焦炉顶和厂区环境中有机碳和元素碳的粒径分布

Aerosol Size Distribution of Organic Carbon and Elemental Carbon on the Top of Coke Oven and in the Plant Area

为了明确焦炉顶和厂区环境空气颗粒物中有机碳(organic carbon,OC)和元素碳(elemental carbon,EC)的污染特征,利用美国Staplex234大流量采样器(粒径:≤1.4μm、1.4～2.1μm、2.1～4.2μm、4.2～10.2μm、≥10.2μm)采集焦炉顶和厂区的环境空气颗粒物样品,并用德国Elementar Analysensysteme GmbH vario EL cube分析其中的OC和EC组分.结果表明,焦炉顶TSP中ρ(OC)和ρ(EC)分别为291.6μg·m-3、255.1μg·m-3,厂区ρ(OC)和ρ(EC)分别为377.8μg·m-3、151.7μg·m-3;厂区≤1.4μm颗粒物中二次有机碳(secondary organic carbon,SOC)的质量浓度为147.3μg·m-3;焦炉顶≤2.1μm颗粒物中ρ(OC)/ρ(EC)值为1.3.厂区TSP中ρ(EC)低于焦炉顶,ρ(OC)明显高于焦炉顶,且厂区≤10.2μm颗粒物中ρ(OC)、ρ(EC)远高于焦化厂所在地区环境空气;焦炉顶和厂区的OC、EC均主要富集在细颗粒物中,焦炉顶和厂区OC的粒径分布差别较大,厂区比焦炉顶OC的粒径分布更趋向于向细颗粒物分布,焦炉顶和厂区EC的粒径分布相似;厂区粒径≤10.2μm颗粒物中,随着粒径的减小,ρ(SOC)和SOC对OC的贡献均呈增大的趋势.

In order to investigate the characteristic of organic carbon （OC） and elemental carbon （EC） in particles on the top of coke oven and in the plant area, the particle matter samples of five size fraction including ≤1.4 μm, 1.4-2.1 μm, 2.1-4.2 μm, 4.2-10.2 μm and ≥10.2 μm were collected using Staplex234 cascade impactor, and OC and EC were analyzed by Elementar Analysensysteme GmbH vario EL cube. The mass concentrations of OC and EC associated with TSP on the top of coke oven were 291.6 μg·m-3 and 255.1 μg·m-3, while those in the plant area were 377.8 μg·m-3 and 151.7 μg·m-3. The mass concentration of secondary organic carbon （SOC） in particles with size of ≤1.4 μm was 147.3 μg·m-3 in the plant area. The value of OC/EC in particles less than 2.1 μm was 1.3 on the top of coke oven. The mass concentration of EC in TSP in the plant area was lower than that on the top of coke oven, while the mass concentration of OC in the plant area was significantly higher than that on the top of coke oven. The mass concentrations of OC and EC associated with particles less than 10.2 μm in the plant area were far higher than those in the atmosphere of area where the coke plant is located. The OC and EC in particles, which were collected both on the top of coke oven and in the plant area, were mainly enriched in fine particles. The size distribution of OC showed a clear distinction between the coke oven top and the plant area, which revealed that OC in the plant area was more preferably enriched in fine particles than that on the top of coke oven, and the same size distribution of EC was found on the top of coke oven and in the plant area. In the plant area, the mass concentration of SOC and the contribution of SOC to OC increased with the decreasing diameter in particles with diameter of less than 10.2 μm.