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.