#前言:颗粒和液滴一般#,大气粒子可以被认为是湿颗粒。例如当我们谈论硫酸盐颗粒($ SO_4 ^{2,} $),这些粒子实际上是液滴与硫酸溶解(或溶解sulfate-cation化合物)。#机制包括二氧化硫# $美元二氧化硫释放气体和它对美元SO_4 ^{2,} $(硫酸)。基本上,有不同的反应途径形成硫酸二氧化硫:美元,美元SO_ {2 g}——(气态反应)——>美元H_2SO_ {4 g} $ (H_2O积累美元)——>“硫酸盐粒子”——美元SO_ {2, (g)}(进入解决方案)——>美元SO_}{2,解决方案——(形成)——> H_2SO_美元{4、解决方案}$一般(deprotonizes直接),第二个途径是占主导地位。* *相关的方面是,它会导致硫酸超细粒子的形成(硫酸滴)。* *硫酸盐粒子云凝结核。这意味着他们支持云的形成。可用的卫星图片,您可以确定航道线的云。这些云形成,因为船舶排放大量的二氧化硫美元以外的(至少[硫排放控制领域][1])。大多数海洋上方的云层比海面反射更多的太阳辐射。一般来说,海洋上方的云层是“好云”对地球降温。 Since a large proportion of the Earth is covered by sea surface, one might wonder to generate clouds above it - e.g. by releasing $SO_2$. However, as far as I know, this process is relevant in the troposphere. Releasing $SO_2$ into the stratosphere (as proposed in the linked article) is not meant to support cloud formation (correct me, if I am wrong). Nevertheless, the released $SO_2$ leads to ultra-fine sulfate particles. These sulfate particles themselves effectively scatter solar radiation and, thus, prevent it from reaching the Earth's surface. There is also a Wikipedia article available [here][2]. Unfortunately, sulfate indirectly degrades the ozone layer: sulfate leads to the release of radicals that (and their successors) catalytically destroy ozone. See [Keith et al. (2016)][3] for a more detailed overview. # Why $CaCO_3$? # The basic idea is to add salts of alkali metals that neutralize sulfuric acid and nitric acid (generated in the presence of sulfuric acid) when we emit $SO_2$. This will reduce the negative impact on the ozone layer. $CaCO_3$ is such a salt [(Keith et al., 2016)][3]. ## Why $Al_2O_3$? ***Foreword:** I am not expert on this and just read some articles on this topic.* According to [Weisenstein et al. (2015)][4], fine aluminum particles (as well as diamonds) are an alternative to sulfate particles. According to them, aluminum is favourable. However, as studies on emissions from missiles and space crafts indicate, $Al_2O_3$ also has negative impacts on the ozone layer ([SomeReport][5]; [DoD, 2004][6]): $Cl$ radicals are released that degrade ozone. $CaCO_3$ also counteracts here, too. [1]: https://en.wikipedia.org/wiki/Sulphur_Emission_Control_Area [2]: https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering) [3]: http://dx.doi.org/10.1073/pnas.1615572113 [4]: http://dx.doi.org/10.5194/acp-15-11835-2015 [5]: https://books.google.de/books?id=a2YrAAAAYAAJ&pg=PA166&lpg=PA166&dq=Al2O3%20stratosphere&source=bl&ots=xnPx9BMx_5&sig=JqqaiIlc2nfSG-fZEBSfGwBHr_A&hl=de&sa=X&ved=0ahUKEwiSlY2m__3SAhWLvhQKHQb_CbgQ6AEIRzAD#v=onepage&q=Al2O3%20stratosphere&f=false [6]: https://books.google.de/books?id=lRQ0AQAAMAAJ&pg=SA4-PA37&lpg=SA4-PA37&dq=Al2O3%20stratosphere&source=bl&ots=CA6b2ssqcP&sig=7vCBpBjykk0m5wtu42sRzuGpI1U&hl=de&sa=X&ved=0ahUKEwiSlY2m__3SAhWLvhQKHQb_CbgQ6AEIOTAB#v=onepage&q=Al2O3%20stratosphere&f=false