🌫️ Global Air Quality, Wildfires, and Health: 2025 Update

see related Substack episode

Every person reading this is participating in the same atmospheric experiment. The air you breathe in New York contains particles from wildfires in Canada, dust from the Sahara, and emissions from factories in China. We're all connected by the same thin layer of atmosphere that surrounds our planet.

The pollution crisis forces us to confront an uncomfortable truth: individual action alone won't save us from collective problems. You can buy the best air purifier money can buy, but you still have to breathe the same air as everyone else when you step outside.

Climate-Driven Wildfires are Reversing Clean Air Progress

Air quality life index

Impacts of Aging and Relative Humidity on Properties of Biomass Burning Smoke Particles

The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house

Anna Alari et al, Quantifying the short-term mortality effects of wildfire smoke in Europe: a multicountry epidemiological study in 654 contiguous regions, The Lancet Planetary Health (2025). DOI: 10.1016/j.l

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Transcript

0:25

globally, fine particulate air pollution, you know, PM 2.5, it isn't just a concern. It's actually still the single biggest external threat to public health. That's right. And get this statistic. It's really powerful. If we could just prominently cut this pollution down to meet the World Health Organization guidelines. Which are quite strict. Exactly. The average person worldwide would gain 1.9 years of life. Wow. That adds up to a staggering 15.1 billion total life years across the globe. 15 billion. That's hard to even comprehend. It really is. And just for context, it's impact. comparable to smoking, more than four times that of high alcohol use, and over six times the impact of HIV. So it's huge. Just massive. Right. So today we're doing a deep dive into this urgent and honestly constantly changing story of air quality. Okay. We've got a few key sources. The brand new 2025 Air Quality Life Index, or AQLI, annual update. That's from the Energy Policy Institute at the University of California. of Chicago. You pick, yeah. Great work. Also, some new guidance on indoor air from the US EPA, which is timely. And some really groundbreaking findings from the Lancet Plantary Health about the specific dangers of wildfire smoke in Europe. Oh, that's interesting. The specificity. Yeah. So our mission here is basically to unpack the latest global trends, shine a light on some maybe surprising regional impacts, explore why data and monitoring are so crucial. Absolutely critical. And then really zoom in on this growing threat from climate driven wildfires. Sounded good. Let's do it. Okay, so the AQLized 2023 data, just out. It shows a slight global increase in PM2.5 concentrations. An increase after all the focus. Yeah, up 1.5% from 2022, which means we're now at levels nearly five times the WHO guidelines. Five times? So, you know, you might think we're generally making progress, but this data, it suggests that, well, in some ways we might actually be slipping backward globally. That slight increase, 1.5 percent, it sounds small, but globally, that's significant, especially when you think about the human cost. Five times. Like you said, that 1.9 years gained if we meet the guideline. That's billions of potential life years just being left on the table. It really is. Which it sort of begs the question, doesn't it? Why does a threat this big, I mean, comparable to smoking, often seem to fly under the radar compared to other big health risks? That's such a good point. Maybe because it's invisible most of the time. Yeah, perhaps. It's insidious, right? You don't always feel it immediately. It's not like, you know, a big infectious disease outbreak grabbing headlines. But the long-term toll is just immense. Precisely. It's chronic. It just sort of erodes... health over decades. It doesn't have that immediate crisis feel. But it's essentially a silent pandemic affecting everyone everywhere. And speaking of everywhere, here's where it gets really interesting. Maybe counterintuitive. Okay. While we often think of, you know, certain industrial regions as having the worst air pollution. Right. The usual suspect. The highest increase in pollution globally in 2023. It actually hit the United States and Canada. Really? North America? Yeah. Those record-breaking wildfires in Canada last year. They fueled Canada's worst air quality since 1998. And then that smoke drifted south, pushing U.S. pollution levels to their highest since 2011. Wow, so the fires had a huge continental impact. Huge. Over half of all Canadians breathed air exceeding their own national standard. That's up from less than 5% in previous years. a massive jump. And in the U.S., states like Wisconsin, Illinois, Ohio, even Mississippi, their counties became