Ambient particulate matter concentrations in Delhi and its peripheral towns has been a matter of serious concern in the last decade. Understanding the changing nature of the chemical composition of particulates, their spatial and seasonal variability can be utilized for identifying probable sources. This study presents an extensive dataset of the chemical composition of PM2.5 and PM10 collected using speciation samplers, from 19 locations representing different activities and spread across Delhi–NCR during summer and winter seasons in the year 2016–17. Identification of contributing sources using chemical ratios as source indicators is attempted. A distinct seasonal variability in both PM2.5 and PM10 was observed, with winter maxima and summer minima. The fine fraction i.e. PM2.5 was dominated by organic matter (OM) with mean concentrations of 40.96±25.74 μg/m3 followed by Sulfate-Nitrate-Ammonium (SNA) ions (31.44±20.69 μg/m3) and Elemental Carbon (EC) (19.56±12.57 μg/m3); while the coarse fraction i.e. PM10 was dominated by OM (73.03±40.55 μg/m3) and SNA (47.25±30.56 μg/m3) along with significant contributions from crustal materials (40.85±18.89 μg/m3). The chemical ratios suggested mixed sources of PM with major contributions from vehicular emissions, re-suspended and/or construction dust, and fossil fuel combustion along with intermittent contributions from biomass and open waste burning. This analysis provides useful insights into the sources and processes affecting the particulate formation and underlines the need to control primary emissions as well as secondary precursors for air quality improvements in the region. The data generated under this campaign can also serve as an essential input for further evaluation using receptor modeling.

中文翻译：

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印度德里-国家首都地区 (NCR) PM2.5 和 PM10 的化学成分和来源归因：广泛季节性活动的结果

在过去十年中，德里及其周边城镇的环境颗粒物浓度一直是一个令人严重关切的问题。了解颗粒物化学成分的变化性质，它们的空间和季节性变化可用于识别可能的来源。本研究提供了使用物种形成采样器收集的 PM2.5 和 PM10 化学成分的广泛数据集，来自代表不同活动的 19 个地点，并在 2016-17 年夏季和冬季分布在德里-NCR。尝试使用化学比率作为来源指标来识别贡献来源。观察到 PM2.5 和 PM10 的明显季节性变化，冬季最大值和夏季最小值。精细部分，即 PM2.5 以有机物 (OM) 为主，平均浓度为 40。96±25.74 μg/m3，然后是硫酸盐-硝酸盐-铵 (SNA) 离子 (31.44±20.69 μg/m3) 和元素碳 (EC) (19.56±12.57 μg/m3)；而粗颗粒即 PM10 主要由 OM (73.03±40.55 μg/m3) 和 SNA (47.25±30.56 μg/m3) 以及地壳物质的显着贡献 (40.85±18.89 μg/m3) 主导。化学比率表明 PM 的混合来源，主要来自车辆排放、再悬浮和/或建筑粉尘和化石燃料燃烧，以及来自生物质和露天废物燃烧的间歇性贡献。该分析为影响颗粒物形成的来源和过程提供了有用的见解，并强调需要控制初级排放物和次级前驱物以改善该地区的空气质量。