Legislation banning smoking in public places will save lives, Northern Ireland's chief medical officer has said.
Smoking will be banned in workplaces from 30 April
The prohibition of smoking in public places begins on 30 April.
Dr Michael McBride said it was an "exciting time for public health right across these islands".
"The Republic of Ireland and Scotland already enjoy a smoke-free environment, and today, Wales will join that club," he said.
"We will also soon enjoy the same health benefits from 30 April, with England following in July.
"It is no coincidence that we are all taking the same steps to protect people's health.
"This legislation will save lives. It will significantly reduce our exposure to the toxic effects of second hand smoke."
Dr McBride said the legislation had meant the air quality in many enclosed places had greatly improved.
"Early indications in Northern Ireland show that more people than ever are trying to quit.
"If the legislation has given some people that extra incentive that they needed, then that can only be a good thing."
The smoking ban will come into effect in all workplaces and enclosed public spaces, including bars and restaurants.