some of the most polluted. For the first time in a decade, it wasn't California dominating that list. That is quite a shift. And it really underscores this critical link, doesn't it, between climate change and air quality. These climate-driven wildfires are actively, you know, reversing decades of clean air progress, at least in those regions. It feels like one step forward, two steps back sometimes. Well, Michael Greenstone at EPIC put it really well. He noted that burning fossil fuels obviously directly causes particulate pollution. Right, the primary source. But it also leads to higher global temperatures, which then fuels more intense, more frequent wildfires. creating this kind of second wave of air pollution. Ah, okay. So it's like a feedback loop. Right. Exactly. Yeah. A dangerous echo, you could say. Yeah. Fossil fuels burned maybe generations ago, now manifesting as these intense fire seasons. So just to make sure I'm following, it's a double hit. burning fossil fuels gives us immediate pollution. Correct. And then through climate change, it helps create these massive wildfires, which give us more and potentially different pollution. It's compounding. That's exactly right. It's a compounding effect. And it means our policies, well, they need to be smarter, more integrated. We have to tackle direct emissions and the climate factors driving these secondary sources like wildfires. Makes sense. Okay, so North America saw that surprising surge. But the global picture, as you'd expect, is really complex, a real patchwork. Right. Always is. Let's start with South Asia. Still consistently the region facing the most severe burden. They saw a 2.8% increase in 2023. Still going up there too. Yeah. Countries like Bangladesh, 60.8 micrograms per cubic meter, India 41. The health burden is just immense. And the potential life gains if they met the WHO standard. Huge. Potentially 5.5 years in Bangladesh, 3.5 in India. And get this, in Delhi, residents could live an estimated 8.2 years longer. 8.2 years. Just from clean air. It's incredible. What does that tell us about the challenges there? Is it policy, industry, geography? Well, it's all of the above, really. The sheer scale of those potential life year gains in South Asia tells you this isn't just an environmental issue. It's a fundamental human rights issue. a massive barrier to health and development. You've got complex factors, rapid urban sprawl, reliance on older, more polluting industries, vehicle emissions, agricultural burning. It's multi-source. Tackling it needs this really integrated approach. Urban planning, energy, health policy, which is frankly, very hard to coordinate effectively. Understood. OK, so from South Asia's ongoing struggles, let's pivot to China, a place that saw a pretty remarkable, though maybe fragile turnaround. Right. The war on pollution. Exactly. After a decade of really significant decline, they actually saw a slight increase in 2023, about 2.8 percent as well. Interesting. A little rebound. Yeah. But context is key. Their air is still over 40 percent cleaner than it was back in 2014. That's added about 1.8 years to average life expectancy. Still, particulate pollution is the second biggest external threat there, right behind smoking. So China's story is fascinating. The war on pollution from 2014 really showed what focused policy can do when there's political will and, crucially, public awareness fueled by data. The dramatic reductions prove that rapid industrial shifts and tough regulations can work. But this recent slight increase, it's a stark reminder, isn't it? Progress is fragile. Yeah. Things like economic recovery, maybe changes in industrial patterns, even just unfavorable weather. They can quickly chip away at those games. It tells you clean air isn't a one and done fix. It needs constant effort, constant adaptation. A really good point about sustained effort. Okay, Europe. The story there seems to be continued benefits from long-term clean air policies. A 31.5% reduction in particulate pollution since 1998. added about 5.5 months to average life expectancy. That's significant progress over decades. But it's not a perfect picture, is it? Eastern Europe, particularly places like Bosnia and Herzegovina, still have high levels. Residents there could potentially gain 1.6 years if they met WHO guidelines. That contrast within Europe is quite telling. Western and Northern Europe have really benefited from decades of strong environmental rules, cleaner cars, shifting away from heavy industries. Right, see the results. Their progress shows that sustained policy does yield major health gains. But then you look at parts of Eastern Europe and you still find a lingering reliance on older coal plants, maybe less strict emission controls, certain types of residential heating. all contributing to PM2.5 and creating these persistent hotspots that still cost lives. It