If I was going to blame anyone it wouldn't be the smokers the only people they hurt is themselves and others around them, on a wider scale i would blame air pollution on Aeroplanes, Factories etc for emitting Carbon Dioxide. But to be perfectly honest I don't believe in this or 'Global Warming' :)

In a mega sense, air pollution is mainly caused by the industrial sector, and thereafter probably by heavy loads of car usage. Smokers, on the other hand, give a hard time to the people around, especially when they smoke indoor or in a crowded public. --- Good day.