Dr Freja F. Oesterstroem
I obtained my PhD in 2016 at University of Copenhagen, Denmark. My PhD research involved kinetic and mechanistic studies of the gas phase reactions of new replacements to the chlorofluorocarbons (CFCs) and their first replacements (hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs)). The new replacement compounds (hydrofluoroethers (HFEs) and hydrofluoroolefins (HFOs)) are in general more reactive than the compounds they are replacing and have a smaller impact on the atmosphere. I studied the rate coefficients of the reactions with different atmospheric oxidants (OH radicals, OD radicals, Cl atoms, and O3), atmospheric lifetimes, products of the reactions, and environmental impact of several HFEs and HFOs.
Other areas of research I have been involved with includes the exchange of carbon monoxide (CO) between the soil and the atmosphere, the oxidation of biodiesel/petroleum mixtures and mechanistic studies of the night-time gas phase chemistry of different alkenes with NO3 radicals.
I am investigating different aspects of the loss and formation of atmospheric radicals. This is being done using both experimental and theoretical methods.
The highly instrumented reactor for atmospheric chemistry (HIRAC) is being used to perform experiments investigating the self- and cross- reactions of different radicals. Rate coefficients and product yields for the reactions will be quantified as these are currently not well understood.
Radicals in the atmosphere can help explain high pollution events of the formation either gas phase compounds or aerosols. Aiding the understanding of the chemistry leading to this, box modelling using the Master Chemical Mechanism (MCM) developed at University of Leeds is being applied comparing the simulations to field (or laboratory) measurement data.
Another aspect of radical chemistry is the interaction with aerosols. This area of research involves a flow tube setup that will be used to measure loss and formation of radicals on the surfaces of aerosols.