| 西安市PM2.5中碳质气溶胶污染特征 |
| 摘要点击 4587 全文点击 1323 投稿时间：2018-07-17 修订日期：2018-10-30 |
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| 中文关键词 PM2.5 有机碳 元素碳 季节性变化 来源解析 |
| 英文关键词 PM2.5 organic carbon element carbon seasonal change source analysis |
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| 中文摘要 |
| 利用热光分析法探究了西安市2017年353个PM2.5样品中的元素碳（EC）、有机碳（OC）、甲醇可萃取有机碳（MSOC）以及热-光分析法得到的7个碳组分（OC1~4、EC1~3）的质量浓度、季节变化趋势以及来源.结果表明，西安市2017年OC、EC以及MSOC的平均质量浓度分别为（17.56±11.83）、（4.08±2.95）和（11.10±6.77）μg·m-3.OC质量浓度的季节性趋势为冬季 > 春季 > 夏季 > 秋季；EC为冬季 > 春季≈秋季 > 夏季.MSOC/OC比值年平均值为0.64±0.20，冬季最高，夏季最低.春季OC和EC相关性较好（r2=0.76），而在冬季的相关性较差（r2=0.43），说明碳气溶胶的来源不同.采用EC示踪法对二次气溶胶的含量进行估算，SOC的平均含量分别占到了春、夏、秋、冬四季OC质量浓度的51.9%、38.4%、37.3%、44.0%.采用主成分分析法得出西安市的碳质气溶胶主要来源于燃煤和机动车排放. |
| 英文摘要 |
| Mass concentration, seasonal variation and sources of organic carbon (OC), element carbon (EC), methanol-soluble organic carbon (MSOC), and seven carbon components (OC1-4, EC1-3) were detected by thermal-optical analysis of 353 PM2.5 samples in Xi'an in 2017. The results show that the average mass concentrations of OC, EC, and MSOC were (17.56±11.83), (4.08±2.95) and (11.10±6.77) μg·m-3, respectively. The seasonal trend of the OC concentration follows the order winter > spring > summer > autumn. The seasonal trend in EC concentration follows the order winter > spring≈autumn > summer. The average MSOC/OC value is 0.64±0.20. The highest value is observed in winter and the lowest in summer. The correlation between OC and EC is good in spring (r2=0.76), but the correlation is poor in winter (r2=0.43). These results indicate that the source of the carbon aerosols was different. The content of secondary organic aerosols was estimated by the EC tracing method. The average mass concentration of SOC accounted for 51.9%, 38.4%, 37.3% and 44.0% of OC in spring, summer, autumn, and winter, respectively. The main sources of carbonaceous aerosols were analyzed by principal component analysis. The results show that carbonaceous aerosols originate mainly from coal and vehicle emissions in Xi'an. |
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