Zhu Jiali, Chen Yueyue, Shang Jing, Zhu Tong
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China.
Chemosphere. 2019 Apr;220:883-891. doi: 10.1016/j.chemosphere.2018.12.107. Epub 2018 Dec 15.
Fuel combustion conditions and atmospheric aging processes can affect the physicochemical properties of soot particles, which further change the oxidative potential (OP) of soot. In this study, we generated two soot samples under higher and lower air/fuel ratio (A/F) conditions, and further treated them with ozone (O) at a level similar to that in the polluted atmosphere. The physicochemical properties and OP values (measured by dithiothreitol (DTT) assay, OP) of fresh and ozonised soot samples were compared to investigate the influences of A/F and O aging. Both A/F and O aging significantly affected soot physicochemical properties and OP values. Lower A/F was favourable for generating soot particles containing more polycyclic aromatic hydrocarbon (PAH), water-soluble organic carbon (WSOC), and light-absorbing organics, but fewer oxygen-containing groups. After O aging, a decline in PAHs and increase in oxygen-containing groups and WSOC were observed in both aged soot samples. In addition, both lower A/F and O aging enhanced soot OP values. Soot generated under lower A/F was more sensitive to O aging, after which there was a significantly greater change in physicochemical characteristics, in turn contributing substantially to the greater OP increase observed in low-A/F soot.
燃料燃烧条件和大气老化过程会影响烟灰颗粒的物理化学性质，进而改变烟灰的氧化潜力（OP）。在本研究中，我们在较高和较低空燃比（A/F）条件下生成了两个烟灰样本，并在与污染大气中相似的水平下用臭氧（O）对其进行进一步处理。比较了新鲜烟灰样本和经臭氧处理的烟灰样本的物理化学性质和OP值（通过二硫苏糖醇（DTT）测定法测量，即OP），以研究A/F和O老化的影响。A/F和O老化均显著影响烟灰的物理化学性质和OP值。较低的A/F有利于生成含有更多多环芳烃（PAH）、水溶性有机碳（WSOC）和吸光有机物，但含氧基团较少的烟灰颗粒。经O老化后，在两个老化烟灰样本中均观察到PAHs含量下降，含氧基团和WSOC含量增加。此外，较低的A/F和O老化均提高了烟灰的OP值。在较低A/F条件下生成的烟灰对O老化更敏感，老化后其物理化学特性变化显著更大，进而导致在低A/F烟灰中观察到的OP增加幅度更大。
