Katrib, Y.Y.KatribMartin, S. T.S. T.MartinHUI-MING HUNGRudich, Y.Y.RudichZhang, H. Z.H. Z.ZhangSlowik, J. G.J. G.SlowikDavidovits, P.P.DavidovitsJayne, J. T.J. T.JayneWorsnop, D. R.D. R.Worsnop2018-09-102018-09-102004http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000223182700011&KeyUID=WOS:000223182700011http://scholars.lib.ntu.edu.tw/handle/123456789/307868Heterogeneous reactions of oleic acid aerosol particles with ozone are studied below 1% relative humidity. The particles have inert polystyrene latex cores (101-nm diameter) coated by oleic acid layers of 2 to 30 nm. The chemical content of the organic layer is monitored with increasing ozone exposure by using an aerosol mass spectrometer. The carbon-normalized percent yields of particle-phase reaction products are 20−35% 9-oxononanoic acid, 1−3% azelaic acid, 1−3% nonanoic acid, and 35−50% other organic molecules (designated as CHOT). There is approximately 25% evaporation, presumably as 1-nonanal. To explain the formation of CHOT molecules and the low yields of azelaic and nonanoic acids, we suggest a chemical mechanism in which the Criegee biradical precursors to azelaic acid and nonanoic acid are scavenged by oleic acid to form CHOT molecules. These chemical reactions increase the carbon-normalized oxygen content (z/x) of the CxHyOz layer from 0.1 for unreacted oleic acid to 0.25 after high ozone exposure. Under the assumption that oxygen content is a predictor of hygroscopicity, our results suggest an increased cloud condensation nuclei activity of atmospherically aged organic particles that initially have alkene functionalities.[SDGs]SDG6journal article10.1021/jp049759d2-s2.0-4344645707WOS:000223182700011