Advocating for better air quality is a grassroots action which doctors and their patients can readily embrace, and it will have tangible health benefits.
By Eric Martin
The latest Doctors for the Environment Australia report, Fossil Fuels are a Health Hazard, was a timely reminder for doctors that they are the ones who will be dealing with the emerging impacts a changing climate.
One of the most immediate concerns highlighted was the growing impact of air pollution on the development of chronic disease and escalating deaths in populations around the world.
The State of Global Air Report 2024 found that “8.1 million people died in 2021 from air pollution, with 58% of these deaths due to particulate matter measuring less than 2.5 micrometres (PM2.5), making air pollution the second largest risk factor for death after high blood pressure, followed by smoking.”
In Australia, traffic-related air pollution from burning fossil fuels causes 11,105 premature deaths per year, which is 8.7 times more than national road toll (1266) and more than 6.3 times the number of alcohol-induced deaths (1742). Yet subsidies to fossil fuel producers totalled $14.5 billion in 2023–24, an increase of 31% on the $11.1 billion recorded in 2022–23.
Perth GP and local representative of Doctors for the Environment Dr George Crisp said that despite the clear science backing a reduction in the amount of fossil fuel investments, there were 124 new fossil fuel projects listed by the Federal Government in 2023, 10 more than at the end of 2021.
“If all the listed projects proceed, they are projected to contribute over 4.8 billion tonnes of emissions by 2030. For context, the global carbon budget to give us a 2 in 3 chance of limiting warming to 1.5°C is 92 billion tonnes. These Australian projects alone would consume over 5% of the global budget by 2030,” he said.
According to the report, this estimate does not include significant proposed gas fields such as the Beetaloo Basin with its estimated lifetime emissions of up to 3.2 billion tonnes, or the Burrup Hub gas project, which has estimated lifetime emissions of 6.1 billion tonnes. These two gas fields alone would account for 10% of the global carbon budget for limiting global heating to 1.5°C.
Associate Professor Alex Larcombe, the head of Respiratory Environmental Health at The Kids’ Institute, said that for every 1000 tonnes of carbon burned, one human being died prematurely. The implication of this was the Bettaloo and Burrup projects would be responsible for 3.2 million and 6.1 million premature deaths, respectively.
Associate Professor Larcombe highlighted that the impacts of pollution would be exacerbated by an ageing population and noted that for the first time in decades the life expectancy in many countries had gone down.
“A component of that would have to be exposure to all sorts of new pollutants that were absent years ago. Despite better healthcare and increased knowledge, more disease is going to manifest in older people and the WHO states that 99% of the planet breathes air that exceeds safety guidelines,” he said.
“And unlike climate change, it is beyond doubt that air pollution is causing large scale health effects across the Australian population in terms of asthma, heart disease, lung cancer, and premature births, which involve a whole range of significant illnesses that affect people’s lives profoundly.”
Both doctors agreed that Perth’s air quality was good but that was not the case for all of Australia or for most of the world, especially in developing countries where air pollution from a range of sources had significant health impacts.
“Much of what we are exposed to is anthropogenic particulate matter, which in Australia, like the report says, comes from primarily burning fossil fuels and many of these pollutants are carcinogenic. For example, diesel combustion, which is used a lot in Australia, is a class one carcinogen on numerous scales,” A/Prof Larcombe said.
“It is known to cause cancer in humans and everything in between. The particulate matter is carbon-based particles with a lot of other nasty stuff absorbed onto them.
“Even if the combustion process is super-efficient and it does output relatively pure carbon (which it never does), that carbon itself is toxic. The particulate matter, regardless of whether it has absorbed other chemicals or polyaromatics, is harmful in and of itself, and the health effects go all the way from minor, irritation from short-term, low-level exposure that everyone would have experienced.
“But over time, if the exposure dose is high enough, it can lead to serious health issues. And there is not a huge amount of information on what the real range of that damage is because the human population is so varied. What might be mildly harmful to a worker, or a healthy adult would be different for a child, an older person, or someone with cardiovascular disease – demographics that are more at risk.”
Dr Crisp said that a lot was known about air pollution from research over the decades.
“And thanks to the countless epidemiological studies, we also know that these impacts have been massively underestimated and occur even at relatively low levels of exposure,” he said.
