Abstract：
To investigate the volatility of atmospheric particulates and the evolution of other particulate properties (chemical composition, particle size distribution and mixing state) with temperature, a thermodenuder coupled with a single particle aerosol mass spectrometer was used to conduct continuous observations of atmospheric fine particles in Chengdu, southwest China. Because of their complex sources and secondary reaction processes, the average mass spectra of single particles contained a variety of chemical components (including organic, inorganic and metal species). When the temperature rose from room temperature to 280°C, the relative areas of volatile and semi-volatile components decreased, while the relative areas of less or non-volatile components increased. Most (> 80%) nitrate and sulfate existed in the form of NH4NO3 and (NH4)2SO4, and their volatilization temperatures were 50-100°C and 150-280°C, respectively. The contribution of biomass burning (BB) and vehicle emission (VE) particles increased significantly at 280°C, which emphasized the important role of regional biomass burning and local motor vehicle emissions to the core of particles. With the increase in temperature, the particle size of the particles coated with volatile or semi-volatile components was reduced, and their mixing with secondary inorganic components was significantly weakened. The formation of K-nitrate (KNO3) and K-sulfate (KSO4) particles was dominated by liquid-phase processes and photochemical reactions, respectively. Reducing KNO3 and BB particles is the key to improving visibility. These new results are helpful towards better understanding the initial sources, pollution formation mechanisms and climatic effects of fine particulate matter in this megacity in southwest China.
摘要：
调查大气颗粒物的挥发性和其他颗粒物性质的演变(化学成分，粒度分布和混合状态)随温度的变化，利用热探测器和单粒子气溶胶质谱仪对成都的大气细粒子进行连续观测,中国西南。由于其复杂的来源和二次反应过程，单个颗粒的平均质谱包含多种化学成分(包括有机、无机和金属物种)。当温度从室温升至280℃时，挥发性和半挥发性成分的相对面积减少，而相对面积较少或非挥发性成分增加。大多数（>80％）硝酸盐和硫酸盐以NH4NO3和（NH4）2SO4的形式存在，其挥发温度分别为50-100°C和150-280°C，分别。在280°C时，生物质燃烧（BB）和车辆排放（VE）颗粒的贡献显着增加，其中强调了区域生物质燃烧和局部机动车排放颗粒核心的重要作用。随着温度的升高,涂覆有挥发性或半挥发性成分的颗粒的粒径减小，它们与次要无机成分的混合明显减弱。硝酸钾(KNO3)和硫酸钾(KSO4)颗粒的形成主要是液相过程和光化学反应,分别。减少KNO3和BB颗粒是提高能见度的关键。这些新结果有助于更好地理解初始来源，西南特大城市细颗粒物污染形成机制及气候效应.
