With special regard to the situation in the Federal Republic of Germany the general air pollution with sulphur dioxide, nitrogen dioxide, carbon monoxide and suspended particulate matter is surveyed, and increased pollutant concentrations during smog episodes are demonstrated. Emissions and ambient air concentrations of the four substances and their trend over two decades are shown in summarizing Tables. The spatial and temproal distributions of air pollutants are described and discussed. Several Tables contain limit values of smog forming substances in the Federal Republic of Germany and in other countries. The Smog Alert System in Germany with alert stages and consequences is presented. The effects of smog on human health are interpreted with respect ot cited literature. In spite of strongly reduced emissions (with exception of nitrogen dioxide) and of mean ambient air concentrations, during smog episodes maximal values of sulphur dioxide and suspended particulate matter occur in hygienic critical concentrations. Long-range transport is one of the sources of this situation.
