Mobile measurements of winter SO 2 levels in London, 1983–1984

Abstract

Regular mobile surveys of SO 2 levels in Central London were made with two vehicles during the winter of 1983–1984. The SO 2 concentrations observed showed a strong inverse dependence on geostrophic wind speed and were higher at low temperatures. If the results are extrapolated to the whole winter, a seasonal mean roadside SO 2 concentration is obtained which is substantially larger than that from fixed point monitors. It is suggested that on busy urban roads a daytime mean of 50 μg SO 2 m −3 may come from motor vehicles.