Canadian researchers find that the pollution levels outside of office buildings in Hong Kong where smokers congregate is 20 times higher than the World Health Organization's guidelines for clean air, thus posing a health danger to passers-by.

http://www.monstersandcritics.com/news/health/news/article_1613946.php/Survey-Office-smokers-who-nip-
out-for-cigarette-pose-health-risk
http://www.earthtimes.org/articles/news/363826,cigarette-pose-health-risk.html