It seems possible. In college I spent a semester in China, and we took a trip through a region where it seemed like most of the young boys were smoking. Really startling to see at first, I didn't see 2-year olds, but these were prepubescent boys smoking cigarettes. Sadly, I'm not sure it was the worst source of airborne contaminants they were exposed to though, because it was a coal-mining region and the overall air quality seemed very bad, and for the men actually working in the mines, it had to be even worse.