The peculiarities of the aerosol particle deposition in the human respiratory tract depending on the particle size and the breathing rate have been analysed. The highest deposition efficiency (0.85) was determined for the largest particles (10-20 µm) and the lowest efficiency (0.28) for the finer particles (0.3 µm). The heavy metal amount penetrating into the human respiratory tract at a different breathing rate in Vilnius has been evaluated. It has been determined that the deposition

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... of heavy metals in the human respiratory tract changes insignificantly with the increase in the breathing rate, and when the breathing rate increases threefold (from 10 to 30 L min −1 ) the efficiency decreases only by about 10%. On the average, about 60% of heavy metals in the inhaled air penetrate into the respiratory tract. The comparison of Pb, V, and Zn concentrations in Vilnius city with those at the Preila background station has shown that they differ up to two times. It means that the contribution to the pollution with these metals in Vilnius city is insubstantial, and there is no considerable threat to human health.