This thesis studies the spatio-temporal patterns and trends in NO2 air pollution over Denmark using the satellite remote sensing product OMNO2e retrieved from the OMI instrument on the NASA AURA satellite.
These data are related to in situ measurements of NO2 made at four rural and four urban stations in the Danish Air Quality Measurement network to find correlation between the two datasets. Clear weekly and annual cycles are found in both datasets and they are shown to be significantly correlated, though with a low
correlation coefficient. Analyses of the patterns in different wind directions are conducted, and it is shown that plumes from major Danish source areas can be detected in all wind directions, and that pollution transported from Europe is seen when the wind has a southern component. Examples of day to day tracking of transport of NO2 are also given to explain two pollution episodes measured in Denmark. Trends in the data are assessed and declining trends are seen over several European cities, whereas no significant trends are found in the Danish area. The mean distribution of NO2 from the satellite data is also used to evaluate the NOx emission inventory.