生态环境学报 ›› 2022, Vol. 31 ›› Issue (9): 1840-1848.DOI: 10.16258/j.cnki.1674-5906.2022.09.014

• 研究论文 • 上一篇    下一篇

基于氮同位素的珠三角典型地区大气PM2.5中NH4+来源解析

江明1(), 张子洋2, 李婷婷2, 林勃机2, 张正恩2, 廖彤1, 袁鸾1, 潘苏红3, 李军2,*(), 张干2   

  1. 1.国家环境保护区域空气质量监测重点实验室/广东省生态环境监测中心,广东 广州 510308
    2.有机地球化学国家重点实验室,中国科学院广州地球化学研究所,广东 广州 510640
    3.广东省科学院生态环境与土壤研究所,广东 广州 5106501;
  • 收稿日期:2022-08-18 出版日期:2022-09-18 发布日期:2022-11-07
  • 通讯作者: *李军,男,研究员,博士,研究方向为环境地球化学。E-mail: junli@gig.ac.cn
  • 作者简介:江明(1977年生),男,高级工程师,硕士,主要研究方向环境空气质量监测与研究。E-mail: jm787@139.com
  • 基金资助:
    广东省重点领域研发计划项目(2020B1111360003);国家自然科学基金项目(41977177)

Source Apportionment of Ammonium in Atmospheric PM2.5 in the Pearl River Delta Based on Nitrogen Isotope

JIANG Ming1(), ZHANG Ziyang2, LI Tingting2, LIN Boji2, ZHANG Zhengen2, LIAO Tong1, YUAN Luan1, PAN Suhong3, LI Jun2,*(), ZHANG Gan2   

  1. 1. National Key Laboratory for Regional Air Quality Monitoring of Environmental Protection/Guangdong Ecological Environment Monitoring Center, Guangzhou 510308, P. R. China
    2. State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
    3. Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, P. R. China
  • Received:2022-08-18 Online:2022-09-18 Published:2022-11-07

摘要:

铵根离子(NH4+)可促进颗粒形成和吸湿长大,是雾霾颗粒(PM2.5)的重要组分,但其源贡献尚不清楚。准确解析大气NH4+来源存在一定挑战。最近,基于NH4+氮同位素(δ15N)的源解析方法被广泛应用到大气NH4+来源解析。以珠三角鹤山大气超级站为研究地点,开展为期1年的大气PM2.5样品采集,选取了53个大气PM2.5样品,在分析了水溶性离子、有机碳、元素碳和无机元素的基础上,测试了NH4+δ15N值。结果表明,鹤山站大气NH4+年均质量浓度为 (3.39±2.21) μg∙m-3,范围为0.07-10.9 μg∙m-3。NH4+与阴离子物质的量比结果显示鹤山地区为富铵状态,且随机森林模型结果表明,NH4+对于鹤山地区PM2.5的生成具有重要影响。大气颗粒物δ15N-NH4+范围为-14.55‰-18.82‰,其中冬季δ15N-NH4+变化最大(-13.27‰-18.82‰),夏季δ15N-NH4+变化最小(-2.32‰-10.94‰)。贝叶斯源解析结果显示,农业源(畜牧和施肥)和非农业源(生物质燃烧、煤燃烧、机动车排放和废弃物)对大气NH3的年均贡献分别为36.26%和63.74%。在冬季重污染天时(2021年1月6日、1月12日和1月18日),NH4+浓度达全年峰值的同时,非农业源排放占比也达全年最高水平,最高达90.80%,其中机动车排放是非污染天的2-4倍,显示化石燃料燃烧是导致冬季污染事件的重要原因。基于同位素源解析方法所得非农业源NH3排放贡献约为源清单方法所得结果的7倍,源清单法可能严重低估了机动车等重要非农业源的排放贡献。为了进一步改善珠三角地区空气质量,需要重视非农业源NH3的排放。

关键词: 珠三角, 鹤山大气超级站, PM2.5, 铵根离子(NH4+), 氮同位素, 源解析

Abstract:

Ammonium (NH4+) could promote particle formation and hygroscopic growth and is an important component of fine particles (PM2.5), but its source contribution is still unclear. There are some challenges in accurately analyzing the source of atmospheric NH4+. In recent years, the source apportionment method based on nitrogen isotope has been widely applied to the source apportionment of atmospheric NH4+. In this study, Heshan atmospheric super-station in the Pearl River Delta was selected as the research site to carry out a one-year collection of atmospheric PM2.5 samples. A total of 53 atmospheric PM2.5 samples were selected. Based on the analysis of water-soluble ions, organic carbon, elemental carbon and inorganic elements, the δ15N value of ammonium was tested. The results showed that the annual average concentration of ammonium at Heshan station was (3.39±2.21) μg∙m-3, ranging from 0.07 to 10.9 μg∙m-3. The results of the molar ratio of ammonium to anions showed that Heshan region was rich in ammonium, and the results of random forest model showed that NH4+ had an important effect on the formation of PM2.5 in Heshan region. The δ15N-NH4+ value in atmospheric particulate matter ranged from -14.55‰ to 18.82‰, with the largest variation in winter (-13.27‰-18.82‰) and the smallest variation in summer (-2.32‰-10.94‰). The source apportionment results analyzed by Bayesian model showed that the average annual contributions of agricultural sources (livestock and fertilizer) and non-agricultural sources (biomass combustion, coal combustion, vehicle emissions and waste) to atmospheric NH3 were 36.26% and 63.74% respectively. During the heavily polluted days in winter (January 6, January 12 and January 18, 2021), while the NH4+ concentration reached the peak of the whole year, the proportion of non-agricultural source emissions also reached the highest level of the whole year, up to 90.80%. Among them, the emission of vehicles was 2-4 times that of the clean days, indicating that fossil fuel combustion was an important cause of pollution events in winter. The contribution of NH3 emission from non-agricultural sources based on isotope source analysis method was about 7 times that of the emission inventory method. The emission inventory method may seriously underestimate the emission contribution of important non-agricultural sources such as vehicles. In order to further improve the air quality in the Pearl River Delta, it is necessary to pay attention to the emission of NH3 from non-agricultural sources.

Key words: Pearl River Delta, Heshan atmospheric super-station, PM2.5, ammonium, nitrogen isotope, source apportionment

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