Legislation for smoke-free workplaces and health of bar workers in Ireland: before and after study.

Objectives: To compare exposure to secondhand smoke and respiratory health in bar staff in the Republic of Ireland and Northern Ireland before and after the introduction of legislation for smoke-free workplaces in the Republic.

Design: Comparisons before and after the legislation in intervention and control regions.

Setting: Public houses in three areas in the Republic (intervention) and one area in Northern Ireland (control).