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C403: The chemistry of highly oxidised organic compounds in the atmosphere and their effects on aerosol particle formation (Priority project with CASE partner) (Lead Supervisor: Markus Kalberer, Chemistry)

Supervisors: Markus Kalberer (Chemistry) and Alex Archibald (Chemistry

Importance of the area of research:

Atmospheric aerosols are key players in the climate system: they strongly affect the radiative balance of the Earth's atmosphere and are important in the formation of clouds. Aerosols are also one of the most important air pollutants. Both climate and health effects of aerosols are poorly understood. A major fraction of the aerosol mass in the atmosphere is composed of organic gaseous compounds forming new particles. Unravelling the enormous chemical complexity of organic aerosol material in the atmosphere is a significant analytical-chemical challenge and a main reason for the low level of understanding of aerosol sources and their effects in the atmosphere and on human health. In recent years is has become evident that very highly oxidised molecules (HOMs, reference 1) are essential for the formation of atmospheric aerosol and new analytical techniques are being developed to accurately characterise and quantify the formation, structure and sources of these compounds, leading to an improved understanding for the formation and composition of organic aerosols to advance our understanding of their effects on the climate system.

Project summary:

The aim of this project is to improve the understanding of oxidation or organic compounds in the atmosphere and aerosol formation processes in laboratory experiments using novel and innovative mass spectrometry techniques in close collaboration with industry partners. Atmospheric organic aerosol will be generated under controlled conditions in our large-scale Cambridge Atmospheric Simulation Chamber where gaseous precursors such as terpenes and small aromatic compounds will be oxidised with ozone and other atmospherically relevant oxidants. The resulting, highly complex reaction products in the gas phase and the particle phase, composed of 100s oxidised compounds will be characterised. A main focus will be the analysis of HOMs in the gas and particle phase with highly sensitive state-of-the-art SIFT and EESI mass spectrometry techniques.

What the student will do:

In this CASE studentship, the PhD student will closely work with an industrial partner using and further characterising a novel mass spectrometry technique (SIFT-MS) for the analysis of highly oxidised gaseous organic compounds such as HOMs. Quantitative calibrations for HOMs with a wide range of ionising agents will be performed. In addition, the student will use EESI-MS, developed in-house (reference 2), to characterise the aerosol composition. The student will use a number of laboratory techniques to generate atmospheric aerosols to mimic atmospheric processes under realistic ambient conditions. The simultaneous analysis of gas and particle components with unprecedented time resolution and sensitivity will allow to study in detail the fast gas/particle transition processes that lead to particle formation in the atmosphere. A range of atmospherically relevant formation processes will be studied to simulate the oxidation of natural and anthropogenic organic compounds and assess their importance in the atmosphere.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.


Ehn M. et al., Nature, 506, 476-479,, 2014.

Gallimore P. et al., Atmos. Chem. Phys., 17, 9853-9868, 2017.

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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