Tropospheric aerosol hygroscopicity in China

Abstract

Abstract. Hygroscopicity largely determines phase state, chemical reactivity, optical properties, and cloud nucleation activities of aerosol particles, thus significantly affecting their impacts on visibility, atmospheric chemistry, and climate. In the last 20 years, a large number of field studies have investigated the hygroscopicity of tropospheric aerosols in China under subsaturated and supersaturated conditions. Aerosol hygroscopicity measurements in China are reviewed in this paper: (1) a comprehensive summary and critical discussion of aerosol hygroscopicity measurements in China are provided; (2) available measurement data are compiled and presented under a consistent framework to enhance their accessibility and usability; and (3) current knowledge gaps are identified, and an outlook which could serve as guidelines for planning future research is also proposed.

Interactions of organosulfates with water vapor under sub- and supersaturated conditions

“…Each activation curve was fitted using a Boltzmann sigmoid function to derive the corresponding critical particle diameter (d 50 ), which was then used to calculate κ ccn using Eqs. (5a)-( 5b) (Petters and Kreidenweis, 2007):…”

“…For pure OS, κ ccn values of methyl-OS (0.459 ± 0.021) and ethyl-OS (0.397 ± 0.010) were smaller than their κ gf values (0.537-0.604 and 0.505-0.548), but the relative differences do not exceed 25 %. Such a difference (< 25 %) may not be significant if all the uncertainties associated with deriving κ from measured hygroscopic growth and CCN activities are considered (Petters and Kreidenweis, 2007). Octyl-OS appears to be an exception, and the average κ ccn (0.206) was ∼ 2.4 times larger than the average κ gf (0.086).…”

“…sorbing solar and terrestrial radiation and also indirectly by acting as cloud condensation nuclei (CCN) or ice-nucleating particles (Moise et al, 2015;Shrivastava et al, 2017). Consequently, it is important to understand the source, formation and physicochemical properties of SOA (Pöschl, 2005;Jimenez et al, 2009;Noziere et al, 2015;Peng et al, 2020). However, SOA concentrations on the global scale are significantly underestimated by many modeling studies (Heald et al, 2005;Kanakidou et al, 2005;Ervens et al, 2011;Mc-Neill et al, 2012;Shrivastava et al, 2017), indicating that there might exist unknown while important precursors and/or formation mechanisms of SOA.…”

“…The κ values derived from CCN activity measurements, κ ccn , have been illustrated above; the κvalues derived from H-TDMA measurements, κ gf , can be calculated using Eq. ( 6) (Petters and Kreidenweis, 2007;Tang et al, 2016):…”

Heterogeneous Reaction of CaCO3 With NO2 at Different Relative Humidities: Kinetics, Mechanisms, and Impacts on Aerosol Hygroscopicity

“…The single hygroscopicity parameter, κ , is widely used to represent aerosol hygroscopicity (Peng et al., 2020; Petters & Kreidenweis, 2007; M. J. Tang et al., 2016), and the κ value was determined to be <0.01 for unreacted CaCO 3 (Sullivan et al., 2009a; M. J. Tang et al., 2015; Zhao et al., 2010). If we assume that the particle volume at 90% RH is equal to the sum of dry particle volume and the volume of water and that the Kelvin effect is negligible, Equation can be used to calculate κ (Guo et al., 2020; M. J. Tang, Gu, et al., 2019): where m w is the mass of water at 90% RH, m 0 is the dry particle mass, ρ w is the density of water, and ρ 0 is the dry particle density.…”