W środowisku, w którym żyjemy znajdują się miliony substancji chemicznych, z których wiele to substancje toksyczne. Jednakże związki chemiczne w przyrodzie pełnią różne funkcje, zarówno pozytywne, jak i negatywne. W pracy przedstawiono rolę i znaczenie substancji zapachowych w komunikowaniu się roślin.
The article presents the changes in a chemical quality of air and in the olfactory noxiousness levels caused by the application of Effective Microorganisms (EM) contained in the EM-FarmingTM preparation. The preparation was applied in selected facilities considered to be substantial sources of odorants. The research was conducted in a wastewater treatment plant, a composting plant, at a waste landfill and in a poultry house. Within the framework of the project, basic indicators of the olfactory effect, namely ammonia and hydrogen sulphide, were examined along with carbon dioxide, the latter used as the indicator of the intensity of biochemical processes, including the odorigenic ones. Moreover, the sensory assessment method was employed to characterise the olfactory effect organoleptically. The analysis of the results showed that the negative impact of the facilities on the surrounding area changed within a limited range of values. No clear upward/downward trends shown by the examined gases were observed. For each facility a different and unique pattern of the changes in the concentrations of NH3, H2S and CO2 as well as in odour intensity was detected.