Ozone pollution: a 'hidden' environmental layer for athletes preparing for the Tokyo 2020 Olympic & Paralympics.

Environmental factors such as climate and pollution form a key part of major championship preparation.1 The Tokyo 2020 Olympic/Paralympic Games will present a unique combination of high thermal and ozone stressors. Japan has the highest levels of ozone in the Organisation for Economic Co-operation and Development; with annual peak values (65–73 ppb) aligning with the Olympic/Paralympic schedules (23 July to 5 September 2021). Herein, we provide a synopsis of the effects and potential mitigating factors of air pollution on athlete health and performance. We integrate these recommendations with established guidelines on heat,1 to provide guidance for the 2020 Summer Olympic/Paralympic Games and beyond (figure 1). Figure 1 Summary of how to concurrently prepare to compete in the heat with high levels of ozone. An athlete performance and health checklist for science and medicine staff. Air pollution is a heterogeneous combination of both particles and gases that varies by location, time and season. Ground level ozone is a gas pollutant resulting from a chemical reaction between nitrogen oxides and hydrocarbons in the presence of ultraviolet radiation.2 3 Due to ozone’s positive …