106 // Service and Information A Aerosols Aerosols are solid and/or liquid particles that are suspended in the air. They reach the atmosphere by means of natural pro- cesses (wind, desert storms, volcanic erup- tions) or human activities (combustion of biomass and fossil fuels). The most impor- tant aerosols are mineral dust, sea salt, cellular (biological) particles, soot, organic compounds, and sulfates. From a climatic perspective, aerosols are the opponents of greenhouse gases, as they can reflect incident light and thus have a cooling effect. aireg e.V. – Aviation Initiative for Renewable Energy in Germany aireg is a registered association of leading German research institutions, Lufthansa and other companies in the aviation indus- try, and bioenergy producers. The goal of this initiative, which was founded in 2011, is to advance the development and intro- duction of regenerative aviation fuels in Germany and to inform the public at large about this topic. www.aireg.de ATM – Air Traffic Management Air traffic management ensures both the safe and the efficient movement of aircraft in all phases of operations. Atmosphere The whole mass of air surrounding the Earth. It is divided into various layers, distin- guished from one another by distinct dif- ferences in vertical bands of temperature. Important for air traffic are the two lower layers: the troposphere and, above it, the stratosphere. The troposphere’s upper boundaries vary depending on season and latitude. They lie at altitudes of 16 to 18 kilometers above sea level at the equator, and at eight to 12 kilometers above sea level at the poles. The temperature in the tropopause, the transition layer between troposphere and stratosphere, drops to about minus 60 degrees Celsius. It rises again in the stratosphere. The so-called ozone layer is also located in the strato- sphere at altitudes of about 25 to 30 kilo- meters. Today’s commercial aircraft fly at cruising altitudes of between eight and 13 kilometers. According to the latest research, air traffic emissions do not con- tribute to the reduction of the ozone layer. B B.A.U.M. – Bundesdeutscher Arbeits- kreis für Umweltbewusstes Manage- ment e.V. (Federal Working Group for Environmentally-Aware Management) B.A.U.M. was founded in 1984 as the first independent environmental initiative of German business. With more than 500 members, it is the largest of its kind in Europe today. Lufthansa has been a mem- ber of the Working Group since 1997. www.baumev.de BDL – Bundesverband der Deutschen Luftverkehrswirtschaft (German Aviation Association) Lufthansa is a founding member of the German Aviation Association (BDL), which has represented the interests of the Ger- man aviation industry with a single voice since December 2010. Its main goals are to make politicians and journalists more aware of aviation’s economic and employ- ment-related importance and to strengthen Germany as a business location for aviation in general. www.bdl.aero C Carbon dioxide (CO2) Gas resulting in nature from the burning or decomposition of organic substances (e.g. plant material) and from human or animal respiration. The greenhouse gas CO2 remains in the atmosphere for about 100 years. Scientists attribute the increase in atmospheric CO2 over the last 100 years to the burning of fossil fuels (e.g. coal, oil, natural gas) by humans. Per tonne of fuel, 3.15 tonnes of CO2 result from the combus- tion process. Currently, about 2.42 percent of the CO2 emissions due to human activi- ties are caused by global air traffic. (Source: International Energy Agency (IEA) 2013, 2011 values) Carbon monoxide (CO) Chemical compound consisting of one carbon and one oxygen atom, formed in the incomplete combustion process of substances containing carbon. For aircraft engines, the level of CO emissions depends greatly on the thrust level: The emissions per kilogram of fuel burned are higher at idle settings, while taxiing, and on approach than during the climbing and cruising phases. CDA – Continuous Descent Approach Procedure for a flight’s approach phase that requires less engine thrust and is therefore quieter and more fuel efficient. However, this type of approach is possible only if there are no constraints due to heavy air traffic in the airspace concerned. CDP (previously Carbon Disclosure Project) The CDP is an independent, charitable organization with a current membership of more than 820 institutional investors world- wide. The goal of this initiative, which was founded in 2000, is to motivate the world’s largest listed corporations to make data on Glossary