§ 27. Mr. Spriggsasked the Secretary of State for the Environment in how many areas of the United Kingdom has photochemical smog occurred; whether tests have been made in the St. Helens area of Lancashire; and if he will make a statement.
§ Mr. Eldon GriffithsOnly the Atomic Energy Research establishment at Harwell makes systematic tests for photochemical smog. I have summarised the present position in a statement which, since it is lengthy, I will, with permission, circulate in the OFFICIAL REPORT.
§ Mr. SpriggsIs the hon. Gentleman aware that Dr. John Reay, head of the Government Pollution Laboratories, has made a recent report about photochemical smog found in the South of the country and that he reports that it has reached danger levels on several occasions? I want to know whether tests have been taken in the industrial North or North-West to ascertain the levels of air pollution in towns like St. Helens. Will the hon. Gentleman urge his right hon. Friend the Secretary of State to do 1438 all in his power to reduce the danger of pollution by the greater use of railways in transferring the great heavy loads from our roads to the railways?
§ Mr. GriffithsThe hon. Gentleman has managed to put several questions into one. The answer to his point about the railways has been given already. As for monitoring of the air, I can assure the hon. Gentleman that those measures which are necessary are being taken.
§ Mr. SpriggsOn a point of order. In view of the unsatisfactory nature of the hon. Gentleman's replies, I beg to give notice that I shall seek an early opportunity to raise the matter on the Adjournment.
Following is the information:
Low degrees of various photochemical reactions occur in the atmosphere through the operation of sunlight on natural constituents. These reactions are intensified when man-made pollutants are present and the concentration of oxidants, principally ozone, is an indicator of the intensity. A high concentration of motor vehicle exhaust gases in strong sunlight tends to produce relatively high local levels of oxidants. In the U.S.A., levels in excess of 10 parts per 100 million have been considered evidence of photochemical smog formation, but the causation is not direct and the occurrence of such a level is by no means always accompanied by haze or reduced visibility.On two days during July, 1971, scientists of the Atomic Energy Research Establishment measured ground-level concentrations of photochemically produced ozone at Harwell slightly exceeding 10 parts per 100 million. However, no occurrence in the United Kingdom of anything that might be termed photochemical smog has yet been reported to me. As urban air continues to become cleaner and sunlight penetrates more strongly, photochemical reactions may need closer attention. Research is continuing and I shall be watching the position closely.