Compared with the average concentration, the EMC also considers the impact of runoff flow on the concentrations of pollutants. Therefore, the EMC is a crucial event-specific parameter representing the actual time variations in concentrations (Perera et al. 2021). The EMC of PAHs in runoff from each athletic field is presented in Table 1. A total of 6 out of the 16 EPA PAHs were detected in all the samples, namely naphthalene (Nap), fluorene (Flu), phenanthrene (Phe), fluoranthene (Fla), pyrene (Pyr), and chrysene (Chr). This indicates that PAHs were ubiquitous in athletic field runoffs. The sources of PAHs in the runoff could be mainly from the surface materials of athletic fields. The EMC of ∑₆PAHs in the five athletic fields ranged from 3.96 to 23.23 μg/L, which was several times higher than the EMC (a few micrograms) of runoff in urban traffic areas (Zheng et al. 2014).