高原低压低氧环境下燃煤烟气中PAHs排放表征及迁移行为研究

Polycyclic aromatic hydrocarbons in particulate and gas phase from the coal-fired flue gas exhibited negative impacts on human health. To identify emission characteristic of PAHs from coal-fired sources and establish effective controlling measures of PAHs, it is necessary to collect representative PAHs samples from various air sources in this study, including coal-fired power plant, industrial boilers and domestic coal-fired by using widely accepted dilution sampling method, sixteen kinds of PAHs will be analyzed, source profiles for PAHs will be established. Emission factors for PAHs will be listed by combining data about sources activities levels obtained by field-test and investigation methods. Based on this，transmission paths of PAHs from coal-fired sources in the plateau mountain regions will be studied by wind tunnel simulation and atmospheric diffusion model.The purpose of the proposal is to know the spatial and temporal variations of coal-fired PAHs emission and transmission in the region of plateau mountains. This study can provide some scientific basis for offering exact and basic source data for emission inventories studies of PAHs in air, controlling PAHs pollution and protecting human health from PAHs pollution.

燃煤烟气中颗粒物载带及气态的多环芳烃（PAHs）排放对人体健康有重要影响。为科学认识高原低压低氧环境下燃煤源烟气中PAHs的排放特征，制定高原山地区域防治大气PAHs污染的有效措施，本项目拟通过烟道气稀释采样方法对主要燃煤源（燃煤电厂、工业锅炉和民用燃煤）排放的气、固态PAHs样品进行采集，分析其中16种PAHs，建立源成分谱，并结合相关源活动水平数据，建立其排放因子。在此基础上，通过环境风洞模拟及局地扩散模型研究高原山地区域燃煤源PAHs空间扩散迁移行为；通过环境样品的采集分析高原大气低压环境对PAHs在气固相态分配的影响。本项目旨在认识具有复杂下垫面的高原山地区域燃煤源烟气中PAHs的排放特性及局地传输特征，为准确建立大气PAHs排放清单、合理控制PAHs污染和保护人体健康提供科学依据。

多环芳烃(PAHs)主要来源于人类活动过程中化石燃料的不完全燃烧,其浓度和种类的差异主要来源于燃料和燃烧条件的不同。高原低压低氧环境下存在明显的不完全燃烧现象，却较少受到人们的关注。本文以昆明地区大气环境及燃煤过程为研究对象，开展PAHs的气固分配特征及成分谱特征研究，并分析了PAHs空间扩散特征。主要结论如下：.（1）昆明PAHs浓度较低，气固两相中PAHs的环数分布有着明显的差异：颗粒态中含量高的是中高环（4环以上）PAHs，而在气态中含量高的主要是低环（2-3环）PAHs。昆明城区全年的PAHs气固比为6.58，其中气固比高的单体有PA、FLU、NAP和FL。温度和相对湿度是影响颗粒态PAHs浓度变化的主要气象因素，气态PAHs浓度则与气压和温度呈现良好的相关性。.（2）建立了高原五种工业固定燃煤源PAHs（颗粒态+气态）成分谱。PM10和PM2.5载带的PAHs成分谱中所占比例较高的单体是ANT、FL、BaA、BbF、DBA和BghiP。气态PAHs主要集中在低环单体，如NAP、PA和FLU。.（3）蜂窝煤明烧和闷烧排放的16种多环芳烃的总排放因子分别为4.42±0.75mg/kg和6.01±1.37mg/kg，表明燃烧效率越低可能会产生更多的PAHs。民用燃料燃烧排放PAHs的排放因子相对较低，且颗粒态多环芳烃的占比相对较高，这可能与云南地区低压低氧环境造成的不充分燃烧有关。.（4）利用风洞实验修正了高原坝子地形大气扩散参数，结合AERMOD模型计算结果表明，大气污染物沿着主导风向迁移扩散，未发现在“坝子”区域形成污染物累积现象。