Researchers have reached the grim conclusion that any type of particulate matter (PM) air pollution is detrimental to human health.

Key points: Majority of particulate matter (PM) air pollution is manmade

Majority of particulate matter (PM) air pollution is manmade PM air pollution could lead to increase in people reporting to hospitals with respiratory or cardiovascular effects

PM air pollution could lead to increase in people reporting to hospitals with respiratory or cardiovascular effects Findings have public policy implications for Australia, research concludes

The results came from Australia's largest ever review into the health impact of tiny air pollution particles from motor vehicles, mining and coal-fired power plants.

The researchers from Woolcock Institute of Medical Research at the University of Sydney recommended immediate efforts to reduce the total amount of particulate matter pollution in the air around us.

There are many sources of ambient PM emissions.

Report author Christine Cowie, a senior research fellow at the University of Sydney, said they include motor vehicles, mining and quarrying, plant and animal fragments, and even sea salt.

"What we actually get in our ambient air around us is a real mixture, or a soup, of a lot of these different sources of PM," she said.

She said in major cities such as Sydney, the majority of the particulate matter pollution is manmade, including motor vehicles.

"Even things like wood-fired heaters in domestic settings and also coal-fired power station emissions, which actually travel quite a way to also affect urban areas," she said.

When it stacks up, the findings of the review were dire.

"This study was actually a literature review and we did review quite a lot of information, predominately international, of course, also whatever national information existed," she said.

"Essentially, we found that any source of PM emissions or any type of PM emissions are detrimental to human health."

Risks to the population 'quite substantial'

The Woolcock Institute and Centre for Air Quality and Health Research and Evaluation weighed up the health risks for the New South Wales Ministry of Health and the state's Environment Protection Authority.

They said the findings have public policy implications for the whole country.

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"Our main message really is that any reduction in exposure to particulate matter is likely to be beneficial to health because, based on current evidence, it looks like there's no threshold for affect," Ms Cowie said.

"So, in other words, it does look like any exposure is likely to be harmful for health and so conversely, any reduction in exposure is likely to be beneficial."

Ms Cowie stressed that the risk to an individual is relatively low, but there is a greater risk for the wider community.

"Because everybody is exposed to air pollution, and particularly PM air pollution, the cumulative risks to the whole of the population is quite substantial," she said.

It might mean more people reporting to hospitals with respiratory or cardio vascular effects.

"On high pollution days we may detect extra cases of stroke, other myocardial infarctions, heart attacks, for instance, and also PM (particulate matter) air pollution has been linked to premature mortality," she said.

"So it will bring forward those few extra deaths - particularly, we think, in more vulnerable people such as the elderly."