Changes in the ecological situation over the last 35 years, corresponding to the period of economic transformations in Russia, were considered using the data of state statistics on atmospheric air pollution and morbidity of the population in St. Petersburg. Two stages of changes in anthropogenic impact on the environment were highlighted. During the first stage (1993-2008) the total volume of pollutant emissions in the atmospheric air decreased threefold due to the decline in industrial production in the city. The second stage (from the beginning of 2009) is characterized by an increase in the total amount of emissions more than twofold, caused by a significant growth the role of vehicles as a polluter of the air. During the period under review, the incidence of the population has increased significantly too. This manifested itself especially clearly in the period 2005-2009 when the primary incidence of the population in St. Petersburg increased by 1,4 times. During the period under review, there were significant changes in the incidence of the population in the districts of St. Petersburg. It was demonstrated that in the industrial Kolpinsky and in the Tsentralny districts the primary morbidity of the child population rose sharply in the late 1990s and, according to this indicator, these districts moved from the 10^th and 11^th places to the first places in the city. Based on the results of the non-carcinogenic health risks assessment associated with the inhalation of priority pollutants into the body, it was concluded that the greatest incidence of the population among the administrative districts of the city could be expected in the Tsentralny district, and the Kolpinsky district will move to the sixth place on this indicator. The lowest risk of development of non-carcinogenic effects during the combined effect of atmospheric pollutants is in the Petrodvortsovy district. It is pointed out the need to take measures to reduce the man-caused (transport) load on the urban environment in districts with high rates of non-carcinogenic health risks. The adoption of priority measures in the Tsentralny District of St. Petersburg is justified.