I was invited by RTHK Radio 3 in Hong Kong to take part in a discussion about smoking and whether it should be banned in all outdoor areas.
It would be broadcast live, they said, between 8.30 and 9.00am, which translates as 12.30 to 1.00am in the UK.
That was last night. In the event the discussion went on until 1.30. It was prompted, they said, by an article in a Hong Kong newspaper headlined 'Workers face demands for smoking ban outside offices'.
Office workers who smoke near the entrances to their buildings make the air quality more than three times worse, researchers found. And there are now calls in Hong Kong for the ban on smoking inside workplaces to be extended to the immediate area outside.
The Ontario Tobacco Research Unit in Canada measured pollution levels in a busy street in downtown Toronto when no smokers were around. Then they compared them with measurements outside 28 entrances to office buildings in the same area when workers were smoking.
The density of PM2.5 air pollutant particles was more than three times higher when up to four people were smoking within nine metres of building entrances. And the density was 20 times higher than the World Health Organisation (WHO) guideline figure for "clean" air.
Toronto researcher Dr Pamela Kaufman said: "Exposure to smoking at entrances to buildings tends to be brief and transient ... [but] there is increasing scientific evidence that even short-term exposure can result in adverse health effects for people with sensitive cardiovascular and respiratory systems."
She urged governments to consider banning smoking within nine metres of building entrances.
Professor Lam Tai-hing, director of the University of Hong Kong's school of public health, agreed. "Even when people move outdoors to smoke, the pollutants can still be blown back indoors."
He said the level of pollutants would be especially high in the busy streets of Hong Kong, where many people smoked in narrow alleys surrounded by tall buildings, which were badly ventilated. Lam said he fully supported a smoking ban outside building entrances.
"Many non-smokers need to pass through entrances of office buildings daily. If there is a ban, they would not be forced to inhale toxic smoke," he said.
Clear The Air committee chairman James Middleton also supported the idea of making building entrances smoke-free zones.
He noted that the ventilation ducts of many buildings were right above entrances. It meant that even when smokers stood outside, the second-hand smoke was still sucked indoors.
My fellow guests last night were Prof Lam Tai-hing, quoted above, and Dr Kwok Ka Ki. Honestly, there was no debating with these people. As far as they are concerned tobacco smoke is toxic and even the slightest exposure is dangerous to non-smokers.
The presenters tried to play devil's advocate but refused to accept anything I said about passive smoking because I am not a "medical expert", unlike Dr Ka Ki and Prof Tai-hing.
My argument that we shouldn't believe everything we hear from so-called "experts" fell on death ears. Talk about banging your head against a brick wall.
All in all, it was a rather tiring way to end a long day.