Do you know which risk factor contributes to more deaths worldwide than obesity, alcohol and physical inactivity combined?Air pollution. Surprising, isn’t it?
These deaths are highly concentrated in high-polluting low and middle income countries such as China and India, but even in high income countries such as the UK and the US, air pollution is still one of the top 10 risk factors.
A bar chart titled "Deaths by risk factor, World, 2021" shows the estimated annual deaths attributed to various risk factors. High blood pressure ranks highest (10.9 million deaths), followed by air pollution (8.08 million) and smoking (6.18 million). Other factors include obesity, alcohol use, unsafe water, poor diet, and low physical activity.
The tragic death of Ella Adoo-Kissi-Debrah – caused, in part, by excessive exposure to air pollution – prompted a UK Government review into air quality information which waspublished earlier this month.
Thereport’s findings and many of the recommendations chime with insights from behavioural science and our ownEAST framework, such as the need for air quality communications to “use accessible language” and for resources to be “be created and/or endorsed by trusted messengers”.
Better information is an important part of reducing air quality harms, but if we want to make real progress this needs to be complemented by a wider set of interventions to tackle thecauses of air pollution.
Below we feature some examples from our own and others’ work to show how behavioural science can be part of more ‘upstream’ solutions.
1. Reducing car use
Fossil-fueled transportation is one of the largest contributors to air pollution worldwide, so encouraging people to switch to less polluting forms of transport can make a big dent on air quality. Ourrecent work with Uber (see image below) demonstrated that, with the right incentives, many people can make do without their car. We’ve also shown that with timely and social nudges, we can encourage people toconsider more sustainable forms of transportation andto adopt electric vehicles in place of their petrol or diesel vehicle.
A bar chart titled "Participants successfully reduced personal car use by 97%" compares personal car usage over time. The baseline week shows 68% of trips using personal cars, while weeks 1 to 4 show a sharp decline to 2%, 2%, 1%, and 2%, respectively, demonstrating a significant reduction in car dependency.
2. Timely prompts to prevent car idling
We recently worked with the London Borough of Merton toreduce idling at a level crossing. The previous sign was a static message encouraging drivers to turn off their engines. Our intervention was a simple electronic sign (see below) designed to grab drivers’ attention by only lighting up when the crossing barriers were down and highlighting the financial benefits of switching off their car engine. After the new sign was installed, we observed a 13 percentage point increase in the number of drivers switching off their engine, which we estimated would lead to an extra 2,000 drivers switching off their engines at the level crossing every month.
The image compares two different road signs discouraging vehicle idling. Previous sign (left side): A rectangular sign with a bold red prohibition symbol (a red circle with a diagonal line through it). Inside the symbol, an illustration of exhaust fumes near pedestrians and a vehicle. Text: "No vehicle idling" at the top and "Turn off engine while waiting" at the bottom. Source: "Idling Action London." New sign (right side): An electronic LED road sign displaying a dynamic message. Text: "SAVE MONEY / SAVE FUEL / TURN OFF / YOUR ENGINE." Positioned on a pole near a traffic signal. In the background, the old sign is still visible. The new sign appears to use an incentive-based approach (saving money and fuel) rather than just prohibiting idling.
3. Choice architecture to reduce delivery miles
Encouraging consumers to choose ‘collection’ instead of home delivery can reduce emissions from delivery vans. We worked with Impact on Urban Health and Centre for London totest choice architecture nudges in a simulated online shopping environment, and found that a pro-environmental framing almost doubled the amount of collection choices compared to the control condition. Collection is typically cheaper for online retailers, so this type of nudge represents a potential win-win for industry and government (so long as it does not affect the overall checkout conversion rate).
An infographic compares two parcel delivery methods. The left panel, titled "Delivery," shows a van icon and states it is "Bad for the environment" due to increased vehicle traffic and air pollution. The right panel, titled "Collect from pick-up point near you," shows a location pin icon and promotes it as "Environmentally-friendly" if done by walking or cycling.
4. ‘Polluter pays’ incentives
An innovative example of smart incentives comes from Gujarat, India, where acap-and-trade market was used to encourage firms to reduce their emissions.
In a recentrandomised controlled trial, factories in the treatment group were required to install emission monitoring systems and could pollute up to 80% of a set ‘cap’ for free.
They were then able to purchase and trade permits with other firms for the remaining 20%, giving them a direct financial incentive to reduce their emissions and find cost-effective ways to do so.
Crucially, those polluting above the permitted cap also incurred substantial fines, more than they would have paid to purchase the necessary permits.
Over two years, the intervention achieved a 20-30% reduction in particulate pollution compared to control firms who were subject to business-as-usual spot checks and fines.
It also reduced enforcement costs, showcasing how well-designed incentives can yield substantial environmental and financial benefits.
While most of Europe and North America already haveemissions trading schemes, most developing countries do not (with the notable exception of China). Given that deaths from air pollution are concentrated indeveloping countries such as India, Indonesia and Egypt, it is crucial that interventions like these are introduced to help encourage industry to be part of the solution.
A world map titled 'Which countries have a carbon emissions trading system? 2022' showing countries with an emissions trading system (ETS). Countries are categorized into four groups: those with an ETS (marked in dark blue), those with an ETS only at the sub-national level (marked in light blue), those without an ETS (marked in beige), and those with no data available (marked with diagonal stripes). The map indicates that the European Union, China, South Korea, and parts of Canada and the United States have an ETS, while countries such as India, most of Africa, and parts of South America do not. The data source is cited as Dolphin and Xiahou (2022), and the map is provided by Our World in Data.
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Behavioural science offers powerful, practical solutions to reduce air pollution – from nudging individual actions to designing smarter incentives. But real change requires collaboration.
If you’re a policymaker, business leader, or advocate, partner with us to create cleaner air and healthier communities. Get in touch today to make an impact.