Tandem Measurements of Aerosol Properties—A Review of Mobility Techniques with Extensions

Park, K.; Dutcher, Dabrina D.; Emery, Mark; Pagels, Joakim; Sakurai, Hiromu; Scheckman, Jacob; Shi, Qian; Stolzenburg, Mark R.; Wang, X.; Yang, Jun; McMurry, Peter H.

doi:10.1080/02786820802339561

Cited by 73 publications

(70 citation statements)

References 121 publications

(121 reference statements)

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“…Mobility diameter (d m ) depends on particle volume and morphology, while aerodynamic diameter (d ae ) in addition depends on the material density (i.e. particle mass) (Park et al 2008). The relationship between the two diameters is determined by the effective density (ρ eff ).…”

Section: As-produced Aggregates Vs Emitted Super-agglomerates -Implimentioning

confidence: 99%

Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

et al. 2013

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Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.1 Nano-objects emitted during maintenance of common particle generators AbstractNanotechnology gives us materials with enhanced or completely new properties. At the same time inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry, for time and size resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02-10 µm, were dominated by large agglomerates (1-5 µm). With aerosol mass spectrometry we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10 3 -10 5 /agglomerate) of nanometer sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer sized particles in exposure and emission assessments.

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Section: As-produced Aggregates Vs Emitted Super-agglomerates -Implimentioning

confidence: 99%

Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

et al. 2013

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“…There are methods to generate monodisperse particles; one example is the electrospray technique (Cheng et al, 1995, Cheng, 2004, Park et al, 2008. TDMA, developed in the 1980s (Rader and McMurry, 1986), is a practical technique demonstrated for the production of monodisperse particles and is the technique selected in this work.…”

Section: Vps Evaluation Using Tdmamentioning

confidence: 99%

Classification of Volatile Engine Particles

Cheng

2013

Aerosol Air Qual. Res.

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Volatile particles cannot be detected at the engine exhaust by an aerosol detector, as they are formed when the exhaust is mixed downstream with the ambient air. The lack of a precise definition of volatile engine particles has been an impediment to engine manufacturers and regulatory agencies involved in the development of effective control strategies. Volatile particles from combustion sources contribute to the atmospheric particulate burden, and this is a critical issue in ongoing research in the areas of air quality and climate change. A new instrument, called a volatile particle separator (VPS), is developed in this work. It utilizes a proprietary microporous metallic membrane to separate particles from vapors. VPS data are used in the development of a two-parameter function to quantitatively classify, for the first time, the volatilization behavior of engine particles. The value of parameter "A" describes the volatilization potential of an aerosol. A nonvolatile particle has a larger A-value than a volatile one. The value of parameter "k," an effective evaporation energy barrier, is found to be much smaller for small engine particles than for large engine ones. The VPS instrument is not simply a volatile particle remover, as it makes possible the characterization of volatile engine particles in numerical terms.

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“…Other techniques to determine Dfm involve inferring the particle mass or effective density from aerodynamic diameter measurements at reduced pressures by applying a low pressure impactor or an aerosol mass spectrometer Park et al 2008) downstream a DMA. Mass fractal dimensions of fresh diesel soot, Dfm, are typically in the range of 2.2-2.4 Maricq and Ning 2004), indicating relatively open structures (Dfm is 3.0 for spherical particles).…”

Section: Introductionmentioning

confidence: 99%

Processing of Soot by Controlled Sulphuric Acid and Water Condensation—Mass and Mobility Relationship

Pagels

Khalizov

McMurry

et al. 2009

Aerosol Science and Technology

189

262

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. To simulate atmospheric processing, combustion soot agglomerates were altered by sulphuric acid vapor condensation, relative humidity (RH) cycling, and evaporation of the sulphuric acid and water by heating. Primary investigated properties were particle mobility size and mass. Secondary properties, derived from these, include effective density, fractal dimension, dynamic shape factor, and the mass fraction of condensed material. A transformation of the soot particles to more compact forms occurs as sulphuric acid and water condense onto fresh soot. The particle mass increases and initially the mobility diameter decreases, indicating restructuring of the soot core, likely due to surface tension forces. For a given soot source and condensing liquid, the degree of compaction depends strongly on the mass (or volume) fraction of condensed material. For water and sulphuric acid condensing on combustion soot, a mass increase of 2-3 times is needed for a transformation to spherical particles. In the limit of spherical particles without voids, the effective density then approaches the inherent material density, the fractal dimension approaches 3 and the dynamic shape factor approaches 1. Our results indicate that under typical atmospheric conditions, soot particles will be fully transformed to spherical droplets on a time scale of several hours. It is expected that the morphology changes and addition of soluble material to soot strongly affect the optical and hygroscopic properties of soot.

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Tandem Measurements of Aerosol Properties—A Review of Mobility Techniques with Extensions

Cited by 73 publications

References 121 publications

Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

Classification of Volatile Engine Particles

Processing of Soot by Controlled Sulphuric Acid and Water Condensation—Mass and Mobility Relationship

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