曾兆荷,张海潇,赵云卿,郭照冰.南京北郊冬夏季大气PM2.5中水溶性有机碳的研究[J].环境科学学报,2019,39(11):3659-3667
南京北郊冬夏季大气PM2.5中水溶性有机碳的研究
- The study of water-soluble organic carbon in PM2.5 during winter and summer in the northern suburb of Nanjing
- 基金项目：国家自然科学基金（No.41373023，91544229-02，41625006）；江苏省"333人才工程"项目；江苏省"青蓝工程"项目
- 曾兆荷
- 1. 南京信息工程大学环境科学与工程学院, 南京 210044;2. 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044
- 张海潇
- 1. 南京信息工程大学环境科学与工程学院, 南京 210044;2. 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044
- 赵云卿
- 1. 南京信息工程大学环境科学与工程学院, 南京 210044;2. 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044
- 郭照冰
- 1. 南京信息工程大学环境科学与工程学院, 南京 210044;2. 江苏省大气环境监测与污染控制高技术研究重点实验室, 南京 210044
- 摘要：为研究南京北郊大气PM2.5中水溶性有机碳（WSOC）的浓度及来源特点，在冬、夏季分别采集PM2.5样品，还同步收集臭氧（O3）浓度与相对湿度（RH）数据，分析了PM2.5、有机碳（OC）、水溶性有机碳（WSOC）浓度特征，并对WSOC冬、夏季来源及其二次来源差异进行了探讨.结果显示，南京北郊冬季大气污染水平明显高于夏季且来源更复杂，与冬季静稳的天气条件及化石燃料和生物质燃烧排放较严重有关.冬季PM2.5平均值为（136.7±42.4）μg·m-3，OC、WSOC浓度分别为（13.4±4.4）、（8.5±3.1）μg·m-3；夏季PM2.5、OC、WSOC平均浓度分别为（61.5±14.6）、（6.7±2.1）、（4.6±1.7）μg·m-3.冬、夏季WSOC/OC值分别为67%±20%、69%±13%，且二次有机碳（SOC）与WSOC显著正相关，说明二次来源对WSOC有显著影响.冬季WSOC与O3的负相关性不显著，与RH显著正相关；而夏季WSOC与O3、RH的相关性正好与冬季相反，说明冬、夏季二次WSOC形成途径存在差异.冬季二次WSOC可能主要来自液相氧化，夏季可能主要来自光化学氧化.通过主成分因子分析法进一步确定南京北郊冬、夏季WSOC分别主要来源于二次来源和生物质燃烧、汽车尾气和扬尘.
- Abstract：In order to study both concentration and source characteristics for water-soluble organic carbon (WSOC) in PM2.5 from the northern suburbs of Nanjing, PM2.5 samples were collected respectively in both winter and summer, and the investigation of data for both ozone (O3) concentration and relative humidity (RH) was done simultaneously. The concentration characteristics were analyzed including PM2.5, organic carbon (OC) and water-soluble organic carbon (WSOC). The sources of WSOC in both winter and summer were discussed, as well as different secondary sources. The results showed that pollution levels in winter were significantly higher than that in summer, and the source in winter was more complicated, which was related to the static meteorological conditions and the serious combustion emissions for both fossil fuels and biomass. The average values of PM2.5, OC and WSOC were respectively (136.7±42.4), (13.4±4.4) and (8.5±3.1) μg·m-3 in winter, while respectively (61.5±14.6), (6.7±2.1) and (4.6±1.7) μg·m-3in summer. The WSOC/OC values in both winter and summer were respectively 67%±20% and 69%±13%, moreover there was an obvious correlation between secondary organic carbon (SOC) and WSOC, which indicated that secondary sources had significant effects on WSOC. WSOC has a weakly negative correlation with O3, while a strongly positive correlation with RH in winter. However, the opposite cases were found in summer. It implied that the formation of secondary WSOC (potentially come from liquid phase oxidation) in winter were different from the one (potentially come from photochemical oxidation) in summer. Through the principal component factor analysis method, it further suggested that WSOC in both winter and summer mainly originated from secondary sources, biomass combustion, automobile exhaust and dust.
