Insights into biogenic secondary organic aerosols produced from five structurally different precursors

Introduction A series of novel experiments were carried out at the Manchester Aerosol Chamber in order to investigate the chemistry and microphysics of the formation and transformation of biogenic secondary aerosols. A selection of compounds covering a wide range of reactivity including monoterpenes, sesquiterpenes and oxygenated VOCs has been studied in detail. The chemical composition of the formed SOA was measured on-line using an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS). A hygroscopicity tandem differential mobility analyser (HTDMA) and a cloud condensation nuclei (CCN) counter were used to probe the hygroscopic properties and of the aerosols in the sub- and super-saturated regimes, respectively. A proton transfer mass spectrometer was used to study the evolution of the gas phase oxidation products. Results and Discussion We presents an overview and synthesis of results covering the chemical composition, hygroscopicity and cloud condensation nuclei (CCN) properties of secondary organic aerosols formed from five structurally different biogenic VOCs (?-caryophyllene, limonene, myrcene, linalool, ?-pinene). The effect of the use of organic [1] and inorganic seed on the limonene SOA will be presented. Results showed that the formed SOA have a wide range of chemical properties, and that the effect of photochemical ageing on their properties was not uniform across all five precursors. A link of these results to the corresponding findings of the hygroscopic properties of the SOA particles and their CCN behaviour will be presented and discussed. [1] Hamilton, J.F., Alfarra, M.R., Wyche, K.P., Ward, M.W., Lewis, A.C., McFiggans, G.B., Good, N., Monks, P.S., Carr, T., White, I.R. and Purvis, R.P. (2010) Atmos. Chem. Phys. Discuss., 10(10), 25117-25151.