Biologically effective solar ultraviolet exposures and the potential skin cancer risk for individual gold medalists of the 2020 Tokyo Summer Olympic Games

Abstract

Personal solar ultraviolet radiation exposure models were developed for 144 Olympic events scheduled outdoors from across the 33 sport disciplines that will compete in Tokyo between 24 July and 9 August 2020. Ambient exposure models were developed from existing atmospheric parameters measured over Tokyo (35.7°N 139.7°E) and were used to weight erythemally effective solar ultraviolet exposure to gold medalists, taking into account body posture and expected protection by competitor's clothing which was assessed in comparison to respective medalists of the 2016 Rio Olympics. Individual exposure models consider the ultraviolet surface albedo (lawn, concrete, water or sand) and timing of daily events held within Olympic venues. Exposure assessments are presented, including assessments of all preliminary rounds and qualifiers. Within scheduled outdoor events, we award first place (representing the highest and most harmful UV exposure) to the women's tennis singles (1680 J/m²), second to men's golf (1530 J/m²) and third to the men's cycling road race (941 J/m²) for the highest expected erythemally effective solar ultraviolet radiation exposures of the 2020 Tokyo Games. The highest expected solar ultraviolet exposures for nations expected to win greater than three gold medals among the outdoor events were found to occur in athletes from Kenya followed closely by the United States and Hungary. Gold medalists from South Korea were found to demonstrate the highest level of sun protection due to clothing at the 2016 Rio Games, and are thus expected to receive the greatest relative reduction in erythemally effective exposure during the 2020 Tokyo Games.

Keywords: Olympics; Sport; clothing; skin cancer; ultraviolet.

Figure 1.

Tokyo (yellow circle) and surrounding sites (red circles) of outdoor events scheduled for the 2020 Olympic Games.

Figure 2.

(a) Ambient ultraviolet irradiance for Tokyo city (35.7°N 139.7°E) from 24 July to 9 August 2020 modeled for an AOD of 0.45, total ozone column of 272 DU, 2 Okta cloud cover and a lawn surface albedo of 3%. (b) Scheduled outdoor exposure periods for gold medal place winners in events likely to receive the highest UV exposure for each of the 20 outdoor Olympic sport categories listed in Table 1.

Figure 4.

Total erythematic ultraviolet exposure of 144 gold medal events scheduled to compete in an outdoor environment arranged by sport category for the 2020 Tokyo Summer Olympics. Events within categories (colored segments) correspond with listed event numbers provided in column 2 of Table 1 and are arranged here from bar base (event no. 1 within category, e.g. Athletics men’s 100 m) to bar top (terminating event no. within category). Athletics includes 48 outdoor events, terminating with Heptathlon (no. 48, light gray), while sports such as golf include only two events (men’s stroke – dark green; women’s stroke – light green) .

Figure 3.

Spot locations for assessing the Normalized Clothing Factor (NCF): NCFsite(head) = 2; NCFsite(navel) = 1; NCFsite(forearm) = 1; NCFsite(shin) = 1. For this model the NCF = 0.2 (shin protected by clothing).

Figure 5.

Calculated total erythematic ultraviolet exposure with (yellow) and without (dark) expected protection by clothing (measured NCF) for each of the leading individual exposure events of the 20 outdoor sports scheduled for 2020 Tokyo.