To ask the Secretary of State for the Environment if he will give the results of stratospheric ozone depletion measurement over the United Kingdom and the northern hemisphere during March; and if he will make a statement on the significance of the results.
Measurements of total ozone made at Lerwick and Camborne during March were between 10 and 13 per cent. below the long-term average for the month. This compares with measurements in February over 20 per cent. below the long-term average which I reported in my answer to the hon. Member for Islington, South and Finsbury (Mr. Smith) on 11 March. These results reflect conditions over a wide area of the northern hemisphere where ozone levels have been affected by meteorological conditions and possibly the impact of the Mount Pinatubo volcanic eruption, as well as any contribution from ozone depleting substances.The risk of an Arctic ozone hole developing this year is now rapidly diminishing as the stratosphere warms up. The reductions in ozone this year have not resulted in any increase in ground level ultraviolet radiation which is within the range expected for the time of year. There are no implications for health. While we rely on stratospheric ozone to absorb the potentially damaging ultraviolet radiation from the sun, radiation is naturally very low at this time of year, even on clear days, because of the low angle of the sun. Analysis of measurements made this year will be included in the next report of the Department's stratospheric ozone review group, due to be published in the autumn.