| 引用本文: | 杨彬，白晓春，吴华成，吴健，周卫青，李朋，王绿.2022.基于单颗粒气溶胶质谱仪的香河采暖季前后含铅颗粒物的组成特征研究[J].地球环境学报,13(1):73-85 |
| YANG Bin, BAI Xiaochun, WU Huacheng, WU Jian, ZHOU Weiqing, LI Peng, WANG Lü.2022.Using single particle aerosol mass spectrum (SPAMS) to study chemical characteristics of Pb-containing particles during heating periods in Xianghe[J].Journal of Earth Environment,13(1):73-85 |
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| 基于单颗粒气溶胶质谱仪的香河采暖季前后含铅颗粒物的组成特征研究 |
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杨彬，白晓春，吴华成，吴健，周卫青，李朋，王绿
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1.国网陕西省电力公司电力科学研究院，西安 710100
2.国网冀北电力有限公司电力科学研究院，北京 100045
3.国网（西安）环保技术中心有限公司，西安 710100
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| 摘要: |
| 为了研究粒径在0.2—2.0 μm的含铅颗粒物的化学组分和粒径分布特征，运用单颗粒气溶胶质谱仪（SPAMS）于2017年10月至2018年1月在河北省香河县开展观测活动。通过自适应神经网络算法（ART-2a）对含铅颗粒物进行命名、合并后，主要分为六类：富钾（Pb-K）、元素碳（Pb-EC）、有机碳元素碳（Pb-OCEC）、有机碳（Pb-OC）、金属（Pb-M）和粉尘（Pb-D）颗粒物。采暖前后含铅颗粒均是Pb-K贡献最大（约46%）。由于受到采暖季煤炭燃烧排放增加的影响，Pb-EC颗粒物占比有所增加。该地区含铅颗粒物与硝酸盐的混合程度最高，Pb-OCEC与硫酸盐的混合程度最高。六种不同类型含铅颗粒物的混合态表明：含铅颗粒物主要与硝酸盐混合（＞50%），与硫酸盐混合程度最高的是Pb-OCEC，其他均＜40%。本文为研究含铅颗粒物在大气中的存在形式和生态健康效应提供了理论依据。 |
| 关键词: 含铅颗粒 单颗粒气溶胶质谱仪 粒径分布 化学组分 混合状态 |
| DOI：10.7515/JEE212019 |
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| 基金项目:国家电网有限公司总部科技项目（52010118000C） |
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| Using single particle aerosol mass spectrum (SPAMS) to study chemical characteristics of Pb-containing particles during heating periods in Xianghe |
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YANG Bin, BAI Xiaochun, WU Huacheng, WU Jian, ZHOU Weiqing, LI Peng, WANG Lü
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1. State Grid Shaanxi Electric Power Research Institute, Xi’an 710100, China
2. State Grid Jibei Electric Power Research Institute, Beijing 100045, China
3. State Grid (Xi’an) Environmental Protection Technology Center Co. Ltd., Xi’an 710100, China
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| Abstract: |
| Background, aim, and scope Lead is one of the most common toxic metals, which has attracted wide attention because of its serious harm to human health, especially the neurotoxicity to fetuses and infants. In addition, lead in the atmosphere can also affect the ecosystem and climate through dry and wet deposition. Lead particles in the atmosphere are mainly sourced from natural and anthropogenic activities. Since lead-containing gasoline was banned worldwide, the sources and concentrations of lead in the environment have changed greatly. However, reducing lead pollution remains a challenge, determining the source and chemical composition characteristics of lead in the atmosphere have great significance for controlling lead pollution. In recent years, online single particle mass spectrometry, which can determine the particle size and chemical composition of a large number of particles at a high time resolution, has made a significant contribution to the study of environmental aerosols, and the research results are of great significance for our in-depth understanding the physical and chemical characteristics of lead-containing particles. In this study, SPAMS was used to determine the chemical composition, size distribution and mixing state of lead-containing particles, the contribution of the heating season to lead particle pollution, and provides scientific basis for related departments to carry out lead pollution prevention and control. Materials and methods The number concentration of PM2.5 in Xianghe were measured by SPAMS, from Oct 5, 2017 to Feb 1, 2018. PM2.5 mass concentration, relative humidity (RH), SO2 concentration and NOx concentration were obtained from the meteorological tower and national Control Station of Xianghe Atmospheric Observatory. We discussed the chemical composition, size distribution and mixing state of lead-containing particles by MATLAB R2014b. In order to explore the influence of heating season on lead particle emission