Because of their unintentional formation and low vapor pressure, polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (XPAHs) in the atmosphere are distributed primarily to aerosolized particles with an aerodynamic diameter less than 2.5 μm (PM_2.5). However, no information is available regarding the occurrence of PM_2.5-bound PAHs and XPAHs in Bangladesh, one of the most highly PM_2.5-polluted regions worldwide. In this study, we investigated the occurrence of PM_2.5-bound PAHs and XPAHs in the atmospheres of Dhaka in Bangladesh and Shizuoka in Japan (as a reference) and estimated their incremental lifetime cancer risks (ILCRs). In addition, we statistically estimated the potential sources of PM_2.5-bound PAHs and XPAHs by using principal component analysis and positive matrix factorization. The median concentration of total PM_2.5-bound PAHs and XPAHs in Bangladesh was 24.2 times that in Japan. The estimated potential sources of PAHs clearly differed between Japan and Bangladesh, whereas those of XPAHs were largely (>80%) unknown in both countries. The median ILCR in Bangladesh was 2.81 × 10⁻³, which greatly exceeded the upper limit of acceptable risk (10⁻⁴). These results indicate that comprehensive monitoring and control of atmospheric PM_2.5-bound PAHs and XPAHs are needed urgently, especially in highly polluted countries.

由于它们的无意形成和低蒸气压，大气中的多环芳烃（PAHs）及其卤代衍生物（XPAHs）主要分布在空气动力学直径小于2.5μm（PM _2.5）的雾化颗粒上。但是，尚无关于孟加拉国PM _2.5结合的PAH和XPAH发生的信息，孟加拉国是全球PM _2.5污染最严重的地区之一。在这项研究中，我们调查了在孟加拉国达卡和日本静冈县大气中与PM _2.5结合的PAHs和XPAHs的发生情况（作为参考），并估计了它们增加的终生癌症风险（ILCRs）。此外，我们从统计学上估算了PM _2.5的潜在来源通过使用主成分分析和正矩阵分解实现绑定的PAH和XPAH。在孟加拉国，与PM _2.5结合的PAH和XPAH的总浓度中值是日本的24.2倍。在日本和孟加拉国之间，估计的PAHs潜在来源显然有所不同，而在两个国家中，XPAH的潜在来源却很大程度上未知（> 80％）。孟加拉国的ILCR中位数为2.81×10 ^-3，大大超过可接受风险的上限（10 ^-4）。这些结果表明，迫切需要对大气中与PM _2.5结合的PAH和XPAH进行全面监控，尤其是在污染严重的国家。