Table 1. Summary of measured hygroscopic growth for inorganic sea salt particles and NaCl.

Measurement	Ddry	(RH=90%)	ge(RH=90%)	κs(RH=90%)
Sea salt (HTDMA, chamber)	50 nm	—	2.12	1.14
Sea salt (HTDMA, chamber)	100 nm	—	2.12	1.04
Sea salt (HTDMA, chamber)	150 nm	—	2.09	0.96
Sea salt (HTDMA, nebulizer)	50 nm	—	2.22	1.31
Sea salt (HTDMA, nebulizer)	100 nm	—	2.20	1.17
Sea salt (HTDMA, nebulizer)	150 nm	—	2.19	1.12
Sea salt (EDB)	∼7 μm	5.24	2.09 (2.11)	0.91 (0.95)
Sea salt (water activity)	Bulk	5.83	2.18 (2.20)	1.04 (1.08)
NaCl (HTDMA, nebulizer)	50 nm	—	2.26	1.39
NaCl (HTDMA, nebulizer)	100 nm	—	2.29	1.34
NaCl (HTDMA, nebulizer)	150 nm	—	2.29	1.30
NaCl (EDB)	∼7 μm	6.1	2.29	1.22
NaCl (theory)	50 nm	6.40	2.33	1.51
NaCl (theory)	100 nm	6.73	2.38	1.49
NaCl (theory)	150 nm	6.85	2.39	1.48
NaCl (theory)	7 μm	7.10	2.42	1.47

Measured hygroscopic growth factors g_e(RH), mass growth factors (RH=90%) and corresponding κ_s values of the inorganic sea salt at RH=90%. The values for g_e(RH) of the EDB and the water activity measurements are calculated using the measured dry density of 2.017 g cm⁻³ and the RH-dependent density parameterization of Tang et al.¹⁰ for seawater. The values in parenthesis are calculated assuming that the volume of solutes and water are additive. The theoretical values for NaCl are shown as a reference (taken from ref. 56). The κ_s values were calculated at RH=90% and room temperature (T=298.15 K) according to Petters and Kreidenweis³⁰ assuming the surface tension of water.