The most known con of them all about air pollution is of course that it causes health issues, but specifically, why does it do so? air pollution is caused by the burning of fossil fuels and the exhaust that comes from vehicles, this is best known as smog. not only does it pollute the air, and thus causing health problems, but it also cause global warming from the chemicals that smog produces, that's why you see a lot of smog shops, because it is important to get rid of smog and have your car checked. Where I am from, in california, I can see the mountains, bht not as clear as you're supposed to, you're supposed to see them crystal clear since they are right next to my town, but now, you can barely see them because of the pollution and smog.