Modelling of Atmospheric Processes and Composition

Validation of modelled inorganic aerosol: comparing models with observations

Supervisor: Guus Velders (g.j.m.velders@uu.nl)

Aerosols are the main component of air pollution and associated with health effects. Inorganic aerosols (ammonium, nitrate, sulphate), formed in the atmosphere by reactions of other air pollutants, are currently a large fraction of total particulate matter in the Netherlands. Other fractions come from primary particulates and organic aerosols. In a previous master project high peaks in inorganic aerosols have been modelled with the state of the art atmospheric chemistry transport model WRF/Chem and compared with daily average observed concentrations. The model underestimates the observed peak concentrations. In this project you will use measurements with an Aerosol Chemical Speciation Monitor (ACSM) of the inorganic aerosols at with high temporal resolution and compare them with WRF/Chem model output to improve the modelled concentrations. You will look both at peak concentrations and background concentrations to improve the understanding of aerosol formation. Depending on the progress you can also look at total particulate matter by including primary and organic aerosols in the model and comparing it with observations.

Measuring and modeling methane emissions from agriculture

Supervisor: Guus Velders (g.j.m.velders@uu.nl)

Methane (CH₄) is the second most important greenhouse gas. In the Netherlands 75% of the CH4 emissions come from the agricultural sector, but there are significant uncertainties in the emissions from all sectors. To reduce emissions, a good understanding of the sources and the potential for mitigation is important. In the project you will perform measurements of CH₄ in agricultural areas with a mobile instrument and perform model simulations with a state of the art atmospheric chemistry transport model (WRF/Chem). You will compare the measured concentrations with the modelled concentrations to estimate and understand the local sources of CH₄. This project will be performed in close collaboration with a tandem project that focusses on measuring and modelling of CH₄ emissions from urban sources, which can be found on this page.

Organic aerosols: observations vs modelling

Supervisor: Guus Velders (g.j.m.velders@uu.nl) and R. Holzinger (r.holzinger@uu.nl)

Aerosols, important for the health effects of air pollution, consist of primary, inorganic, and organic aerosols. The first two have received the most attention in mitigation measures and are better understood than organic aerosols. The organic aerosols are formed in the atmosphere by chemical reactions of many volatile organic compounds. In the project you will use observations from PTR-MS (Proton-transfer-reaction mass spectrometry) and ACSM (Aerosol chemical speciation monitor) and perform model simulations with the state of the art atmospheric chemistry transport model WRF/Chem. PTR-MS gives concentrations of many organic compounds in the gas phase with high temporal resolution. The ACMS measures different components organic aerosols You will perform simulations with WRF/Chem to simulate organic aerosol and it precursors and compare with the observations to better understand the aerosol formation. For this you will have to dig into the model to include the relevant reactions and species for the formation of organic aerosol.