At the Institut für Physik der Atmosphäre the impact of different traffic emissions on the composition of the atmosphere and the climate is investigated. Among other aspects, the relative contributions of single traffic modes are quantified. For these studies we rely on laboratory measurements of exhaust gases, airborne measurements with the research aircraft Falcon and global model simulations with ECHAM.
Traffic emissions affect the environment in various ways. Emissions of carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons, nitrogen oxide (NOx), and particles (e.g. soot) are important for the chemical composition of the atmosphere. Nitrogen oxides lead to ozone production in most areas of the troposphere. Hydrocarbons enhance the ozone production.
While the importance of surface traffic decreases with hight, air traffic enhances the concentration of NOx mainly at the flight altitude (approx. 12 km). Emissions from ships lead to an increase of species like NOx over the sea, where they have a prominent role because other sources are absent. In addition, traffic emissions alter the formation of clouds: air traffic leads to contrails and additional cirrus. Ships form so-called ship tracks, i.e. low cloud lines that are triggered by the emitted aerosols.