which successfully passed the QA-process (i.e., met the Data Quality Objectices) were included into the TFS-central data bank. The following summary of major results obtained in TFS would not have been possible without the contribution of many experimentalists and modellers participating in this project. I would like to thank these colleagues for their support. All participants are grateful for the financial support by the BMBF and for the assistance by the Projekttragerschaft (UKF-GSF-Miinchen). Garmisch-Partenkirchen, WOLFGANG SEILER February 2002 DEVELOPMENT AND APPLICATION OF A MESOSCALE...

Photochemical oxidants are secondary air pollutants formed under the influence of sunlight by complex photochemical reactions in air which contains nitrogen oxides and reactive hydrocarbons as precursors. The most adverse components formed by photochemical reactions in polluted air are ozone (0 ) 3 and peroxyacetyl nitrate (PAN), among many other products such as aldehydes, ketones, organic and inorganic acids, nitrates, sulfates etc. An analysis and evaluation of the available knowledge has been used to characterize the relationships among emissions, ambient air concentrations, and effects,...

The Arctic troposphere (0 to ca. 8 km) plays an important role in environmental concerns for global change. It is a unique chemical reactor influenced by human activity and the Arctic ocean. It is surrounded by industrialized continents that in winter contribute gaseous and particulate pollution (Arctic haze). It is underlain by the flat Arctic ocean from which it is separated by a crack-ridden ice membrane 3 to 4 m thick. Ocean to atmosphere exchange of heat, water vapor and marine biogenic gases influence the composition of the reactor. From September 21 to December 21 to March 21, the...