哈尔滨市一次降雪过程多环芳烃的污染特征研究

Pollution Characteristics of Polycyclic Aromatic Hydrocarbons of Snowfall Process in Harbin City

摘要:

为研究我国高寒地区典型城市降雪中多环芳烃（PAHs）的污染水平及空间分布特征，根据哈尔滨市不同功能区域划分，共布设9个采样点进行降雪样品的采集，并利用GC—MS测定PAHs的浓度。结果表明，哈尔滨市降雪中16种PAHs的总质量浓度范围为33.2~2306.6ng/dL，平均质量浓度为1144.38ng/dL，PAHs质量浓度具有明显的功能区域差异，其空间分布体现为：农村1724.1ng/dL，商业交通混合区1662.6ng/dL，市区公园832.0ng/dL，居民区528.6ng/dL和郊区33.2ng/dL，农村和商业交通混合区PAHs的浓度约为郊区的50倍，其中污染源和大气扩散条件是影响降雪中PAHs浓度呈现区域化差异的主要原因。研究发现3~4环PAHs含量相对较高，约占PAHs总浓度的66.8%~77.3%，PAHs的单体含量也存在较大差异，其中菲（Phe）的含量在所有单体中最高。降雪样品中2环PAHs处于强变异，而其他环数PAHs则表现为中等变异，污染来源与理化性质的不同均可能会造成PAHs的空间异质。结合比值法和因子分析法，初步判定哈尔滨市降雪中PAHs主要来源为煤和生物质的燃烧，以及汽车尾气排放等。

Abstract:

The pollution level and spatial distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in snowfall of typical city of the alpine region of China were investigated. According to different functions, nine snowfall sampling points were collected in Harbin, and concentration of PAHs was measured by GC—MS. The results demonstrated that the concentration of 16 kinds of PAHs was ranged from 33.2ng/dL to 2306.6ng/dL in Harbin snowfall, the average concentration was 1144.38ng/dL. The concentration of PAHs had obvious regional difference in different functional areas, its spatial distribution showed that the concentration in rural was 1724.1ng/dL, in commercialtraffic area was 1662.6ng/dL, in city park was 832.0ng/dL, in residence community was 528.6ng/dL and that in suburb was 33.2ng/dL, the concentration in rural and commercialtraffic area was about 50 times lager than that in suburb. Pollution sources and atmospheric diffusion conditions were the major reasons for regional difference of PAHs concentration in snowfall. It was found that the 3~4 rings PAHs content was relatively higher, which accounted for 66.8%~77.3% of total PAHs concentration. The monomer content of PAHs was also quite different, and phenanthrene (Phe) was the highest in all the monomer. In snowfall samples, the 2 ring PAHs was in strong variation, while the other ring PAHs was in moderate variation, pollution sources and physical and chemical properties might be expected to result in existence of PAHs spatial heterogeneity characteristic. Diagnostic ratio and factor analysis method were adopted to analyze the data, preliminary results showed that the source of PAHs in Harbin snowfall were coal and biofuel combustion and automobile emissions. The research results would provide reference and scientific basis for numerical simulation of secondary emission of PAHs during snow melting process, snowmelt runoff numerical simulation and formulation of environmental pollution control measures and its management policies.