Niu Zhenchuan, Zhang Fuwang, Kong Xiangrui, Chen Jinsheng, Yin Liqian, Xu Lingling
Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Environ Monit. 2012 Nov;14(11):2961-7. doi: 10.1039/c2em30337j.
To understand the influence of the urbanization process on the air quality in the urban neighbourhood area, the size distribution and seasonal variations of elemental and organic carbon in aerosols were studied at a coastal and suburban site in Xiamen City, China. A total of 87 samples were obtained during the one-year measurement campaign from June 2009 to May 2010. The results indicated that 79.3 ± 3.2% of the organic carbon (OC) and 88.3 ± 1.7% of the elemental carbon (EC) were associated with fine particles (PM(2.5)), which consist of 32.0 ± 8.3% of the total carbonaceous aerosol (TCA). The concentrations of the OC and EC in PM(2.5) were 17.8 ± 11.2 and 3.8 ± 1.9 μg m(-3), respectively, and high concentrations were usually observed when the wind direction was northeast (NE). High OC/EC ratios (average 5.1) in PM(2.5) indicated the formation of secondary organic carbon (SOC), which contributed 60.0% to the OC and 11.0% to the particulate matter. At this site, SOC had a significant negative correlation with the temperature (R(2) = 0.42), and a favorable meteorological condition for SOC formation was found in the wintertime. The OC/EC ratios increased with particle size, while the fractions of the carbonaceous aerosols to particulate matter decreased. OC, EC and SOC concentrations and OC/EC ratios followed the same seasonal pattern of winter > spring > autumn > summer, which mainly resulted from the various origins of the air masses in different seasons. This study indicates the requirement for mitigating the pollution of carbonaceous aerosol at this coastal and suburban area in Xiamen City.
为了解城市化进程对城市居民区空气质量的影响，在中国厦门市的一个沿海和郊区站点，对气溶胶中元素碳和有机碳的粒径分布及季节变化进行了研究。在2009年6月至2010年5月为期一年的测量活动中，共采集了87个样本。结果表明，79.3±3.2%的有机碳（OC）和88.3±1.7%的元素碳（EC）与细颗粒物（PM(2.5)）相关，细颗粒物占总碳质气溶胶（TCA）的32.0±8.3%。PM(2.5)中OC和EC的浓度分别为17.8±11.2和3.8±1.9μg m(-3)，通常在风向为东北（NE）时观测到高浓度。PM(2.5)中高OC/EC比值（平均5.1）表明二次有机碳（SOC）的形成，其对OC的贡献率为60.0%，对颗粒物的贡献率为11.0%。在该站点，SOC与温度呈显著负相关（R(2)=0.42），且在冬季发现了有利于SOC形成的气象条件。OC/EC比值随粒径增大而增加，而碳质气溶胶在颗粒物中的占比则下降。OC、EC和SOC浓度以及OC/EC比值遵循冬季>春季>秋季>夏季的相同季节模式，这主要是由于不同季节气团来源各异。本研究表明了在厦门市这个沿海和郊区地区减轻碳质气溶胶污染的必要性。
