I majored in atmospheric sciences in my undergraduate study in Nanjing University, where the course setting was expansive and I benefited a lot from the spirits of holding a systematic view towards understanding the Earth’s atmosphere and its interactions with other spheres. My academic journey through this wide spectrum helped me gradually build up my knowledge framework from air pollution to climate change, where aerosols play a significant role across all the domains. The chemically complex sources and the unclear contribution to the cloud formation in the changing world make atmospheric aerosols the largest remaining uncertainty in the human forcing of the climate system, which solidified my determination to specialize in this field during my graduate program.
Atmospheric New Particle Formation
Atmospheric new particle formation (NPF) as an aerosol source accounts for half of the global cloud condensation nuclei (CCN). As the onset of NPF is driven by the phase transformation from nucleating vapors to the molecular clusters, the past decade has seen profound efforts dedicated to reveal the mechanism and vapors driving NPF in the atmosphere. With well-defined lab-derived NPF rates coupled with ground-based field observations, the atmospheric relevance of NPF induced by different species and in diverse environments has been progressively discovered and evaluated. I am lucky enough to have participated in various field campaigns and daily maintenance of state-of-art instruments as a platform for decoding molecular mechanism forming aerosol particles.
Nanoparticle Growth
As a phase-transition process, NPF includes both the initial nucleation of low-volatility vapors and the subsequent growth of the newly formed particles. What makes the growth process crucial is that they can grow to critical sizes and get activated by water to form cloud condensation nuclei (CCN), and exert impact on cloud properties, and hence the climate globally. However, the highly diffusive new particles can be readily scavenged by larger pre-existed particles and removed from the air, which is recognized as the coagulation loss. Therefore, the growth rate of the particles can determine the fate of the particles- faster growth will avoid the scavenge. There is a wide spectrum of species contributing to particle growth and through lab experiments, the growth process can be parameterized, before getting represented in global models to evaluate the role of aerosol in introducing uncertainties to future climate.