Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
Environ Sci Technol. 2014 Dec 2;48(23):13743-50. doi: 10.1021/es5035188. Epub 2014 Nov 19.
Secondary organic aerosol (SOA) is a major component of atmospheric fine particle mass. Intermediate-volatility organic compounds (IVOCs) have been proposed to be an important source of SOA. We present a comprehensive analysis of atmospheric IVOC concentrations and their SOA production using measurements made in Pasadena, California during the California at the Nexus of Air Quality and Climate Change (CalNex) study. The campaign-average concentration of primary IVOCs was 6.3 ± 1.9 μg m(-3) (average ± standard deviation), which is comparable to the concentration of organic aerosol but only 7.4 ± 1.2% of the concentration of speciated volatile organic compounds. Only 8.6 ± 2.2% of the mass of the primary IVOCs was speciated. Almost no weekend/weekday variation in the ambient concentration of both speciated and total primary IVOCs was observed, suggesting that petroleum-related sources other than on-road diesel vehicles contribute substantially to the IVOC emissions. Primary IVOCs are estimated to produce about 30% of newly formed SOA in the afternoon during CalNex, about 5 times that from single-ring aromatics. The importance of IVOCs in SOA formation is expected to be similar in many urban environments.
二次有机气溶胶 (SOA) 是大气细颗粒物质量的主要组成部分。中间挥发性有机化合物 (IVOCs) 被认为是 SOA 的重要来源。我们使用在加利福尼亚州帕萨迪纳进行的加利福尼亚空气质量和气候变化关系研究 (CalNex) 期间的测量结果，对大气 IVOC 浓度及其 SOA 生成进行了全面分析。运动期间的一次 IVOC 浓度平均值为 6.3 ± 1.9 μg m(-3)（平均值 ± 标准偏差），与有机气溶胶的浓度相当，但仅为挥发性有机化合物种类浓度的 7.4 ± 1.2%。一次 IVOC 中只有 8.6 ± 2.2%被指定了种类。几乎没有观察到环境中一次和总 IVOC 浓度的周末/工作日变化，这表明除了道路柴油车之外，石油相关来源对 IVOC 排放有很大贡献。在 CalNex 期间，一次 IVOC 估计会在下午产生约 30%的新形成的 SOA，比单环芳烃产生的 SOA 多 5 倍。IVOCs 在 SOA 形成中的重要性预计在许多城市环境中是相似的。
