This is an interdisciplinary course where the challenge of air pollution is introduced with a focus on urban areas. The interdependencies between transportation, air quality, and health are demonstrated. The city and the behaviour of its inhabitants constitute the context for the following course topics: overview of air pollutants in urban areas, urban air quality monitoring networks, mobile source emissions, air pollution and meteorology, atmospheric dispersion, chemical processes specific to cities, personal mobility and exposure to traffic-related air pollution, epidemiology of air pollution.