Pollution characteristics and risk assessment of ambient PM2.5-bound PAHs and NPAHs in typical Japanese and New Zealand cities and rural sites

Özet

Nine polycyclic aromatic hydrocarbons (PAHs) and six nitro-PAHs (NPAHs) were measured in PM2.5 samplescollected over one year (2016–2017) in two cities: Kanazawa (Japan) and Auckland (New Zealand) and theirrespective rural background sites: Wajima in Noto Peninsula (Japan) and Tapora in Okahukura Peninsula (NewZealand). The mean concentrations of ΣPAHs and ΣNPAHs followed similar distribution profiles in both countries,with higher concentrations in the urban than rural sites. The mean of ΣPAHs in Kanazawa City was0.53 ng/m3 and represented the highest total concentration compared to the other three sites. Conversely, thehighest ΣNPAHs concentrations were measured in Auckland City (48.2 pg/m3). Diagnostic ratios and principalcomponent analysis revealed that automobiles were the main sources of PAHs and NPAHs in both cities, whereascoal combustion and domestic wood burning were the dominant sources of PAHs and NPAHs in rural sites inJapan and New Zealand. Back trajectory analyses showed that high levels of PAHs detected at Wajima were theresult of long-range transport from China and Mongolia in winter, which was not observed at the other sites.Considering the adverse health effects of PM2.5, further studies and continuous monitoring of atmospheric PAHsand NPAHs are necessary to evaluate mitigation strategies in both hemispheres.