characteristics, our work was divide into the following two stages for analysis: (1) before heating (from 15∶00 on Oct 5, 2017 to 23∶00 on Nov 14, 2017); (2) after heating (00∶00 on November 15, 2017 to 23∶00 on January 31, 2018). Results The average mass concentration of PM2.5 before and after heating were 77.2 μg·m−3 and 102.5 μg·m−3, its maximum was 145.0 μg·m−3 and 256.3 μg·m−3, respectively. The relative coefficient between the variation trend of particles number concentration measured by SPAMS and the mass concentration of PM2.5 during the observation period was 0.8. The average relative humidity (RH) before and after heating was 52% and 36%, respectively. The average gas concentration before and after heating were similar, only the average O3 concentration decreased from 8.5 μg·m−3 to 0.8 μg·−3. According to the natural isotopic abundance of lead, particles with mass charge ratio (m/z) in 206, 207 and 208 were defined as lead-containing particles, accounting for 0.79% of the total number of particles. Based on the mass spectrum characteristics of lead-containing particles, six categories were classified by ART-2a method: potassium-rich (Pb-K), elemental carbon (Pb-EC), organic carbon (Pb-OCEC), organic carbon (Pb-OC), metal (Pb-M) and dust (Pb-D) particles. Pb-K particles were the main contribution (larger than 45%) of lead type particles. Lead-containing particles was mainly distributed between 0.5 μm and 1.2 μm. Each particle was exhibited the peak of secondary species, such as nitrate (46NO2-, 62NO3-) and sulfate (97HSO4-), with different degrees of intensity in the average mass spectra. When RH lowered than 40%, the percentage of all lead particle types were basically stable. With the increase of humidity, except for Pb-D, the percentage of other lead particle types were show different trends. Discussion Before and after the heating season, the percentage of Pb-K particles ranged from 45.6% to 46.6%, while the proportion of Pb-EC particles changes significantly, rising from 29.7% to 31.7%, indicating the important contribution of coal combustion to lead particles. The size distribution of Pb combined with carbonaceous component (Pb-EC, Pb-OCEC, Pb-OC) were from fine mode particles and mainly concentrate on ＜600 nm, Pb combined with other component (Pb-K, Pb-M, Pb-D) were from coarse mode particles and mainly concentrate on ＞600 nm. The results of mixing state shown that Pb-containing particles are mainly mixed with nitrate, especially Pb-K and Pb-D. The prevalence of nitrate in Pb-containing particles may be due to the formation of lead nitrate particle, which is a ubiquitous mode of existence of lead. Overall, RH has no significant influence on inorganic components of Pb particles, but has a certain degree of influence on organic components. Conclusions SPAMS were used to investigate the particle size distribution, chemical composition and mixing characteristics of lead particles in the year 2017 heating season in BTH region. The degree of Pb-OCEC mixing with sulfate was the highest, indicating that carbon particles of organic elements were tend to combined with sulfate. Through the analysis of the relationship between RH and the relative proportions of six types of lead-containing particles, it was found that with the increase of RH, the proportions of sulfate and nitrate in lead-containing particles changed different, showing that liquid phase reaction promoted the formation of sulfate and contributed to the formation of nitrate to a certain extent. Recommendations and perspectives Real-time monitoring of the composition characteristics of metal particles in aerosol particles through SPAMS is of great significance to human health and plays an important role in taking effective measures to control lead pollution. |
| Key words: lead-containing particles single particle aerosol mass spectrometer size distribution chemical
composition mixed state |
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