Ambient ultraviolet radiation and skin cancer incidence.

Environmental ultraviolet radiation (UVR) was monitored for one year at Durham (latitude 55 degrees N) using a stationary, horizontal sensor, and a sensor rotating in a vertical plane designed to simulate the random motion of subjects outdoors. From these data it was possible to calculate the personal solar UVR representative of populations living at different geographical locations and experiencing varying patterns of cloud cover. The conclusion was that present monitoring programmes that record ambient solar UVR in a horizontal plane at different locations as input data to studies on the epidemiology of skin cancer are appropriate for obtaining a relative estimate of the population exposure in locations with different climatic conditions, providing, of course, that the outdoor exposure habits of different populations are comparable.