Athletes' exposure to air pollution during World Athletics Relays: A pilot study

Abstract

Potential adverse consequences of exposure to air pollutants during exercise include decreased lung function, and exacerbation of asthma and exercise-induced bronchoconstriction. These effects are especially relevant for athletes and during international competitions, as they may impact athletic performance. Thus, assessing and mitigating exposure to air pollutants during exercising should be encouraged in sports venues. A comprehensive air quality assessment was carried out during the World Relays Yokohama 2019, in the stadium and the warm-up track. The pilot included on-line and off-line instrumentation for gaseous and particulate pollutants and meteo- rological parameters, and the comparison with local reference data. Air quality perception and exacerbation of symptoms of already-diagnosed diseases (mainly respiratory and cardiovascular) were assessed by athletes by means of questionnaires during training sessions. Median NO2 concentrations inside the stadium (25.6–31.9 μgm−3) were in the range of the Yokohama urban background, evidencing the impact of urban sources (e.g., traffic) on athletes' exposure during training and competition. The assessment of hourly air pollutant trends was identified as a valuable tool to provide guidance to reduce atheletes' exposure, by identifying the periods of Inhalation Track and field Respiratory diseases World Athletics 1. Introduction Evidence supports adverse effects from short-term and long-term inhalation of air pollution to the respiratory and the cardiovascular sys- tems (Brook et al., 2002; Pietropaoli et al., 2004; Gauderman et al., 2007; de Prado Bert et al., 2018). Health impacts have been assessed for gen- eral and high-risk populations, and even for general populations performing physical activities such as walking or cycling while com- muting (de Nazelle et al., 2012; Hofman et al., 2018; Luengo-Oroz and Reis, 2019; Qiu et al., 2019; Quiros et al., 2013; Rivas et al., 2014). How- ever, research is scarce on the effects of ambient air pollution on exercis- ing athletes and their athletic performance, who may have greater than average susceptibility and exposure to air pollutants because of the physiological changes that occur during prolonged exercise (Quin et al., 2019). Specifically, there are 3 reasons why athletes are at higher risk from air pollution (McCafferty, 1981): (1) increased ventilation during exer- cise; (2) a greater fraction of air is inhaled through the mouth during ex- ercise, effectively bypassing the normal nasal filtration mechanisms; and (3) the increased airflow velocity carries pollutants deeper into the respiratory tract. Furthermore, pulmonary diffusion capacity in- creases with exercise (Turcotte et al., 1997; Stokes et al., 1981; Fisher and Cerny, 1982; Flaherty et al., 2013), increasing gaseous pollutant in- take. Nasal mucociliary clearance, impaired in long-distance runners, may also contribute to the higher susceptibility of endurance athletes given that pollutants which are normally cleared from the respiratory system, are instead absorbed (Atkinson, 1987). Even though research is scarce, studies on the relationship between air quality, athletic performance, and respiratory symptoms encourage pursuing further investigations. Lichter et al. (2015) assessed the effects of particulate air pollution on soccer players in German stadiums, re- vealing that performance was reduced under poor air quality condi- tions. Bos et al. (2011) and Quin et al. (2019) observed that the health benefits of active commuting could be negatively influenced by exercis- ing in polluted environments, while Rundell and Caviston (2008) re- ported that the acute inhalation of PM1 at concentrations in the range of many urban environments could impair exercise performance. Carlisle and Sharp (2001) and Cakmak et al. (2011) concluded that O3 was particularly damaging to athletes, with subjects achieving a lower aerobic fitness score on high ozone days. Finally, long-term exposure to outdoor air pollution may trigger intermittent endogenous airway acidification episodes indicative of pollution-related lung inflammation (Ferdinands et al., 2008). These results have particularly relevant impli- cations for top-level athletes participating in international competi- tions: the performance of athletes training in highly polluted environments may be impaired compared to athletes training in cleaner environments and, similarly, athletes used to training in cleaner envi- ronments may be adversely affected when competing in highly polluted locations. Thus, assessing exposure to air pollution in athletics venues becomes a necessity when aiming at understanding environmental drivers of both athletic performance, and athletes' health. In this framework, the aim of this study was to characterize air pol- lutant concentrations in the Yokohama stadium (in the competition and the training area) during the Yokohama 2019 World Relays the day with lowest ambient concentrations. This strategy could be adopted to define training and competition schedules, and would have special added value for athletes with respiratory conditions. Personal exposure to polycyclic aromatic hydrocarbons was quantified through wearable silicone wristbands, and showed highly var- iability across volunteers. The wristbands are a simple approach to assess personal exposure to potentially toxic organic compounds. Further research would be necessary with regard to specific air pollutants that may trigger or exacerbate respiratory conditions typical of the athlete community. The availability of high time-resolved ex- posure data in the stadiums opens up the possibility to calculate doses of specific pollutants for individual ath- letes in future athletics events, to understand the impact of environmental factors on athletic performance.