The paper presents the data on specific characteristics of chemical pollution of air, soil and drinking water in rural and urban areas of the Irkutsk Region. These data were used as the underlying foundation for the «Information-analytical database: Assessment of the health and environmental situation and identification of high-risk zones in the Baikal Region». In urban areas, the dominant air contaminants are primarily benz(a)pyrene, formaldehyde, particulate matter, and nitrogen dioxide. The quality of potable water that fails to meet hygiene requirements is usually marked in rural settlements because of higher natural content of iron, manganese and anthropogenic pollution by nitrogen compounds. The content of chemical elements in the community soils does not exceed the maximum permissible concentrations. However, in the non-ferrous industrial zones there are areas of technogenic pollution where background levels of pollutants are significantly higher. Levels of aggregate risk to public health under the influence of chemicals polluting the environment (air, potable water, topsoil) have been calculated. It has been established that a significant contribution to the systemic toxicity is made by chemicals that people inhale. In the urban areas, the risk of exposure to systemic toxic effects of chemicals through inhalation ranks as very high. The pollution levels in the cities of Bratsk, Irkutsk, Usolye-Sibirskoye, and Shelekhov are found to be record high in terms of cumulative health risks. The aggregate risk in the rural areas of the region corresponds to the allowable level.Keywords: Irkutsk Region, chemicals, pollution, environment, the aggregative health risk.