Abstract
The PM2.5 samples at an urban site (JN) and a suburban site (QXT) were simultaneously collected in a heavily polluted city in North China Plain (Jinan) from March to December in 2016, and eighteen polycyclic aromatic hydrocarbons (PAHs) were analyzed. The annual average ∑PAHs concentrations were 39.8 ± 36.6 and 23.6 ± 14.0 ng m–3 at JN and QXT, respectively, with the highest concentrations observed during winter. PHE and CHY were the two most abundant PAHs, accounting for 31.1% at JN and 34.2% at QXT. Source apportionment analyses from the results of Principal Component Analysis (PCA) revealed that coal/biomass combustion and vehicle emission were the major PAH sources in PM2.5. The ratio of LMW + MMW (LMW: low molecular weight; MMW: middle molecular weight) PAHs to ∑PAHs at JN was significantly lower (p < 0.001) than that at QXT, indicating coal/biomass burning made more significant contribution to suburban area than that to urban area. Conversely, vehicle emission worked more effectively to urban area. The total benzo[a]pyrene (BaP) equivalent concentration (BaPeq) of PAHs (gas + particle phases) was 9.66 times higher than the standard value (1.00 ng m–3) and mainly originated from PAHs in particles (93.1%) with the highest contributor of Benzo(a)pyrene (BaP, 60.8%) at the urban site of Jinan in winter. The total incremental lifetime cancer risk (ILCR) assessment suggested that all age groups may have potential health risk at JN in winter except for infant. The Concentration Weighted Trajectory (CWT) model indicated that local emission and short-distance transport were the main sources of PAHs during spring and winter, and long-range transport played a key role on PAH concentrations in summer and autumn.
Highlights
The biggest emitter of polycyclic aromatic hydrocarbons (PAHs) in the world is China in 2007 with 21.0% (106 Gg a–1) burden of the global emissions (Zhang et al, 2007; Shen et al, 2013)
The Concentration Weighted Trajectory (CWT) model indicated that local emission and short-distance transport were the main sources of PAHs during spring and winter, and long-range transport played a key role on PAH concentrations in summer and autumn
The more prominent seasonal variation of PAH concentrations at JN may be attributed to more frequent impact of human activity in urban area
Summary
The biggest emitter of PAHs in the world is China in 2007 with 21.0% (106 Gg a–1) burden of the global emissions (Zhang et al, 2007; Shen et al, 2013). PAHs are a group of semivolatile and toxic organic compounds and exist both in the gaseous and particulate phases in atmosphere (Ravindra et al, 2008; Dat et al, 2018). Toxic PAHs mainly occur in particles (Jin et al, 2018) and the total BaP equivalent concentrations (BaPeq) of PAHs in particulate phase account for 87.9% to 97.0% in previous studies (Table S1) (Wang et al, 2011a; Tomaz et al, 2016; Pratt et al, 2018; Zhang et al, 2018a; Gaga and Arı, 2019). Studies on particulate-bound PAHs are with more significant importance. PM2.5-bound PAHs have received more academic concern (Wang et al, 2011b; Kim et al, 2013; Wang et al, 2016; Alves et al, 2017; Simayi et al, 2018)
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