Hold your breath

Even people living in areas with low levels of air pollution may be at risk. Photo: Ezra Kaye. (CC BY-NC-SA).

Growing evidence indicates that there may be no safe level of air pollution for human health.

A recent study from the University of Western Australia found a significant association between lung cancer in older men, and low levels of air pollution. It also found a possible association with bladder cancer.

The study was based on the monitoring of nearly 12,000 men aged over 65, from 1996-2018 in Perth, Western Australia.

Air pollution is the contamination of the environment by any chemical, physical, or biological substance. Common sources include industry, motor vehicles, heating appliances as well as bushfires, dust storms, and prescribed burnings.

Pollutants such as particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulphur dioxide, all pose a significant risk to human health.

Associate Professor Peter Franklin, who is the director of the Occupational Respiratory Epidemiology Research group at UWA, said “air pollution is the biggest environmental health problem globally.”

He said while Perth generally had very good air quality, some pollutants are “non-threshold,” meaning that any level of the pollutant above zero will affect human health.

Dr Kathryn Emmerson, who is the principal research scientist on air quality modelling at the CSIRO, said in Australia there were occasional events which caused the air quality to become very poor, such as the summer bushfires that occurred in 2019-20.

Australia has national environmental protection measures created by the National Environmental Protection Council that provide air quality limits for certain pollutants to ease health risks.

Particulate matter, otherwise known as particle pollution, is made up of tiny pieces of liquid or solids in the air such as dust, dirt, soot, and smoke.

For particulate matter, the air quality limit is 25 micrograms per metre cubed over a 24-hour average.

However, during the 2019 bushfires, Dr Emmerson said the amount of particulate matter in Canberra was around 40 times the limit, which was extremely concerning.

Car driving through Melbourne smoke
Bushfires are a significant source of air pollution. Photo: Ezra Kaye. (CC BY-NC-SA)

Dr Ivan Hanigan is the Director of the World Health Organisation Collaborating Centre for Environmental Health Impact Assessment, and a senior lecturer in climate change and health at Curtin University. He said while the national measures assume there is a safe level of air pollution, the evidence was showing that even low levels can have health impacts, and a lifetime of exposure can cause premature mortality.

Dr Hanigan said he was concerned that despite reducing air pollution from industry and transport, climate change would cause more bushfires and dust storms.

“All of our efforts to improve air pollution in cities may be undone. We must act now on climate change quite urgently,” he said.

According to Dr Emmerson, another source of air pollution which is often overlooked are woodfired heaters. In Sydney, she said they actually were responsible for more smoke then prescribed burns.

“Wood burners are terrible for air quality,” she said.

She said while fires generally can be bad for one or two days, in winter, people turn their wood-fired heaters on for multiple evenings.

She said this is exacerbated by the meteorology of cooler temperatures, which results in a more concentrated level of air pollution closer to the ground, which increases health risks.

“The one thing Australia can do to improve air quality is the removal of wood heaters,” she said.

Asthma Australia is campaigning for the removal of wood-fired heaters in residential areas, however the ACT is the only jurisdiction in Australia that has committed to phasing them out.

WA has live air quality monitoring stations across the state which provides up to date information and suggestions for levels of exposure. This can be accessed online via the Air Quality Index for Western Australia.