Wolfgang Jaeschke – författare

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 East this lack of sufficient water coupled with the high growth rates of pop­ ulation constitutes serious water problems which has become e real political issue. The German-Arabic Society for Environmental Studies, Frankfurt, in co-opera­ tion with the Centre for Environmental Studies at the University Frankfurt has raised up this problems for a scientific discussion. With the Symposium on "Water of the Middle East and North Africa: Resources, Protection and Management" in Frankfurt on November 25 and 26, 2002 a platform was created, which enabled participants - scientists and politicians - from twelve countries to discuss the water problems facing the region. It was the intension of the organisers to deepen the knowledge about the hydrologic regimes, to increase our understanding of the complex integrated processes and to draw the necessary conclusions with regard to an integrated sustainable water management.

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 East this lack of sufficient water coupled with the high growth rates of pop­ ulation constitutes serious water problems which has become e real political issue. The German-Arabic Society for Environmental Studies, Frankfurt, in co-opera­ tion with the Centre for Environmental Studies at the University Frankfurt has raised up this problems for a scientific discussion. With the Symposium on "Water of the Middle East and North Africa: Resources, Protection and Management" in Frankfurt on November 25 and 26, 2002 a platform was created, which enabled participants - scientists and politicians - from twelve countries to discuss the water problems facing the region. It was the intension of the organisers to deepen the knowledge about the hydrologic regimes, to increase our understanding of the complex integrated processes and to draw the necessary conclusions with regard to an integrated sustainable water management.

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. The various steps within gas-to-particle conversion are constantly interacting with condensation processes, which are caused by the tropospheric water content. Thus in addition to the gaseous state, a liquid and solid state exists within the troposphere. The solid phase consists of atmospheric conversion products or fly ash and mineral dust. The liquid phase consists of water, conversion products and soluble compounds. The chemistry occurring within this system is often referred to as hydrogeneous chemistry. The chemist interprets this term, however, more strictly as reactions which occur only at an interphase between phases. This, however, is not always what happens in the atmosphere. There are indeed heterogeneous processes such as reactions occurring on the surface of dry aerosol particles. But apart from these, we must focus as well on reactions in the homogeneous phase, which are single steps of consecutive reactions running through various phases.

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. The various steps within gas-to-particle conversion are constantly interacting with condensation processes, which are caused by the tropospheric water content. Thus in addition to the gaseous state, a liquid and solid state exists within the troposphere. The solid phase consists of atmospheric conversion products or fly ash and mineral dust. The liquid phase consists of water, conversion products and soluble compounds. The chemistry occurring within this system is often referred to as hydrogeneous chemistry. The chemist interprets this term, however, more strictly as reactions which occur only at an interphase between phases. This, however, is not always what happens in the atmosphere. There are indeed heterogeneous processes such as reactions occurring on the surface of dry aerosol particles. But apart from these, we must focus as well on reactions in the homogeneous phase, which are single steps of consecutive reactions running through various phases.