really highlights the variation even on one continent. Now, Latin America, PM2.5 concentrations there actually hit their highest level since 1998. Highest since 98? Wow. Bolivia, Honduras, El Salvador are the most polluted. And in Bolivia, get this, pollution's impact on life expectancy is nine times greater than the impact of self-harm and violence combined. Nine times. Yeah. It's incredibly sobering. It just elevates air pollution to this, well, this urgent crisis level that needs immediate attention. It really does. And the challenges in Latin America, especially with things like the Amazon fires you mentioned, They show a different dimension again. It's often the strong interplay between land use, farming practices, deforestation, and climate change driving the pollution. Not just industrial smokestacks. A different set of drivers. Okay. And what about Central and West Africa? The report says pollution levels there have been largely unchanged for a decade. It's a check then. Yeah. Yeah. And the AQLI points out that in countries like Cameroon, the Democratic Republic of Congo, air pollution takes a bigger toll on life expectancy than HIV AIDS, malaria and unsafe water combined. That is just a profound statistic. It really raises questions about equitable access to clean air, but also equitable public health focus. How so? Well, in many of these regions, the health narrative has understandably focused on infectious diseases for decades. But this data clearly shows air pollution is an equally, maybe even more devastating, silent killer. Yet it often gets far less funding, far less attention. Right. And the fact that levels haven't changed in a decade, it suggests a real gap in policy and monitoring and awareness, a truly overlooked crisis. Definitely. Okay, let's end the global tour on a slightly brighter note. Oceania. Residents there, breathing the cleanest air in the world. Over 73% of the population meets the WHO guideline. Well, that's good news for someone. A little glimmer of hope in a pretty challenging global picture. Absolutely. So we've walked through the numbers, the regions. One thing that keeps coming up across all these sources is the power of information itself. Yeah. Does air pollution information, you know, data actually matter? The short answer seems to be allowed. Yes. But what is it about data that makes it such a game changer? I think a key insight here is how transparent data can really mobilize people and push policymakers. Look at the U.S. example again. Okay. After those deadly smog events like Denora in 48, it was the data disclosure, the public outcry that directly led to the Clean Air Act. Right. A landmark piece of legislation. And that act has cut particulate concentrations by over 60 percent since 1970, added, what, 1.4 years to American limes on average? That's tangible impact. Totally. Or China's war on pollution in 2014. That was scurred by widely available real-time data, studies showing the life expectancy loss. And it led to that huge 37% drop in pollution. Right. So data fueled the political will. Exactly. And it works locally, too. In Poland, you had groups like Polish Smog Alert. using data to push for local action, national reforms like banning solid fuel heating in Krakow. Okay, so it's not just having the data, it's making it accessible, relatable. You mentioned the AQLI translating pollution into life expectancy earlier. That really hits home. That is a personal, yeah. But here's the catch, the big problem. Nearly 5.5 billion people around the world still don't have access to meaningful air quality and 5.5 billion. That's most of the planet. Yeah. About 68% of people live in countries with fewer than three air monitors per million people. That's the bare minimum recommended in the U.S. and Europe. It's a massive information desert out there. It's an enormous gap. And it directly holds back progress, doesn't it? I mean, how can people protect themselves? How can they demand change if they don't even know the air they're breathing is dangerous? And that's why tools like the AQLI are so important, making the limited data we do have relatable. And it's why EPEX-C launched the Air Quality Fund in 2024. Right. You mentioned that. To address the monitoring gaps. Precisely. Supporting local groups to install monitors. They've helped get over 700 monitors up in 19 countries so far. That's great. And we're seeing early results like the Gambia developing its very first PM 2.5 standards based on new data or the DRC setting up its only air quality monitoring network. These are crucial first steps building that baseline knowledge needed for policy for health interventions down the road. That's fantastic progress getting those foundational monitors in place. Okay, now let's dive deeper into this wildfire issue specifically. All right, the second wave. Yeah. This new study in the Lancet Planetary Health, it has a really sobering message, PM2.5 from wildfire smoke. It's not just another source, it's significantly more harmful than PM2.5 from other sources. This is a really critical distinction with major implications for how we assess wildfire. risk. How so? Well, the study looked at 654 regions across 32 European countries. It found that just a one microgram per cubic meter increase in fire-related PM2.5 was linked to a 0.7% increase in deaths from all causes and a 1.3% increase in respiratory deaths, 0.9% in cardiovascular deaths. But here's the really striking part. Yeah. If you just use the standard risk assessments for general PM2.5, you would underestimate the actual death toll from wildfire smoke by an incredible 93%. 