Ice nucleation by kaolinite: Morphology shapes the size dependence of ice nucleation active sites on dust particles.

Kaolinite particles of 6 to 12 μm show up to 100 times higher ice nucleation active site densities at 260 K, revealing size-dependent activity influenced by morphology.

• Why it matters: Understanding how dust particle size affects ice nucleation is crucial for accurate cloud formation and climate modeling, yet the validity of surface area assumptions across sizes remains unverified.
• What they did: Researchers used compositionally pure, size-segregated kaolinite from submicron to 48 μm to measure ice nucleation active site densities, identifying two distinct temperature-dependent regimes.
• The result: Findings suggest that particle morphology, particularly multilayered platelet edges, modulates size-dependent ice nucleation activity, challenging the reliance on simple surface area-based models.