§ Mr. Formanasked the Secretary or State for the Environment what action he proposes to take to ensure that smoke levels in London, especially on the busier streets, do not exceed the WHO limit of 40 microgrammes per cubic metre daily average.
§ Mr. Denis HowellThe figure to which the hon. Member refers, which appears in WHO Technical Report No. 506, is an annual, not a daily, average. It is recommended as a long-term goal subject to review as more information becomes available. The objective has not been adopted officially in this country but was achieved at 80 per cent. of monitoring sites in London in 1975–76. The WHO Report also states that the condition of sensitive groups such as 405W bronchitic patients seemed to be aggravated by pollutant levels of 250–500 microgrammes per cubic metre of sulphur dioxide and 250 microgrammes of smoke occurring together over 24 hours. The operation of the Clean Air Acts, especially domestic smoke control, has made such conditions rare in London.