Contribution of New Particle Formation to Cloud Condensation Nuclei Activity and its Controlling Factors in a Mountain Region of Inland China

Abstract

A 1‐month field campaign (May 29–June 29, 2018) was conducted at a mountain site (862 m above sea level) on the Wudang Mountains in China. The particle number size distribution (3–400 nm), size‐resolved cloud condensation nuclei (CCN, at 0.2% and 0.8% SS), and nonrefractory PM1 chemical composition were measured, respectively. The occurrence of the three chosen new particle formation (NPF) events (June 4, 7, and 11) was facilitated by southwest or west winds with a speed of about 3–4 m s−1. The hygroscopicity parameter (κ) value of newly grown particles varied in a wide range (0.25–0.8) during the events, leading to large uncertainties (−98% to 38%) on the NCCN prediction compared to the campaign. During growth of the newly formed particles for the three events, condensation of sulfuric acid vapor accounts for 14%–42%, 2%–8%, and 3%–9%, respectively, indicating that organic vapors may play an important role in particle growth. For plume‐type events with rapid growth, the observed high CCN activity (i.e., June 7 event) may be explained by the contribution of amines and depression of surface tension in the presence of organic surfactants during particle growth. Our study demonstrates that the contribution of NPF to CCN concentration is modulated by many key factors including growth rate, hygroscopicity, concentrations of new particles and preexisting particles, and variation of those factors from one event to another leads to large uncertainties on the CCN prediction.

Characterization, Sources, and Chemical Processes of Submicron Aerosols at a Mountain Site in Central China

“…More details of the site and instruments can be found in M. F. Cai et al. (2021). No chemical composition data were available after 14 June due to the instrumental failure.…”

“…The NR-PM 1 chemical composition was measured by a ToF-ACSM (model 031, Aerodyne Inc.), including sulfate, organics, ammonium, nitrate, and chloride at a size range of 50-1,000 nm. More details of the site and instruments can be found in M. F. Cai et al (2021). No chemical composition data were available after 14 June due to the instrumental failure.…”

“…Wudang, where the sampled air could be a representative of regional atmosphere with minimal local anthropogenic sources in central China. We recently reported the contribution of new particle formation to the cloud condensation nuclei and its controlling factors from this field campaign (M. F. Cai et al, 2021). Here, more in-depth and comprehensive OU ET AL.…”

“…Wudang, where the sampled air could be a representative of regional atmosphere with minimal local anthropogenic sources in central China. We recently reported the contribution of new particle formation to the cloud condensation nuclei and its controlling factors from this field campaign (M. F. Cai et al., 2021). Here, more in‐depth and comprehensive analyses of the chemical composition and particle number size distribution (PNSD) were made to further investigate the characterization, source origins, and formation processes of submicron particles on Mt.…”