People living in cities are exposed to a greater extent, as a consequence of increased industrialization and demands for energy and motor vehicles. Occupational exposure is also an important factor that should be taken into consideration. During the last decade, health effects of air pollution are studied more in developed countries, while more and better environmental
monitoring data are required in order to setup threshold levels. In addition efforts should be intensified by taking the
appropriate measures, in order to reduce the possibility of human pollutant exposure.