A Cochrane Library review suggests that smoking bans may reduce harms of passive smoking, unclear as they are, since there has never been evidence that second-hand smoke has harmed anyone. Yet epidemiologists have linked it to risks of heart disease and some have even claimed third-hand smoke - particulate matter residues on clothing or in a room - can cause cancer. 

But the review does correlate lower rates of cardiovascular disease with bans. 

Cigarette smoking is the second major cause of mortality in the world, and currently lunked to deaths of 10 percent of adults worldwide. It is one the greatest public health disasters of the 20th century, with over 20 million attributable deaths and the World Health Organisation believes 600,000 deaths per year may be linked to second hand smoke. The first ban on indoor smoking in all public places was introduced in Ireland in 2004 and numerous countries have followed suit, with the stated goal being to protect non-smokers from second hand smoke, but the real reason was to pressure people to stop smoking by making the behavior a social ill, and difficult to do. 

The review included 77 studies from populations of 21 countries around the world, including the US, UK, Canada and Spain.  Unfortunately for creating an evidence-based case, 44 of the studies were observational but still specifically tried to assess cardiovascular disease, and 33 of them studies reported evidence of a significant reduction in heart disease following the introduction of these bans. 

The previous review examined how smoking legislation had reduced smoke in public places, the new review included studies that attempted to prove that passive smoking was linked to heart disease.The new paper claims that the greatest reduction in admissions for heart disease following smoking legislation were identified in populations of non-smokers.