摘要
为研究西安市夏、秋、冬3季大气细颗粒物中碳组分的污染变化规律,于2013年夏、秋、冬3季在西安市明城墙内采集大气中的PM2.5样品,测定了样品中的有机碳和元素碳的含量。结果显示,PM2.5中OC和EC的季节平均浓度冬季最高,秋季次之,夏季最低。OC/EC的比值在夏、秋、冬3季均超过2.0,说明采样期间夏、秋、冬3季均存在二次污染。OC/PM2.5的比值夏秋两季差异较小,冬季明显高于夏秋两季;EC/PM2.5的比值在夏、秋、冬3季的变化不大。OC和EC的相关性:夏季>秋季>冬季。OC与PM2.5的相关程度冬季>秋季>夏季,且随季节更替变化明显;EC与PM2.5的相关性:秋季>夏季>冬季。即随着季节变化PM2.5浓度水平整体升高、污染加重时,PM2.5中的OC所占比例明显升高,EC比较稳定,说明受人为影响的二次排放为主要成分的OC对PM2.5贡献更大。
In this paper, PM2.5 samples were collected within the city wall of Ming Dynasty in Xi'an City during the summer, autumn and winter of 2013 to determine the content of organic carbon(OC) and elemental carbon(EC) for the study of the pollution characteristics of the carbon contained in the atmospheric fine particles. The result showed that seasonal average concentration of OC and EC in PM2.5 was highest in winter, followed by autumn and summer in a descending order. The ratio of OC/EC in summer, autumn and winter was all exceeding 2.0, indicating that there was secondary pollution during the sampling period. The ratio of OC/PM2.5 was obviously higher in winter than that in summer and autumn, but there was little difference between the ratio of OC/PM2.5 in summer and in autumn. The ratio of EC/PM2.5 in the three seasons varied slightly. Correlation between OC and EC was in the descending order of summer, autumn and winter. Relevance between OC and PM2.5 was highest in winter, followed by autumn and summer, clearly changed with the seasonal alternation. Correlation between EC and PM2.5 was in the descending order of autumn, summer and winter. That was, when the concentration level of PM2.5 was overall increased with the seasonal alternation and the pollution got more serious, the proportion of OC in PM2.5 was increased noticeably, but that of EC was comparatively stable, showing that as the main component of the secondary emission primarily influenced by human activities, OC contributed more to PM2.5.
出处
《环境保护科学》
CAS
2015年第2期80-85,共6页
Environmental Protection Science
关键词
细颗粒物
有机碳
元素碳
西安
相关性
Fine Particle
Organic Carbon (OC)
Elemental Carbon (EC)
Xi'an
Correlation