Size distributions and particle number concentrations of atmospheric aerosols in the size (diameter) range from 15 mn to 10 mu m were measured on board of a research ship during three cruises in China adjacent seas. The total particle number concentrations were in average around 4000 cm(-3) in Yellow Sea, 2000 cm(-3) in East China Sea and 1000 cm(-3) in South China Sea. The observed size distributions were fitted with two or three log-normal modes and the data were classified according to time, regions and calculated air mass back-trajectories. The size distribution spectra of air masses of polluted continental origin as their back-trajectories showed were characterized by single mode with total number concentrations between 1000 and 10000 cm(-3). The size distributions in marine air masses showed dual mode characteristics, one maximum at 40-60 nm and the other at 160-190 nm with total number concentrations below 1000 cm(-3). This type of dual mode was more pronounced at longer residence time of the air masses over the ocean. The burst of ultra-fine (UF) particles and the consequent growth processes were observed twice in Yellow Sea and possible reasons leading to these events are discussed. The particle growth rate (GR) was 3.4 +/- 0.9 and 3.5 +/- 1.6 nm h(-1), respectively (95% confidence interval), indicating that the UF particles can grow to cloud condensation nuclei (CCN) within the next 1-2 days.) (C) 2007 Elsevier Ltd. All rights reserved.

Particle number size distributions between 3 nm and 10 mm were measured in Beijing, China. New particle formation events were observed on around 40% of the measurement days from March 2004 to February 2005 and were generally observed under low relative humidity and sunny conditions. Though occurring during all seasons, new particle formation events had highest frequency in spring and lowest frequency in summer. Events were classified as "clean'' or "polluted'' groups mainly according to the condensational sink and the local wind. The formation rate range was from 3.3 to 81.4 cm(-3) s(-1). The growth rate varied from 0.1 to 11.2 nm h(-1). The seasonal variation of condensable vapor concentration showed the highest values during summer months due to enhanced photochemical and biological activities as well as stagnant air masses preventing exchange with cleaner air.