Measurement of Particle Density by Inertial Classification of Differential Mobility Analyzer–Generated Monodisperse Aerosols

Kelly, Wayne P.; McMurry, Peter H.

doi:10.1080/02786829208959571

Cited by 174 publications

(154 citation statements)

References 23 publications

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“…In principle, one can determine the density by combined inertial and mobility measurements on the sample aerosol (Kelly and McMurry 1992). Following this idea, Ahlvik et al (1998) measured the effective density of diesel PM using a tandem combination of SMPS and ELPI.…”

Section: Elpimentioning

confidence: 99%

Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

Maricq¹,

Podsiadlik²,

Chase³

2000

Aerosol Science and Technology

176

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ABSTRACT. Particle size measurements using the electrical low pressure impactor (ELPI) and scanning mobility particle sizer (SMPS) are compared from the perspective of characterizing the particulate matter in motor vehicle exhaust. Both steady state vehicle operation and transient drive cycles are considered, and both gasoline and diesel fueled vehicle emissions are compared. Although the ELPI and SMPS measure different physical properties, respectively, the aerodynamic diameter and mobility diameter, the steady state particle size distributions are in close agreement, except for the 37 nm impactor stage of the ELPI which may overestimate particle number by up to a factor of two relative to the SMPS. This has little effect on the volume, or mass, weighted distribution. These, too, are generally in good agreement, though discrepancies appear at large particle size due to multiple charging effects in the SMPS and to electrometer offsets and the small particle loss correction in the ELPI. Selecting particles based on their electrical mobility with the SMPS, and then measuring their aerodynamic diameter with the ELPI, reveals that diesel particulate matter with well-speci ed mobility diameter exhibits a wide range in aerodynamic diameter and, therefore, also in effective density. Over transient drive cycles, the ELPI provides second by second particle distributions, whereas the SMPS must be run in a xed particle size mode and size distributions constructed from repeated tests. The ELPI registers higher instantaneous PM emission rates during transients than the SMPS due to the faster time responses of the ELPI. The time integrated ELPI and SMPS size distributions, however, remain in good agreement. The relative merits of the two instruments for steady state and transient tests are discussed.

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Section: Elpimentioning

confidence: 99%

Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

Maricq¹,

Podsiadlik²,

Chase³

2000

Aerosol Science and Technology

176

View full text Add to dashboard Cite

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“…This suggests that most of the particles were too small to make any significant contribution to the total particulate mass and that the origin of these particles is not related to the abundance of any ionic compound in the particulate phase. An impactor-based mass size distribution consisting of lognormal modes can be converted to a particle number size distribution using the known relations between the particle aerodynamic and mass equivalent diameter [Kelly and McMurry, 1992] The only dicarboxylate above the analytical limit of detection in our aerosol samples was oxalate. The concentration of particulate oxalate was low, being about an order of magnitude lower than concentrations reported in coastal Antarctica.…”

Section: Relation Between Ionic Compounds and Particle Number Concentmentioning

confidence: 99%

A study of size‐segregated aerosol chemistry in the Antarctic atmosphere

Teinilä¹,

Kerminen²,

Hillamo³

2000

J. Geophys. Res.

101

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Abstract. During austral summer 1998, aerosol particles were sampled at the Finnish station Aboa in continental Antarctica. The collected aerosol samples were analyzed for major inorganic ions, methane sulphonate, and dicarboxylates. Measured ions composed on average about one third of the total gravimetric mass in fine particulate matter (particle diameter <2 !am). Particulate sulphate, ammonium, and methane sulphonate were internally mixed and found predominantly in the submicron size range. The submicron mass size distribution of these three ions had a dominant mode peaking at -0.3 !am of particle aerodynamic diameter, another mode peaking at 0.6 !am, and an identifiable Aitken mode below 0.2 !am. The mass size distribution of sodium, a tracer for sea salt particles, peaked in most samples slightly below 2 !am; in addition, it had a submicron mode between -0.5 and 1.0 !am and a mode with great variability between 3 and 10 !am. The overall concentration of sea salt was 1-2 orders of magnitude lower than concentrations measured in coastal Antarctica. Particulate nitrate was found almost entirely in the supermicron size range, the most likely formation pathway being the interaction of nitric acid or some other reactive nitrogen compound with sea-salt particles in the Antarctic atmosphere. The only dicarboxylate above the analytical limit of detection was oxalate, which was distributed in about equal quantities between the submicron and supermicron size ranges.The average total particle number concentration varied in the range 235-955 cm -3 between the samples and showed no obvious correlation with any aerosol species. The great majority of these particles (>80-90%) were shown to be smaller than -0.1 !am in diameter.

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“…A DMA (Differential Mobility Analyzer, Knutson and Whitby (1975), type "Vienna medium") was used to select a dry particle size. When using NaCl, a shape factor of 1.08 (Kelly and McMurry, 1992) was used when determining the dry particle size selected by the DMA. Number concentrations of the quasi monodisperse aerosol after the DMA were determined with a CPC (TSI 3010, TSI Inc., St. Paul, Minnesota, USA), and were kept at 400-600 cm −3 with a dilution system up stream of the DMA.…”

Section: Methodsmentioning

confidence: 99%

Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

et al. 2006

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Abstract. A calibration for LACIS (Leipzig Aerosol CloudInteraction Simulator) for its use as a CCN (cloud condensation nuclei) detector has been developed. For this purpose, sodium chloride and ammonium sulfate particles of known sizes were generated and their grown sizes were detected at the LACIS outlet. From these signals, the effective critical super-saturation was derived as a function of the LACIS wall temperature. With this, LACIS is calibrated for its use as a CCN detector. The applicability of LACIS for measurements of the droplet activation, and also of the hygroscopic growth of atmospheric aerosol particles was tested. The activation of the urban aerosol particles used in the measurements was found to occur at a critical super-saturation of 0.46% for particles with a dry diameter of 75 nm, and at 0.42% for 85 nm, respectively. Hygroscopic growth was measured for atmospheric aerosol particles with dry diameters of 150, 300 and 350 nm at relative humidities of 98 and 99%, and it was found that the larger dry particles contained a larger soluble volume fraction of about 0.85, compared to about 0.6 for the 150 nm particles.

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Measurement of Particle Density by Inertial Classification of Differential Mobility Analyzer–Generated Monodisperse Aerosols

Cited by 174 publications

References 23 publications

Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

Size Distributions of Motor Vehicle Exhaust PM: A Comparison Between ELPI and SMPS Measurements

A study of size‐segregated aerosol chemistry in the Antarctic atmosphere

Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

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