Atmospheric organic aerosols (AOA) have important effects on atmospheric climate and human health. In order to better understand the composition and source characteristics of AOA in the coastal atmosphere, we collected PM_2.5 samples in the coastal suburbs of Qingdao in four seasons of 2020-2021, and determined the primary and secondary organic species by gas chromatography mass spectrometry (GC-MS). The results showed that primary organic aerosols (POA) was dominated compared to secondary organic aerosols (SOA) during the observation period, with SOA tracer concentrations highest in summer and lowest in winter, while POA was the opposite. Monoterpene SOA was the predominant SOA in four seasons, and the contribution of sesquiterpene SOA increased significantly in winter. Nine anthropogenic and biogenic sources of AOA was determined via organic tracer based positive matrix factorization model, and the contributions of local emissions and transport influence were investigated. The composition and sources of AOS under the influence of land and sea winds were further discussed, and the influence of summer enteromorpha emission on AOA in coastal areas was discussed by comparing two summers. The results of this study will help to further understand the sources and marine-related effects of AOA in coastal areas.

atmospheric organic aerosol, organic source tracer, sources, coastal areas, land and sea winds