Well, people cannot affect factories' emissions or tankers crashes. But, if the question is about own health - what prevents to leave where there are no these emissions? In a village, in a solitude... In
Africa there are no cars and factories. However, there are no TVs and computers, microwave ovens and air conditioners - but there is a lot of pure air! Why not? So, we are dissatisfied with the dirty air, but we are not ready to refuse using our car and to walk on foot. We worry about "ozone gap" above Antarctica, but we are also not ready to refuse conditioners! Deadlock?