Variations and health risk of polycyclic aromatic hydrocarbons in ambient PM2.5 in industrial and residential areas in Fuzhou City

[Background] PM2.5 pollution has become a widely concerned environmental health problem. Polycyclic aromatic hydrocarbons(PAHs) are the main harmful components of PM2.5, and their sources and carcinogenic risk deserve attention. [Objective] To analyze the source apportionment of PAHs in ambient PM2.5 in Fuzhou, and to evaluate the potential carcinogenic risk through inhalation due to exposure to PAHs. [Methods] In this study, two sampling sites were set up in Cangshan (industrial area) and Taijiang (commercial and residential area) districts in Fuzhou City. PM2.5 was collected from 10th to 16th of each month from 2017 to 2020 by membrane filtration method. The concentrations of ambient PM2.5 were measured by weighing, and the concentrations of 16 PAHs, including naphthalene(NAP), acenaphthylene(ACY), acenaphthene(ACE), fluorene(FLU), phenanthrene(PHE), anthracene(ANT), fluoranthene(FLT), pyrene(PYR), benzo[a]anthracene(BaA), chrysene(CHR), benzo[b]fluoranthene(BbF), benzo[k]fluoranthene(BkF), benzo[a]pyrene(BaP), indeno[1,2,3-cd]pyrene(IcdP), dibenzo[a,h]anthracene(DahA), and benzo[g,h,i]perylene(BghiP), were determined by ultra-high performance liquid chromatography coupled with diode array detector and fluorescence detector. The concentrations of PM2.5 and PAHs were compared in the two districts and the concentrations of PAHs were also compared in different seasons. The diagnostic ratio [FLT/(FLT+PYR), IcdP/(IcdP+BghiP), BaA/(BaA+CHR), and BaP/BghiP] method and positive matrix factorization (PMF) analysis were used to determine the sources of PAHs in PM2.5 in Fuzhou. The excess carcinogenic risk (ECR) model was used to assess the potential health risk of inhalation exposure to PAHs. [Results] During 2017–2020, the M (P25, P75) concentration of ambient PM2.5 in Cangshan and Taijiang districts of Fuzhou were 35.0 (25.0, 47.5) and 34.0 (25.5, 46.0) μg·m−3 respectively, and the percentages of PM2.5 exceeding the national standard in Cangshan and Taijiang were 2.68% and 4.17%, respectively, without significant differences (P＞0.05). The M (P25, P75) concentrations of ΣPAHs in Cangshan was 5.03 (3.07, 7.67) ng·m−3, higher than that in Taijiang, 3.20 (2.05, 5.59) ng·m−3 (P＜0.05). The M (P25, P75) concentrations of PAHs monomers except ACY, FLU, and ACE in Cangshan were higher than those in Taijiang (P＜0.05). The concentrations of ΣPAHs in PM2.5 in four seasons in Cangshan were higher than those in Taijiang (P＜0.05). In both districts, the concentration of ΣPAHs