Abstract: In this process for the selective noncatalytic reduction of the emission of pollutants from oil-fired boiler plants, chemical compounds which affect the combustion process are admixed, in solutions miscible with the liquid fuel, in metered amounts to the liquid fuel or to the combustion air, among these compounds being salts of organic acids, such as naphthenates, octoates, tallates, salts of sulfonic acids, saturated or unsaturated fatty acids, such as oleic acid, and tall oil, with metals from the group of K, Ba, Mg, Ca, Ce, Mn, Fe; rare earth metals; organometallic compounds, such as carbonyl compounds, mixed cyclopentadienylcarbonyl compounds, or aromatic complexes of the transition metals Fe or Mn. For the purpose of minimizing the NO.sub.