A very interesting paper “Ozone perturbation from medium-size asteroid impacts in the ocean” by Pierazzo et al. has been published in Earth and Planetary Science Letters. These authors have shown by simulations that if an asteroid 500 m to 1 km in diameter were to hit the Pacific Ocean it would eject enough water vapor and sea salt into the atmosphere to affect the ozone layer.
The simulations showed that mid-latitude oceanic impacts of 1 km asteroids could produce a significant, global perturbation of upper atmospheric chemistry, including multi-year global ozone depletion comparable to ozone hole records registered in the mid-1990s. In addition, this ozone depletion would produce ultraviolet index (UVI) levels higher than 20 at the Earth’s surface during about two years in both the northern and southern hemispheres.