Ambient air pollution in China poses a multifaceted health threat to outdoor physical activity

While outdoor physical activity has been shown to promote health and well-being,1 ,2 exercising in environments with high levels of air pollution can increase the risk of health problems ranging from asthma attacks to heart or lung pathologies.3 ,4 The interaction of these two phenomena is of specific significance in China, where outdoor physical activity has been a traditional practice but where rapid industrialisation has led to major degradation of the environment. This situation raises the spectre of an emergent major public health crisis in the most populous country in the world. There is clear and compelling evidence that regular physical activity produces substantial physical and mental health benefits, including improved health-related quality of life and decreased risk of premature morbidity and mortality.1 ,5 ,6 However, it is important to note that in contrast to the commodification of exercise in many western industrialised nations, where exercise for health is often carried out in indoor facilities such as fitness centres, the physical and mental health benefits of physical activity can be achieved outdoors in settings such as community green spaces, parks and trails.1 ,2 Therefore, public health policies designed to encourage participation in physical activity should focus on outdoor settings for promoting public health and improving overall quality of life,5–8 because outdoors settings can accommodate a much larger scale population involvement at substantially lower costs than can physical activity in indoor facilities. In China, cultural norms, history and public policy have presaged this logistical reality, with a significant portion of the population, especially in the older demographic, exercising daily in outdoor settings such as parks, village squares and along streets, through leisure walking, jogging, dancing, bicycling or Tai Ji Quan.9–11 Studies in China have shown a positive association between traditional …