<p>The compositions and distributions of monoterpenes, isoprene, aromatics and sesquiterpene SOA tracers (SOA_M, SOA_I, SOA_A and SOA_S, respectively) at an island site (Da Wan Shan Island, DWS) were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary (PRE) region in winter 2021. The sum concentration of SOA tracers was 6.2–132.8 ng m⁻³, with SOA_M and SOA_I as the main components in both continental (scenarios A1 and A2) and marine air masses (scenario A3), as well as their combination (scenario A4). The highest and lowest levels of SOA_M were observed in A1 and A3, respectively, which were mainly related to the variations in meteorological conditions, precursor concentrations, and the degree of photochemical processes. Higher MBTCA/HGA (3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid) ratios suggested a less significant contribution from α-pinene to SOA_M. The variations of SOA_I in the different scenarios were associated with differences in relative humidity, particle acidity, and isoprene/NO_<i>x</i> ratios. The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas, which was confirmed by the correlation among biogenic and anthropogenic precursors. The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes, with the highest concentrations in A1. A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25% to the total SOA at DWS, while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.</p>