厦门市冬季大气PM_(2.5)中有机碳和元素碳的污染特征

Characteristics of Organic Carbon( OC) and Elemental Carbon( EC)in PM_(2.5) in Winter in Xiamen City,China

为探讨厦门市冬季大气PM_(2.5)含碳组成特征,于2014-12-10至2015-01-09同步采集了城区和郊区的PM_(2.5)样品。采用热光透射法分析了PM_(2.5)中OC、EC的质量浓度。结果表明,近年来厦门市PM_(2.5)、OC、EC的浓度表现出逐年降低的趋势。城区和郊区的OC平均浓度分别为9.77±1.87和9.17±2.42μg/m^3,EC平均浓度分别为1.87±0.73和2.43±1.10μg/m^3,与国内外其他城市相比,厦门市冬季大气PM_(2.5)中的OC、EC浓度均处于较低水平,人为引起的大气含碳成分污染相对较轻。城区和郊区的OC/EC值均大于2,SOC占OC比例分别高达34.96%、39.03%,厦门大气PM_(2.5)中的OC受到二次污染较严重。PM_(2.5)、OC、EC的分布规律表明,OC、EC受到了除天气条件以外的其他因素如OC和EC污染源种类、源强以及二次转化程度的影响。城区(R2=0.107 9)和郊区(R2=0.341 9)的OC与EC相关性不明显,初步判断厦门市冬季PM_(2.5)中OC和EC的来源较复杂,EC可能主要来自化石燃料和生物质不完全燃烧等一次排放源,OC则主要受到化石燃料燃烧和二次污染的影响,城区污染源还包括烹饪源以及生物质燃烧。

Abstract： In order to investigate the characteristics of carbon pollution in atmospheric PM2.5, PM2.5 samples had been synchronously collected in urban and suburban areas of Xiamen City, China from December 10th , 2 014 to January 9th , 2015.Concentrations of organ- ic carbon （OC） and elemental carbon （EC） were analyzed by thermal optical transmission （TOT）.Concentrations of OC, EC and PM25 have showed a decreasing trend in recent years. The average OC concentrations in PM2.5 of urban and suburban areas are 9.77± 1.87 μg/m3 and 9. 17 ± 2.42 μg/m3, respectively. And the average EC concentrations are 1.87 ± 0. 73 μg/m3 and 2.43± 1. 10 μg/m3, respectively. Xiamen shows a lighter anthropogenic carbon pollution level with the comparative lower concentrations of OC and EC comparing with some domestic and foreign cities. However, OC/EC ratios of urban and suburban areas are higher than 2, and the SOC/OC ratios are 34.96% and 39.03%, respectively, suggesting that the secondary OC pollution in Xiamen City is serious. Distributions of PM2.5 , OC and EC indicate that the concentrations of OC and EC in PM2.5 are affected by not only weather conditions but also types of pollution sources, source strength and secondary pollution levels. The correlations between OC and EC in urban（R2= 0. 107 9） and suburban（ R2= 0. 341 9）areas are not significant, indicating that the sources of OC and EC in PM2.5 are relatively com- plex. EC might mainly come from primary emission sources, such as fossil fuel and biomass incomplete combustion. OC is mainly influ- enced by the effects of fossil fuel burning and secondary pollution. In addition, sources of cooking and biomass burning have great con- tribution to urban areas.