Secondary organic aerosol (SOA) is one of the most important components of PM_2.5. It significantly influences air quality, radiation balance and human health. Thus, studying the formation and control of SOA has a significant meaning in revealing the cause of particulate pollution and improving eco-environment. However, there are still many challenges in the field of SOA study because of the complexity of organic compounds, reactions and atmospheric conditions. The purpose of the paper is to summarize the progress of SOA research based on investigating the literature published on the top international academic journals in the field of environment and atmospheric chemistry in 2019. The molecular characteristics and sources of SOA are delved into with a variety of novel or modified methods and instruments in both field studies and laboratory simulations. The formation process and major influence factors of SOA from some natural and anthropogenic precursors are investigated. Atmospheric aqueous chemistry and the interaction between organic and inorganic compounds are found playing an important role in the formation and aging of SOA. In addition, the contribution of SOA to the change of aerosol optical property and the impact of aerosol on human health are estimated. In conclusion, it is necessary to pay attention to the further research of SOA so as to take effective actions to control particulate pollution.

fine particles  /  secondary organic aerosol  /  formation and aging mechanism