Letter: Thinner ozone layer

Sir: Whilst Charles Arthur is right to report ongoing damage to the ozone layer ("Ozone layer over western Europe falls by two-thirds", 3 December), it really is mischievous to say that the gradual thinning of this layer has increased the occurrence of skin cancer due to over- exposure to ultraviolet rays. There is simply no evidence for this.

Monitoring of ultraviolet radiation reaching the Earth's surface by agencies such as the National Radiological Protection Board in this and other European countries is showing no long-term upward trend.

The incidence of skin cancer is certainly rising and we can debate why this might be. What it is not due to, however, is changes in ambient ultraviolet consequent to ozone depletion.

Professor BRIAN DIFFEY

Regional Medical Physics Department

Newcastle General Hospital