Solar UV Radiation in Saint-Denis, La Réunion and Cape Town, South Africa: 10 years Climatology and Human Exposure Assessment at Altitude

Cadet Cadet,Bencherif Bencherif,Auriol Auriol,Belus Belus,Du Preez Du Preez,Portafaix Portafaix,Metzger Metzger,Ncongwane Ncongwane,Brogniez Brogniez,Sultan-Bichat Sultan-Bichat,Coetzee Coetzee,Wright Wright

doi:10.3390/atmos10100589

Abstract

Solar ultraviolet radiation (UVR) monitoring is important since it depends on several atmospheric parameters which are associated with climate change and since excess solar UVR exposure and has significant impacts on human health and wellbeing. The objective of this study was to investigate the trends in solar UVR during a decade (2009–2018) in Saint-Denis, Reunion Island (20.9°S, 55.5°E, 85 m ASL) and Cape Town, South Africa (33.97°S, 18.6°E, 42 m ASL). This comparison was done using total daily erythema exposure as derived from UVR sensors continuously at both sites. Climatology over the 10-year period showed extreme UVR exposure for both sites. Slight changes with opposite trends were found, +3.6% at Saint-Denis and −3.7% at Cape Town. However, these two sites often experience extreme weather conditions thereby making the trend evaluation difficult. Human exposure assessment was performed for hiking activities at two popular high-altitude hiking trails on the Maïdo–Grand Bénare (Reunion) and Table Mountain (Cape Town) with a handheld radiometer. Extreme exposure doses of 64 SED and 40 SED (Standard Erythemal Dose, 1 SED = 100 J.m−2) were recorded, respectively. These high exposure doses highlight the importance of raising public awareness on the risk related to excess UVR exposure at tourist sites, especially those at high altitude.

Highlights

The effects of ultraviolet radiation (UVR) on humans are well known today and depend on several factors including atmospheric variables influencing the amount of surface solar UVR such as cloud cover and altitude, as well as skin phototype which determines the individual risk to excess solarUVR [1]
This study focused on understanding total daily UVR exposure doses in Saint-Denis, Reunion
The most important forcing that drives the annual course of UVR doses is the annual oscillation, with maximum UVR doses during austral summer for UVR doses is the annual oscillation, with maximum UVR doses during austral summer for both both sites but showing a greater amplitude for Cape Town

Summary

Introduction

The effects of ultraviolet radiation (UVR) on humans are well known today and depend on several factors including atmospheric variables influencing the amount of surface solar UVR such as cloud cover and altitude, as well as skin phototype which determines the individual risk to excess solarUVR [1]. The effects of ultraviolet radiation (UVR) on humans are well known today and depend on several factors including atmospheric variables influencing the amount of surface solar UVR such as cloud cover and altitude, as well as skin phototype which determines the individual risk to excess solar. The harmful effects of excess ultraviolet (UV) exposure include sunburn, skin cancer, cataracts, and ocular melanoma [3,4]. 90% of skin-related health impacts are related to UVR exposure [5]. In South Africa, the melanoma rate is stable at 5 and 3 cases per 100,000 persons (computed for a world standard population) for males and females, respectively [6]. For 2006 to 2015, in a male standard population, the increase was 2.7 to 7.1 cases per 100,000 persons and 3.0 to 6.1 cases per

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