摘要
对2015年1月9日~2015年1月31日临安、南京和苏州3个站点采集的PM_(2.5)样品(共计279组),使用热光反射法(thermal/optical reflectance,TOR)分析了样品中有机碳(OC)与元素碳(EC)的含量,并研究了长三角地区冬季PM_(2.5)中OC和EC的污染特征.结果表明,采样期间临安、南京和苏州的PM_(2.5)平均质量浓度分别为(123.56±61.11)、(144.77±62.91)和(156.5±68.97)μg·m-3,均超过我国《环境空气质量标准》(GB 3095-2012)规定的PM_(2.5)日均值75μg·m-3;其中3个站点OC与EC的平均质量浓度依次分别为(21.93±11.69)/(6±3.6)、(20.32±10.3)/(5.39±3.07)和(27.08±14.35)/(6.4±4.29)μg·m-3.临安作为长三角大气环境背景点,OC与EC的污染也较为严重.3个站点OC与EC的相关性为临安(R2=0.83)、南京(R2=0.72)和苏州(R2=0.72),表明冬季长三角地区的碳质气溶胶的来源较为一致和稳定.3个站点样品中的OC/EC值均大于2.0,样品的OC/EC值主要分布在2.5~6.0这个区间内,表明燃煤源和机动车尾气排放源是OC与EC的主要来源.使用EC示踪法估算临安、南京和苏州3个站点的二次有机碳(SOC)平均质量浓度分别为(9.23±5.26)、(6.82±4.36)和(12.56±7.52)μg·m-3,在OC中占比为42%、34%和46%,表明SOC是OC的重要组成部分.后向轨迹显示,PM_(2.5)、OC和EC的质量浓度与主要气团的传输路径有较好的相关性,自空气质量较差区域气团的PM_(2.5)、OC和EC的质量浓度是来自空气质量较好区域的1.14~1.7倍、1.55~2.1倍和1.94~2.47倍.
Two hundred seventy-nine PM2.5 samples were collected from January 9,2015 to January 31,2015 in Lin＇an,Nanjing,and Suzhou. They were analyzed for organic carbon（OC） and elemental carbon（EC） following the thermal/optical reflection protocol.The pollution characteristics of OC and EC in PM2.5 during the winter in the Yangtze River Delta were discussed in detail. The average mass concentrations of PM2.5 in the three sample sites were（123. 56 ± 61. 11）,（144. 77 ± 62. 91）,and（156. 5 ± 68. 97） μg·m^-3,respectively,which were in excess of the Ambient Air Quality Standard（GB 3095-2012） 24-hr mass-based standard of 75 μg·m^-3.The average mass concentration of OC and EC were（21. 93 ± 11. 69）/（6 ± 3. 6）,（20. 32 ± 10. 3）/（5. 39 ± 3. 07）,and（27. 08 ±14. 35）/（6. 4 ± 4. 29） μg·m^-3,respectively. Lin＇an,which is regarded as the background site for the atmospheric environment in the Yangtze River Delta,is also polluted seriously. The OC was strongly correlated with EC in Lin＇an（R^2= 0. 83）,Nanjing（R^2= 0. 72）,and Suzhou（R^2= 0. 72）. This shows that the carbonaceous aerosols have similar sources during the winter in the Yangtze River Delta.All of the samples＇ OC/EC ratios exceeded 2. 0,with the sample OC/EC ratios mainly distributed in the range of 2. 5-6. 0,indicating that coal combustion and vehicle exhaust are the main sources of OC and EC. The estimated mass concentrations of SOC were（9. 23 ±5. 26）,（6. 82 ± 4. 36）,and（12. 56 ± 7. 52） μg·m^-3,respectively,which contributed 42%,34%,and 46% to the OC,indicating that SOC is an important part of OC. Backward-trajectory shows that the mass concentrations of PM2.5,OC,and EC have a good correlation with the transmission path of the main air mass. The mass concentrations of PM2.5,OC,and EC controlled by the air mass from poor air quality areas are 1. 14-1. 7 times,1. 55-2. 1 times,and 1. 94-2. 47 times higher than that in the air mass from good air quality areas.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第3期961-971,共11页
Environmental Science
基金
国家自然科学基金项目(91544229)
国家重点研发计划项目(2016YFA0602003)
南京信息工程大学人才启动经费资助项目(2016r040)
关键词
PM2.5
长三角
有机碳
元素碳
浓度分布
PM2.5
Yangtze River Delta
organic carbon（OC）
elemental carbon（EC）
concentration distribution
