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Climate change and air pollution seriously threaten public health, adding more pressure on state healthcare systems. Urban planning and health research are strongly interconnected in tackling this problem, especially in wildfire and bushfire-prone regions. To better grasp how air quality affects urban health in Australian cities and why the data analysis should be contextualized, we talked with Dr. Nimish Biloria from the University of Sydney and Dr. Hamish Robertson from the Queensland University of Technology.
Isam D., ATMO: Thank you, Dr. Robertson and Dr. Biloria, for coming and meeting with us for this interview. I will kick it off with the first question we have today. How does climate change affect public health, in your opinion?
Hamish R.: I think it operates at many levels and will have a substantial impact universally going forward. In many countries, we have an aging population, rising disability, and complex chronic diseases, which are now impacting healthcare systems, and climate change intersects with all of those.
One of the things we need to consider is heat stress. However, we also have issues in terms of flooding and zoonotic diseases. The number of people who are at risk in any given community is climbing. We have issues around cost containment and support, and we have impacts on the workforce because they will be part of the affected population, too. We have impacts on infrastructure, which Nimish can talk to you more about in terms of design, architecture, and response strategies.
We also have a growing need for what I would call localized notes, as in data collection and analysis, which will inform response models so that they are contextualized to local communities and local regions and not just a sort of general top-down government-type response that we've often seen in the past.
We also need improved local and timely data to inform planning and response approaches. I think ATMO could also support capacity building at a community or citizen science level.
Nimish B.: A big yes to almost all your points. Plus, some interesting statistics are coming out of Australia. For instance, 11,000 Australians die prematurely every year from just transport emissions which is one of the biggest contributors to climate change. This is an alarming rate that has been increasing. Nothing is curtailing this back. Similarly, asthma cases spike by 66,000 each year. I mean, these statistics are telling you that climate change is a big, big reality. And its impending health costs – $4.8 billion a year go into how the government healthcare is trying to curtail and treat patients who are suffering from these kinds of diseases.
Another big issue connected with social and economic inequity crops up almost everywhere when studying urban and demographic patterns and how these are spread out.
“And this is true for almost every city in the world, where the most socially disadvantaged people are the ones who suffer the most.”
The problem is, no matter how much impact you want to create with mitigation measures, this is a big issue because first, they don't have financial stability and, therefore, cannot move to regions that are much better, much greener, etc.
Well, again, urban green space is drastically decreasing, which again impacts walkability, mobility, etc., and health. But from the equity perspective, I think Australia itself is almost 2.2 times greater in terms of the impact that these particular socioeconomically challenged people are actually facing right now.
So I think there's a lot to do in terms of the impacts of climate change on public health and on a large scale, even our infrastructure levels. I think this is a humongous problem. It's interesting. Everybody talks about large-scale migrations. Everybody talks about, you know, increasing the urban density. Still, nobody talks about the counterpart of it in terms of how much permeable surfaces are drastically being reduced or how much urban heat is actually being produced. What are the results and impacts of these? So I think these equations don't count where real estate governs everything. On the other hand, when you look at public health sectors, everything is a receptive scenario. Okay, this is happening; therefore, we must be prepared. But I think we need to interject in between. And that's where people like us come in, where we say, “How do we work with devices? How do we work with datasets? How do we tie things together and, therefore, project the outcome? What is the reality of the situation, and what possible measures that are very, very contextual?”
Isam D., ATMO: Thanks a lot for your answers. In addition to discussing climate change and its effects and some of the statistics and numbers you've just mentioned, we’d like to look into air quality. Can you tell us how air quality impacts urban health in Sydney and other cities in Australia from your experience or the data you were able to acquire?
Hamish R.: I'll talk more broadly, and then I think Nimish will come up with some specifics. One of the cases you can consider in the Australian context is the 2016 major Melbourne asthma event. That was a reaction to environmental conditions in the Melbourne metropolitan area.
And one of the interesting things is that it almost crashed the healthcare system. Part of the problem was communication with affected people. For example, people calling the ambulance would be given times to expect an ambulance to roll up. But as the event progressed, those numbers rose dramatically. Therefore, ambulances were backing up at acute care hospitals. And then, of course, the time blew out. So, people in the community waiting for an ambulance started to take matters into their own hands, hop in the car, and be driven to a hospital. So they not only had the ambulances waiting, but you had individuals in the car park rushing to emergency departments because they had acute respiratory responses.
