A monumental new era was ushered in today when smoking was completely stubbed out in the Northern Ireland workplace - including pubs and restaurants.
At the stroke of 6am, it became illegal to smoke in almost all enclosed public and work places across the province.
Experts estimate the new laws will save around 250 lives across the province every single year through protecting people from second-hand smoke and prompting smokers to kick the habit.
Health minister Paul Goggins was among the first to applaud the arrival of the new legislation which is considered the biggest public health initiative of our time.
"Second-hand smoke is a toxic cocktail of around 4,000 chemicals, many of which cause cancer. It is internationally accepted that there can be no safe level of exposure to second-hand smoke," he said.
"Non-smokers exposed to second-hand smoke are 20-30% more likely to develop lung cancer ? not to mention the other illnesses and diseases. It is regrettable and astonishing that second-hand smoke accounts for the loss of around 278 lives each year in Northern Ireland.
"People do not want to breathe in other people's smoke. That was made very clear at the consultation stage of this legislation. By reducing our level of exposure, this legislation will improve health and save lives."
Today's eagerly-awaited development has overwhelming public support, despite fears of the impact it may have on pub trade. The legislation sees Northern Ireland fall into line with Scotland, Wales and the Republic. England will follow suit in July.
Evidence from Scotland and the Republic has shown that there has been a massive improvement in air quality in bars and restaurants as a result of smoke-free legislation. The Republic has already seen an 83% reduction in air pollution in pubs and an 80% decrease in airborne carcinogens for both patrons and staff since the introduction of their smoke-free legislation.
Dr Brian Gaffney, chair of the Smoke-free Northern Ireland coalition and chief executive of the Health Promotion Agency for Northern Ireland (HPA), said today is one for celebration.
"Smoking is the single greatest preventable cause of premature death and avoidable illness in Northern Ireland. It claims around 3,000 lives every year ? most of which are preventable ? and one person dies every two weeks due to exposure to second-hand smoke.
"Everyone has the right to clean air and from today, as people across Northern Ireland make their way into work, they will know that they are guaranteed protection from the deadly effects of second-hand smoke."
The new legislation has the support of major health charities and lobbying organisations across Northern Ireland including the Health Promotion Agency, Ulster Cancer Foundation, Action Cancer, Macmillan Cancer Support, the British Medical Association, Chartered Institute of Environmental Health, Royal College of Nursing, Chest, Heart and Stroke NI and the Institute of Public Health. The Department of Health is hosting a celebration breakfast at The King's Head in Belfast this morning.
Mike Unger, chief executive of The Roy Castle Lung Cancer Foundation, said he is "delighted" Northern Ireland is going smoke-free.
"There's been a significant improvement in public health in Scotland since the smoking ban was implemented just over a year ago. We've seen a significant increase in the number of people seeking advice from our patient care and smoking session services," he said.
"We're looking forward to July 1 when England will join the rest of the UK as smoke-free and Great Britain can look forward to a healthier future."