الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
present time, a large number of the trace elements (e.g. iron manganses, zinc, nickel, copper, cobalt, iodine, fluorine, vanadium...etc) have been recognized as performing functions essential to life and health of living organisms. These essential trace elements are necessary for optimal function of mammalian organisms, for growth, healing, and activity of metalic processes. Trace elements function primarily as catalysts in enzyme systems in the cells. The present study was directed towards the assessment of some trace elements in the ambient air pollution over the city of Alexandria during the period from October 1986 to September 1987. It included a description of the geography of Alexandria, the different activities, the main sources of air pollution and the meteorological data during this period. The sampling station was chosen to be the roof of the Occupational Research Building in Semoha. This site is nearly in the center of the city of Alexandria and hence it is a good representative of pollution over the city. Also, it compromises with the recommended basis for selecting sampling sites.Nine elements; lead, iron, copper, manganese, nickel, cobalt, magnesium, cadmium and zinc, were chosen for this study and three types of dusts have been collected for this purpose (airbone, settled and directional dust). Samples of airbone dust were collected for24 hours, while samples of settled and directional dust were collected monthly. After collection, the three types of dust were analyzed to organic contituents Air Borne Dust. The yearly average concentration of airborne dust was 116.2pg/m3 during the period of study, while the air quality criteria for airborne dust is 60pg/m3, thus harmful effects mayoccur for public health. The highest concentration of dust was during December 1986 (215.6 pg/m3) whereas the lowest one was (77.4 pg/m3 ) was during July 1987.Generally, in the present study, it was found that the concentrations of trace elements in airborne dust were lower than or equal with annual means for most world cities. . For example, the yearly average concentration of lead during the year of study was 0.24 pg/m3 while the air quality criteria for Pb is 0.7 p.g/m3 in SO:16 cities, and the annual me8J1S for urb8J1 air lead in most ~~rope~n cities are in the range of 0.5to 3.0 pg/ m3. ’fhe yearly average concentration of sulfate in airbor:r,c dust in the present study was 18.2 pg/m3 (15.7