Rovelli, Grazia, Miles, Rachael E. H., Reid, Jonathan P. and Clegg, Simon L. (2017) Hygroscopic properties of aminium sulfate aerosols. Atmospheric Chemistry and Physics, 17 (6). pp. 4369-4385. ISSN 1680-7324

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Abstract

Alkylaminium sulfates originate from the neutralisation reaction between short-chained amines and sulfuric acid and have been detected in atmospheric aerosol particles. Their physicochemical behaviour is less well characterised than their inorganic equivalent, ammonium sulfate, even though they play a role in atmospheric processes such as the nucleation and growth of new particles and cloud droplet formation. In this work, a comparative evaporation kinetics experimental technique using a cylindrical electrodynamic balance is applied to determine the hygroscopic properties of six short-chained alkylaminium sulfates, specifically mono-, di-, and tri-methylaminium sulfate and mono-, di-, and tri-ethyl aminium sulfate. This approach allows for the retrieval of a water-activity-dependent growth curve in less than 10 s, avoiding the uncertainties that can arise from the volatilisation of semi-volatile components. Measurements are made on particles > 5 µm in radius, avoiding the need to correct equilibrium measurements for droplet-surface curvature with assumed values of the droplet-surface tension. Variations in equilibrium solution droplet composition with varying water activity are reported over the range 0.5 to > 0.98, along with accurate parameterisations of solution density and refractive index. The uncertainties in water activities associated with the hygroscopicity measurements are typically < ±0.2 % at water activities > 0.9 and  ∼  ±1 % below 0.9, with maximum uncertainties in diameter growth factors of ±0.7 %. Comparison with previously reported measurements show deviation across the entire water activity range.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Related URLs:	http://www.atmos-chem-phys.net/17/4369/2...
Depositing User:	Pure Connector
Date Deposited:	25 Apr 2017 05:09
Last Modified:	24 Nov 2020 01:06
URI:	https://ueaeprints.uea.ac.uk/id/eprint/63292
DOI:	10.5194/acp-17-4369-2017

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