GRONFOPCCN

Growth of Newly Formed Particles and Formation of Cloud Condensation Nuclei

1 April 2016 - 30 September 2017

Lead Scientist: Jian Wang

Observatory: SGP (Southern Great Plains)

New particle formation (NPF) in the atmosphere strongly influences the concentration of atmospheric aerosol particles, and therefore their impact on clouds and climate. Model simulations show that nearly half of the global cloud condensation nuclei (CCN) in the planetary boundary layer may be formed through NPF. Because newly formed particles contain too few solute molecules, they need to grow to a sufficient size before they become CCN and are capable of impacting cloud formation. As the coagulation rate of small particles with pre-existing aerosol population is very high, particle growth also increases the lifetime of these ultrafine particles. As a result, the growth rate is one of the key determinants of the probability that ultrafine particles survive the coagulation scavenging and become CCN. Here we propose targeted analyses focusing on the elemental composition, molecular structure, and functional groups of size-selected ultrafine particle samples collected during NPF events and subsequent growth to CCN size. This study will provide detailed information on organic species in growing ultrafine particles, and insight into the processes that drive the growth of newly formed particles and their formation of CCN. This research was performed under the EMSL-ARM Pilot Program for Joint Research Projects and used resources at the Environmental Molecular Sciences Laboratory and the Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains site in Oklahoma.