Abstract: There has recently been growing interest in the study of atmospheric particulate matter, specifically towards improved understanding of the long-term transport and impact of different elements of the lithosphere on atmospheric pollution. Close to the ground level, a fairly thin layer of the lithosphere and atmosphere, on both sides of their interface, serves as the major platform for human life and activity. Both the lithosphere and the atmosphere are mutually responsible for sustaining their natural equilibrium. Investigations related to the studies of atmospheric particulate matter are intended to provide information that is still required for the implementation and the eventual revision of European standard tolerance norms for environmental protection. To this aim, WHO (the World Health Organization) and the EU (European Union) Working Groups on airborne particles are requiring additional information in this field.Airborne particles of heavy metals, especially in overdose, may harm population health in a long or a short term. Our objective in the present study is to describe and compare the presence of heavy metals in the Brussels atmosphere during three days periods including Saturdays, Sundays and Mondays and their possible effect on human health. The heavy metals were divided into three main groups for: “high dangerous elements” (Pb, Sb, Cd and As); “non dangerous and low dangerous elements” (Sn, Cu, Ti, Cs, Bi, Zr, W, Ag, V, Ni and Al) and “micro-elements” (Co, Zn, Mn, Mg and Cr). This study has been carried out during the period extending from September 2002 up to October 2003.