Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change, Nanjing University of Information Science and Technology, Nanjing 210044, China; Key Laboratory Meteorological Disaster, Ministry of Education & Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster, Nanjing University of Information Science and Technology, Nanjing 210044, China; Jiangsu Provincial Key Laboratory of Agricultural Meteorology, College of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change, Nanjing University of Information Science and Technology, Nanjing 210044, China; Key Laboratory Meteorological Disaster, Ministry of Education & Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster, Nanjing University of Information Science and Technology, Nanjing 210044, China; Jiangsu Provincial Key Laboratory of Agricultural Meteorology, College of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
Sci Total Environ. 2022 May 1;819:152007. doi: 10.1016/j.scitotenv.2021.152007. Epub 2021 Nov 29.
Biomass burning (BB) is an important source of carbonaceous aerosols in Northeast China (NEC). Quantifying the original contribution of BB to organic carbon (OC) [BB-OC] can provide an essential scientific information for the policy-makers to formulate the control measures to improve the air quality in the NEC region. Daily PM samples were collected in the rural area of Changchun city over the NEC region from May 2017 to May 2018. In addition to carbon contents, BB tracers (e.g., levoglucosan and K, defined as potassium from BB) were also determined, in order to investigate the relative contribution of BB-OC. The results showed that OC was the dominant (28%) components of PM during the sampling period. Higher concentrations of OC, levoglucosan, and K were observed in the autumn followed by the winter, spring, and summer, indicating that the higher BB activities during autumn and winter in Changchun. By using the Bayesian mixing model, it was found that burning of crop residues were the dominant source (65-79%) of the BB aerosols in Changchun. During the sampling period, the aging in air mass (AAM) ratio was 0.14, indicating that 86% of levoglucosan in Changchun was degraded. Without considering the degradation of levoglucosan in the atmosphere, the BB-OC ratios were 23%, 28%, 7%, and 4% in the autumn, winter, spring, and summer, respectively, which were 1.4-4.8 time lower than those (14-42%) with consideration of levoglucosan degradation. This illustrated that the relative contribution of BB to OC would be underestimated (59%) without considering degradation effects of levoglucosan. Although some uncertainty was existed in our estimation, our results did highlight that the control of straw burning was an efficient way to decrease the airborne PM, improving the air quality in the NEC plain.
生物质燃烧（BB）是中国东北地区（NEC）碳质气溶胶的重要来源。量化 BB 对有机碳（OC）的原始贡献[BB-OC]可以为决策者提供重要的科学信息，以制定控制措施来改善 NEC 地区的空气质量。2017 年 5 月至 2018 年 5 月，在 NEC 地区的长春市农村地区采集了每日 PM 样本。除了碳含量外，还测定了 BB 示踪剂（例如左旋葡聚糖和 K，定义为 BB 中的钾），以研究 BB-OC 的相对贡献。结果表明，OC 是采样期间 PM 的主要（28%）成分。OC、左旋葡聚糖和 K 的浓度在秋季最高，其次是冬季、春季和夏季，这表明长春秋季和冬季的 BB 活动较高。通过使用贝叶斯混合模型，发现燃烧农作物残余物是长春 BB 气溶胶的主要来源（65-79%）。在采样期间，空气团老化比（AAM）为 0.14，表明长春约 86%的左旋葡聚糖在大气中降解。不考虑左旋葡聚糖在大气中的降解，在秋季、冬季、春季和夏季，BB-OC 比分别为 23%、28%、7%和 4%，这与考虑左旋葡聚糖降解时的（14-42%）相比低 1.4-4.8 倍。这说明，如果不考虑左旋葡聚糖的降解效应，对 OC 的 BB 相对贡献会低估（~59%）。尽管我们的估计存在一些不确定性，但我们的结果确实强调了控制秸秆燃烧是减少空气中 PM、改善 NEC 平原空气质量的有效方法。