93%, wow. So we've been massively undercounting the danger. Essentially, yes. The specific nature of wildfire smoke makes it far more dangerous, microgram for microgram. So what is it scientifically? What makes wildfire smoke so much worse than, say, traffic pollution? It really comes down to its unique characteristics. wildfire smoke has a different chemical makeup different particle sizes and crucially a higher oxidative potential coxidative potential mean the particles are more chemically reactive mm-hmm they cause more damage at a cellular level when you breathe them in they generate more harmful free radicals in your lungs. Oh, okay. Studies out of California, for instance, suggested wildfire PM2.5 could be up to 10 times more harmful than other PM2.5 sources. 10 times? Yeah. And this likely explains why it's linked more strongly to things like triggering asthma attacks or COPD exacerbations. Makes sense. And there's more complexity, too. Research shows that as smoke ages in the atmosphere. or interacts with humidity, its physical properties can change. Things like its effective density can increase. Making it stickier in the lungs, sort of? Kind of. It changes how the particles behave, how they deposit in your respiratory system, potentially making them even more problematic. That's, yeah, that's a really clear picture of why it's so uniquely bad. And with wildfires, there's also the indoor air problem, right? The US EPA guidance touches on this. Yes, a big challenge. Especially when you're told to shelter in place during a fire. There's this trade-off. Normally you want more fresh air, more ventilation to clear out indoor pollutants, maybe viruses. Right, like during the pandemic. Exactly. But with wildfire smoke, you want to minimize ventilation to keep the smoke out. So how do you hit that contradiction? That's a really practical and critical question for safety. The key, often, is increased air filtration indoors. Okay, filters. Yeah, because good filters can capture both the smoke particles and other airborne things like viruses without needing to bring in smoky outside air. So the EPA recommends creating a clean room at home. A clean room? How? Basically, pick a room, keep windows and doors shut tight. If you have an air conditioner, run it on recirculate mode. Use fans to circulate the indoor air. And most importantly, run a portable air cleaner, ideally one with a HEPA filter, in that room. Got it. So seal it up and filter the air inside. Creates a safe breathing space. Exactly. A refuge from the smoke outside. Okay. So as we start to wrap up this deep dive, it feels like we're facing this dual challenge that really needs our focus. Yeah, it's clear. On one hand, the persistent widespread threat of just regular global air pollution, which is cutting lives short on a massive scale. Still the biggest killer overall. And on the other hand, this escalating uniquely dangerous impact of climate driven wildfire smoke, which we're now realizing is much worse than we thought. The science seems pretty stark on both fronts. It is. And what's really evident from everything we've discussed is that knowledge truly is power here. Data is the fuel for action. Whether it's national policies like the Clean Air Act or community monitoring networks popping up, getting accurate, accessible air quality information out there empowers people. It drives policy change. But the data alone isn't enough, is it? No, absolutely not. That data has to be met with sustained political will, with ambitious policies to actually use that information to clean up the air. That's how we truly turn the tide and protect health globally. Which really brings up a final important question, maybe for you, our listener, to think about what steps can you take as an individual, maybe as a community member? How can you advocate for or maybe support better air quality information and action right where you live, especially now as climate change, makes things like wildfires more intense. And how do those local decisions, those local actions ripple outwards? How do they ultimately connect to this bigger global picture of health and life expectancy for absolutely everyone?