New research shows that air pollution has dropped by 83% in Dublin pubs since the smoking ban was introduced three years ago.
The study also found a significant improvement in the respiratory health of bar workers.
The findings are published today in the American Journal of Respiratory and Critical Care Medicine in what its authors say is one of the largest and most detailed examinations of the effects of environmental tobacco smoke.
Researchers measured particles and benzene in 42 Dublin pubs and 73 male bar staff underwent lung tests.
The bar staff also answered detailed health questionnaires.
Before the ban, workers were exposed to 40 hours of tobacco smoke a week and after the ban this fell to 25 minutes.
The study was conducted by the Research Institute for a Tobacco Free Society with the Dublin Institute of Technology and a research team headed by Professor Luke Clancy, Chairman of ASH Ireland.
Professor Clancy said the research demonstrated the success of the smoking ban in reducing the exposure of bar workers to second-hand smoke.
He added: 'Our previous research shows that a reduction in air pollution from smog in the surrounding air results in marked health benefits in terms of respiratory and cardiovascular mortality.'