For decades now, GDP has been the standard measure of a nation’s well-being. But it is becoming clear that an economic boost may not be accompanied by a rise in individual happiness.
While there are many reasons for this, one important factor is that as nations become richer, environmental features such as green space and air quality often come under increasing threat. The mental health benefits of access to parks or waterfronts, for instance, have long been recognised but more recently researchers have also started to look at the role air pollution can play in our general mental health and happiness.
With more tangible outcomes such as health, cognitive performance or labour productivity, the adverse effects of poor air are significant and well-established. The link to infant mortality and respiratory disease is well known, and the World Health Organisation estimates that around seven million deaths are attributable to air pollution each year.
But while many people will die and many more will acquire a chronic health condition, focusing on objective indicators such as these may still understate the true welfare cost. This is because there is now good evidence of a direct link between air quality and overall mental health and happiness.
Evidence from all over the world
This evidence comes from a diverse array of studies in different countries and using different analytical approaches. The most compelling of these studies track the same people over time, and find that changes in the air quality in these people’s neighbourhoods are related to changes in their self-reported happiness.
One particularly innovative study looked at what happened when large power plants in Germany were fitted with equipment designed to reduce emissions. Researchers had access to happiness data from a long-term survey of a panel of around 30,000 Germans, and categorised everyone by whether they lived upwind or downwind of a power plant (or nowhere near.
The research found that those downwind underwent a significant improvement in their happiness levels after the installation, while their upwind neighbours did not benefit. This sort of comparison – a natural experiment that would be impossible and perhaps unethical to replicate in a lab – helps to ensure that the improvement in happiness was due to the improvement in air quality as opposed to other factors.