Reunion Island is a popular tourist destination with sandy beaches, an active volcano
(Piton de la Fournaise), and Piton des Neiges, the highest and most dominant geological feature
on the island. Reunion is known to have high levels of solar ultraviolet radiation (UVR) with an
ultraviolet index (UVI) which can reach 8 in winter and 16 in summer (climatological conditions).
UVR has been linked to skin cancer, melanoma, and eye disease such as cataracts. The World Health
Organization (WHO) devised the UVI as a tool for expressing UVR intensity. Thresholds ranging
from low (UVI 1–2) to extreme (UVI > 11) were defined depending on the risk to human health.
The purpose of the study was to assess UVR exposure levels over three of the busiest tourist sites on
the island. UVR was measured over several hours along popular hiking trails around Piton de la
Fournaise (PDF), Piton des Neiges (PDN), and St-Leu Beach (LEU). The results were compared with
those recorded by the local UV station at Saint-Denis. In addition, cumulative standard erythemal
dose (SED) was calculated. Results showed that UVI exposure at PDF, PDN, and LEU were extreme
(>11) and reached maximum UVI levels of 21.1, 22.5, and 14.5, respectively. Cumulative SEDs were
multiple times higher than the thresholds established by the Fitzpatrick skin phototype classification.
UVI measurements at the three study sites showed that Reunion Island is exposed to extreme UVR
conditions. Public awareness campaigns are needed to inform the population of the health risks
related to UVR exposure.