Weitkamp Emily A, Sage Amy M, Pierce Jeffrey R, Donahue Neil M, Robinson Allen L
Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA.
Environ Sci Technol. 2007 Oct 15;41(20):6969-75. doi: 10.1021/es070193r.
Diluted exhaust from a diesel engine was photo-oxidized in a smog chamber to investigate secondary organic aerosol (SOA) production. Photochemical aging rapidly produces significant SOA, almost doubling the organic aerosol contribution of primary emissions after several hours of processing at atmospherically relevant hydroxyl radical concentrations. Less than 10% of the SOA mass can be explained using a SOA model and the measured oxidation of known precursors such as light aromatics. However, the ultimate yield of SOA is uncertain because it is sensitive to treatment of particle and vapor losses to the chamber walls. Mass spectra from an aerosol mass spectrometer (AMS) reveal that the organic aerosol becomes progressively more oxidized throughout the experiments, consistent with sustained, multi-generational production. The data provide strong evidence that the oxidation of a wide array of precursors that are currently not accounted for in existing models contributes to ambient SOA formation.
在烟雾箱中对柴油机稀释废气进行光氧化，以研究二次有机气溶胶（SOA）的生成。光化学老化迅速产生大量SOA，在与大气相关的羟基自由基浓度下经过数小时处理后，有机气溶胶对一次排放的贡献几乎翻倍。使用SOA模型以及已知前体（如轻质芳烃）的实测氧化情况，只能解释不到10%的SOA质量。然而，SOA的最终产率并不确定，因为它对颗粒和蒸汽在腔壁上的损失处理很敏感。气溶胶质谱仪（AMS）的质谱显示，在整个实验过程中，有机气溶胶的氧化程度逐渐增加，这与持续的多代生成一致。这些数据提供了有力证据，表明现有模型中目前未考虑的多种前体的氧化对环境SOA的形成有贡献。
