The most wide-spread heavy metal aerosols, contaminating atmospheric air are the lead ones.
Their concentrations in atmospheric air vary depending on the number and the capacity of the sources – metallurgical plants, and on the number of vehicles and the type of consumed petrol.

Impact on human health
Lead gets into the human body mainly through the respiratory (20 – 60%) and through the gastrointestinal (10% for adults and about 40 – 50 % for children) tracts. Its toxic effects are due to the inactivation of the SH-groups or to competitive substitution of essential metal ions in the molecules of a number of vital enzymes. Thus many organs and systems are found to be vulnerable to the harmful effect of lead. The reproduction processes may as well be affected.
For population exposed for a long time to low concentration lead aerosols, disorders of the haemoglobin synthesis, erythropoiesis, and nervous system are mainly witnessed, as well as hypertension. Lead is a cumulative poison with prolonged elimination period (from several days to 25 years).

The LV for lead aerosol content in the atmospheric air was set with Regulation No. 9 (State Gazette No. 46/1999, amended and supplemented, SG No. 86/2005). - average annual LV for lead aerosols (for 1 calendar year) - 0,5 mg/m3.