CityZen aims at determining the air pollution distribution and change in and around hotspots over the last decade from extensive satellite and in-situ observations and employs a series of different scale models to analyze the impacts of air pollution hot spots on regional and global air quality, including potential future changes for various climate scenarios.

The focus is on ozone and particulate matter (chemical and physical characterization), and their precursors. The Eastern Mediterranean (Istanbul, Athens, Cairo), the Po Valley, the BeNeLux region, the Pearl River Delta in China (including Guangzhou and Hong Kong) and the hot and polluted European summers 2003 and 2007 are chosen for case studies. The consortium includes experts on observations, emission data and modeling. A set of chemical transport models connecting the most important spatial and temporal scales is further developed and used to quantify how the observed air pollution arises.