Disputas: Li Liu

Prøveforelesning

Bedømmelseskomité

Prof. George Kallos, School of Physics, University of Athens
Dr. Hilde Fagerli, Air pollution Section, Norwegian Meteorological Institute
Prof. Frode Stordal, Department of Geosciences, University of Oslo

Sammendrag

Tropospheric ozone (O₃) is one of the most important trace gases in the atmosphere. Ozone is harmful both to human health and vegetation, and it is also directly contributing to global warming. Surface ozone levels have increased by more than a factor of two from the beginning of industrialization, due to increased anthropogenic emissions from fossil fuel combustion and biomass burning. Two highly polluted regions, China and the Po Basin (Italy), were chosen for our photochemical studies, and the results were interpreted to gain better understanding of the tropospheric ozone production and evolution over those regions. This work has been carried out at the Department of Geosciences, University of Oslo.

China has the largest population in the world and one of the fastest growing economies. Concurrent with the economic expansion is a tremendous need for energy. The intensive use of the fossil fuels gives rise to air pollution problems, such as acid rain, photochemical smog etc. The sub-area of Central and Eastern China, which has the highest population density and emissions, is found to be the largest contributor to ozone production in China and acts as a net source for the global ozone budget. The Po basin in northern Italy is one of the most densely populated and strongly industrialized regions of Europe. This region receives large emissions from the Milan metropolitan area, and both the topography and the weather are favorable during the summer time for ozone production. The study shows the importance of the origin of the polluted air masses as well as the path followed over different types of landscape. The study also shows that biogenic emissions are not important for the O₃ and HCHO peaks in the Po valley. The opposite is true for the emissions from traffic and industry.

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