“Separating out the individual pollutants such as particulates, oxides of nitrogen and volatile organics is extraordinarily complex, as are the pathways by which these pollutants cause disease. For example, both oxides of nitrogen and particulates occur in combination, and both have significant impacts. In fact, it is oxides of nitrogen that are the biggest drivers of asthma rather than particulates.
“While the nitrogen dioxide in our cities is produced by motor vehicles, it is produced in the home is by the burning of gas. We also know that households with gas cookers have much higher rates of childhood asthma, and 12% of all childhood asthma episodes in Australia are the result of a gas cooker.
“If you’re a GP and you have a family that comes in with a child with asthma and you’re talking to them about managing it, it’s highly likely they will be asked if anyone in the house smokes, or if they have pets, but I suspect that very rarely does someone say, ‘do you cook with gas’?”
A recent expert statement by Melbourne Climate Futures recommended that Australian estimates of death and illness attributed to vehicle emissions should be updated to incorporate NO2 impacts as well as those of PM2.5.
“One of the most crucial factors is the interaction between the original waste, the process used for combustion, and the size of the particulate matter produced,” A/Prof Larcombe explained. “Not only are smaller particles breathed in more readily, but they also stay suspended in the atmosphere for longer, making them more likely to be inhaled.
“A PM gradient does not mean that they are all produced at that size, rather, it includes everything up to that size including nano-sized particles and that hampers efforts to estimate the level of damage caused.
“The issue is further complicated by changes in the atmosphere as well. Once the exhaust leaves the vehicle and enters the atmosphere, the particles change and aggregate. They interact with the UV light from the sun and change, producing potentially worse volatiles.
“But the general trend is the smaller they are, the more harmful – for a range of reasons. We have our own built-in defence mechanisms with mucus in our noses and throats that trap the bigger particles, and we effectively swallow those most of the time and they pass through and don’t cause too much trouble.
“But smaller particles can bypass that mucus, penetrate the lungs, and enter circulation in the bloodstream. And concerningly, they can cross the blood-brain barrier and cause neurological disease.
“There are now established links between these types of exposures and diseases such as Alzheimer’s, for example, as well as all sorts of cardiovascular issues as well as exacerbating existing disease and impairing immunity.
While your body is working overtime to compensate for the particulate matter, your ability to fight off other exposures to viral or bacterial pathogens is significantly compromised. There is a lot of evidence accumulating that diesel exhaust and others promote the development of asthma if it was not already there.”
He said that the cells and macrophages in our lungs were designed to recognise a virus or bacteria and attack that. When they see a carbonaceous particle from combusting fossil fuel, they will also try their best to clean it up too.
“Macrophage means big eater and while this tactic works reasonably well in the short-term, as they keep trying to devour these particles over time, they become overwhelmed and die. All the carbonaceous particles that they have previously consumed are rereleased into your body, triggering an ongoing inflammatory process,” he said.
Dr Crisp said that many local councils already had noise pollution zones indicated next to main roads for real estate buyers to consider, but there was no equivalent demarcation that showed the amount of air pollution people living in the vicinity would be exposed to.
“Why is that? We know that living within 50m of a main road has significant effects for your health and the proximity is important. So, why do we not say something about living near those areas? More importantly, why are we still building childcare centres and schools next to main roads when we know that they are the most vulnerable populations? There is a big disconnect here,” he said.
“There is an extraordinarily strong correlation between proximity to major roads and your levels of exposure to vehicular pollution, just like there is a correlation between how close you are to a coal fired power plant – it is a well-established link,” A/Prof Larcombe added.
“Which is why it is so concerning that so many childcare centres are built on major roads – these levels of exposure exacerbate underlying asthma. Don’t build our daycare centres next major roads, because moving away even a couple of hundred metres makes an enormous difference in terms of health.”
Dr Crisp said GPs had an important role to play as leaders within the local community when it came to sharing information and spearheading action.
“Just like we have done for smoking cessation, immunisations, and a host of changing areas of medicine and health beyond the consulting room. Our voice is important because we are informed about the medical science and because we can bridge the gap between information and the actions that we need to take to improve our health, both individually and collectively,” he said.
“GPs are on the ground. They can see and monitor the impacts in their local clinic, and we can change outcomes. There is a wonderful opportunity here for improving our patient’s health through air pollution literacy and advising our patients and communities about local impacts.”