Particulate-bound Polycyclic Aromatic Hydrocarbons (PAHs) have been identified as pollutants of serious concern due to their severe health impacts on human and animal life. In the present work, 16 USEPA (United States Environmental Protection Agency) identified PAHs present in PM_2.5 at Jorhat, India during the winter months (Jan-March, 2020) were analyzed. Apart from the temporal variability of these compounds, the impact of varying meteorological factors like temperature, wind speed, relative humidity, and planetary boundary layer height on PAHs concentration have also been studied. It has been observed that the effect of ambient air temperature and planetary boundary layer on PAHs concentration are significant compared to other meteorological parameters during the winter season. The average concentration of total PAHs during this period was 157.2 ± 127.7 ng/m³ with dominance of high molecular weight aromatics compared to the low molecular weight ones. Among all 16 PAHs studied, the contribution of benzo(b,j)fluoranthene (27.26%) to total PAHs concentration was found to be the highest followed by di-benzo(a,h)anthracene (10.37%). Source identification analysis using isomeric PAHs ratios indicated that crop residue burning, vehicular emission, coal, and wood combustion are the major emission sources of PAHs. A comparative study of PAHs emission at the present site with other northern cities of India has been performed and it is observed that vehicular emission contributing to PAHs is common to all cities but in Kolkata, wood and coal combustion were also responsible for PAHs emission. Biomass burning is also seen to be a contributor to Amritsar. Whereas in Jorhat, crop residue and coal/wood combustion are seen to be major contributors to PM_2.5 bound PAHs unlike other cities.

Graphical abstract

中文翻译：

---

印度东北部颗粒物多环芳烃 (PAH) 的冬季趋势：化学特征和来源识别

颗粒结合的多环芳烃 (PAH) 由于对人类和动物生命的严重健康影响而被确定为令人严重关注的污染物。在目前的工作中，16 个 USEPA（美国环境保护署）确定了 PM _{2.5中存在 PAH}对印度乔尔哈特市冬季（2020 年 1 月至 3 月）的情况进行了分析。除了这些化合物的时间变化外，还研究了不同的气象因素（如温度、风速、相对湿度和行星边界层高度）对多环芳烃浓度的影响。据观察，与冬季其他气象参数相比，环境气温和行星边界层对多环芳烃浓度的影响显着。在此期间总PAHs的平均浓度为157.2±127.7ng/m ³与低分子量芳烃相比，高分子量芳烃占主导地位。在所有研究的 16 种 PAH 中，苯并（b，j）荧蒽（27.26％）对 PAH 总浓度的贡献最高，其次是二苯并（a，h）蒽（10.37％）。利用异构体PAHs比率进行来源识别分析表明，农作物秸秆燃烧、车辆排放、煤炭和木材燃烧是PAHs的主要排放源。对当前地点与印度其他北部城市的多环芳烃排放量进行了比较研究，发现车辆排放造成多环芳烃的情况在所有城市都很常见，但在加尔各答，木材和煤炭燃烧也是多环芳烃排放的原因。生物质燃烧也被认为是阿姆利则的一个贡献者。而在焦尔哈特，_{与其他城市不同， 2.5}约束多环芳烃。

图形概要