Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China.
Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China; School of Environment and Planning, Liaocheng University, Liaocheng 252000, China.
J Environ Sci (China). 2022 Jan;111:185-196. doi: 10.1016/j.jes.2021.03.031. Epub 2021 Apr 3.
Black carbon (BC) plays an important role in air quality and climate change, which is closely associated with its mixing state and chemical compositions. In this work the mixing state of BC-containing single particles was investigated to explore the evolution process of ambient BC particles using a single particle aerosol mass spectrometer (SPAMS) in March 2018 in Zhengzhou, China. The BC-containing particles accounted for 61.4% of total detected ambient single particles and were classified into five types including BC-nitrate (BC-N, 52.3%) as the most abundant species, followed by BC-nitrate-sulfate (BC-NS, 22.4%), BCOC (16.8%), BC-fresh (BC-F, 4.5%) and BC-sulfate particles (BC-S, 4.0%). With enhancement of the ambient nitrate concentration, the relative peak area (RPA) of nitrate in BC-N and BCNS particles both increased, yet only the number fraction (N) of BCN particles increased while the N of BC-NS particles decreased, suggesting that the enhanced mixing state of BC with nitrate was mainly due to the increase in the ambient nitrate mass concentration. In addition, the N of BC-N decreased from 65.3% to 28.4% as the absorbing Ångström exponents (AAE) of eBC increased from 0.75 to 1.45, which indicated the reduction of light absorption ability of aged BC particles with the enhanced formation of BC-N particles. The results of this work indicated a change in the mixing state of BC particles due to the dominance of nitrate in PM, which also influenced the optical properties of aged BC particles.
黑碳（BC）在空气质量和气候变化中起着重要作用，其混合状态和化学成分与其密切相关。本工作利用单颗粒气溶胶质谱仪（SPAMS）于 2018 年 3 月在中国郑州对含 BC 的单颗粒的混合状态进行了研究，以探索环境 BC 颗粒的演化过程。含 BC 的颗粒占总检测到的环境单颗粒的 61.4%，并分为五种类型，包括最丰富的物种 BC-硝酸盐（BC-N，52.3%），其次是 BC-硝酸盐-硫酸盐（BC-NS，22.4%）、BCOC（16.8%）、BC-新鲜（BC-F，4.5%）和 BC-硫酸盐颗粒（BC-S，4.0%）。随着环境硝酸盐浓度的增加，BC-N 和 BC-NS 颗粒中硝酸盐的相对峰面积（RPA）均增加，而只有 BCN 颗粒的数分数（N）增加，而 BC-NS 颗粒的 N 减少，表明硝酸盐与 BC 的混合状态增强主要是由于环境硝酸盐质量浓度的增加。此外，随着 eBC 的吸收 Ångström 指数（AAE）从 0.75 增加到 1.45，BC-N 的 N 从 65.3%降低到 28.4%，这表明随着 BC-N 颗粒的形成，老化 BC 颗粒的光吸收能力降低。本工作的结果表明，由于 PM 中硝酸盐的主导地位，BC 颗粒的混合状态发生了变化，这也影响了老化 BC 颗粒的光学性质。
