On the relation between changing meteorological circumstances and the decrease of the sulphur dioxide concentration around Rotterdam

Due to the ever growing anxiety about the effects of air pollution on the health of the inhabitants of industrialized regions, every decrease of the average concentration of a pollutant such as SO2 is welcomed, by the authorities as well as by the public. In various cases such a decrease may be attributed to improved methods to reduce the escape of noxious gases but sometimes meteorological circumstances play an important role. During the last six winters there was an almost continuous decrease of the SO2 content of the air in the region of Rotterdam. Although an improvement of some industrial processes may have helped to bring about this decrease, it can be shown that meteorological circumstances contributed significantly