A hygroscopicity-tandem differential mobility analyzer (H-TDMA), a scanning mobility CCN analyzer (SMCA), and an aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) were used to respectively measure the hygroscopicity, condensation nuclei activation, and chemical composition of aerosol particles at the Panyu site in the Pearl River Region during wintertime 2014. The distribution of the size-resolved cloud condensation nuclei (CCN) at four supersaturations (SS = 0.1 %, 0.2 %, 0.4 %, and 0.7 %) and the aerosol particle size distribution were obtained by the SMCA. The hygroscopicity parameter κ (κ CCN , κ H-TDMA , and κ AMS ) was respectively calculated based upon the SMCA, H-TMDA, and AMS measurements. The results showed that the κ H-TDMA value was slightly smaller than the κ CCN one at all diameters and for particles larger than 100 nm the κ AMS value was significantly smaller than the others (κ CCN , and κ H-TDMA ), which could be attributed to the underestimated hygroscopicity of the organics (κ org ). The activation ratio (AR) calculated from the growth factor – probability density function (Gf-PDF) without surface tension correction was found to be lower than that from the H-TDMA measurement, due most likely to the uncorrected surface tension (σ s/a ) that did not consider the surfactant effects of the organic compounds. We demonstrated that better agreement between the calculated and measured AR could be obtained by adjusting σ s/a . Various schemes were proposed to predict the CCN number concentration (N CCN ) based on H-TDMA and AMS measurements. In general, the predicted N CCN agreed reasonably well with the corresponding measured ones using different schemes. For H-TDMA measurements, the N CCN value predicted from the real time AR measurements was slightly smaller (~6.8 %) than that from the activation diameter (D 50 ) method due to the assumed internal mixing in the D 50 prediction. The N CCN values predicted from bulk PM 1 were higher (~11.5 %) than those from size-resolved composition measured by the AMS because a significant fraction of PM 1 was composed of inorganic matter. The N CCN calculated from AMS measurement were under-predicted at 0.1 % and 0.2 % supersaturations, which could be due to underestimate of κ org and overestimate of σ s/a . For SS = 0.4 % and 0.7 %, slight over-predicted N CCN was found because of the internal mixing assumption. Our results highlight the need for accurately evaluating the effects of organics on both the hygroscopic parameter κ and the surface tension σ in order to accurately predict CCN activity.