Bar workers' respiratory health has improved as a result, the researchers write in the American Journal of Respiratory and Critical Care Medicine.
A team from the Research Institute for a Tobacco Free Society in Dublin (RITFS) examined the effect of the ban on environmental tobacco smoke exposure in 42 pubs in Dublin and among 73 male staff members, who were tested before and after the ban.
The results found a 99 per cent decrease in exposure to tobacco smoke (40 hours down to 25 minutes) and an 83 per cent reduction in tiny particles in bar air.
Tests of lung function showed an improvement in non-smoking barmen after the ban and the workers reported reductions in health problems.
Significant improvements in cough and phlegm production were found in non-smoking employees.
Workers who smoke saw their health continue to decline, with a ban only benefiting their sensitivity to irritants.
"These results confirm that the approach of a total ban on smoking in the workplace is successful in reducing the exposure of workers to particles," said Dr Luke Clancy, director of the RITFS.
In an editorial on the research, Dr Fiona Godfrey European Union policy advisor at the European Respiratory Society in Brussels, said: "The article…adds to the evidence from other studies that what smoke-free advocates have said all along is true: comprehensive smoking bans in bars dramatically reduce the levels of fine-particulate matter, chemicals and gases in the air and improve bar workers' health."
Dr Godfrey added that if all European countries were to introduce a smoking ban in public places, between five to ten million premature deaths from smoking could be prevented over the next generation.
In the UK Welsh workplaces went smokefree on April 2nd following on from Scotland in March last year.
Northern Ireland's public places will be smokefree from April 30th this year while England will introduce a smoking ban on July 1st.
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