Even people living in countries known for pollution problems such as China are less affected by the potentially deadly condition, but why  remains a mystery.

Guy Marks, a professor of respiratory medicine at the Woolcock Institute and the University of NSW, who co-authored the 2014 Global Asthma Report, said many people suffered from asthma attacks simply because they could not afford daily preventer medication.

"If you have several people in your family on daily medication the cost is not trivial, particularly when you add it up over the whole year," he said.

"There is evidence to suggest people who are not eligible to get it at the concession rate ... use a lot less of the inhaled steroids, which is the preventer medication."

Figures from NSW Health show more than 12,000 asthmatics aged over four were admitted to hospital  each year over the past three years, all of which are considered potentially preventable hospital admissions.

The report said globally 334 million people suffer from asthma, with most now in low and middle income countries. While children and young people suffer disability and sickness as a result of asthma, it is most deadly for older people.

Some countries lack national treatment guidelines, and when they do have them they are often partially sponsored by pharmaceutical companies, as is the case in Australia.

Professor Marks said it was important to have independent guidelines: "The pharmaceutical industry has commercial imperatives, and governments and health care providers have other priorities".

It is not known why so many Australians suffer from asthma, with  an estimated one in 10 people affected,  and many more also suffering wheezing symptoms.

"It's clear that air pollution is responsible for a lot of morbidity, but it's not the whole story," Professor Marks said. "There is no dominant theory, there are theories about diet, about hygiene, about the beneficial effects from early life microbial exposure, and then there's exposure to allergens."

According to the Australian Institute for health and welfare, nearly 380 Australians died from asthma in 2011, the vast majority of whom were older.

Kristine Whorlow, the chief executive officer of the National Asthma Council Australia, said last month the federal government had announced funding for a national asthma strategy, which would attempt to improve asthma treatment for older Australians.

"Australia has seen reduced deaths in children and young people, but with most of the deaths in the over 55s they often have co-morbidities, other lung diseases, as well," she said.