Air pollution is a major environmental and social issue, causing a vast array of negative health effects. Approximately 7 million deaths and an economical cost of 3.28 trillion euros worldwide can be attributed to air pollution. In this research a new, promising method will be tested to fight high urban air pollution levels. More specifically, the potential of leaf-dwelling or phyllosphere bacteria (PB) to degrade urban air pollutants (particulate matter and volatile organic compounds) into less toxic forms, also called bioremediation potential. This will be done with both field and laboratory experiments. The project is divided into four workpackages (WP). In WP1, the different PB present on 70 plant species will be determined and their preferences for leaf characteristics will be tested. WP2 will map which PB typically occur under high levels of urban pollutants and how they change through the growing season. In WP3 the specific bioremediation potential of promising PB will be tested and in WP4 all these results will be brought together. Then the first realistic numbers of what the application of the right plant-PB-combination could mean for the ambient urban pollutant levels will be estimated on the basis of computer models. The ultimate aim of this research is to find the optimal plant-PB-combination to optimize the bioremediation potential of vegetation in the city.