Measurement Report: New insights into the boundary layer revolution impact on new particle formation characteristics in three megacities of China

Abstract. New particle formation (NPF) events contribute more than 60 % of ultrafine particles particularly in the boundary layer. This study retrieved the particle number size distribution and the NPF parameters and their relationship with planetary boundary layer height (PBLH) evolution, as well as the air mass back trajectories during NPF events in three Chinese cities: Beijing, Guangzhou, and Shanghai. Furthermore, all NPF events has been classified into three types: new particles grow rapidly during the initial rise of the boundary layer in Type Ⅰ events, while they grow after the boundary layer reaches a certain height (above 800 m) in Type Ⅱ events, and the shrinkage cases are the Type III. The results show that particle growth dynamics categorized into distinct types demonstrate that sustained particle growth predominantly occurred under conditions of stable and elevated PBLH. Survival parameters ranged from 13.1 to 115.9 in Beijing, 9.0 to 110.2 in Guangzhou, and 8.4 to 25.6 in Shanghai. Specifically, Type I events were associated with survival parameters between 14.0 and 45.2. A significant negative correlation is observed between survival parameters and PBLH (R2 = 0.2 in Beijing, R2 = 0.02 in Guangzhou, and R2 = 0.99 in Shanghai, respectively). The main source of Aitken mode transport to Beijing is from Mongolia region. In Guangzhou, the contribution mainly comes from Jiangxi and Fujian provinces located in the northeast, while in Shanghai, the source lies to the northwest. This research provides valuable insights into developing strategies to manage the atmospheric environment.