Super Pollutants

Laura Anderson, campaigner, environmental scientist and ethical influencer: What if I told you there's an emergency break for climate change? A surprisingly fast solution that doesn't involve those two words. Carbon dioxide.

Carbon dioxide is the original bad guy for the climate crisis. And rightly so. CO2 contributes to around half of global warming. But what about the other half?

Okay, plot twist. For the next five or so minutes, let's put carbon dioxide to one side. There's actually another group of dangerous pollutants around us right now, also known as the super pollutants. 

On screen text: Nitrous oxide, black carbon, methane, tropospheric ozone (ground-level), HFCs

Laura Anderson: And not only are they fueling climate change, they're also linked to millions of premature deaths around the world every year. But there is good news. If we reduce them, we'll improve our air quality and health almost immediately. This is our emergency break for climate change explained. 

Okay, I've come down to Wellcome in central London. And if you've been around here recently, you might have seen a sign that looks like this.

On screen: Low emission zone sign.

Laura Anderson: It's one of many government policies attempting to improve air quality in cities all around the world, specifically by reducing super pollutants like black carbon. 

On screen: Images of cities including: New York, Mexico city, Beijing, Amsterdam, Paris

Laura Anderson: We're already noticing the benefits of these policies reducing the pollution emitted from large vehicles and old engines on the road. However, to make our air cleaner and healthier, countries need to do more than just cut down on traffic. In the UK, every year, toxic air is linked to 30,000 deaths, and the wider health impacts also cost us £50 billion. If you zoom out, every year globally, 6.7 million people die from toxic air. 

Super pollutants get their name from their supercharged ability to trap heat, warming the planet a whole lot more than carbon dioxide.* 

On screen text: *When compared by weight.

Laura Anderson: They also get a whole lot less attention when it comes to policy. However, there is hope. A lot of hope in fact. These pollutants only stay in the atmosphere for a few years, weeks, or even days. Whereas CO2 sticks around for centuries.

Because of their shorter lifespans, reducing them will lead to immediate improvements in not just the quality of our air, but our quality of life.

And another bit of good news, when you address one super pollutant, you'll often start addressing others without realizing. They're rarely found alone. So, it can help to understand a little bit about our atmosphere, different chemicals and how particles mix.

Drew Shindell, Nicholas Professor of Earth Sciences, Duke University: Some are dark and some are light. They have different colors, different properties, and so it's a little bit more of a complex, nuanced story for policy makers.

Laura Anderson: That was Drew, a professor at Duke University, formerly with NASA. And this is Jonathan. He's an assistant professor at Boston University. They're both going to join me today and have a quick rundown of the three main culprits. 

Black carbon is one example of a super pollutant. 

Assistant Professor Jonathan Buonocore, Boston University: It's just particles. It's in the air. you can breathe it, it's bad for you. It is a big deal for health and it's something that as an air quality health community, we’ve been dealing with and studying for decades.

Laura Anderson: Black carbon, it comes from vehicles and trucks, but also burning like wood stoves or wildfires. And like Jonathan said, these processes all release tiny black particles that combine to make soot, absorbing heat and lingering in our atmosphere for around 12 days. 

Jonathan Buonocore: There's strong relationships between increased exposure to that and a whole variety of health outcomes including premature mortality, respiratory hospitalization, cardiovascular hospitalizations and stroke. And there's been a lot of literature coming out recently even about neurodegenerative diseases like Parkinson's, Alzheimer's and those kinds of things.

Laura Anderson: There's a few things we can do to reduce the risks like switching to more sustainable transport systems and creating low emission zones. The solutions can really differ depending where you are or what you're focusing on.

Drew Shindell: There are billions of people who still lack access to modern forms of energy and they use solid biofuels and that can release enormous quantities of black carbon when those are burned and can lead to really terrible health impacts as well – especially for biofuel burning indoors.

Laura Anderson: Next up on the agenda, methane. Methane is the second most significant greenhouse gas after carbon dioxide. It warms the planet 86 times the power of carbon dioxide when measured over a couple of decades.* 

On screen text: *When compared by weight. 

Laura Anderson: We often associate methane with cows, which is valid, but there are many other causes such as fossil fuel leaks and filling landfills with food waste. 

Drew Shindell: One solution is to capture that methane where a tarp was pulled over the entire landfill. You have a vent, you capture the methane and that can pay for itself because you use that methane to generate electricity, say. But it's much more a question of behavior, reducing food loss in the first place and then composting when there is food waste.  

Jonathan Buonocore: When there’s methane leaks, whatever else is also in the gas is leaking alongside of it. Benzene especially is a pretty potent cancer-causing compound. So you’re worried about those kinds of health outcomes in folks living near any piece of infrastructure that’s susceptible to a gas leak.

Laura Anderson: As well as addressing these fossil fuel leaks, whether it's through a pipe, power plant, or stove, countries can also ban flaring and improve livestock feed to minimize methane emissions. Over 160 countries have also signed the Global Methane Pledge, a promise to cut methane emissions by 2030. Reducing around half of our methane emissions could lower global warming by 0.3°centigrade, which might seem tiny, but it's a huge difference for our climate.

Now, let's jump to tropospheric ozone, also known as ground level ozone. 

Drew Shindell: Ozone is our friend up in the stratosphere where it protects us from ultraviolet radiation. But down at the surface, it's not so nice. And when we breathe it in, ozone can exacerbate respiratory diseases. It can exacerbate cardiovascular diseases, diabetes.

Laura Anderson: Exposure to ground level ozone can worsen people's asthma, bronchitis, and other lung conditions, especially in children, the elderly, and those with pre-existing health issues.

Tropospheric ozone is another major ingredient of smog like black carbon which is often found in urban cities around the world. Ground level ozone isn't directly admitted like methane or black carbon. Instead, it's created when different pollutants mix together with sunlight. There's thousands of ways we release these chemicals. So, cutting down on this is a start.

On screen text: Precursors for ozone: 

Power industry

Transport

Industrial combustion

Energy for buildings

Industrial processes

Fuel exploitation

Agriculture

Waste

Drew Shindell: There are also some solutions which have a really nice bridge between something like black carbon and tropospheric ozone. For example, reducing burning of agricultural waste from fields after the crops are harvested. That releases a lot of black carbon, which we've already talked about, but it also releases a lot of carbon monoxide, which like methane is another important precursor of tropospheric ozone.

Laura Anderson: Okay, 5 minutes is up. These super pollutants need to be on every government's climate agenda, just like carbon dioxide. And unlike CO2, super pollutants don't linger for centuries. But for every extra day they're hanging around, they're just getting another opportunity to cause supercharged harm to our health and our planet. 

On screen: Industrial site, vehicles, someone using a spray paint can.

Laura Anderson: Cutting them alongside carbon dioxide will deliver immediate results. Cleaner air, fewer deaths, lower temperatures, all within years. I know I could use some optimism right now, and I'm sure you could too. And cutting super pollutants can give us just that.

So, let's make sure we take our chance whilst we can.