THE twenty-second report on atmospheric pollution contains an account of observations for the year ending March 31, 1936 (London: H.M. Stationery Office, 1937. 6s. net). Reviewing the last twenty years, it is concluded that the effort and propaganda of the period have brought about an appreciable reduction in air contamination. This now seems to have ceased, or even changed to a slight rise, probably on account of the increased industrial activity. Again the figures for some London stations are very high, especially for sulphur. Westminster shows some of the highest figures, and compares very unfavourably with some of the industrial areas. In some cases, remarkable improvements have been rendered over a period of years, and the causes deserve scrutiny. The report is cautious in its interpretation, as the difficulty of sampling is obvious. At Burnley a fifty per cent fall has been recorded in ten years—attributed to the removal of a factory. Attention is directed to the high drop at Wakefield in total deposit, from 613 tons per square mile in 1924 to 227 tons in 1935. This may be associated with the persistent efforts made by the authorities there, and shows what is possible when those who wield political power treat seriously the problem of cleaner air. Unfortunately, it is only too rare that in local authorities the will and wish to improve the atmosphere are combined. The most important development recorded is the initiation of an intensive survey in and around Leicester—selected because it is relatively isolated from other industrial areas likely to prove disturbing factors.