Approximately how many college-aged students smoke in the United States?

Hello.

"More than 31% of the over 15 million college students in American smoke daily."
source:
Campus Tobacco Coalitions?Unleashing the Power to Fight Tobacco?s Newest Target
http://ncth.confex.com/ncth/2003/techprogram/paper_8899.htm

31 percent of 15 million is 4.65 million.


Your question involved "students," so I don't know if you're
interested in the total population of smokers who are college-aged,
i.e., 18-24/25 (but not necessarily attending college).  Figures for
that statistic are obviously larger:

"Currently 7.2 million smokers are between 18-24 years of age."
source: Cal State Long Beach - Health Newsletter:
http://www.csulb.edu/divisions/students2/departments/Health_Resource_Center/documents/newsletters/Nov03Newsletter.pdf

"At the present time, it is estimated that there are approximately 11
million smokers between the ages of 19 and 25 in the USA."
source:
PM Lantz, Tobacco Control 2003;12:i60
Smoking on the rise among young adults: implications for research and policy
http://tc.bmjjournals.com/cgi/content/full/12/suppl_1/i60

---------
search strategy:
"million college students" smoke
 "young adults" "million smokers"

I hope this helps.