The role of functional groups in the understanding of secondary organic aerosol formation mechanism from α-pinene
•The SOA is characterized by O–H groups in the OH channel and C=O groups in the O3 channel
•The nO−H/nC=O ratio is a good parameter in revealing the difference of SOA between the O3 and OH oxidation channels
•The SOA from OH channel is mainly formed by autoxidation of RO2 radicals
•Different structures of RO2 radicals are responsible for the difference functional group signatures of SOA
Role of liquid water in the formation of O3 and SOA particles from 1,2,3-trimethylbenzene
• Liquid water can affect the formation of O3 and SOA from 1,2,3-trimethylbenzene.
• The hygroscopic growth factors of SOA from 1,2,3-trimethylbenzene were measured.
• Hydrolysis of N2O5 is the major reason for the decrease of O3.
• The major contribution of SOA under high LWC conditions comes from aqueous reaction.
Luo, H., Jia, L., Wan, Q., An, T., Wang, Y., 2019. Role of liquid water in the formation of O3 and SOA particles from 1,2,3-trimethylbenzene. Atmos. Environ. 217, 116955. https://doi.org/10.1016/j.atmosenv.2019.116955
Short Summary: The significantly negative effects of relative humidity (RH) on secondary organic aerosol (SOA) formation from m-xylene under low NOx conditions were observed. The significant RH effects on chemical compositions of SOA are identified, in which highly oxygenated molecules (HOMs) are dominant. Our results show that the decrease of SOA formation under high RH conditions is mainly attributed to the suppression of the formation of oligomers and HOMs.
Zhang, Q., Xu, Y., and Jia, L.: Secondary organic aerosol formation from OH-initiated oxidation of m-xylene: effects of relative humidity on yield and chemical composition, Atmos. Chem. Phys., https://www.atmos-chem-phys.net/19/15007/2019/acp-19-15007-2019.html, 2019.