Hygroscopicity and optical properties of alkylaminium sulfates
Dawei Hu , Chunlin Li , Hui Chen , Jianmin Chen*
,
Xingnan Ye
,
Ling Li
,
Xin Yang
,
Xinming Wang*
,
Abdelwahid Mellouki
,
Zhongyang Hu
DOI:10.1016/S1001-0742(13)60378-2
Received ,Revised , Accepted , Available online January 09, 2014
Volume 26,2014,Pages 37-43
The hygroscopicity and optical properties of alkylaminium sulfates (AASs) were investigated using a hygroscopicity tandem differential mobility analyzer coupled to a cavity ring-down spectrometer and a nephelometer. AAS particles do not exhibit a deliquescence phenomenon and show a monotonic increase in diameter as the relative humidity (RH) ascends. Hygroscopic growth factors (GFs) for 40, 100 and 150 nm alkylaminium sulfate particles do not show an apparent Kelvin effect when RH is less than 45%, whereas GFs of the salt aerosols increase with initial particle size when RH is higher than 45%. Calculation using the Zdanovskii-Stokes-Robinson mixing rule suggests that hygroscopic growth of triethylaminium sulfate-ammonium sulfate mixtures is non-deliquescent, occurring at very low RH, implying that the displacement of ammonia by amine will significantly enhance the hygroscopicity of (NH4)2SO4 aerosols. In addition, light extinction of AAS particles is a combined effect of both scattering and absorption under dry conditions, but is dominated by scattering under wet conditions.
