ИСТИНА

In order to reconstruct the history of aerosol concentration in the atmosphere in Europe and Middle East we have studied the ice cores from Mount Elbrus in the Caucasus, Russia. The 182 m long West Plateau (WP) and the 96 m East Summit (ES) ice cores were drilled in 2009 and 2020 respectively. WP ice core provided a record of aerosol concentration for the period 1748-2009 with seasonal resolution. Due to winds and snow redistribution, there is a significant loss of winter accumulation at the ES. Here we present data on the chemical composition (NH 4 + , Ca 2+ , SO 4 2- , NO 3 - ) of both ice cores over the past 250 years, including the pre-industrial and industrial periods. The content of Ca 2+ in the Elbrus ice cores depends on mineral dust emissions from the arid regions of Northern Africa and Middle East. Dust concentrations prominently increase over the past 200 years confirming the recent trend in temperature and precipitation in the source regions leading to increase in droughts frequency. Anthropogenic SO 4 2- levels show a 6- and 7-fold increase from 1774- 1900 to 1980–1995 indicating much later onset and a less pronounced decrease in the sulfur pollution over the last 3 decades when compared to the Alps. The Elbrus NH 4 + ice-core record indicates a 4-fold increase from prior to 1780 to 1990-2020. The well-marked 3-fold increase also seen for NO 3 - between 1950 and 1980 followed by a stabilization of levels between 1980 and 2020. Study supported by the Megagrant project (agreement № 075-15-2021-599, 8.06.2021)