On 29 March 2004, the Republic of Ireland introduced a comprehensive smoke-free law, covering all indoor workplaces, including bars and restaurants. The law was not introduced in neighbouring Northern Ireland, creating a natural experiment for identifying effects of the new law.
In the BMJ study, researchers surveyed 329 staff working in rural and urban pubs in the Republic of Ireland and Northern Ireland in the six months leading up to the ban in the Republic. One year later, 249 were followed up to assess changes in exposure to secondhand smoke and respiratory symptoms.
Hours of exposure to secondhand smoke (including work, home, and other regular activities) were recorded. Details about respiratory and sensory symptoms, such as coughing, red eyes and sore throat, were taken and levels of cotinine (a by-product of nicotine) were measured.
In non-smokers, cotinine concentrations in the saliva declined significantly in both regions, but with a much greater decline in the Republic (80%) than in Northern Ireland (20%).
Work-related exposure to secondhand smoke dropped significantly in the Republic but dropped only slightly in Northern Ireland. Exposures outside work also dropped significantly in the Republic but increased in Northern Ireland, challenging the view that banning smoking in pubs and restaurants would lead to increased smoking in the home.
Furthermore, in the Republic, after the ban there was a significant drop in the proportion of bar staff experiencing respiratory symptoms.
The smoke-free workplace law in the Republic of Ireland has provided protection for one of the most heavily exposed occupational groups by reducing their exposure to secondhand smoke both in and out of the workplace, say the authors.
The increase in support for this law since its introduction, even among smokers, underpins its effectiveness. These findings have implications for policy makers and legislators in other countries currently considering the nature and extent of their smoke-free workplace legislation, they conclude.
In the Tobacco Control study, a representative sample of 769 adult smokers in Ireland and 416 in the UK were surveyed three months before, and nine months after, the smoke-free law took effect in Ireland in March 2004.
The findings show that smoking in public venues, including workplaces, has fallen dramatically since the legislation. Smoking in restaurants fell from 85% to 3%, and from 98% to 3% in bars/pubs.
Furthermore, public support for a total ban also rose from 43% to 67%. In bars/pubs, this increased to 46% from 13%.
More than eight out of 10 Irish smokers surveyed said that the smoke free law was "a good or very good thing," while nearly half said that the law had made them more likely to give up. Of those who had stopped smoking, over 80% said that the law had helped them do it.