The purpose of this work is to obtain biodiesel from waste oil, through the transesterification process, in order to evaluate the SOx emissions generated by the combustion thereof. This procedure was carried out in the boiler, with the help of an emission analyzer equipment known as Bacharach, and thus a comparison of the emissions, both for biodiesel created from waste oil, and for the ACPM. The purpose is to look for alternatives that generate emissions lower than traditional fuels, taking into account that these are known as compounds emitted into the atmosphere in the form of gas during the burning of fuels and the processing of minerals, which in turn generate an impact in the same. During the evaluation it was possible to show that the SOx emissions in the combustion of ACPM were lower than those emitted by biodiesel, obtaining 15 ppm and 360 ppm respectively, presenting a negative impact on the atmosphere due to the increase of SOx emissions, reason for which a second experiment was carried out, which yielded much lower values ​​of emission compared to the first experiment, due to the change of concentrations of the reagents.