Air pollution and climate change are intrinsically linked. In this month’s magazine, editor Pippa Neill explores how.
The climate crisis and air pollution are two of the biggest threats facing humankind, but like with most things, it would be foolish to address these as two separate issues.
Across the world, air pollution is responsible for an estimated 7 million premature deaths every single year and according to research conducted by Greenpeace Southeast Asia, pollution from burning coal, oil and gas is responsible for 4.5 million of these.
However, the relationship between air pollution and the climate crisis doesn’t end here. In fact, increasingly academics are starting to understand how climate change mitigation can help to reduce air pollution and how clean air measures can help to reduce greenhouse gas emissions.
Short-lived climate pollutants
When talking about greenhouse gases, it would be easy to think that our only concern is carbon dioxide (CO2). However, as the name suggests there are many other less-discussed but equally dangerous gases, which when grouped together are known as short-lived climate pollutants.
Black carbon, a pollutant produced largely by household burning or diesel vehicles, is one of these pollutants that is a growing cause for concern. Like other commonly known air pollutants, black carbon is dangerous to our health, but it also has a global warming potential up to 1,500 times greater than CO2.
Dr James Allan, expert in black carbon at the University of Manchester explains: ‘Black carbon is very short-lived in the atmosphere meaning it only sticks around for a few days. However, where it does have an effect it can be really profound because it has a really high climate warming potential in terms of watts per square meter.
‘There is also some evidence to suggest that gram for gram, black carbon is worse for human health than particulate matter (PM2.5) pollution.’
Inhalation of black carbon is associated with cardiovascular disease, cancer and birth defects. In India alone it is responsible for over 400,000 premature deaths every single year.
Alongside its health impacts, black carbon is also known to interact and disturb certain weather patterns. Dr James Allan explains: ‘Research also seems to suggest that black carbon may be impacting specific regions more than others and that this may even be affecting local weather patterns and contributing to localised climate events.
‘For example, there is some evidence to suggest that black carbon may be perturbing the Indian and East African monsoons. This is because the black carbon is heating a specific part of the atmosphere which can then have various knock on effects, for example, it can make it difficult for clouds to form.
‘Clouds are very good at reflecting the sun’s light back into space, so if you have fewer or thinner clouds, then this has an even bigger warming effect on Earth because it means you then get more of the sun’s radiation.
‘Eventually, the black carbon will get rained or snowed out, and if it lands on ice or snow it can make the ice darker, meaning it absorbs more sunlight and therefore will melt faster.’
With clear climate and public health benefits, the case for reducing black carbon has never been stronger. Yet despite this, the UK and many other countries across the world have no legal limit restricting the amount of black carbon that can be emitted. According to the United Nations Climate and Clean Air Coalition, the implementation of control measures could reduce global black carbon emissions by as much as 80%, helping to limit global warming in line with the Paris Agreement and potentially saving thousands of lives.
Another short-lived climate pollutant that has mutual public health and climate impacts is methane. Methane comes from a variety of anthropogenic sources such as food waste, agricultural activities, coal mining, oil and gas systems and combustion and similarly to black carbon, methane is much more potent than carbon dioxide, with a warming potential up to 86 times greater than CO2.
In 2019, the oil and gas industry was responsible for an estimated 82 Mega tonnes of methane emissions, with the majority of these emissions coming from leaks.
Dr Aiden Farrow, air quality scientist at the Greenpeace Research Laboratories tells Air Quality News: ‘A lot of people are touting methane as a slightly cleaner greenhouse gas but it actually has a lot of problems associated with it.
‘Methane is dangerous to public health because it goes on to produce other pollutants like ozone, but it is also a really important climate forcing gas.
‘The recent IPCC report highlighted that by controlling methane we can have a relatively quick impact on the climate situation, and at the same time, we can have relatively fast turnaround improvements to our health.
‘Methane is something we really need to be on top of, it needs to make its way to the top of the climate conversation so we aren’t just focused on CO2.’
According to the Climate and Clean Air Coalition, because methane is a key ingredient in the formation of ground-level ozone, a pollutant known to attack all bio-tissues including the lungs and skin, reducing methane leaks could prevent 260,000 premature deaths and 775, 000 asthma-related hospital visits annually.
However, even if we were to slash ozone pollution overnight, scientists have expressed concern that it will continue to get worse as the climate warms. Professor James Lee from the University of York, explains: ‘We are more likely to get high levels of ozone when we have periods of high pressure, which generally comes with heatwaves.
‘This means that as the climate warms, we will likely have more intense ozone pollution, which will lead the climate to warm, and so on.’
Ozone is not the only pollutant that may get worse as the planet warms. At the time of writing this article, uncontrollable fires are burning in Greece, Turkey, the U.S and Canada, with many countries recording the worst fires on record. It is now impossible to ignore the connection between climate change and wildfires, with numerous studies highlighting that warmer and drier conditions alongside increased drought is boosting the wildfire risk.
Wildfires of the magnitude seen today are responsible for excess greenhouse gas emissions, with forest burning producing around three times more CO2 than the forest absorbs.
The smoke produced from wildfires is also a major health hazard, globally wildfire smoke has been estimated to cause over 339,000 premature deaths a year. However, the long-term health impacts are still poorly understood. According to one study, wildfire smoke may have caused an extra 19,700 Covid cases in the US.
Dr Aiden Farrow explains: ‘In the latest IPCC report the headline message was that forest fires and wildfires will become more common in all of the places where humans live.
‘I think there is a real reason to be concerned and without action it is only going to get worse. Wildfire smoke is an increasing health concern not just for public health officials but also for ordinary citizens.’
Despite the clear and necessary benefits of reducing air pollution, there are some concerns that any immediate reductions could lead to a spike in temperatures. Certain climate pollutants, including particulate matter (PM2.5) can have a cooling effect by reflecting solar energy away from the Earth, known as global dimming.
However, despite these concerns, Dr Farrow highlights that this is not reason enough to prolong or prevent remediative action, he says: ‘Overall, action to reduce greenhouse gas emissions is going to improve air quality.
‘However, the end goal has to be that we stop producing and using fossil fuels and we need to do that as fast as possible. Every time we’re extracting, transporting and burning fossil fuels we’re losing pollutants into the atmosphere and we are coming one step closer to catastrophic climate impacts.’
This article first appeared in the Air Quality News magazine, which is available to view here. Subscribe