"We present studies with the AER 2-D model of stratospheric aerosol injection with alternative materials, including H2SO4, alumina particles, and calcite particles. These substances overcome some of the drawbacks of SO2 injection by improving the response linearity (H2SO4), minimizing longwave stratospheric heating (alumina and calcite), and potentially restoring the ozone layer (calcite)." https://ams.confex.com/ams/98Annual/webprogram/Paper333410.html