A new electromobility spectrometer for the measurement of aerosol size distributions in the size range from 1 to 1000 nm

Winklmayr, Wolfgang; Reischl, G.; Lindner, Andreas; Berner, A.

doi:10.1016/s0021-8502(05)80007-2

Cited by 520 publications

(313 citation statements)

References 13 publications

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“…The cluster ions were then passed into a differential mobility analyzer (DMA, a type of IMS instrument 34,35 ), which was a Vienna-type model 36 designed for sub 100 nm diameter particles. This DMA was operated with a recirculating sheath flowrate of 15 l min -1 of air and all 1.5 l min -1 of the cluster ion flow was sampled into the DMA.…”

Section: Figurementioning

confidence: 99%

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Higashi

Tokumi

Hogan

et al. 2015

Phys. Chem. Chem. Phys.

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We use a combination of tandem ion mobility spectrometry (IMS-IMS, with differential mobility analyzers), molecular dynamics (MD) simulations, and analytical models to examine both neutral solvent (H2O) and ion (solvated Na + ) evaporation from aqueous sodium chloride nanodrops. For experiments, nanodrops were produced via electrospray ionization (ESI) of an aqueous sodium chloride solution. Two nanodrops were examined in MD simulations: a 2,500 water molecule nanodrop with 68 Na + and 60 Cl -ions (an initial net charge of z = +8), and (2) a 1,000 water molecule nanodrop with 65 Na + and 60 Cl -ions (an initial net charge of z = +5). Specifically, we used MD simulations to examine the validity of a model for the neutral evaporation rate incorporating both the Kelvin (surface curvature) and Thomson (electrostatic) influences, while both MD simulations and experimental measurements were compared to predictions of the ion evaporation rate equation of Labowsky et al [Anal Chim Acta, 2000, 406, 105-118]. To within a single fit parameter, we find excellent agreement between simulated and modeled neutral evaporation rates for nanodrops with solute volume fractions below 0.30. Similarly, MD simulation inferred ion evaporation rates are in excellent agreement with predictions based on the Labowsky et al equation. Measurements of the sizes and charge states of ESI generated NaCl clusters suggest that the charge states of these clusters are governed by ion evaporation, however, ion evaporation appears to have occurred with lower activation energies in experiments than was anticipated based on analytical calculations as well as MD simulations. Several possible reasons for this discrepancy are discussed.

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Section: Figurementioning

confidence: 99%

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Higashi

Tokumi

Hogan

et al. 2015

Phys. Chem. Chem. Phys.

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“…A particle counter (TSI 3025a) measured the total particle number concentration greater than 3 nm diameter and a Differential Mobility Particle Sizing system (DMPS) was used to measure the number size distribution of particles with diameters between 3 and 750 nm. The DMPS was built to the Vienna design (Winklmayr et al, 1991) and is described in Williams et al (2000) and more fully in Williams (1999). The DMPS comprised two differential mobility analysers, the smaller of the two was run with an aerosol flow of 1.5 lpm and a sheath flow of 15 lpm, the larger DMA was run with flows of 1 and 10 lpm respectively.…”

Section: Measurements and Instrumentationmentioning

confidence: 99%

Chemical and physical characteristics of aerosol particles at a remote coastal location, Mace Head, Ireland, during NAMBLEX

et al. 2006

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Abstract.A suite of aerosol physical and chemical measurements were made at the Mace Head Atmospheric Research Station, Co. Galway, Ireland, a coastal site on the eastern seaboard of the north Atlantic Ocean during NAMBLEX. The data have been used in this paper to show that over a wide range of aerosol sizes there is no impact of the intertidal zone or the surf zone on measurements made at 7 m above ground level or higher. During the measurement period a range of air mass types were observed. During anticyclonic periods and conditions of continental outflow Aitken and accumulation mode were enhanced by a factor of 5 compared to the marine sector, whilst coarse mode particles were enhanced during westerly conditions. Baseline marine conditions were rarely met at Mace Head during NAMBLEX and high wind speeds were observed for brief periods only.The NAMBLEX experiment focussed on a detailed assessment of photochemistry in the marine environment, investigating the linkage between the HO x and the halogen radical cycles. Heterogeneous losses are important in both these cycles. In this paper loss rates of gaseous species to aerosol surfaces were calculated for a range of uptake coefficients. Even when the accommodation coefficient is unity, lifetimes due to heterogeneous loss of less than 10 s were never observed and rarely were they less than 500 s. Diffusional limitation to mass transfer is important in most conditions as the coarse mode is always significant. We calculate a minimum overestimate of 50% in the loss rate if this is neglected and so it should always be considered when calculating loss rates of gaseous species to particle surfaces. HO 2 and HOI have accommodation coefficients of around 0.03 and hence we calculate lifetimes due to loss to particle surfaces of 2000 s or greater under the conditions experienced during NAMBLEX.Correspondence to: H. Coe (hugh.coe@manchester.ac.uk) Aerosol composition data collected during this experiment provide representative information on the input aerosol characteristics to western Europe. During NAMBLEX the submicron aerosol was predominately acidified sulphate and organic material, which was most likely internally mixed. The remaining accumulation mode aerosol was sea salt. The organic and sulphate fractions were approximately equally important, though the mass ratio varies considerably between air masses. Mass spectral fingerprints of the organic fraction in polluted conditions are similar to those observed at other locations that are characterised by aged continental aerosol. In marine conditions, the background input of both sulphate and organic aerosol into Europe was observed to be between 0.5 and 1µg m −3 . Key differences in the mass spectra were observed during the few clean periods but were insufficient to ascertain whether these changes reflect differences in the source fingerprint of the organic aerosol. The coarse mode was composed of sea salt and showed significant displacement of chloride by nitrate and to a lesser extent sulphate in polluted conditio...

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“…The aerosol and the sheath flows entering DMA2 were humidified separately. The DMAs used were of the Vienna type (Winklmayr et al 1991).…”

Section: Principle Of the H-tdmamentioning

confidence: 99%

Hygroscopic Behavior of Aerosol Particles Emitted from Biomass Fired Grate Boilers

Rissler

Pagels

Swietlicki

et al. 2005

Aerosol Science and Technology

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This study focuses on the hygroscopic properties of submicrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth factor (Gf ) was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar diameter growth and the Gf at RH = 90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.5 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovski-Stokes-Robinson (ZSR) mixing rule and a chemical composition of potassium salts only, taken from ion chromatography analysis of filter and impactor samples (KCl, K 2 SO 4 , and K 2 CO 3 ). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluted with hot particle-free air, the fractallike structures remained intact until humidified in the H-TDMA. A method to estimate the fractal dimension of the agglomerated combustion aerosol and to convert the measured mobility diameter hygroscopic growth to the more useful property volume diameter growth is presented. The fractal dimension was estimated to be ∼2.5.

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A new electromobility spectrometer for the measurement of aerosol size distributions in the size range from 1 to 1000 nm

Cited by 520 publications

References 13 publications

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations

Chemical and physical characteristics of aerosol particles at a remote coastal location, Mace Head, Ireland, during NAMBLEX

Hygroscopic Behavior of Aerosol Particles Emitted from Biomass Fired Grate Boilers

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