The results of scientific research with interdisciplinary assessment of the effect of main factors acting on the state of forest ecosystems are the basis of development of special programs for the recovery, maintaining and improving their status, both at the global and regional scale, as well as national and local scale. Therefore, for the studies to this end are very necessary. Scientific investigations in the forest ecosystem "Hâncești Forest" on atmospheric deposition have provided quantification of the influence of atmospheric pollutant inputs under the environment factors - constituents of the ecosystem. It has been established that the impact of pollutants on the forest and the soil directly correlates with the quantity and quality of rainfalls. Comparative analysis of the results obtained (2011-2014), showed great variability in the amount of rainfall and mineral ions concentration of atmospheric depositions, this one between 422 and 604 mm. 2015 amount of rainfall fell over the summer was the only 70 mm or 30% of the norm, and their average values of pH evolved between 5.8-6.7. As a rule, the waters prevailed with weak acid and neutral (pH = 5.61-7.5), which quote reaches 56% of total rainfall dropped, but it is alarming that "acid" rain (pH < 5.6) accounted for 20 percent.           It should be noted, that the dynamics of emissions of SO2, NOx (pollutants with acidifying and eutrophication impact) from stationary and mobile sources at both Europe and for the Republic of Moldova, indicate a growing impact over time in emissions of NOx. This increase is due to the intake of auto transport (from 12.5 kilo tones (2007) until 21.1 in 2014. However, estimating the impact of air pollution on the forest ecosystem "Hancesti Forest" by wet and dry precipitation indicates an acidifying effect with low risk being at the level 3.1 kg N/ha and 4.9 kg S/ha .