| Synopsis: |
In 1952 a particularly severe smog epsiode in London drew attention to their effects on human health, and it was estimated that some 4000 excess deaths occurred as a result of that pollution. The original studies of the effects of the London smogs identified two pollutants, sulphur dioxide and smoke particles, as the ones most likely to have been responsible for the excess number of deaths. However, more recently, as motor vehicles have become the major sources of urban particulate pollution, oxides of nitrogen have become the main associated urban pollutants. This report looks at the effects of particles, discussing the sources and their chemical and physical properties, the method by which they are measured and monitored, and the concentrations currently found in the UK. The report discusses the evidence and concludes by recommending an Air Quality Standard for the United Kingdom intended to reduce the magnitude of such effects. |