Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S Nagar, Manauli PO, Punjab, 140306, India.
Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S Nagar, Manauli PO, Punjab, 140306, India.
Environ Pollut. 2023 Dec 1;338:122656. doi: 10.1016/j.envpol.2023.122656. Epub 2023 Oct 2.
Paddy-residue burning is associated with poor air quality in north-west India during October-November every year. However, till date a quantitative study of its contribution to ambient volatile organic compounds (VOCs) using highly time-resolved measurements within the region has been lacking. Several VOCs like benzene are carcinogenic and also fuel formation of secondary pollutants such as secondary organic aerosol (SOA) and ozone. Here, we undertake quantitative source-apportionment using a PMF source-receptor model on a high-quality in-situ measured dataset of 54 VOCs in Punjab, India, and validate the model results using source profiles. The contribution of the seven most dominant sources to the total VOC mass concentrations were: daytime photochemistry and biogenic VOCs (BVOCs) (26%), followed by solid-fuel usage and waste-disposal (18%), traffic (two-wheeler 14% and four-wheeler 10%), photochemically aged biomass burning (17%), industries and solvent usage (9%), and fresh paddy residue burning (6%). Ozone production potential was dominated by solid fuel usage and waste disposal (25%), followed by traffic (two-wheeler 11% and four-wheeler 12%), BVOCs and photooxidation products (21%), photochemically aged biomass burning (16%), industries & solvent usage (9%) and fresh paddy residue burning (6%). SOA production was dominated by traffic (two-wheeler 26% and four-wheeler 28%) followed by solid fuel usage and waste disposal (22%), photochemically aged biomass burning emissions (15%) with minor contribution from industries & solvents (6%), fresh paddy residue burning (2%) and photochemistry and biogenic VOCs (1%). Comparisons with global emission inventories REASv3.2.1 and EDGARv4.3.2, showed both overestimate the industry and solvent source. Further, EDGARv4.3.2 underestimated the traffic source whereas paddy residue burning emissions are absent in REASv3.2.1. Although the overall mass contribution of paddy-residue burning emissions isn't high, our results show that health-relevant compounds emitted directly and formed photochemically from biomass burning sources active at this time are majorly responsible for the unhealthy air.
每年 10 月至 11 月，印度西北部的水稻残茬燃烧与空气质量差有关。然而，到目前为止，该地区还缺乏使用高时间分辨率测量对其对环境挥发性有机化合物（VOC）贡献的定量研究。几种 VOC，如苯，具有致癌性，也是二次污染物如二次有机气溶胶（SOA）和臭氧形成的燃料。在这里，我们使用 PMF 源受体模型对印度旁遮普邦的 54 种 VOC 的高质量原位测量数据集进行定量源分配，并使用源谱验证模型结果。对总 VOC 质量浓度贡献最大的七个主要来源分别是：白天光化学和生物源 VOC（BVOCs）（26%），其次是固体燃料使用和废物处置（18%），交通（两轮车 14%，四轮车 10%），光化学老化生物质燃烧（17%），工业和溶剂使用（9%），以及新鲜稻茬燃烧（6%）。臭氧生成潜力主要由固体燃料使用和废物处置（25%）、交通（两轮车 11%和四轮车 12%）、BVOCs 和光氧化产物（21%）、光化学老化生物质燃烧（16%）、工业和溶剂使用（9%）和新鲜稻茬燃烧（6%）控制。SOA 生成主要由交通（两轮车 26%和四轮车 28%）、固体燃料使用和废物处置（22%）、光化学老化生物质燃烧排放（15%）以及工业和溶剂（6%）、新鲜稻茬燃烧（2%）和光化学和生物源 VOC（1%）的少量贡献。与全球排放清单 REASv3.2.1 和 EDGARv4.3.2 的比较表明，两者都高估了工业和溶剂源。此外，EDGARv4.3.2 低估了交通源，而 REASv3.2.1 中没有稻茬燃烧排放。尽管水稻残茬燃烧排放的总体质量贡献不高，但我们的研究结果表明，此时活跃的生物质燃烧源直接排放并光化学形成的与健康相关的化合物是造成空气质量不健康的主要原因。
