Hmm, Paris definitely is a megacity with a lot of charming, exciting and beautiful places and nice people. Of course, as every other city of this size, it also has its problems. Regarding the pollution, Rome isn't much different in this aspect. You can live a boring life, no matter where you actually live. But if you live in Paris and got the feeling your life is boring, the problem rather is you, than Paris. However, keep on travelling, it may broaden your horizon