Jang Myoseon, Czoschke Nadine M, Northcross Amanda L
Department of Environmental Sciences and Engineering, CB# 7431, Rosenau Hall, The University of North Carolina at Chapel Hill Chapel Hill, NC 27599, USA.
Chemphyschem. 2004 Nov 12;5(11):1647-61. doi: 10.1002/cphc.200301077.
Exploratory evidence from our laboratories shows that acidic surfaces on atmospheric aerosols lead to very real and potentially multifold increases in secondary organic aerosol (SOA) mass and build-up of stabilized nonvolatile organic matter as particles age. One possible explanation for these heterogeneous processes are the acid-catalyzed (e.g., H2SO4 and HNO3) reactions of atmospheric multifunctional organic species (e.g., multifunctional carbonyl compounds) that are accommodated onto the particle phase from the gas phase. Volatile organic hydrocarbons (VOCs) from biogenic sources (e.g., terpenoids) and anthropogenic sources (aromatics) are significant precursors for multifunctional organic species. The sulfur content of fossil fuels, which is released into the atmosphere as SO2, results in the formation of secondary inorganic acidic aerosols or indigenous acidic soot particles (e.g., diesel soot). The predominance of SOAs contributing to PM2.5 (particulate matter, that is, 2.5 microm or smaller than 2.5 microm), and the prevalence of sulfur in fossil fuels suggests that interactions between these sources could be considerable. This study outlines a systematic approach for exploring the fundamental chemistry of these particle-phase heterogeneous reactions. If acid-catalyzed heterogeneous reactions of SOA products are included in next-generation models, the predicted SOA formation will be much greater and have a much larger impact on climate-forcing effects than we now predict. The combined study of both organic and inorganic acids will also enable greater understanding of the adverse health effects in biological pulmonary organs exposed to particles.
我们实验室的探索性证据表明，大气气溶胶上的酸性表面会导致二次有机气溶胶（SOA）质量非常真实且可能呈数倍增加，并且随着颗粒老化，稳定的非挥发性有机物会不断累积。这些非均相过程的一种可能解释是，大气中多功能有机物种（如多功能羰基化合物）从气相进入颗粒相后发生的酸催化反应（如硫酸和硝酸）。来自生物源（如萜类化合物）和人为源（芳烃）的挥发性有机碳氢化合物（VOCs）是多功能有机物种的重要前体。化石燃料中的硫以二氧化硫形式释放到大气中，会导致二次无机酸性气溶胶或原生酸性烟尘颗粒（如柴油烟尘）的形成。对细颗粒物（PM2.5，即直径为2.5微米或小于2.5微米的颗粒物）有贡献的SOA占主导地位，以及化石燃料中普遍存在硫，这表明这些源之间的相互作用可能相当可观。本研究概述了一种探索这些颗粒相非均相反应基本化学原理的系统方法。如果下一代模型纳入SOA产物的酸催化非均相反应，那么预测的SOA形成量将比我们目前预测的要大得多，并且对气候强迫效应的影响也会大得多。对有机酸和无机酸的综合研究还将有助于更深入了解暴露于颗粒的生物肺部器官的不良健康影响。
