I was just going to say that the difficulty for us is that even the modelling of air pollutants is very complex. It's not a simple model that we have. As you've heard about the complexity of the relationship between greenhouse gases and climate change and air pollutants, it's even more complex and we just don't have the models. I don't think there's anywhere in the world where they do right now.
On May 17th, 2007. See this statement in context.