研究报告

  • 刘瑜存,朱雯斐,王毓旻,李挺,陶士康,乔利平,陈军,苏明旭,沈俏会,楼晟荣.基于高质量分辨率质谱仪研究上海城区秋季大气亚微米级颗粒物化学特性[J].环境科学学报,2018,38(7):2746-2756

  • 基于高质量分辨率质谱仪研究上海城区秋季大气亚微米级颗粒物化学特性
  • Characterization of atmospheric submicron particles at an urban site in Shanghai in autumn using a high-resolution aerosol mass spectrometer
  • 基金项目:国家自然科学基金青年基金(No.21407107,21507088)
  • 作者
  • 单位
  • 刘瑜存
  • 1. 上海理工大学 能源与动力工程学院, 上海 200093;2. 国家环境保护城市大气复合污染成因与防治重点实验室, 上海市环境科学研究院, 上海 200233
  • 朱雯斐
  • 1. 国家环境保护城市大气复合污染成因与防治重点实验室, 上海市环境科学研究院, 上海 200233;2. 上海交通大学 环境科学与工程学院, 上海 200240
  • 王毓旻
  • 上海市静安区环境监测站, 上海 200042
  • 李挺
  • 上海市静安区环境监测站, 上海 200042
  • 陶士康
  • 国家环境保护城市大气复合污染成因与防治重点实验室, 上海市环境科学研究院, 上海 200233
  • 乔利平
  • 国家环境保护城市大气复合污染成因与防治重点实验室, 上海市环境科学研究院, 上海 200233
  • 陈军
  • 上海理工大学 能源与动力工程学院, 上海 200093
  • 苏明旭
  • 上海理工大学 能源与动力工程学院, 上海 200093
  • 沈俏会
  • 浙江省环境监测中心, 杭州 310012
  • 楼晟荣
  • 国家环境保护城市大气复合污染成因与防治重点实验室, 上海市环境科学研究院, 上海 200233
  • 摘要:利用先进的高分辨飞行时间气溶胶质谱仪(High Resolution Time-of-Flight Aerosol Mass Spectrometer,HR-ToF-AMS),于2017年9月8日-2017年10月8日对上海市城区开展了亚微米级颗粒物化学组分、粒径及其污染来源的在线测量.结果表明,观测期间上海城区亚微米颗粒物质量浓度平均为(22.0±17.2)μg·m-3;其中,有机物是PM1的主要贡献者,平均占总颗粒物浓度的49.3%,硫酸根、硝酸根和铵根的占比分别为24.2%、10.5%和9.7%.上海城区亚微米级颗粒物中无机盐组分类(硝酸根,硫酸根和铵根)具有较为一致的粒径分布,峰值粒径主要集中在空气动力学粒径500~600 nm.有机物的粒径分布峰值位于空气动力学粒径400~500 nm,且在小粒径范围内有较高的有机物浓度,表明存在一定程度的一次排放.观测期间有机气溶胶呈现明显的多峰分布,硫酸根、铵根和氯离子呈白天低、夜间高的特点,而硫酸根和黑碳的日变化并不明显.基于高分辨率有机质谱计算得到上海城区有机气溶胶氧碳比(O/C)的平均比值为0.37;有机物与有机碳(OM/OC)的平均比值1.65.利用正矩阵因子解析(PMF)模型对有机气溶胶高质量分辨率质谱进行来源解析,得到4类有机气溶胶:HOA(还原态有机气溶胶)、COA(餐饮源有机气溶胶)、MO-OOA(高氧化性有机气溶胶)和LO-OOA(低氧化性有机气溶胶),分别占有机气溶胶总量的15%、20%、32%和26%,说明观测期间上海城区有机气溶胶主要来自二次气溶胶的贡献.
  • Abstract:On-line measurement of chemical composition, size distribution and pollution sources of submicron particles was conducted in Shanghai urban area by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) during September 8 to October 8, 2017. Results shows that the average concentration of submicron particles was (22.0 ±17.2) μg·m-3 during the period. The organic matters (OA), sulfate ions, nitrate ions and ammonium ions accounted for 49.3%, 24.2%, 10.5% and 9.7%, respectively. The size distributions of the inorganic salts (nitrate, sulfate and ammonium ions) had a uniform peak at 500~600 nm in aerodynamic diameter. The size distribution pattern of organic matters was mainly at sizes (400~500 nm) and showed higher concentration at small sizes, indicating an obvious contribution from local primary sources. Organic matters showed multi-peak distributions while nitrate, ammonium and chloride ions showed a single-peak pattern, of which the night-time concentration is higher than day-time concentration. The diurnal changes of sulfate radical and black carbon were not obvious. The average O/C ratio and OM/OC ratio of HR-ToF-AMS measurements were 0.37 and 1.65 respectively. Four groups of OA were identified by analyzing the high-resolution organic mass spectral dataset by positive matrix factorization (PMF), which are hydrocarbon-like (HOA), food-sourced organic aerosol (COA), High oxidizing organic aerosols MO-OOA (MO-OOA) and low oxidizing organic aerosols LO-OOA (LO-OOA), accounting for 15%, 20%, 32% and 26% of the total organic mass, respectively. This results indicating the formation of OA in Shanghai urban area were mainly contributed by secondary organic aerosol during the observation period.

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