Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
Department of Earth Sciences, Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
Environ Res. 2022 Nov;214(Pt 1):113801. doi: 10.1016/j.envres.2022.113801. Epub 2022 Jul 1.
A year-long sampling campaign of ambient PM (particulate matter with aerodynamic diameter ≤2.5 mm) at a regional station in the North-Eastern Region (NER) of India was performed to understand the sources and formation of carbonaceous aerosols. Mass concentration, carbon fractions (organic and elemental carbon), and stable carbon isotope ratio (δC) of PM were measured and studied along with cluster analysis and Potential Source Contribution Function (PSCF) modelling. PM mass concentration was observed to be highest during winter and post-monsoon seasons when the meteorological conditions were relatively stable compared to other seasons. Organic carbon (OC) concentration was more than two times higher in the post-monsoon and winter seasons than in the pre-monsoon and monsoon seasons. Air mass back trajectory cluster analysis showed the dominance of local and regional air masses during winter and post-monsoon periods. In contrast, long-range transported air masses influenced the background site in pre-monsoon and monsoon. Air mass data and PSCF analysis indicated that aerosols during winter and post-monsoon are dominated by freshly generated emissions from local sources along with the influence from regional transport of polluted aerosols. On the contrary, the long-range transported air masses containing aged aerosols were dominant during pre-monsoon. No significant variability was observed in the range of δC values (-28.2‰ to -26.4‰) during the sampled seasons. The δC of aerosols indicates major sources to be combustion of biomass/biofuels (C3 plant origin), biogenic aerosols, and secondary aerosols. The δC variability and cluster/PSCF modelling suggest that aged aerosols (along with enhanced photo-oxidation derived secondary aerosols) influenced the final δC during the pre-monsoon. On the other hand, lower δC in winter and post-monsoon is attributed to the freshly emitted aerosols from biomass/biofuels.
在中国东北地区的一个区域站进行了为期一年的环境 PM（空气动力学直径≤2.5mm 的颗粒物）采样活动，旨在了解碳质气溶胶的来源和形成。测量并研究了 PM 的质量浓度、碳成分（有机碳和元素碳）和稳定碳同位素比（δC），以及聚类分析和潜在源贡献函数（PSCF）建模。与其他季节相比，冬季和后季风季节的气象条件相对稳定，PM 质量浓度最高。后季风和冬季的有机碳（OC）浓度比前季风和季风季节高两倍多。空气团后轨迹聚类分析表明，冬季和后季风期间，本地和区域空气团占主导地位。相比之下，长程输送的空气团在季风和前季风期间影响背景站点。空气团数据和 PSCF 分析表明，冬季和后季风期间的气溶胶主要由当地来源的新生成排放物以及受污染气溶胶的区域传输影响。相反，长程输送的空气团含有老化的气溶胶，在前季风期间占主导地位。在所采样的季节中，δC 值（-28.2‰至-26.4‰）的变化范围不大。气溶胶的 δC 表明主要来源是生物质/生物燃料（C3 植物起源）的燃烧、生物气溶胶和次生气溶胶。δC 的变化和聚类/PSCF 建模表明，在前季风期间，老化的气溶胶（以及增强的光氧化衍生的次生气溶胶）影响了最终的 δC。另一方面，冬季和后季风的 δC 较低归因于生物质/生物燃料新排放的气溶胶。
