Although hospitals are listed as a non-smoking area under the Shanghai's smoke control laws, they appear to be one of the hardest places to enforce the ban, especially at night.

The biggest challenge hospitals face is not how to control night-shift doctors and staff members, but how to prevent patients and their family members from smoking. Persuasion is the only solution - this is because doctors have no way to impose penalties on people who flout the ban.

To control smoking more strictly in local hospitals, health authorities yesterday asked hospitals to make at least 10 percent of staff, including guards and cleaners, wear "no-smoking" badges.

According to the city's smoking-control law, enacted on March 1, both indoor and outdoor areas of maternity and children's hospitals and the indoor areas of other hospitals must be smoke-free zones from now on.

Xia Lin, an official at the Shanghai Children's Medical Center, said hospitals have taken action since the law came into effect.

The store at the hospital has stopped selling cigarettes and lighters, for example.

"Medical staff are also required to promote knowledge of the dangers of smoking to people and their children while serving patients. No-smoking signs can also be seen everywhere," she said.

Hospital officials said they can stop medical staff from smoking while at work, but have no rights to punish patient's families - persuasion doesn't always work.

"We understand some people smoke because they are anxious about their children," Xia said. "We will put free chewing gum and samples of smoking-control medicines around the hospital to help ease their anxiety."