More than 3,700 deaths have been prevented in Ireland thanks to the cleaner air we breathe due to the smoking ban, according to a study.
An estimated 3,726 smoking-related deaths have been spared because people are less exposed to second-hand smoke.
Prof Luke Clancy, director of the Tobacco Free Research Institute Ireland, said: "Previous studies have shown decreases in cardiovascular mortality following the implementation of comprehensive smoking bans.
"Ireland became the first country in the world to implement a comprehensive national workplace smoking ban in March 2004 and it is important to establish that there are significant health benefits.
"Our study shows that mortality decreases were primarily due to reductions in passive smoking, rather than a reduction in active smoking, and we remember that this protection from passive smoke was the basis for the introduction of the 2004 legislation."
The findings in the scientific paper were published this week in the medical journal 'PLOS One' and follow research by Brunel University, London; the Environmental Health Sciences Institute; Dublin Institute of Technology; and the Tobacco Free Research Institute.
Prof Clancy said the study showed a 26pc reduction in heart disease, a 32pc fall in strokes and a 38pc drop in chronic obstructive pulmonary disease mortality.
"The national Irish smoking ban was associated with immediate reductions in early mortality. This study corroborates previous evidence for cardiovascular causes, and is the first study to demonstrate reductions in stroke and respiratory causes," he said.
Breathing in somebody else's cigarette smoke is known to increase the risk of cancer and other health problems and it is particularly harmful for children. Smoke can stay in the air for up to two-and-a-half hours even with a window open. Secondhand smoke contains more than 4,000 chemicals.
Exposure to second-hand smoke increases the risk of morbidity and premature mortality due to cardiovascular and respiratory causes.
Prof Clancy said that due to excise tax increases in Ireland, cigarette prices increased by more than 10pc in 2000, 2003, and 2007.
However, the estimated effects on smokers aged over 35 years were minimal. In 2002, Ireland adopted non-graphic, non-pictorial health warnings for cigarette packages, and extended the existing TV and print media advertising ban to include selected types of indirect advertising.
"The advertising ban was further extended in 2004, but product placements and certain forms of sponsorship were still allowed. Although these additional tobacco control interventions may have resulted in synergistic health improvements with the national smoking ban, their estimated effects were small and gradual."