Buseck P R, Pósfai M
Department of Geology, Arizona State University, Tempe, AZ 85287, USA.
Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3372-9. doi: 10.1073/pnas.96.7.3372.
Aerosol particles are ubiquitous in the troposphere and exert an important influence on global climate and the environment. They affect climate through scattering, transmission, and absorption of radiation as well as by acting as nuclei for cloud formation. A significant fraction of the aerosol particle burden consists of minerals, and most of the remainder- whether natural or anthropogenic-consists of materials that can be studied by the same methods as are used for fine-grained minerals. Our emphasis is on the study and character of the individual particles. Sulfate particles are the main cooling agents among aerosols; we found that in the remote oceanic atmosphere a significant fraction is aggregated with soot, a material that can diminish the cooling effect of sulfate. Our results suggest oxidization of SO2 may have occurred on soot surfaces, implying that even in the remote marine troposphere soot provided nuclei for heterogeneous sulfate formation. Sea salt is the dominant aerosol species (by mass) above the oceans. In addition to being important light scatterers and contributors to cloud condensation nuclei, sea-salt particles also provide large surface areas for heterogeneous atmospheric reactions. Minerals comprise the dominant mass fraction of the atmospheric aerosol burden. As all geologists know, they are a highly heterogeneous mixture. However, among atmospheric scientists they are commonly treated as a fairly uniform group, and one whose interaction with radiation is widely assumed to be unpredictable. Given their abundances, large total surface areas, and reactivities, their role in influencing climate will require increased attention as climate models are refined.
气溶胶颗粒在对流层中普遍存在，对全球气候和环境有着重要影响。它们通过散射、透射和吸收辐射以及作为云形成的凝结核来影响气候。气溶胶颗粒负荷的很大一部分由矿物质组成，其余大部分——无论是天然的还是人为的——都由可以用与细粒矿物质相同的方法研究的物质组成。我们的重点是单个颗粒的研究和表征。硫酸盐颗粒是气溶胶中的主要冷却剂；我们发现，在偏远的海洋大气中，很大一部分与烟灰聚集在一起，烟灰这种物质会削弱硫酸盐的冷却效果。我们的结果表明，SO₂ 可能在烟灰表面发生了氧化，这意味着即使在偏远的海洋对流层中，烟灰也为非均相硫酸盐的形成提供了凝结核。海盐是海洋上空占主导地位的气溶胶种类（按质量计）。除了是重要的光散射体和云凝结核的贡献者外，海盐颗粒还为非均相大气反应提供了很大的表面积。矿物质在大气气溶胶负荷中占主导质量分数。所有地质学家都知道，它们是一种高度不均匀的混合物。然而，在大气科学家当中，它们通常被视为一个相当均匀的群体，并且人们普遍认为它们与辐射的相互作用是不可预测的。鉴于它们的丰度、巨大的总表面积和反应活性，随着气候模型的完善，它们在影响气候方面的作用将需要更多关注。
