识别聚合物作为大气有机气溶的主要成分
1Department of Chemistry and Applied Biosciences, ETH Zurich, 8053 Zurich, Switzerland. kalberer@org.chem.ethz.ch
Science (New York, N.Y.)
|March 16, 2004
概括
芳香化合物的光氧化在有机气溶中形成显著的聚合物质量. 这种聚合降低了挥发性,增加了气溶产量,影响了大气模型.
科学领域:
- 大气化学 大气化学
- 有机气溶形成有机气溶形成
背景情况:
- 二次有机气溶 (SOA) 显著影响气候和空气质量.
- 了解SOA的化学组成和演变对于准确的大气建模至关重要.
研究的目的:
- 研究芳香化合物的光氧化过程中聚合物的形成和特性.
- 评估聚合物对二次有机气溶挥发性和产量的影响.
主要方法:
- 在反应室中对芳香化合物的受控光氧化实验.
- 气溶质量组成和分子重量分布的分析.
- 将实验结果与基于个体物种蒸汽压力的模型预测进行比较.
主要成果:
- 有机气溶质量的很大一部分是由碳烯反应形成的聚合物组成的.
- 经过20小时的老化,聚合物 (高达1000Da) 约占颗粒质量的50%.
- 与没有这种工艺的模型相比,聚合会导致挥发率降低和气溶产量更高.
结论:
- 聚合是芳香衍生SOA的老化过程中的一个关键过程.
- 聚合物的形成显著改变了SOA的特性,影响了它的大气寿命和直接的辐射强迫.
- 当前的大气模型可能低估了SOA质量及其对气候的影响,因为忽视了聚合.
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