§ 59. Mr. John Hallasked the Secretary of State for Education and Science, what tests of air pollution at ground level are made in London during fogs; when the last test was made; and whether this test showed an increase in the concentration of sulphur dioxide in fog conditions.
§ Mr. HoggDaily measurements are made at some 150 sites in Greater London and at selected sites additional measurements are made in fog. The last such additional measurements were made in January, 1964. The concentration of sulphur dioxide was much greater than that in normal conditions but there is no evidence that London fogs are becoming worse in this respect.