Die Einführung der Umweltzone in Leipzig wird durch Messungen an Luftmessstationen wissenschaftlich begleitet. Neben den gesetzlich vorgegebenen Schadstoffen werden erstmalig Ruß und ultrafeine Partikel überwacht. Der dritte Teil der Berichterstattung dokumentiert die Ergebnisse bis 2013. Die Umweltzone bewirkte eine beschleunigte Modernisierung der Fahrzeugflotte in der Stadt. In verkehrsnaher Außenluft wurden ein deutlicher Rückgang von Ruß und ultrafeinen Partikeln und eine Stagnation von Stickoxiden nachgewiesen. Erfolgreich wurden die hochtoxischen Bestandteile im Feinstaub gemindert.

Non-thermal plasma generated in a dielectric barrier packed-bed reactor has been used for the remediation of chlorinated volatile organic compounds. Chlorinated VOCs are important air pollutant gases which affect both the environment and human health. This thesis uses non-thermal plasma generated in single and multiple packed-bed plasma reactors for the decomposition of dichloromethane (CH2Cl2, DCM) and methyl chloride (CH3Cl). The overall aim of this thesis is to optimize the removal efficiency of DCM and CH3Cl in air plasma by investigating the influence of key process parameters. This thesis starts by investigating the influence of process parameters such as oxygen concentration, initial VOC concentration, energy density, and plasma residence time and background gas on the removal efficiency of both DCM and CH3Cl. Results of these investigations showed maximum removal efficiency with the addition of 2 to 4 % oxygen to nitrogen plasma. Oxygen concentrations in excess of 4 % decreased the decomposition of chlorinated VOCs as a result of ozone and NOx formation. This was improved by adding an alkene, propylene (C3H6), to the gas stream. With propylene additives, the maximum remediation of DCM was achieved in air plasma. It is thought that adding propylene resulted in the generation of more active radicals that play an important role in the decomposition process of DCM as well as a further oxidation of NO to NO2. Results in the single bed also showed that increasing the residence time increased the removal efficiency of chlorinated VOCs in plasma. This was optimized by designing a multiple packed-bed reactor consisting of three packed-bed cells in series, giving a total residence time of 4.2 seconds in the plasma region of the reactor. This reactor was used for both the removal of DCM, and a mixture of DCM and C3H6 in a nitrogen-oxygen gas mixture. A maximum removal efficiency of about 85 % for DCM was achieved in air plasma with the use of three plasma cells and the addition of C3H6 to the gas stream. Nitrogen oxides are air pollutants which are formed as by-products during the decomposition of chlorinated VOCs in plasmas containing nitrogen and oxygen. Results illustrate that the addition of a mixture of DCM and C3H6 resulted in the formation of the lowest concentration of nitric oxide, whilst the total nitrogen oxides concentrations did not increase. A summary of the findings of this work is presented in chapter eight as well as further work. To conclude, the maximum removal efficiency of dichloromethane was achieved in air plasma with the addition of 1000 ppm of propylene and the use of three packed-bed plasma cells in series. The lowest concentration of nitric oxide was formed in this situation.

South African Air Quality Units are continuously undergoing changes, and improving their performance remains a constant endeavour. In addition, these units are also experiencing several challenges in terms of improving communication across the different spheres, accessing air quality data and using the information to support the decision-making required for efficient management of air quality in South Africa. This study investigated the concept of output efficiency within the South African air quality management context. Models that enable efficient resource allocation can be used to assist managers in understanding how to become efficient. There are, however, few models that focus on the output efficiency of the public sector and air quality management units. The primary purpose of the study was to develop a model to predict the extent to which organisational efficiency could be explained by the percentage of man-hours allocated to a range of management activities. In this study, the development of a model using the logistic regression technique is discussed. Data was collected for two financial years (2005/6 and 2006/7) from the air quality officers in the national, provincial and local spheres of government (N=228). The logistic regression model fitted indicates that the proportion of time spent on knowledge management activities contributes the most to the likelihood of an Air Quality Unit being efficient. The resource allocation model developed will ensure that air quality officers allocate resources appropriately and improve their output performance. / Graduate School for Business Leadership / D.B. L.

South African Air Quality Units are continuously undergoing changes, and improving their performance remains a constant endeavour. In addition, these units are also experiencing several challenges in terms of improving communication across the different spheres, accessing air quality data and using the information to support the decision-making required for efficient management of air quality in South Africa. This study investigated the concept of output efficiency within the South African air quality management context. Models that enable efficient resource allocation can be used to assist managers in understanding how to become efficient. There are, however, few models that focus on the output efficiency of the public sector and air quality management units. The primary purpose of the study was to develop a model to predict the extent to which organisational efficiency could be explained by the percentage of man-hours allocated to a range of management activities. In this study, the development of a model using the logistic regression technique is discussed. Data was collected for two financial years (2005/6 and 2006/7) from the air quality officers in the national, provincial and local spheres of government (N=228). The logistic regression model fitted indicates that the proportion of time spent on knowledge management activities contributes the most to the likelihood of an Air Quality Unit being efficient. The resource allocation model developed will ensure that air quality officers allocate resources appropriately and improve their output performance. / Graduate School for Business Leadership / D.B. L.