The geoengineering scheme, known as stratospheric aerosol injection, would not be cheap, but scientists say it could buy us some time until we reach net-zero carbon.
No chance at all of a basically indestructible material not being destructed if absorbed by lungs (or gills) and leading to some disease. You don't need to check. There's no way this could go wrong.
Or, rather... I believe lead is cheaper... Given how much people like to use it, maybe it's a better option.