Below are some statistics I looked up. I don't have anything to compare cigarette pollution to yet (except for the segment from the Italian Institute for Higher Health), but I'll see what I can come up with. I think my math is right, but I welcome corrections.
According to a study conducted by the the Italian Institute for Higher Health, three smouldering cigarettes produced a 10-fold increase in air particles compared to those produced by an idling 2002 Ford Mondeo turbo diesel with a two-litre engine, fuelled with low-sulphur diesel. (http://www.newscientist.com/article.ns?id=dn6312)
The mean average of milligrams of CO per cigarrette is 11.5mg (taken from data corresponding to 103 different kinds of cigarettes, a sampling of the statistics found here: www.ftc.gov/reports/tobacco/1998tar&nicotinereport.pdf , a Federal Trade Commission report).
Estimated number of cigarettes smoked in U.S. in 2005 by the U.S.D.A.: 389 billion
Estimated number of cigarettes produced in the world in 2004: 5.662 trillion
Approximately 4.5 million kilos or 9.9 million lbs of carbon monoxide released into the atmosphere via smoking in the U.S. (11.5mg x 389,000,000,000 / 1,000,000 = # of kilos x 2.2 = # of pounds).
The 465 billion cigarettes smoked in the United States in 1998 translates to a total of 176,250,000 pounds of discarded butts in one year in the United States alone.
The average diameter of a cigarette is approximately 10mm or 1cm (http://en.wikipedia.org/wiki/Cigarette). One football field is approximately 110m x 50m (http://www.ncaa.org/champadmin/football/football_field.gif). If you stood each cigarette on end, like a chimney stack, you would need 55 million cigarettes1 to cover an entire football field. It would take about 7,072 football fields, or slightly over 15 square miles2, to house all of the cigarettes produced in the U.S. Now imagine those cigarettes burning.
1. 110m = 11000cm; 50m = 5000cm;(11000cm*5000cm)*(1 cigarette / 1cm^2) = 5.5x10^7 cigarettes
2. 1m = 0.000621371192 miles; 110m = 0.06835083112 miles; 50m = 0.0310685596 miles; 7072*0.06835083112 miles*0.0310685596 miles = 15.017829547194793606144 miles^2