If you stripped all of the ozone from the atmosphere today, the UV light from the sun would replace it very quickly. UV light makes ozone (O3) by splitting oxygen molecules (O2) into atomic oxygen (O) which quickly re-combine to form ozone. This paper suggests that the ozone layer was "blasted" away, which implies a shock wave. (rather than radiation) If he is suggesting a shock wave, then why would it only take the ozone layer? What about the rest of the atmosphere? If the density of the dust and gas in the shockwave was high enough to strip away the ozone layer, it would also deposit huge amounts of dust and gas into the atmosphere.
The asteroid theory of mass extinctions claims that dust in the upper atmosphere blotted out the sunlight, causing plants and the rest of the food chain to collapse. The shock wave remnant of a supernova would contain lots of dust and gas, and due to its velocity, lots of that dust (including Iron 60) would be dumped into the upper atmosphere, causing global extinction by the same method as the asteroid impact. (No need to invoke the ozone layer and UV light to explain this one)
Hopefully not any more Star Blast Gum,that stuff is aweful,can't even blow square bubbles with it.
Gamma,I'm late for my Lunar morphology class,got to jet!