Hi Yogesh, I would say very good. I've worked as a consultant on air dispersion modelling studies for over 10 years for a wide variety of clients (in Australia), and been very busy for most of that time - sometimes too busy! I imagine the situation would be the same in other parts of the world. Good luck!
Even though I don't have much experience with Air Quality Modeling, I've been reading some material about it. I can tell you that it has been used for a few years now and it is the best and pretty much the only way to know the future possibilities regarding the behavior and concentrations of air pollutants. It is the best way to help politicians to make the right decisions.
I can point you in the direction of good reference materials if you like.