Air pollution is a bad thing, and it might have as much as little if any affect on weather in the area it’s produced such as cities, industrial areas or areas directly down wind of cities and industrial areas. What is bad about air pollution is the effect it has on our health, especially our lungs. If you live in any of these areas, the last thing you want to do is exercise to a point where your lungs are laboring. You could just as well be a smoker. Changing climate is a cyclical thing, brought on by solar activity on the Sun, not man-caused use of internal combustion machines.
Lucky for us the air quality in the U.S. has improved by huge leaps over recent years.