Molecular composition and sources of water-soluble organic aerosol in summer in Beijing
• Water-soluble organic aerosol was the major fraction of OA in summer in Beijing.
• SOA from regional and photochemical processing contributed dominantly to WSOA.
• A high diversity of CHO and CHOS molecular compounds in WSOA was observed.
• Formation of more organosulfates during polluted days than clean days in summer.
Qiu, Y., Xu, W., Jia, L., He, Y., Fu, P., Zhang, Q., Xie, Q., Hou, S., Xie, C., Xu, Y., Wang, Z., Worsnop, D.R., Sun, Y., 2020. Molecular composition and sources of water-soluble organic aerosol in summer in Beijing. Chemosphere 255, 126850.
Influence of relative humidity on cyclohexene SOA formation from OH photooxidation
• Combined effects of OH and RH on cyclohexene SOA formation were studied.
• The formation of oligomers at high RH was responsible for the increase of the SOA yield.
• High RH increases the OH uptake coefficient of SOA, and promotes SOA aging.
• Oligomers formation mechanism from cyclohexene photooxidation at high RH was proposed.
Liu, S., Tsona, N.T., Zhang, Q., Jia, L., Xu, Y., Du, L., 2019. Influence of relative humidity on cyclohexene SOA formation from OH photooxidation. Chemosphere 231, 478–486. https://doi.org/10.1016/j.chemosphere.2019.05.131
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.