Mario Molina: It really started asking the question, “What happens to these compounds once released to the environment?” Our starting point was that these compounds have been measured to be throughout the atmosphere. Not just close to cities, but in the Northern Hemisphere, the Southern Hemisphere. That was just a starting point. These compounds are very stable. They are non-toxic, you can even breathe them. So the assumption was that there was no worry, because of the presence of these relatively small amounts — parts per trillion amount — of these compounds in the global environment. So that was just the starting point. The rest was just scientific research. We were asking the question, “What happens to these compounds?” We realized that they would eventually diffuse to the stratosphere, because nothing else would destroy them. In the stratosphere they would be destroyed, but that was not the end of the question. We had to pursue it several steps more. So what? And we had to follow what happens to the decomposition products from these compounds, and that’s of course where the effects on ozone begin. So it’s really taken a complete — an overall — picture of the problem that led us to our discoveries.