And that's just one example. In 2019, we had pretty significant bushfires yet again across metropolitan Sydney.
To some degree, one of the issues is that we don't talk much about the long-term health impacts for individuals, similar to COVID at the political level. Lots of interest after the acute event tends to be quite rapid even though the health professions and others across the social care domain know there will be a long-term effect at a population level.
So I think one of those things that we need to consider, as Nimish mentioned before, is the role of technology and monitoring these long-term health trajectory effects that individuals and their families and communities might experience. So, not only social inequality issues but also the fact that you have been exposed to 2.5-micron particulates and their potential impact over time on your health.
Another point to consider is that emissions in urban areas don't affect every place equally. Some areas experience greater effects than others. If you have more ameliorating infrastructures such as green and blue space, or if you have been able to buy a Tesla or Polestar, your risk curve will start to reduce compared to other groups in the community. Suppose you're driving a 10- or 15-year-old car because you can't afford the latest tech, and you perhaps can't afford wearable health monitoring equipment. What's your scenario regarding current and future healthcare risks in this case?
Nimish B.: It's good that you raised that point. I also come from an architecture, built environment, and urban design background, so it's also very interesting for me to understand, for instance, topography, weather, climate, road traffic, industry, and industrial estates. Almost everything impacts air pollution levels.
So apart from everybody talking about Sydney as one of the world's most livable cities, there is a divisive line between the East and West. But the problem is also the geolocation. I think this is a very, very big issue. Pollution also happens in the Sydney CBD region. The problem is that Western Sydney is almost like a valley, away from the sea breezes. Still, the problem is in the summertime, especially when the prevailing wind condition is the northeasterly wind condition. So what's happening is that the wind is hotter. So, the air and associated pollutants are rising. It travels towards South-west Sydney, where they start settling down. So, the massive burden of the overpopulated nature of this rampant urban development is also creating multiple issues. The tree canopy is so different in the West versus what we'll see in the East.
There is also a big question of political will regarding what should and should not be done. At the same time, this whole issue of equitable development is still very important. I mean, no matter what you consider. Even World Health Organization guidelines for PM2.5 are five micrograms per cubic meter over a year of exposure. From that scenario, even if you look at Sydney's current level, it is almost 6.4. If you travel upwards, let's say towards the Hunter region, it again changes till the point that almost reaches 12.
You must understand that even if you look at New South Wales and Sydney, they have very interesting contexts. Where I live, for instance, in the Blue Mountains, wood stoves are big. In New South Wales, almost 10% of households still use wood stoves. The impacts of this are endless, considering that the pollutants you breathe are also associated with lung and heart disorders, and these are growing.
So, wood heaters are attributed to 269 premature deaths annually, almost costing $2 billion for the healthcare system to mitigate. So, on average, if you think about it, in the regions, almost 12 years of your life are simply being deleted because of the nature of wood stoves. Who is responsible? It's not that everybody likes to light wood stoves. Still, the cost of energy and your socioeconomic status should be evaluated contextually to amend the fact that nothing changes and everything becomes a blanket policy.
I think it becomes a big issue in places like Sydney, a city like mine, or a state like New South Wales. Almost everything is entangled. We can't talk about air quality without talking about the rate of urban development, without inward migration, and without talking about cutting down forests. So, in terms of mitigation, I think solutions need to come in a way that still talks about this interrelationship so that we can establish and create models to project and say which regions need what kind of mitigation measures.
Isam D., ATMO: Based on what you shared, we've seen that air quality has a big impact on people in Sydney and Australia in general, especially in urban environments. So, when discussing individuals who are more sensitive to air pollution and elderly individuals, what is the connection between air pollution and dementia? And is there a way we can protect elderly people from the negative impact of this urban environment?
Hamish R: It's a really interesting question. Now, there is growing evidence to show a direct connection between air quality and the expression of dementia. I guess one of the things that we need to consider is different dimensions. Neurodegenerative diseases cover about two hundred different conditions. The primary ones in Western countries are obviously Alzheimer's disease, vascular dementia, and Lewy body dementia. So, we know what the population is experiencing. We're still starting to unpack the connection between air quality and particulates such as 2.5 microns and their effect on cognitive processing, cognitive ability, and neurodegeneration over time.
