Increased UV exposure in Finland in 1993

Area of Science:

• Atmospheric Science
• Ozone Layer Depletion
• UV Radiation Studies

Background:

• Exceptionally low total ozone levels (up to 40% below normal) were observed over Northern Europe during the winters and springs of 1992 and 1993.
• Ozone depletion in 1993 persisted until the end of May, leading to a significant increase in biologically effective ultraviolet (UV) radiation.

Purpose of the Study:

• To evaluate the UV exposure of the Finnish population during periods of low total ozone.
• To quantify the increase in biologically effective UV radiation due to ozone depletion.

Main Methods:

• Measurements of erythemal UV radiation on horizontal surfaces were compared to model calculations for average ozone levels.
• Theoretical calculations were performed for both erythemal and carcinogenic UV radiation on vertical surfaces.
• UV reflection from snow was considered for facial UV dose estimations in Northern Finland.

Main Results:

• The increase in measured erythemal UV radiation was, on average, 10% from April to May 1993, with a maximum increase of 34%.
• Theoretical calculations indicated a 8-13% annual increase in erythemal and carcinogenic UV radiation for vertical surfaces in Finland during 1993.
• Snow reflection significantly increased facial UV doses in Northern Finland.

Conclusions:

• The 1992-1993 ozone depletion events in Northern Europe resulted in substantial increases in biologically effective UV radiation.
• The Finnish population experienced significantly elevated UV exposure, particularly in 1993, with snow cover exacerbating facial doses.
• These findings highlight the health risks associated with severe ozone depletion events.