In the EU-FP7 project MarcoPolo the focus is placed on emission estimates from space and the refinement of these emission estimates by spatial downscaling and by source sector apportionment. A wide range of data is used from various satellite instruments. From these satellite data, emission estimates are made for anthropogenic and biogenic sources. With various state-of-the-art techniques, up-to-date emission inventories are created. By combining these emission data with known information from the ground, a new emission database for China has been constructed. The new emission inventory is input to air quality models on both regional and urban scale. An ensemble forecast service for air quality in China is also provided in cooperation with the Panda project.