You can even push that further back when you look at, for example, a growing body of research on our cognitive impairment over the past decade. So essentially, we are looking for precursors indicative of subsequent neurodegeneration and older people that we're familiar with but which we think have earlier onset, if you like, indicators. So in terms of, for example, preventive action that Nimish is talking about, we can't just rely on treatment modalities when people are 75, 80, or 85.
To prevent dementia of any particular kind, we have to go much further back down the trajectory of their life course to be able to affect their health status as they get older. And the intersectionality of that with environmental monitoring, I guess, comes down to what we're also thinking about. If we can track what their exposures are and what their relative physiological health statuses are at an individual level and conduct a cognitive assessment of rigorous intervals, we will be in a position to evidence-base that relationship.
“And I guess if we're looking at even in the bigger picture, particularly at a global level, that neurological development starts in utero. Therefore, childhood exposure to air pollutants leads to eventual potential neurodegeneration across the life course.”
So dementia, in that sense, becomes, if you like, an endpoint for disease, a question of the kind of neurodegenerative lifecycle. What happens in utero and childhood can potentially contribute to, say, mild cognitive impairment in midlife and then onwards into a specific coverage or combination of dementias in older life. So it's a really interesting and challenging area. And I don't see us being able to do much about it without the capacity that technology provides to monitor individual situations and then aggregate those into meaningful knowledge.
Nimish B.: Yeah, I fully agree. Honestly, I'm not a health expert, so I cannot comment much on that. However, one study from the US, which I read, said that the increase in air pollution is directly connected with the increase in the levels of the protein amyloid, which is connected with the whole development of Alzheimer's disease. So this was a very interesting benefit proposition. Some people state that, after longitudinal studies, an almost 17% increase in risk for developing dementia happens for almost every two micrograms increase in the average annual exposure. And this is only PM2.5 levels. And this is quite interesting. Almost every time we circle back, the whole issue becomes all about what we do in such scenarios, right? For instance, there's no actual cure for dementia.
But then, how do we create preventive situations? Hamish also suggests that technologies play a big role. And how do we, in fact, even start communicating in a timely fashion and start nudging directions toward people to avoid, let's say, streets that are much more polluted?
How do we develop predictive models that suggest that tomorrow is not a good day? Or maybe the day after tomorrow is not good? Do you tell them not to go out the door? Or do you start suggesting alternative routes that could be better for them?
So the whole idea is not to say whether it's yes or no, but it's also our responsibility to suggest what to do in such cases. Therefore, it is also our responsibility to reduce exposure to such pollutants. Yet, how do we encourage walking? How do we encourage what equals sustainable and responsible mobility? This is a big one – can we start reducing gasoline- and diesel-powered vehicles? If so, what is the role of the government in subsidizing electric vehicles? Everything is tied together, right? So, policy structures are also interlinked.
How do we increase urban green? Even if you plant 5 million trees today, in New South Wales, it'll only reduce the temperature by one degree or a maximum of 1.2 degrees. So, in such scenarios, how can we become strategic about where to do this planting? How and to whom is it the most beneficial? And again, at the community-wide level, so Hamish did speak about the individual level, how can you increase this awareness? What hotspots do people visit that make it essential for us to advertise, relate information, and relay information regarding equality, which can be immediately absorbed conveniently rather than getting stuck in this whole process of grasping? Making the information more accessible is very, very important as well.
Again, as I said earlier, this whole idea of how it's connected with where we live is critical. So how do we increase green and permeable surfaces that are really important? For example, in Sydney, they're now trying to change the color of your roof from black to white. Would that impact the temperature around you and air quality conditions?
It's not just about large-scale planning; even small details matter. Consider the design of a public square, the selection of urban greenery, and the types of outdoor furniture. These elements create a sense of place and belonging and contribute positively to our health. To make a real difference, to be very honest, we need to implement these changes simultaneously.
Hamish R.: And can I raise another point too? I'd say that Nimish has raised an issue around communication. So if we've got, for example, people who are in their late 70s, or early 80s, and they already have some form of cognitive impairment, the way we communicate about these issues is going to matter, too. So we can't overload them with complexity. So, something like Atmotube personal monitors has an overall measure and the specifics. This way, monitoring can help us communicate that risk information to individuals and offer them alternative actions. And if it's not them, it's the carer or carers.
