The average smoker loses about seven minutes at the end of their life for every cigarette they smoke. The average smoker over their life time dies at least 15 years sooner than a non smoker. It costs society about $10 for every pack of cigarettes that is smoked. the smokers are higher rates on disability which is really straining the Social Security system and the insurance premiums of all people even if they don't smoke.
The average non smoking spouse living with a a smoker dies about 8 years sooner than a spouse who lives with a non smoker.
As you see, smoking is a form of extremely slow motion suicide. The average smoker doesn't get his first heart attack until about 52. Of course by that time his entire body is pretty well shot. Its all down hill from there. the next time you see someone walking around with an oxygen tank, I'll bet cigarettes were involved.
One pack may do some damage, but very little unless you are extremely susceptible to the poisons in cigarettes. You will probably not notice any health or age problems from one pack.
Studies in Canada, show that a person in a smoked fill bar is inhaling smoke as if they were smoking a pack an hour. You have to take into account those smoking around you.Even though you may not be lighting up, you can still be suffering the effects from those around you who are poisoning themselves, the air around and anyone who breathes their toxic fumes.
Any sight dedicated to the dangers of cigarette smoking and tobacco usage. Any demographic or actuary chart or insurance company statistics. try the American Surgeon General. The above facts are now common knowledge in any medical circle.