Singh Gyanesh Kumar, Choudhary Vikram, Rajeev Pradhi, Paul Debajyoti, Gupta Tarun
Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
Environ Pollut. 2021 Feb 1;270:116082. doi: 10.1016/j.envpol.2020.116082. Epub 2020 Nov 20.
Post-harvest crop residue burning is extensively practiced in North India, which results in enhanced particulate matter (PM) concentrations. This study explores the PM (particulate matter with aerodynamic diameter ≤ 2.5 μm) emissions during various time periods (pre-monsoon, monsoon, and post-monsoon) over the biomass burning source region in Beas, Punjab. The PM concentrations during the pre-monsoon period (106-458 μg m) and the post-monsoon period (184-342 μg m) were similar but much higher than concentrations during the monsoon season (23-95 μg m) due to enhanced wet deposition. However, the carbonaceous aerosol fraction in PM was nearly double in the post-monsoon season (∼27%) than the pre-monsoon period (∼15%). A higher contribution of secondary organic carbon (SOC) observed during the pre-monsoon season can be attributed to enhanced photochemical activity in dry conditions. Stable carbon isotope ratio (δC value) of ambient PM allowed elucidation of contributing sources. δC correlation with SOC during post-monsoon and pre-monsoon periods suggests significant influence of secondary formation processes during both time periods. The concentrations of carbon fractions in sampled sources and aerosols suggests contribution of biofuels, resulting in enhanced PM concentration at this location. δC values of pre- and post-monsoon samples show dominance of freshly emitted aerosols from local sources. Impact of biomass and biofuel combustion was also confirmed by biomass burning K tracer, indicating that major agriculture residue burning occurred primarily during nighttime. C plant derived aerosols dominated at the sampling location during the entire sampling duration and contributed significantly during the pre-monsoon season. Whereas, both fossil fuel and C plant combustion contributed to the total mass of carbonaceous aerosols during the post-monsoon and monsoon seasons.
印度北部广泛存在收获后焚烧农作物残余物的现象，这导致颗粒物（PM）浓度增加。本研究探讨了旁遮普邦贝斯生物质燃烧源区域在不同时间段（季风前、季风期和季风后）的PM（空气动力学直径≤2.5μm的颗粒物）排放情况。由于湿沉降增强，季风前期（106 - 458μg/m³）和季风后期（184 - 342μg/m³）的PM浓度相似，但远高于季风季节（23 - 95μg/m³）的浓度。然而，季风后期PM中的碳质气溶胶组分（约27%）几乎是季风前期（约15%）的两倍。在季风前期观测到的二次有机碳（SOC）贡献较高，这可归因于干燥条件下光化学活性增强。环境PM的稳定碳同位素比值（δ¹³C值）有助于阐明其贡献源。季风后期和前期δ¹³C与SOC的相关性表明这两个时间段二次形成过程都有显著影响。采样源和气溶胶中碳组分的浓度表明生物燃料有贡献，导致该地点PM浓度增加。季风前和季风后样品的δ¹³C值表明本地源新排放的气溶胶占主导。生物质燃烧钾示踪剂也证实了生物质和生物燃料燃烧的影响，表明主要的农业残余物燃烧主要发生在夜间。在整个采样期间，C₃植物源气溶胶在采样地点占主导，在季风前期贡献显著。而在季风后期和季风期，化石燃料和C₃植物燃烧都对碳质气溶胶的总质量有贡献。
