二次有机气溶胶(SOAs)是挥发性有机化合物在大气中氧化形成的细小气载颗粒。气态 VOC 会与 [latex]O_3[/latex]、[latex]/bullet OH[/latex] 或 [latex]NO_3\bullet[/latex] 等氧化剂发生反应,生成低挥发性产品。然后,这些产物可以通过形成新颗粒(成核)或冷凝到预先存在的气溶胶上,进行气体到颗粒的转化。SOAs 是 PM2.5 的主要成分,会影响气候和人类健康。.

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二次有机气溶胶(SOAs)是挥发性有机化合物在大气中氧化形成的细小气载颗粒。气态 VOC 会与 [latex]O_3[/latex]、[latex]/bullet OH[/latex] 或 [latex]NO_3\bullet[/latex] 等氧化剂发生反应,生成低挥发性产品。然后,这些产物可以通过形成新颗粒(成核)或冷凝到预先存在的气溶胶上,进行气体到颗粒的转化。SOAs 是 PM2.5 的主要成分,会影响气候和人类健康。.
气态有机物(SOA)的形成是大气中至关重要但极其复杂的过程。该过程始于母体挥发性有机物(VOC)的气相氧化反应,这些VOC可源于生物源(如α-蒎烯)或人为源(如甲苯)。 这一初始氧化步骤会在碳主链上添加羟基(-OH)、羰基(=O)和羧基(-COOH)等官能团。这些官能团的引入会降低分子的挥发性(即其保持气态的倾向)。.
After one or more oxidation steps, the resulting products may have sufficiently low vapor pressure to partition into the particle phase. This partitioning is governed by absorptive partitioning theory, where the semi-volatile gas dissolves into an existing organic aerosol phase. Alternatively, if concentrations of very low volatility products are high enough, they can nucleate to form entirely new particles. The chemistry can continue within the aerosol particle itself (aqueous-phase or multiphase chemistry), leading to the formation of even larger, more complex molecules and further increasing the particle’s mass. Because SOAs can scatter and absorb solar radiation and act as cloud condensation nuclei, they play a significant, yet uncertain, role in the Earth’s climate system.
二次有机气溶胶(SOA)
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