ИСТИНА

Ammonia and nitrate ice core records covering years 1774-2009 were extracted from 182 m ice core drilled in 2009 at Mount Elbrus in the Caucasus, Russia in order to reconstruct the history of atmosphere nitrogen pollution. Ammonia ice core record exhibits a 4-fold rising from pre 1780 to 1990-2010 preceded by a temperate increase from 1774 and 1880 in summer seasons. Summer ammonium growth accelerated for the first time in the early 20th century, and for the second time after 1950, levels reached plateau between 1980 and 2010. This ice core trend is compered with estimates of anthropogenic emissions of NH3 in Europe in the past using state-of-art atmospheric transport (FLEXPART model driven with 0.5°x0.5° ERA-5 reanalysis data) simulations of submicron aerosol. It is found that the ammonium Elbrus ice core trend is in excellent agreement with estimates of past NH3 emissions from south-eastern Europe. Prior to the agricultural activities, ammonium level is ~11-15% of the 1980-2010 values. It is in the lower range of estimates at the global scale of the contribution of natural ammonia emission to total (natural plus anthropic) ammonia emissions. A potential level of nitrate in the Elbrus ice core remained negligible until 1945. The well-marked 3-fold increase observed between 1950 and 1980, followed by levels stabilizing between 1980 and 2010, is in line with estimates of NOx emissions from south-eastern Europe. According to the global distribution of natural and anthropogenic emissions of NOx, nitrate levels in Elbrus ice deposited prior to 1940 represented 26% of those deposited at the end of the 20th century. Study supported by the Megagrant project (agreement № 075-15-2021-599, 8.06.2021)