After facilities for reduction of dust emissions were deemed to be state-of-the-art worldwide, beginning in 1970, tests were performed in Germany for the reduction of emissions of SO2 and x. The first measures for the use of combustion technology to limit nitrogen oxide development during combustion were performed, which resulted in lower NOx emissions at new sites.

The requirement targets “limitation of NOx emissions” for oil, gas and brown-coal firing systems were achieved using solely combustion technology measures, i.e. without resorting to downstream processes. Secondary measures are required for hard coal and heavy oil-firing systems, due to their higher burning temperature, which will be addressed in this VGB-Standard.