南京北郊夏季大气颗粒物中有机碳和元素碳的污染特征

Pollution Characteristics of Organic and Elemental Carbon in Atmospheric Particles in Nanjing Northern Suburb in Summer

采用DRI Model 2001A热/光碳分析仪对2013年5-7月期间南京北郊大气气溶胶9级惯性撞击式分级Andersen采样器膜采样样品中有机碳（OC）和元素碳（EC）的质量浓度进行了分析.结果表明,南京北郊夏季EC、OC的平均浓度,在PM2.1（空气动力学直径≤2.1μm）中分别为（2.6±1.1）μg·m^-33.0±5.2）μg·m^-3，在PM9.0（空气动力学直径≤9.0μm）中,分别为（3.4±1.7）μg·m^-3（20.3±7.3）μg·m^-3,EC主要富集在超细颗粒物中,OC主要存在于细颗粒物中,EC的PM1.1/PM9.0比值和OC的PM2.1/PM9.0比值分别为0.62和0.64.EC和OC浓度的平均最高值都出现在≤0.43μm粒径段中,分别占PM9.0中的总元素碳的33.4%和总有机碳的21.1%.南京北郊夏季PM1.1、PM2.1和PM9.0中EC、OC的相关性较好,说明存在共同的一次污染源.通过OC/EC特征物比值的方法得到南京夏季碳质颗粒物的主要来源有机动车尾气排放、燃煤排放和地面扬尘排放.

To understand organic carbon（ OC） and elemental carbon（ EC） mass concentration,the particles samples were collected by an Andersen cascade impactor and analyzed with the DRI analyzer in Nanjing northern suburb during May to July in 2013. The results showed that the average mass concentrations of EC and OC in PM2. 1were（ 2. 6 ± 1. 1） μg·m^-3 13.0 ±5.2） μg·m^-3d（ 3.4 ±1.7） μg·m^-3 20.3 ±7.3） μg·m^-3 PM9. 0,respectively. EC was mainly enriched in ultrafine particles,and OC was mainly in fine particles. The ratios of PM1. 1（ EC） /PM9. 0（ EC） and PM2. 1（ OC） /PM9. 0（ OC） were 0.62 and 0.64,respectively. The average peak of concentration of both EC and OC appeared in 0. 43 μm,accounting for 33. 4% of TEC and 21. 1% of TOC. EC and OC in PM1. 1,PM2. 1and PM9. 0had a good relation during the summer in Nanjing northern suburb,suggesting that they shared the same source. Ratios of OC and EC indicated that the main origins of carbonaceous particles were attributed to automobile exhaust fumes,coal combustion and road dust.