The coastal zone represents a critical boundary region where sea-land interactions influence chemical characteristics to atmospheric particles. Atmospheric particles over the west coast of Taiwan Strait are impacted by both anthropogenic and marine emissions, with monsoon transitions significantly affecting the chemical composition. In this study, single particle characterization in Dongshan Island was obtained by computer-controlled scanning electron microscope and energy dispersive X-ray spectroscopy. More than 290,000 particles collected in different seasons were classified by K-means clustering algorithm based on their elemental composition. Particles in winter are dominated by carbonaceous, sulfur-containing, and K-rich particles, while the fraction of sea salt increases in spring and summer. The mixing state is used to quantify the compositional diversity within a particle population. The proportion of carbonaceous and sulfate particles is negatively correlated with the mixing state index (