Freshwater is the most precious and valuable natural resource essential for all kind of life on the land surface. Especially man depend on the availability and quality of the water, it is vital for the socio-economic growth of societies and nations as well as for the sustainability of the environment. Freshwater resources are not distrib uted in an equal way over the continents. Regions with surplus facing areas with shortage or even lack of water. From their nature arid and semi-arid areas are char acterized by scarcity of water with all the affiliated unfavourable attributes. In the Middle...

Rapidly increasing interest in the problems of air pollution and source-receptor relationships has led to a significant expansion of knowledge in the field of atmospheric chemistry. In general the chemistry of atmospheric trace constituents is governed by the oxygen content of the atmosphere. Upon entering the atmosphere in a more or less reduced state, trace substances are oxidized via various pathways and the generated products are often precursors of acidic compounds. Beside oxidation processes occurring in the gas phase, gaseous compounds are often converted into solid aerosol particles....