Researchers at Washington University in St. Louis report that diamond dust made by detonation synthesis is a poor choice for stratospheric aerosol injection (SAI). SAI aims to mimic the cooling effect of volcanic eruptions by sending reflective particles into the stratosphere to reflect sunlight back to space. Sulfate particles can do this but have known harms, so scientists have searched for alternatives.
The team used first-principles calculations to study detonation-produced nanodiamonds and how composition, size and chemical structure affect optical behaviour. Their simulations show the material contains residual carbon impurities, typically 1–5% by mass, and sp2-hybridized carbon that can form a hard carbon shell on a diamond core. These impurities increase light absorption and can reduce scattering by up to 25%.
The findings, published in the Journal of Aerosol Science, lead the authors to conclude that detonation-synthesized nanodiamonds would likely absorb more heat than they reflect, making them unsuitable for SAI.
Difficult words
- stratospheric aerosol injection — Sending reflective particles into the upper atmosphere.
- detonation synthesis — Method of making materials by controlled explosions.
- nanodiamond — Very small diamond particle measured in nanometres.nanodiamonds
- impurity — Small unwanted substance inside a material.impurities
- absorption — Process of taking in light or energy.
- scattering — When particles spread light in different directions.
- sulfate — A chemical particle often produced by volcanoes.
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Discussion questions
- What do you think are the main risks of sending particles into the stratosphere?
- If scientists found a safe material for SAI, would you support using it? Why or why not?
- Why is it important to study material composition before doing real-world experiments?
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