基于毒性效应的民用固体燃料燃烧源细颗粒物的排放特征与减排机理研究

Residential solid fuel combustion (RSFC) such as coal and biofuel is the most important emission source of both indoor and outdoor PM2.5 and also the biggest source of black carbon and polycyclic aromatic hydrocarbons in China, and should be taken as the first point of health effect study of PM2.5. The physicochemical properties and toxic effects of RSFC PM2.5 are key parameters for intensive study on breathing-exposure health hazard and comprehensive effects of various fuel/stove combinations. .In this project, RSFC PM2.5 from typical fuel/stove combination of will be taken as the objective, and after collection by electrostatic precipitator (ESP) from residential chimneys, PM2.5 will be measured for detailed physicochemical properties, including particle size spectra, number concentration, morphology, chemical composition of size-fractionated particles. In addition, PM2.5 and its components such as water soluble fraction, solvent soluble fraction and residual particles will be analyzed for toxicity by DTT method and in vitro cells (including BEAS-2B and HUVECs). Then the internal relationship will be built between physicochemical properties and toxicity of PM2.5, in order to find out its important toxic components. With the help of condition controlled burning experiments in the laboratory, the key factors will be extracted out from fuel properties such as volatile matter content and burning conditions such as serial settings of temperature and oxygen content, which affect the emission factors of the important toxic components, together with their emission reduction mechanism. Finally, suggestions on pollution emission control will be given from the public health viewpoint, which are helpful for policy-makers on pollution priority control measures.

民用煤和生物质等固体燃料燃烧是我国最重要的室内室外PM2.5污染源和最大的黑碳与多环芳烃排放源，可作为我国PM2.5健康影响研究的首要切入点。民用源PM2.5的理化性质和毒性效应是研究呼吸暴露健康危害和评估炉灶改进效果的关键参数。.本项目以典型燃料/炉灶组合排放的PM2.5为研究对象，结合入户测量和静电沉降法（ESP），采集和分析PM2.5的理化性质（粒径谱、数浓度、形态、粒径分级的化学成分），并对PM2.5及组分（水溶性、脂溶性、不溶性部分）开展非细胞法（DTT）和离体细胞（人气道上皮细胞BEAS-2B、人脐静脉血管内皮细胞HUVECs）毒性测试，构建PM2.5理化与毒性的关联，识别重要致毒组分；结合条件控制燃烧实验，探究燃料化学（如：挥发份含量）和燃烧条件（温度和供氧的变化）影响PM2.5致毒组分排放的关键因子及减排机理，提出减排建议，为从公众健康保护角度制定污染优先控制策略提供依据。

针对民用固体燃料燃烧对我国室内室外空气污染及人体健康危害的重要性，急需开展民用源PM2.5的毒性效应测量并识别其重要致毒组分，为从公众健康保护的角度制定致毒组分减排和炉灶技术改进措施提供科学依据。本项目：1）广泛开展典型民用源的入户测量，构建我国现阶段民用源PM2.5的理化特征数据库：利用烟气稀释采样测量系统，在我国东部10个省市160余户农家开展典型民用燃料及炉灶组合的烟气测量，涉及各种固体燃料（秸秆、木柴、煤及其不同形态）和炉灶类型（传统炊事炉和采暖炉、改良采暖炉、蜂窝煤炉），采集了380余组PM2.5样品并详细分析其化学成分，构建了我国民用源PM2.5的成分谱和排放因子数据库；2）开展民用源PM2.5组分分离和毒性表征，识别重要致毒组分：首先设计和优化了一套适用于燃烧源新鲜颗粒物采集与组分分离的方法，即结合多通道大流量采样器和石英纤维滤膜（用于PM2.5水溶性和脂溶性组分分离）、金属纤维滤膜（用于PM2.5不溶性组分分离，主要为黑碳），采集各种典型燃料及炉灶组合的PM2.5样品；再用溶剂连续萃取法对PM2.5样品进行组分分离，分别得到水溶性、脂溶性和不溶性组分，用于毒性测量，并比较不同来源PM2.5及各组分之间的毒性差异；最后，基于DTT实验和多种离体细胞模型对民用源PM2.5的各种组分开展毒性测试，研究了分子生物学机制，为关键致毒组分的识别提供依据；3）探讨民用源PM2.5致毒组分生成排放的影响因素和减排建议：针对民用源PM2.5中两类重要的致毒组分（黑碳和多环芳烃），结合石英管式炉燃烧测量系统，对5种生物质及其三组分提取物（纤维素、半纤维素和木质素）和4种烟煤分别开展控制燃烧实验，燃烧条件包括：起始燃烧温度为300~900oC（以100oC为梯度），氧气氛围为正常空气（21%的O2）和稀释空气（10.5%的O2），探究了生物质和煤燃烧生成黑碳和多环芳烃的影响因素和化学机制，为炉灶技术改进和污染减排措施制定提供了科学依据。