ABSTRACT

Organic substances are a main source of air pollution. It has been estimated [79] that 1.8 million chemical compounds (both organic and inorganic) have been synthesized by man, and 250,00 new ones are devised each year. About 3000 of these are known to be carcinogenic, and 20,000-30,000 are industrially produced. Today the chemical industry worldwide makes more than 50,000 harmful organic compounds, and over 1000 new harmful ones are synthesized each year [184]. Of these only a small number have been investigated for carcinogenic or mutagenic properties. In the United States 6 billion pounds of vinyl chloride and 10 billion pounds of dichloroethylene are produced annually whose carcinogenic effect has been definitely proved [184] . Many pesticides used all over the world are carcinogenic and mutagenic [73] . Up to 80% of the air pollutants at industrial centers are carcinogenic; the number of carcinogenic substances is particularly large in the wastes of petrochemical works [109]. The air over cities in industrial countries is the most polluted [41]. For example, in the air over Los Angeles (U.S.A.) 60 harmful pollutants (alkanes, alkenes, acetylenes, and aromatic derivatives) have been identified, which have not only a toxic but also a photochemical effect [80].