We are happy to announce that our student Simon Bittner has been awarded
the M.Sc degree for his thesis entitled Analysis of NOx emissions sources of
Bremen using WRF-CHEM and DOAS.
The thesis of Simon aimed at quantifying nitrogen oxides (NOx = NO + NO2) emissions in Bremen. NOx emissions in cities emanate mainly from fossil fuel combustion and are responsible for the deterioration of air quality. Two NOx emission sources were chosen for the presented analysis, the airport of Bremen at the south of the city and a waste incineration plant in northern Bremen.
Observations of NOx columns (in the form of NO2) were performed using a bicycle-DOAS setup where DOAS stands for Differential Optical Absorption Spectroscopy. The vertical columns of NO2 were used to calculate the emissions of the target source based on the divergence theorem of Gauss. These emissions were then averaged to yield annual emissions and compared to the state-of-the-art bottom-up emission inventories.
To complement the emission quantification, two models, namely the lagrangian flexible particle dispersion (FLEXPART) and the eulerian weather prediction model (WRF), coupled to chemistry (WRF-CHEM), were used to assess the importance of the above local sources to the air quality of Bremen. In short, FLEXPART was used to simulate the dispersion of the NOx plumes, while WRF-CHEM was used to simulate the atmospheric conditions, meteorology and chemistry for June 2022.