“…Thanks to control measures, peak O 3 concentrations tend to decline in North America and Europe (Paoletti, De Marco, Beddows, Harrison, & Manning 2014;Sicard et al 2016), while annual averages are still increasing in many other regions, in particular in Asia, due to increasing O 3 -precursor emissions (Feng, Liu, & Zhang 2015). For example, high concentrations of O 3 frequently occur in many regions and cities of China, where the daily 8 h average may exceed 50 ppb during the crop growth season (Wang, Wei, Ding, et al 2009;Tang et al 2013;Xin et al 2016). Yuan et al (2015) observed frequent peaks exceeding 170 ppb during summer days in Beijing.…”