Changes in solar energy reaching the earth: a study of total solar, UVA and UVB radiation in a highly polluted Northern Italian area

The environment can cause and maintain a number of dermatoses, such as contact dermatitis and photodermatitis. We have recently noted a greater incidence of photodermatitis, even in subjects who declared that they had had no excessive photo exposure and/or who had tolerated normal exposure to sun in previous years. This indicated a possible change in solar irradiation. Consequently, we undertook a study of the climatic and meteorological conditions in northern Italy over the last 12 years (1978-1990). The following variables were considered: air temperature, relative humidity, solar UVA and UVB radiation, both scattered and direct. Annual data show that there has been an increase in scattered solar energy but no change in direct irradiation. There has been a clear reduction in humidity and slight increases in temperature. This is the first Italian report of climatic variations, especially of scattered sun irradiation.