How does pollution hurt health? Scientists recreated sections of lungs in a lab to try to understand

Even today, in a world increasingly powered by renewable energy and clean technologies, air pollution poses a real risk to human health. In the UK alone, it is estimated to be responsible for 28,000 to 36,000 deaths every year, and can vastly increase the risk of developing many lung and heart-related diseases, such as asthma or lung cancer.

Polluted air forms a complex mixture that changes depending on where the pollution is coming from, and what the local weather is doing at the time. People in towns and cities are more at risk since they live closer to most cars, factories and other sources of emissions.

Although there are many different types of pollutants within the air we breathe, two in particular are detrimental to our health: the gas nitrogen dioxide (NO₂) and particulate matter (specifically, PM₂.₅), formed of floating, microscopic solid or liquid particles smaller than 2.5 micrometres in diameter (for reference, a human hair is about 70 micrometres in diameter).

In 2017, a report found that all areas of London exceeded World Health Organisation recommended levels for PM₂.₅, with many areas being more than double the recommended levels. Scenarios like these have allowed researchers to investigate the dangers of breathing in really polluted air.

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