煤矸石风化颗粒的潜在致霾作用研究

Coal combustion, dust, vehicle exhaust, industries, etc. are the key factors causing air pollution. Weathered coal gangue particles are considered to be another potential source of pollution in coal-mining areas, however, the experimental evidence is insufficient. Previously, the applicant found that suspected weathered coal gangue particles were found in the atmospheric PM2.5 in the residential area of the downwind coal gangue hills, which was speculated to originate from the nearby gangue hills. This project aims to compare the distribution patterns of 16 kinds of polycyclic aromatic hydrocarbons, inorganic water-soluble ions and metallic element in the sample system of "nature weathered coal gangue particles-surface dust-atmospheric particulate matter", and the correlation between them is studied. This project also targets to clarify the possibility of the presence of coal gangue weathered particles in atmospheric aerosols, and further reveal its possible impact and contribution to the atmospheric environment combing with the corresponding test data of artificial weathered coal gangue particles. In addition, the study of particles with single particle analysis method using SEM-EDX would examine the long-range transportation and haze-inducing potentials of weathered coal gangue particles. This project would reveal whether the weathered coal gangue particles are involved in the atmospheric particulate matter from multiple perspectives, so as to provide a scientific basis for the prevention and control of air pollution in coal-mining areas.

燃煤、扬尘、机动车排放、工业生产等是引发大气污染的关键因素。煤矸石风化颗粒被认为是导致煤矿区空气质量下降的潜在污染源，但实验证据相对不足。申请者初步研究发现，在煤矸石山下风向居民区大气PM2.5中发现疑似煤矸石风化颗粒，推测其源自附近煤矸石山。本项目以淮北市三个矿区的煤矸石山表层自然风化颗粒、附近居民区地表降尘及大气颗粒物等为研究样本，通过测定样品中16种优控PAHs、无机水溶离子和金属元素，分析比对上述参数在“煤矸石自然风化颗粒-地表降尘-大气颗粒物”样品体系中的分布模式，研究相互之间关联性；结合人工煤矸石风化颗粒的相应测试数据，明确煤矸石风化颗粒在大气气溶胶中存在的可能性，揭示其对煤矿区大气环境的影响及贡献；综合扫描电镜-单颗粒表征，验证部分煤矸石风化颗粒的潜在致霾作用和迁移传输能力。本项目从多角度证明煤矸石风化颗粒是否参与大气颗粒物形成，为煤矿区空气污染防治提供科学依据。

燃煤、扬尘、机动车排放、工业生产等是引发大气污染的关键因素。煤矸石风化颗粒被认为是导致煤矿区空气质量下降的潜在污染源，但实验证据相对不足。本项目围绕煤矸石风化颗粒的潜在致霾作用展开研究，主要研究内容包括：煤矸石山附近大气PM2.5及重金属污染特征；煤矸石单颗粒表征；煤矿区尘土中多环芳烃（PAHs）分布模式。结果表明：采样期间煤矸石场附近大气PM2.5的平均质量浓度为国家空气质量二级日标准的2.26倍，PM2.5中重金属含量也呈现较高水平，且下风向浓度整体高于上风向，下风向距离煤矸石山越近浓度越高，表明煤矸石场可能是重要的空气污染源。主成分分析法显示，煤矸石场附近大气重金属的来源主要有燃煤、土壤尘、煤矸石尘、矿业尘机动车排放和农业活动，其中煤矸石尘、矿业尘贡献较大，占比49.82%。对矸石山附近居民区采集的部分大气PM2.5颗粒进行单颗粒表征，发现其中不仅观察到硅铝酸盐、含硫颗粒和飞灰颗粒等这类常见颗粒(图3(b)(c))，还观察到了煤尘颗粒和风化煤矸石疑似颗粒这类特殊颗粒。进一步分析煤矸石和煤矸石山附近尘土中多环芳烃（PAHs）的分布模式，发现煤矸石和地表尘土中PAHs中分布模式存在一定相似性。 地表灰尘和地表土中aPAHs的平均浓度均远高于16种多环芳烃。来源识别表明，地表尘土中PAHs主要来自石油源和车辆排放，其次是生物质和燃煤。地表灰尘和地表土指纹图谱信息与煤矸石一致，表明PAHs最有可能来源于煤矸石这种被忽视的成岩源。