A Field Intercomparison of Three Cascade Impactors

Howell, S. G.; Pszenny, Alexander A. P.; Quinn, Patricia K.; Huebert, B. J.

doi:10.1080/02786829808965585

Cited by 47 publications

(34 citation statements)

References 36 publications

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“…In this case, the mass spectrum of the ammonium sulfate was compared with that derived from accurate in situ measurement of the droplet size and a shift in the mass distribution obtained with the impactor was not observed. This measured absence of growth supports the hypothesis that the reduced pressure in the Berner impactor compensates for the increase in RH due to adiabatic cooling (e.g., Howell et al, 1999).…”

Section: Addendum: Aerosol Growth In Low-pressure Impactionsupporting

confidence: 67%

A high-flow humidograph for testing the water uptake by ambient aerosol

Tenbrink¹,

Khlystov²,

Kos³

et al. 2000

Atmospheric Environment

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A`humidographa with an air #ow rate of 0.4 m s\ was built to investigate the uptake of water and its e!ect on sizing, collection and light scattering of ambient aerosol. In the humidograph the relative humidity (RH) can be scanned over a large RH trajectory. Its performance was assessed with laboratory particles of ammonium nitrate, ammonium sulfate and sodium chloride that are the major hygroscopic components of ambient aerosol. The increase in size at the deliquescence points, which ideally is a stepwise function of RH, occurs over a range of 3% RH units. This is shown to be an optimum value in a system of such large dimensions. Because the vapor pressure of ammonium nitrate increases signi"cantly with temperature, its evaporative loss was investigated as a function of heating/drying temperature. The loss of pure test aerosol, with a mass distribution similar to that in the ambient atmosphere, was found to be acceptable for drying temperatures of up to 403C. The sizing of deliquesced aerosol by LAS-X monitors was tested and found to be a complex function of RH. In Berner low-pressure impactors growth of hygroscopic aerosol was not observed, not even at an RH approaching saturation.

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Section: Addendum: Aerosol Growth In Low-pressure Impactionsupporting

confidence: 67%

A high-flow humidograph for testing the water uptake by ambient aerosol

Tenbrink¹,

Khlystov²,

Kos³

et al. 2000

Atmospheric Environment

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“…Solid line is for marine chloride, calculated from its ratio to sodium in sea salt. 2 NaC1 + H2SO4-->Na2SO4 q-HC1 or NaC1 + H2SO4-->NaHSO4 + HC1 [Quinn et al, 1998]. Nevertheless, no bilinear correlation between chloride loss, nitrate, and sulfate (in the form C1]oss = a NO 3 q-b SO4)was found.…”

Section: Hno3(g) + Nh3(g) --> Nh•-no• (3)mentioning

confidence: 79%

“…While laboratory calibrations often demonstrate performances close to design specifications, field sampling conditions can cause significant deviations in collection characteristics [Howell et al, 1998]. Mass distributions are possibly shifted to lower impactor stages because of particle bounces.…”

Section: Sampling and Analysismentioning

confidence: 99%

Chemical composition of marine aerosol in a Mediterranean coastal zone during the FETCH experiment

Sellegri¹,

Gourdeau²,

Putaud³

et al. 2001

J. Geophys. Res.

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Abstract. The chemical composition of marine aerosols was studied during the Flux, Etats de la mer, T616d6tection en Conditions de fetch variable (FETCH) experiment that took place in the northwestern Mediterranean Sea in March/April 1998. Coastal marine aerosols were collected using a 13-stage low-pressure impactor and analyzed by ion chromatography. Samples were characterized according to their continental or marine origin in order to better understand the processes affecting the chemical composition of particles during advection over a coastal zone. Strong anthropogenic influence was observed up to 100 km from the coast illustrated by (1) NH4/nss-SO 4 association with ratios ranging from 0.9 to 2.1, and for some cases NH4/nss-SO4-NO 3 bicorrelation; (2) chloride depletion associated with supermicron NO3, indicating previous reaction between nitric acid and NaC1; and (3) elevated NO 3 fraction in the submicron range when the air mass was rain-washed. New particle formation was not detected during the campaign from either bubble bursting or from dimethylsulfide oxidation products. Nss sulfate and methanesulfonic acid appear to condense on the numerous preexisting particles rather than undergoing gas-to-particle conversion. Formation of sea-salt supermicron aerosol takes place rapidly to represent 80% of the total ionic species as little as 25 km from the coast. IntroductionThe chemical and physical properties of aerosols in coastal zones result from the complex interaction of several kinds of sources that act at different spatial and temporal scales. Thus these areas are of great interest for understanding the mechanisms involved in aerosols formation and the mixing processes between natural and anthropogenic aerosols.Open waters are a very important source of primary particles of composition similar to sea salt, generated by the evaporation

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“…Analyses of aerosol inorganic components and water soluble organic carbon (WSOC) were performed on tedlar foils (Matta et al, 2003;Cavalli et al, 2004). The uppermost impactor stage (8.0-16.0 µm) was not analyzed, because of the very low collection efficiency of the impactor inlet at wind speed of 5 m s −1 and above (Howell et al, 1998). Aliquots of the high volume samples were analysed for Total Carbon (TC) and WSOC.…”

Section: Experimental Set Upmentioning

confidence: 99%

On the representativeness of coastal aerosol studies to open ocean studies: Mace Head – a case study

et al. 2009

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Abstract.A unique opportunity arose during the MAP project to compare open ocean aerosol measurements with those undertaken at the Mace Head Global Atmosphere Watch Station, a station used for decades for aerosol process research and long-term monitoring. The objective of the present study is to demonstrate that the key aerosol features and processes observed at Mace Head are characteristic of the open ocean, while acknowledging and allowing for spatial and temporal gradients. Measurements were conducted for a 5-week period at Mace Head and offshore, on the Research Vessel Celtic Explorer, in generally similar marine air masses, albeit not in connected-flow scenarios. The results of the study indicate, in terms of aerosol number size distribution, higher nucleation mode particle concentrations at Mace Head than offshore, pointing to a strong coastal source of new particles that is not representative of the open ocean. The Aitken mode exhibited a large degree of similarity, with no systematic differences between Mace Head and the open ocean, while the accumulation mode showed averagely 35% higher concentrations at Mace Head. The higher accumulation mode concentration can be attributed equally to cloud processing and to a coastal enhancement in concentration. Chemical analysis showed similar or even higher offshore concentrations for dominant species, such as nss-SO −2 4 , WSOC, WIOC and MSA. Sea salt concentration differences determined a 40% higher supermicron mass at Mace Head, although this difference can be attributed to a higher Correspondence to: M. Rinaldi (m.rinaldi@isac.cnr.it) wind speed at Mace Head during the comparison period. Moreover, the relative chemical composition as a function of size illustrated remarkable similarity. While differences to varying degrees were observed between offshore and coastal measurements, no convincing evidence was found of local coastal effects, apart from nucleation mode aerosol, thus confirming the integrity of previously reported marine aerosol characterisation studies at Mace Head.

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A Field Intercomparison of Three Cascade Impactors

Cited by 47 publications

References 36 publications

A high-flow humidograph for testing the water uptake by ambient aerosol

A high-flow humidograph for testing the water uptake by ambient aerosol

Chemical composition of marine aerosol in a Mediterranean coastal zone during the FETCH experiment

On the representativeness of coastal aerosol studies to open ocean studies: Mace Head – a case study

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