الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Air pollution is a major problem facing all nations of the world. It may be defined as any atmospheric condition in which substances are present at concentrations high enough above or low enough below their normal ambient levels to produce a measurable effect on man, animals, vegetation or materials. Major emission sources of air pollutants are transportation, power generation, refuse burning, industrial and domestic fuel burning and industrial processes (Seinfeld, 1986)1.
Air pollutants do not remain confined near the source of emission, but spread over distances, transcending natural and political boundaries depending upon topography and meteorological conditions, especially wind direction, wind speed and vertical and horizontal thermal gradients (Smodis and Bleise, 2000)2.
Increasing industrialization and human activities intensify the emission of various pollutants into the environment and introduce various harmful sub-stances into the atmosphere. Air pollution is aesthetically offensive and can be a genuine health hazard to humans as well as to plants. The sampling use of plant tissues has long been shown to be an effective indicator of atmospheric pollution (Goodman and Roberts, 1971)3. Vegetation is an effective indicator of the impact of a pollution source in its vicinity, because most plants have the ability to accumulate heavy metals so that their metal levels are much higher than those in the air. Further, the effect observed is a time-averaged result, which will be more reliable than that obtained from direct determination of the pollutant concentrations in air for a short period. Hence, analyzing plant tissues can give better results in terms of sensitivity and reproducibility (Lau and Luk, 2001)4.
Plants are especially useful as biological indicators to assess air pollution because of their wide distribution (Kardel et al., 2010)5. Several plant species have already been applied as bioindicator (Aksoy et al., 20006; Celik et al., 20057; Baycu et al., 20068; Mingorance and Oliva, 20069; El-Darier and Ahmad, 201210). Heavy metals and inorganic contaminants can be emitted into the environment by transportation, industry, fossil fuels (Celik et al2005)7. The settling contaminants can deposit on the surface of leaves from air (Salma et al2001)11, and increase their harmful effects on human health (Temesi et al., 2003)12.