This report presents tabulated monitoring results from the National Air Quality Monitoring Network for city stations and street stations in all regions for the calendar year 1991, the summer of 1991, the winter of 1990-1991 and the period 1 April 1990 - 31 March 1991 (tropical year: EC reference period); SO2, black smoke (= suspended matter measured by the black smoke method), NO2, NO, NOx (=NO2+NO), O3, Ox (=NO2+O3) and CO are the components concerned. Furthermore, for every station in the network it was checked whether Dutch limit values were exceeded. Nationally only exceedance of the limit value for black smoke was observed. The limit value for NO2 was possibly exceeded at the station Utrecht Wittevrouwenstraat. However, regarding the NO2 measurements this station did not comply with the requirements stated within the framework of the Dutch Law regarding Air Pollution. In 1991 almost no summer smog episodes occured. The draft limit value for O3 was not exceeded. A detailed discussion of the results can be found in the Air Quality Annual Report 1991 (in Dutch) of the National Institute of Public Health and Environmental Protection (RIVM) in the Netherlands (in preparation).