Biogenic and anthropogenic organic gases undergo oxidation in the atmosphere,resulting in the formation of secondary organic aerosols (SOA).SOA plays a crucial role in climate change and human health.While considerable advancements have been made in understanding SOA production and its precursors,the intricate interactions among organic gases and the complex mechanisms governing SOA formation still presents challenges.Currently,knowledge gaps persist regarding SOA formation arising from the oxidation of different organic gases present within complex systems.This review aims to provide insights into the evolving research landscape concerning the oxidation of organic gases in complex systems leading to SOA formation.The review encompasses two primary aspects.Firstly,it summarizes the variations in mass concentration,yield,composition,volatility,and optical properties of SOA resulting from the oxidation of organic gases within complex systems.This section explores the different effects of organic gas oxidation within complex systems on SOA formation.Additionally,it delves into the evolving constituent elements and molecular composition of SOA.Furthermore,this review collates current laboratory-based simulation studies on generating SOA from composite systems and evaluating model accuracy.Secondly,it investigates the effects of environmental factors,including relative humidity (RH),temperature (T),and inorganic gases such as nitrogen oxides (NO_x),sulfur dioxide (SO₂),and ammonia (NH₃),on the interaction with organic gases within complex systems,ultimately leading to SOA formation.This exploration provides valuable insights into the interplay of environmental variables in shaping SOA characteristics.Therefore,this review contributes to a deeper understanding of the chemical evolution of organic gases in the real atmosphere.It highlights the necessity of studying the multi-source and complex interactions of organic gases and mapping the intricate atmospheric oxidation mechanisms,leading to SOA formation,and outlines avenues for future research,aiming to enhance the interpretation of laboratory simulation results within complex systems.