Particle-fluid interaction

Davies, Catherine

doi:10.1016/0021-8502(79)90006-5

Cited by 156 publications

(115 citation statements)

References 28 publications

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“…However, we found that using the Fuchs (1964) approach results in much lower values of χ (∼1.007-1.034) than those determined from direct measurements of χ (∼1.11-1.50). According to Davies (1979), sand particles composed of a mixture of different minerals have a dynamic shape factor of 1.3-1.6. Therefore, in this study non-sphericity corrections are performed for all species considering χ = 1.3 ± 0.2 as this covers as possible values of measured χ.…”

Section: Accounting For Dust Non-sphericitymentioning

confidence: 99%

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

2011

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Abstract. This study reports laboratory measurements of cloud condensation nuclei (CCN) activity and droplet activation kinetics of aerosols dry generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. Based on the observed dependence of critical supersaturation, s c , with particle dry diameter, D dry , we found that FHH (Frenkel, Halsey and Hill) adsorption activation theory is a far more suitable framework for describing fresh dust CCN activity than Köhler theory. One set of FHH parameters (A FHH ∼ 2.25 ± 0.75, B FHH ∼ 1.20 ± 0.10) can adequately reproduce the measured CCN activity for all species considered, and also explains the large range of hygroscopicities reported in the literature. Based on a threshold droplet growth analysis, mineral dust aerosols were found to display retarded activation kinetics compared to ammonium sulfate. Comprehensive simulations of mineral dust activation and growth in the CCN instrument suggest that this retardation is equivalent to a reduction of the water vapor uptake coefficient (relative to that for calibration ammonium sulfate aerosol) by 30-80%. These results suggest that dust particles do not require deliquescent material to act as CCN in the atmosphere.

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Section: Accounting For Dust Non-sphericitymentioning

confidence: 99%

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

2011

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“…According to the literature studies, the particle shape factor (χ ) can vary as a function of the origin of the aerosol (Dahneke 1982;Davies 1979;Johnson et al 1987). The knowledge of the aerosol sampled can reduce the uncertainty of the shape factor.…”

Section: Pm Uncertainty Budget Using Apsmentioning

confidence: 99%

Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀

Buonanno

Dell’Isola

Stabile

et al. 2009

Aerosol Science and Technology

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The effects of particulate matter on environment and public health have been widely studied in recent years. In spite of the presence of numerous studies about this topic there is no agreement on the relative importance of the particles' size and origin with respect to health effects among researchers. Nevertheless, air quality standards are moving, as the epidemiological attention, towards greater focus on the smaller particles. The most reliable method used in measuring particulate matter (PM) is the gravimetric method since it directly measures PM concentration, guaranteeing an effective traceability to international standards. This technique, however, neglects the possibility to correlate short term intraday atmospheric parameter variations that can influence ambient particle concentration and size distribution as well as human activity patterns. Besides, a continuous method to determine PM concentrations through the measurement of the number size distribution is the system constituted by a Scanning Mobility Particle Sizer (SMPS) and an Aerodynamic Particle Sizer (APS). In this article, the evaluation of the uncertainty budget in measuring PM through the SMPS-APS system, as well as a metrological comparison with the gravimetric reference method in order to analyze the compatibility, was carried out and applied with reference to an experimental campaign developed in a rural site. This choice allowed to assume the hypothesis of spherical particle morphology. The average PM 10 , PM 2.5 , and PM 1 uncertainties obtained for the SMPS-APS system are equal to 27%, 29%, and 31%, respectively. Here the principle influence parameter is the particle density that has to be directly measured with low uncertainty in order to reduce the PM uncertainty.

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“…(4) was assumed to be valid for these tests. The following shape factors were used to perform equivalent diameter and mass conversions (Davies, 1979;Noll, Fang, & Watkins, 1988)…”

Section: Sample Analysismentioning

confidence: 99%

Field tests of a passive aerosol sampler

Wagner

Leith

2001

Journal of Aerosol Science

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Particle-fluid interaction

Cited by 156 publications

References 28 publications

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀

Field tests of a passive aerosol sampler

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Particle-fluid interaction

Cited by 156 publications

References 28 publications

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

Uncertainty Budget of the SMPS–APS System in the Measurement of PM1, PM2.5, and PM10

Field tests of a passive aerosol sampler

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Product

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Uncertainty Budget of the SMPS–APS System in the Measurement of PM₁, PM_2.5, and PM₁₀