»Urban Traffic: The Interaction Between Air Quality Law and Car Approval Rules. A Systemizing and Overarching Legal Analysis«: Traffic-induced urban air quality issues do not only provoke heated discussions but can also be subject of legal debates. Hence, this work aims to shed light on its legal backgrounds. Therefor, it analyses air quality planning as an instrument and systematizes the legal requirements for car emissions, including the EU approval procedure. In conclusion, the author undertakes to examine the interdependence between both regulatory fields and closes with legislative suggestions for improvement.