The important roles of surface tension and growth rate in the contribution of new particle formation (NPF) to cloud condensation nuclei (CCN) number concentration: evidence from field measurements in southern China

Abstract. The contribution of new particle formation (NPF) to cloud condensation nuclei (CCN) number concentration (NCCN) varies largely under different environments and depends on several key factors such as rate (J), growth (GR), distribution preexisting particles, properties particles during NPF events. This study investigates the NCCN its controlling based measurements conducted at Heshan supersite, in Pearl River Delta (PRD) region China fall 2019. size-resolved activity hygroscopicity were measured by a counter (CCNc) hygroscopic tandem differential mobility analyzer (HTDMA), respectively, along with scanning sizer (SMPS) diethylene glycol (DEG-SMPS) for size (PNSD). A typical event 29 October was chosen investigate supersaturation (SS) ratios. Two (hygroscopicity surface tension) affect CCN activation latter being more important terms (NCCN). lower value tension (i.e., 0.06 N m−1) than pure-water assumption (0.073 could increase SS = 1.0 % about 20 nonevent period 40 event. In addition, an earlier peak time corresponding critical diameter (D50) also observed. results show that high rate, low background lead concentrations newly formed particles. found have most significant impact NCCN, which can be attributed fact higher grow shorter before they are scavenged other events (an 18 this campaign 12 December 2014 Panyu) perform sensitivity tests scenarios (growth concentration). calculated significantly from two re-simulated using taken resulted similar between (12 October), implying is major factor activation. Our highlight importance when evaluating NCCN.