Annual concentrations of SO₂ and PM have decreased in Kraków since the early 1970s by 70-80%. At present, both pollutants still show the same seasonal pattern as in the 1970s, with maximum in winter and minimum in summer. PM10 is the most abundant air pollutant reaching permanently the levels far behind the allowed values. Since 2001, an increasing concentration trend has been observed, while the concentrations of SO₂ usually stay below the allowed limits. The concentrations of NO₂ and O₃ have been measured since 1992. The allowed values of NO₂ are exceeded only in the high-traffic site (about 10 times per year) while the levels of O₃ are usually within the allowed limits. Studies concerning plant and animal contamination with heavy metals (Cd, Pb, Fe, Zn, Cu) show that cadmium is at present the main danger. In spite of a significant improvement of aerosanitary conditions in Kraków after 1990, negative long-term effects of air pollution on human health can be still observed, especially in children.