State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Key Laboratory of Atmospheric Chemistry, China Meteorological Administration, Beijing 100081, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
J Environ Sci (China). 2021 Apr;102:185-197. doi: 10.1016/j.jes.2020.09.015. Epub 2020 Oct 2.
Understanding the formation mechanisms of secondary air pollution is very important for the formulation of air pollution control countermeasures in China. Thus, a large-scale outdoor atmospheric simulation smog chamber was constructed at Chinese Research Academy of Environmental Sciences (the CRAES Chamber), which was designed for simulating the atmospheric photochemical processes under the conditions close to the real atmospheric environment. The chamber consisted of a 56-m fluorinated ethylene propylene (FEP) Teflon film reactor, an electrically-driven stainless steel alloy shield, an auxiliary system, and multiple detection instrumentations. By performing a series of characterization experiments, we obtained basic parameters of the CRAES chamber, such as the mixing ability, the background reactivity, and the wall loss rates of gaseous compounds (propene, NO, NO, ozone) and aerosols (ammonium sulfate). Oxidation experiments were also performed to study the formation of ozone and secondary organic aerosol (SOA), including α-pinene ozonolysis, propene and 1,3,5-trimethylbenzene photooxidation. Temperature and seed effects on the vapor wall loss and SOA yields were obtained in this work: higher temperature and the presence of seed could reduce the vapor wall loss; SOA yield was found to depend inversely on temperature, and the presence of seed could increase SOA yield. The seed was suggested to be used in the chamber to reduce the interaction between the gas phase and chamber walls. The results above showed that the CRAES chamber was reliable and could meet the demands for investigating tropospheric chemistry.
了解二次空气污染的形成机制对于制定中国的空气污染控制对策非常重要。因此，中国环境科学研究院（CRAES 室）建造了一座大型户外大气模拟烟雾箱，用于模拟接近真实大气环境条件下的大气光化学反应过程。该室由一个 56 米长的氟化乙烯丙烯（FEP）聚四氟乙烯薄膜反应器、一个电动不锈钢合金屏蔽、一个辅助系统和多个检测仪器组成。通过进行一系列的特征实验，我们获得了 CRAES 室的基本参数，如混合能力、背景反应性以及气态化合物（丙烯、NO、NO、臭氧）和气溶胶（硫酸铵）的壁损失率。还进行了氧化实验，以研究臭氧和二次有机气溶胶（SOA）的形成，包括α-蒎烯臭氧分解、丙烯和 1,3,5-三甲基苯的光氧化。本工作获得了温度和种子对蒸气壁损失和 SOA 产率的影响：较高的温度和存在种子可以减少蒸气壁损失；SOA 产率反比于温度，而存在种子可以增加 SOA 产率。建议在室中使用种子来减少气相和室壁之间的相互作用。上述结果表明，CRAES 室是可靠的，可以满足研究对流层化学的要求。
