The problem is that it all depends on your genes. For many people air pollution doesn't affect them..but I thought it doesn't affect me before it started.

Regarding living close to highways: air pollution close to them are much higher than farther away, and you spend a significant amount of time sleeping at home, so you if you are not lucky, you are affected.

Generally background noise is a good predictor of air pollution in my experience, just open the window, and if you hear cars all the time, you should look for another place to live.