A survey, released today on No Smoking Day, reveals that nationally as many as 2.8 million smokers will give up when the ban comes into force next year.
Campaigners have hailed the figures.
The threat of a smoking ban is spurring more smokers to seek help in quitting, found the survey by Cancer Research UK.
One in five GPs have already seen an increase in the number of patients asking about help.
Prof Alex Markham, chief executive of the charity and a cancer specialist at St James's Hospital in Leeds, said: "This first indication that the ban is helping people quit is exciting."
Prof Robert West, director of tobacco studies at the charity, added: "This should be a bumper year for No Smoking Day."
In Yorkshire, 20 per cent of smokers said the ban would make them quit.
Smokers can find out about NHS stop smoking services by calling the free NHS stop smoking helpline on 0800 1690169 or they can go to www.nosmokingday.org.uk