Why an air pollution mask is now a health essential for even short visits to Asian cities.

It’s official. A city can be a health hazard.

Diana*, an Australian visiting relatives in Hong Kong with her two young children earlier this year, got very clear advice when she was finally hospitalised with asthma and pneumonia after struggling to breathe that city’s notoriously polluted air.

“If you have the option to be elsewhere, for you it is really, definitely, better not to be in Hong Kong,” were doctor’s orders.

“I was advised not to exercise outdoors and to check the air quality daily [with an online index],” says Diana, who asked to remain anonymous, given sensitivities about perceived criticism of the Chinese-controlled region. “Every single day that I was in Hong Kong the level was either extreme or dangerous … way above what was considered to be safe and normal.”

At home in Melbourne, Diana, a non-smoker with mild asthma, might use an inhaler once a year but, in Hong Kong, persistent trouble breathing, and having to keep the puffer on hand all the time, finally took its toll. “It was the reason I left. I didn’t want to spend another month restricting our activities according to air quality,” she says.

Diana’s story is salutary.

A major review in the Lancet in October reported air pollution killed 4.2 million people in 2015, a figure projected to rise 50 per cent by 2050. And most die in rapidly industrialising, lower-middle income countries.

But as the footprint of Australian businesspeople and travellers increasingly takes in Asian pollution hotspots – according to the Australian Bureau of Statistics, our visits to India tripled, and to China nearly doubled in the decade to 2016 – the effect of air quality on health should be front of mind.

That’s because of the mounting evidence for just how broad the health risks are, and how little time spent in polluted air is needed to bring them on.

“For a long time now we have known air pollution can cause effects within a day of exposure,” says Howard Kipen, a professor at Rutgers University School of Public Health. “But there is an increasing accumulation of evidence that health effects may be caused by an increase in pollution over only an hour or two.”

Read the full feature in the Australian Financial Review here