Polycyclic aromatic hydrocarbons (PAHs) are the carcinogenic component of carbonaceous aerosols and the toxicity of PAHs depends on their molecular structure. PM_2.5-bound PAHs concentration, their isomeric ratios and health impacts during wintertime (fog and non-fog episodes) are assessed at two heavily polluted sites (Allahabad and Kanpur) in central IGP (Indo-Gangetic plains) to better understand the spatial-temporal variability of PAHs as well as identification of their major sources. The highest contribution to PAH loading is reported from indeno (1,2,3-c,d) pyrene, benzo(g,h,i) perylene, benzo (b,j) fluoranthene and benzo (a) pyrene at the two sites during studied winter campaigns. Significantly higher contribution from 6-ring PAHs to total PAH concentration at Allahabad has been observed as compared to Kanpur. Moreover, lower PAHs concentration observed during dense fog episodes can be attributed to wet scavenging of aerosols by fog droplets. Isomeric ratios of PAHs indicated significant contribution from diesel engine exhaust at Allahabad and gasoline combustion at Kanpur. Substantial contribution from coal combustion and biomass burning emissions during wintertime over these sites was also observed. Estimation of health risk due to PAHs indicate potential health hazard to adults as well as children at both the sites. Furthermore, health risk observed due to carcinogenic metals (Cr(VI), Cd, Ni, As) and PAHs is nearly twice at Allahabad as compared to Kanpur. Diesel exhaust emissions (a dominant source of Cd and PAHs) appeared to be responsible for increased cancer risk at Allahabad. Whereas, higher Cr(VI) and PAHs concentration in the ambient aerosol is aggravating cancer risk at Kanpur.

多环芳烃（PAHs）是碳质气溶胶的致癌成分，PAHs的毒性取决于其分子结构。下午_2.5在中部IGP（印度-恒河平原）两个严重污染的地点（阿拉哈巴德和坎普尔）评估了绑定PAHs的浓度，其异构体比率和冬季对健康的影响（阿拉加巴德和坎普尔），以更好地了解时空变化PAHs及其主要来源的识别。据报道，两个位置的茚并（1,2,3-c，d）,、苯并（g，h，i）,、苯并（b，j）荧蒽和苯并（a）to对PAH负载的贡献最大。在研究冬季运动期间。与坎普尔相比，在阿拉哈巴德，六环PAH对总PAH浓度的贡献明显更高。此外，在浓雾中观察到的PAHs浓度较低，可归因于雾滴对湿气的清除作用。PAHs的比率不均衡表明，安拉阿巴德的柴油机排气和坎普尔的汽油燃烧起了很大的作用。在这些地点冬季还观察到了煤炭燃烧和生物质燃烧排放的巨大贡献。估计由于多环芳烃引起的健康风险表明这两个地点的成年人和儿童都有潜在的健康危害。此外，与坎普尔相比，阿拉哈巴德的致癌金属（Cr（VI），Cd，Ni，As，As）和多环芳烃引起的健康风险几乎是其两倍。柴油废气排放（镉和多环芳烃的主要来源）似乎是阿拉哈巴德癌症风险增加的原因。然而，周围的气溶胶中较高的Cr（VI）和PAHs浓度加剧了坎普尔的癌症风险。在这些地点冬季还观察到了煤炭燃烧和生物质燃烧排放的巨大贡献。估计由于多环芳烃引起的健康风险表明这两个地点的成年人和儿童都有潜在的健康危害。此外，与坎普尔相比，阿拉哈巴德的致癌金属（Cr（VI），Cd，Ni，As，As）和多环芳烃引起的健康风险几乎是其两倍。柴油废气排放（镉和多环芳烃的主要来源）似乎是阿拉哈巴德癌症风险增加的原因。然而，周围的气溶胶中较高的Cr（VI）和PAHs浓度加剧了坎普尔的癌症风险。在这些地点冬季还观察到了煤炭燃烧和生物质燃烧排放的巨大贡献。估计由于多环芳烃引起的健康风险表明这两个地点的成年人和儿童都有潜在的健康危害。此外，与坎普尔相比，阿拉哈巴德的致癌金属（Cr（VI），Cd，Ni，As，As）和多环芳烃引起的健康风险几乎是其两倍。柴油废气排放（镉和多环芳烃的主要来源）似乎是阿拉哈巴德癌症风险增加的原因。然而，周围的气溶胶中较高的Cr（VI）和PAHs浓度加剧了坎普尔的癌症风险。此外，与坎普尔相比，阿拉哈巴德的致癌金属（Cr（VI），Cd，Ni，As，As）和多环芳烃引起的健康风险几乎是其两倍。柴油废气排放（镉和多环芳烃的主要来源）似乎是阿拉哈巴德癌症风险增加的原因。然而，周围的气溶胶中较高的Cr（VI）和PAHs浓度加剧了坎普尔的癌症风险。此外，与坎普尔相比，阿拉哈巴德的致癌金属（Cr（VI），Cd，Ni，As，As）和多环芳烃引起的健康风险几乎是其两倍。柴油废气排放（镉和多环芳烃的主要来源）似乎是阿拉哈巴德癌症风险增加的原因。然而，周围的气溶胶中较高的Cr（VI）和PAHs浓度加剧了坎普尔的癌症风险。