This study was designed to assess the occurrence, relationships, sources, spatiotemporal variations, and source-specific multi-pathway cancer risk of PM_2.5-bound PAHs at three urban environments in Tehran, Iran during a one-year campaign (2018–2019). The mean concentrations of PM_2.5-bound ∑16PAHs were 24.6, 26.7, and 38.9 ng m⁻³ in HFT, AZD, and SHR sites, respectively. High molecular weight (HMW) PAHs were the main PAHs in the fine particle phase (76–83.4%) compare to low molecular weight (LMW) PAHs (16.6–24%). Redundancy analysis (RDA) showed that relative humidity (RH) and temperature (T) along with O₃, NO₂, and PM_2.5 were critical driving factors affecting PAHs concentrations. Positive matrix factorization (PMF) extracted five PAHs emission sources: heavy-duty vehicles, light-duty vehicles, petrogenic, natural gas and coal/biomass combustion, industrial emissions, with different source contributions for each sampling site. The principal component analysis-multilinear regressions (PCA-MLR) and diagnostic ratios (DRs) methods indicated that the pyrogenic sources were the major sources of PM_2.5-bound PAHs. The coefficient of divergence (COD) and Pearson correlation coefficient (R) of PAHs compounds and PMF derived source contributions (ng m⁻³) at paired sites indicated a relatively divergent spatiotemporal distribution. Based on incremental lifetime cancer risk (ILCR) levels of ∑PAHs source contributions, adults showed a more significant risk (1.33E-2.28E-05) than children (5.40E-9.22E-06). Source-specific-ILCR indicated that heavy-duty vehicles and natural gas-coal/biomass combustion emissions had the highest cancer risk contributions than the other apportioned sources.

本研究旨在评估伊朗德黑兰三个城市环境中PM _2.5结合多环芳烃在为期一年的运动（2018-2019）中的发生、关系、来源、时空变化和特定来源的多途径癌症风险. 在 HFT、AZD 和 SHR 站点中，PM _2.5结合的 ∑16PAH的平均浓度分别为24.6、26.7 和 38.9 ng m ^-3。与低分子量 (LMW) 多环芳烃 (16.6-24%) 相比，高分子量 (HMW) 多环芳烃是细颗粒相中的主要多环芳烃 (76-83.4%)。冗余分析 (RDA) 显示相对湿度 (RH) 和温度 (T) 以及 O ₃、NO ₂和 PM _2.5是影响 PAHs 浓度的关键驱动因素。正矩阵分解 (PMF) 提取了五种 PAHs 排放源：重型车辆、轻型车辆、石油、天然气和煤/生物质燃烧、工业排放，每个采样点的源贡献不同。主成分分析-多元线性回归 (PCA-MLR) 和诊断比率 (DR) 方法表明，热源是 PM _2.5结合多环芳烃的主要来源。PAHs 化合物和 PMF 衍生源贡献的散度系数 (COD) 和皮尔逊相关系数 (R) (ng m ^-3) 在成对的地点表示相对不同的时空分布。根据 ∑PAHs 来源贡献的终生癌症风险 (ILCR) 递增水平，成年人 (1.33E-2.28E-05) 比儿童 (5.40E-9.22E-06) 显示出更显着的风险。特定来源的 ILCR 表明，重型车辆和天然气-煤/生物质燃烧排放的癌症风险贡献高于其他分配来源。