Development of a Horizontal Cloud Condensation Nuclei Counter to evaluate the role of semi-volatile organic compounds in cloud drop activation

Aerosol particles play a critical role as cloud condensation nuclei (CCN) in the atmosphere. The CCN ability is conventionally measured using CCN counters (CCNCs), which determine the proportion of particles that activate into cloud droplets when exposed to water vapor at a pre-set supersaturation. However, recent findings suggest that the co-condensation effect of semi-volatiles can greatly enhance aerosol particle growth, for example, in polluted cities. This co-condensation effect is not captured accurately in conventional CCNCs, such as streamwise CCNC developed by DMT Inc, since the particles are heated as they pass through the CCNC column. To address this limitation, we have developed the Horizontal Cloud Condensation Nuclei Counter (H-CCNC) based on the concept of a continuous-flow thermal-gradient diffusion chamber. The H-CCNC operates at lower temperatures (
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)