammonium, sulfate, and nitrate increased with aging up to ∼81-88 min and resulted in acidic particles. Decreasing black carbon mass concentrations occurred due to Correspondence to: K. A. Prather (kprather@ucsd.edu) dilution of the plume. Increases in the fraction of oxygenated organic carbon and the presence of dicarboxylic acids, in particular, were observed with aging. Cloud condensation nuclei measurements suggested all particles >100 nm were active at 0.5 % water supersaturation in the smoke plumes, confirming the relatively high hygroscopicity of the freshly emitted particles. For immersion/condensation freezing, ice nuclei measurements at −32 • C suggested activation of ∼0.03-0.07 % of the particles with diameters greater than 500 nm.

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Using ATOFMS to Determine OC/EC Mass Fractions in Particles

Cited by 93 publications

References 62 publications

Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements

Flight-based chemical characterization of biomass burning aerosols within two prescribed burn smoke plumes

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