Ship measurements of submicron aerosol size distributions over the Yellow Sea and the East China Sea

During the spring of 2005, the total particle concentrations and the submicron aerosol size distributions were measured on board the research vessel over the south sea of Korea and the Korean sector of the Yellow Sea. Similar measurements were made over the East China Sea in autumn 2005. The aerosol properties varied dynamically according to the meteorological conditions, the proximity to the land masses and the air mass back trajectories. The average total particle concentration was the lowest over the East China Sea, 4335 2736 cm(-3), but the instantaneous minimum, 837 cm(-3), for the entire ship measurement was recorded during the Yellow Sea cruise. There was also a long (more than 6 h) stretch of low total particle concentrations that fell as low as 1025 cm(-3) during the East China Sea cruise when the ship was the farthest from the shores and the air mass back trajectories resided long hours over the sea. These observations lead to the suggestion of similar to 1000 cm(-3) as the background total particle concentration over the marine boundary layer in the studied region of the Yellow Sea and the East China Sea, implying significant anthropogenic influence even for the background value. In the mean time, average aerosol size distributions were unimodal and the mode diameter ranged between 52 and 86 nm, excluding the fog periods, which suggests that the aerosols measured in this study experienced relatively less aging processes within the marine boundary layer. (C) 2009 Elsevier B.V. All rights reserved.