As a former smoker, let me just say.... it doesn't matter. Smokers know that smoking is bad for them already. One more added risk won't change anything.
If many of them smoke, it's especially unlikely that they will quit: particularly if smoke breaks are allowed but personal breaks are otherwise frowned upon.
Even if smokers don't get extra breaks, there is a social factor to smoking together making smoke breaks different from other breaks. If you can still smoke inside the workplace, it's less of a social issue and more simply the constant smell of the substance you are addicted to, although there is of course still a social factor.
Every workplace is different, of course, with different policies and different social dynamics. The one thing that remains the same is that quitting smoking while working in a majority-smokers workforce is extraordinarily difficult. One more factoid on one more poster won't make it any easier.
Changing break policies and where smoking is permitted can make it easier for those who want to quit, but you cannot make people want something.