Urban–rural differences in mortality during the 2010 heatwave in European Russia

Supplementary material The 2010 summer heatwave in European Russia led to a notable increase in mortality due to extreme heat and associated wildfires. However, the diverse settlement patterns and the uneven impact of the heatwave in European Russia have left many geographical aspects of this event unexplored. For instance, the variations in excess mortality between major cities and smaller urban and rural areas remain unclear. According to our findings, during the 27–33 weeks of 2010, the total number of excess deaths was estimated at 56.0, with nearly 20% of them concentrated in Moscow. The age-standardized mortality rate in cities with more than one million inhabitants exceeded the expected values by 52% during the heatwave, while the excess mortality rate in rural areas was only 17%. The geographical area experiencing the highest excess mortality rate aligned with the zone of the greatest heatwave extent, as indicated by deviations from the climatic norm in temperatures and other measures of thermal stress. The risk of death from this increase in thermal stress more accurately represented by the Heat Index was found to be substantially higher in larger cities of 500,000 or more inhabitants, with the risk of death being especially high in major cities. Notably, air pollution was not found to be a significant modifier of excess mortality. It is important to note that the results obtained may have been influenced by the use of raster-based data from climate reanalysis, which may be expected to underrepresent local urban heat island effects, and consequently to underestimate risk exposure in urban areas.