Abstract Number: 135 Working Group: Remote/Regional Atmospheric Aerosol
Abstract Nucleation and new particle formation (NPF) in the East Asia region is strongly influenced by the photochemical processes during long range and trans-boundary transport of air pollutants. Our previous measurements (Seto et al., 2013; Indra et al., 2016) related with the incomplete and weak NPF (starting from ~10 nm) at Fukue island (downstream) are suggesting the nucleation in upstream flow. Aerial observation has great advantages for the investigating nucleation and NPF over certain region. Vertical structure of atmospheric nanoparticle concentration (particle size >6 nm and altitude 1), and air mass backward trajectory analysis. The stronger NPF event (Event I, >35,000 cm-3) than our previous measurements (from 2012 to 2016, ~20,000 cm-3) with the particle size as small as 5 nm affected by the long range transport of air pollutants under a high pressure system was detected. In addition, sudden increase of particle number concentration and SO2 concentration with weak NPF (onset diameter above than 10 nm) caused by the change of air mass origin (Event II, <10,000 cm-3) and no NPF with aged sulfate particles under low particle number concentration and low SO2 condition (-3) were observed. Vertical profile and size distribution of nanoparticles, meteorological condition, chemical composition of submicron (< 1 µm) particles, SO2 concentration and air mass backward trajectory based on different events were analyzed.