The problem for which solutions are proposed in this report is ambient air pollution, which causes health risks for people living indoors worldwide. This research focuses on the two Major Air Pollutants nitrogen dioxide and particulate matter, that cause the most problems now and in the future. The starting point of this research is to solve the problem within the building industry and with the use of natural ventilation. This distinguishes it from existing solutions in mechanical ventilation systems such as the HEPA filter. The purpose of this research is to add a new function to the façade by filtering the incoming air using existing air purification technologies and applying them in an innovative way. The research focuses on high-rise buildings in urban areas in industrialized regions, because there the exposure to polluted air is mainly indoors. Despite the fact that in those regions other measures are or already have been taken to reduce air pollution, this is still not enough and in these regions the willingness to apply technological solutions in the building industry is high. The focus is on a facade type that is fully or partially closed and placed in a building that uses ventilation type C, which means natural supply of air through the facade and mechanical exhaust within the building. The research question answered is as follows: 'How can the façade of a high-rise building in an industrialized region be designed to improve the indoor air quality by using ventilation type C?' An answer to this question is given in this research by six concept designs and two elaborations in two case studies of the building 'Montevideo' in Rotterdam, the Netherlands. To obtain that answer, a literature study was carried out to examine existing air purification technologies, five of which were further elaborated and their relationship to each other determined. It was also investigated what has to be taken into account when designing ventilation openings. Hereby it was examined which ventilation openings are relevant for this research and how they relate to each other. Partly to validate the literature, partly to discover how air purification technologies work and mainly to support the concept designs, a test set-up was made to test filters for filtering out particulate matter. A sub-goal was to do this with a test set-up at home instead of in a laboratory. For this research, hard criteria have been formulated that the concepts must meet. Soft criteria have been defined in order to be able to compare the different concepts and determine which concept is best to be worked out in which case study. The concept designs and case studies, which are answers to the main question were created to serve as inspiration for designers interested in developing facade systems that filter air. As such, the designs in this research are primarily conceptual examples and are not yet a product. This research provides a theoretical basis for further concepts to be developed and applied in case studies.